Food and Health Archives - Page 5 of 9 - Health Tips From The Professor

What Causes ADHD?

March 3, 2015 by Dr. Steve Chaney

Do Foods Make Kids Fidget?

Author: Dr. Stephen Chaney

When I was a kid we didn’t have all of these fancy words like hyperactivity, ADD and ADHD. If a kid had trouble sitting still and trouble focusing on the task at hand, they were just considered “fidgety”. So, what causes ADHD in kids?

Now that I’ve dated myself once again, let’s get to the real topic which is: “Can the foods that your kids eat have any relationship to ADD and ADHD symptoms?”

To put things into perspective, the CDC just announced that 11% of all school age children in the US have been diagnosed with ADHD. That is a 41% increase in the last decade alone. I am not going to discuss the controversy about why the incidence of ADHD is rising so rapidly in this country. That is another story for another time.

My concern is that two thirds of those children are being given stimulant medications like Ritalin and Adderall. While those medications can help reduce the symptoms, they can also cause serious side effects such as addiction, anxiety and psychosis.

So it might be time to stop and ask, is there a better way? Could the foods those children are eating cause ADHD? If so, could something as simple as changing their diet control the symptoms of ADHD without any side effects?

I’ve talked about the effect of food additives, Do Artificial Colors Cause Hyperactivity , and the sugar content of the diet on hyperactivity in previous issues of my “Health Tips from the Professor”.

The question that I’m posing today is whether sensitivities to foods that we would otherwise consider to be healthy could also trigger ADHD symptoms?

Could The Foods Our Children Eat Cause ADHD?

Could food be what causes ADHD in kids? Many clinicians have long felt that food sensitivities could be associated with ADHD symptoms because many of the children that they were treating for ADHD also had food sensitivities that showed up as eczema, asthma and gastrointestinal problems. But no definitive clinical studies had been performed in this area, so the idea that food sensitivities might cause ADHD symptoms remained an open question.

However, a major clinical study called The Impact of Nutrition on Children with ADHD was recently performed that suggests the answer to this question is a resounding YES – food sensitivities can cause ADHD symptoms (Pelesser et al, Lancet, 377: 494-503, 2011).

100 children from the Netherlands and Belgium with a definitive diagnosis of ADHD were enrolled in the study. The age of the children was 4 to 8 years old because it is easiest to control the food intake of children in that age group.

At the beginning of the study every child was given IgG blood tests to identify food sensitivities. During the first 5 weeks of the program the children were divided into two groups.

One group was put on a restricted elimination diet consisting of rice, meats, vegetables, pears and water for 5 weeks (An elimination diet is the “gold standard” for evaluating food sensitivities because it eliminates almost every food known to cause sensitivity from the diet).

The second group was put on a “healthy diet” – one which met current nutritional guidelines, but did not eliminate any food or food group from the diet.

At the end of this 5-week period all of the children were evaluated for ADHD symptoms in a blinded fashion by a pediatrician specializing in diagnosing and treating ADHD.

An astonishing 78% of the children on the elimination diet had a reduction in their ADHD symptoms!

Those on the “healthy diet” showed no significant improvement in symptoms.

Can IgG Tests Identify Children Who Will Benefit From Changing Their Diet?

The first phase of the study (described above) was followed by a second phase in which restricted foods were added back to the diet of those children who had responded positively to the elimination diet.

But the foods were not added back randomly. Each child was exposed for two weeks to foods with a high IgG response in their initial screen and for two weeks to foods with a low IgG response in their initial screen. In others words the foods added back were different for each child and were based on their individual IgG results.

This phase of the trial was done in a crossover fashion – meaning that half of the children received low IgG foods during the first two weeks followed by high IgG foods during the second two weeks – and for the other half of the children the order was reversed.

And this phase of the study was also done in a double blind fashion – meaning that neither the children nor the evaluators knew whether they were receiving low IgG foods or high IgG foods during the test period.

The results of this phase of the study were also very interesting:

There was a substantial worsening of ADHD symptoms in 63% of the children when restricted foods were added back to the diet

AND – it didn’t matter whether the foods were low IgG foods or high IgG foods.

The authors’ conclusions were simple:

Food sensitivities make a substantial contribution to ADHD symptoms in children.

Don’t waste your money on the IgG tests (They have been controversial for some time).

The Bottom Line

What is the significance of this study if you have a child with ADHD? According to a recent study:

Food sensitivities make a substantial contribution to ADHD symptoms in children.

Don’t waste your money on the IgG tests (They have been controversial for some time).

The best way to see if foods trigger your child’s ADHD symptoms is to put them on an elimination diet, and if they show an improvement on the elimination diet, add the restricted foods back one or two at a time so you can identify the ones that should be avoided in the future.

Some of you might be saying that sounds difficult (it is), so why bother?

The answer is that 11% of school age children in this country are diagnosed with ADD or ADHD – and almost all of them are treated with drugs that can have serious side effects.

Using an elimination diet to find out whether your child’s ADHD is triggered by food sensitivities and then changing their diet has absolutely no side effects!

Some of you might be asking, “Are there any easier drug-free approaches that one could try, or is there any natural approach that might work for the 22% of children who don’t respond to the elimination diet?”

The answer to both questions is yes.

Simply eliminating food additives, junk foods and/or sugary foods from the diet helps reduce ADHD symptoms in many children.

You also shouldn’t neglect the role that supplementation can play in laying a strong nutritional foundation for your child. I recommend a good children’s multivitamin to make sure that they are getting the nutrients they need, a protein supplement to help prevent blood sugar swings, a good omega-3 (preferably DHA) supplement to support brain health and a supplemental source of friendly bacteria to promote gut health.

But if all else fails I would recommend trying an elimination diet to identify problem foods and then eliminating those foods from your child’s diet before putting them on drugs.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Do Avocados Lower Cholesterol?

January 20, 2015 by Dr. Steve Chaney

Should Avocados Be On The Super Fruits List?

Author: Dr. Stephen Chaney

You may have seen the recent headlines suggesting that avocados lower cholesterol, are a miracle fruit, and reduce your risk of heart disease. Some of those articles are suggesting that you try to eat an avocado every day. Are those headlines true? Should you be eating more avocados?

If you are like me that would be a bit of a stretch. I prefer my fruits tastier and a bit less greasy, but I won’t let my personal preferences color my analysis of the data. Let’s start by looking at the rationale for testing the effect of avocados on cholesterol levels.

The 2013 American Heart Association Guidelines on Lifestyle Management to Reduce Cardiovascular Risk recommends reducing saturated fats to no more than 5% to 6% of total calories (In the typical American diet about 13% of calories come from saturated fat). The AHA recommends replacing the saturated fat with either monounsaturated fat or polyunsaturated fat (vegetable oils and fish oil).

In addition, a major clinical study has recently shown that a Mediterranean diet supplemented with either olive oil or mixed nuts (walnuts, hazelnuts and almonds) lowers cholesterol and reduces the incidence of major cardiovascular events by ~30% over 5 years in men and women aged 50 to 80 who were at high risk for cardiovascular disease (Estruch et al, N Engl J Med, 368: 1279-1290, 2013).

One avocado has about the same amount of oleic acid (a monounsaturated fat) as 2 tablespoons of olive oil or 1.5 ounces of almonds, so it is logical to suspect that avocados might have a similar effect as olive oil or nuts.

How Was The Clinical Study Designed?

Because there is still a lot of controversy as to whether diets in which the saturated fat is replaced with healthier fat or no fat at all (low fat diets) are better, this study (Wang et al, J Am Heart Assoc, 2015;4: e001355 doi:10.1161/JAHA.114.001355) compared 3 diets:

A low fat diet in which most of the saturated fat was replaced with carbohydrate (24% total fat, 7% saturated fat, 11% monounsaturated fat, 6% polyunsaturated fat, 59% carbohydrate, 16-17% protein).

A moderate fat diet in which most of the saturated fat was replaced with pure oleic acid (34% total fat, 6% saturated fat, 17% monounsaturated fat from oleic acid, 9% polyunsaturated fat , 49% carbohydrate, 16-17% protein).

A moderate fat diet in which most of the saturated fat was replaced with avocado (34% total fat, 6% saturated fat, 17% monounsaturated fat from avocado, 9% polyunsaturated fat , 49% carbohydrate, 16-17% protein).

The study subjects were 45 healthy overweight or obese men and women (age 21 to 70, average = 45). Each subject was put on all 3 diets sequentially for 5 weeks each in a random order. That way each subject served as his or her own control.

The diets were carefully controlled to keep the calories the same so that none of the subjects lost weight during the study (weight loss would have confounded the results because weight loss lowers cholesterol in most individuals). The subjects were also told not to change their exercise habits. In short, it was a small study, but it was very well designed.

When the low fat diet was compared to the moderate (healthy) fat diets, the results were pretty similar to a number of other studies:

Total cholesterol and LDL cholesterol (the bad type) were lowered to about the same extent by both types of diets.

Triglycerides were higher and HDL cholesterol (the good type) was lower for the low fat diet compared to the moderate (healthy) fat diets.

Because this has been shown in previous studies, I won’t discuss it further here.

Do Avocados Lower Cholesterol?

When the authors compared the diet in which saturated fat was replaced with avocados to the diet in which saturated fat was replaced with oleic acid there were a number of significant differences.

Both LDL-cholesterol and non-HDL cholesterol were significantly lower on the avocado diet than the oleic acid diet. The decrease was about 10%. Based on the metrics adopted by the American Heart Association this has the potential to translate into a 20% decrease in heart disease risk.

The avocado diet was the only one of the three diets that significantly decreased LDL particle number, small dense LDL cholesterol and LDL/HDL ratio, Many experts think that these parameters are better indicators of hearts disease risk than LDL cholesterol levels.

Do avocados lower cholesterol? The short answer is yes, eating an avocado a day can lower cholesterol levels and might possibly lower heart disease risk. But to understand the true implications of this study we need to dig a little deeper.

What Is the Significance of This Study?

This study has one important take home lesson and raises two important questions.

Take Home Lesson: Foods Are More Important Than Fats We often hear about the benefits of including more monounsaturated fats in our diet, but when you actually make a direct comparison, such as was done in this study, it turns out that it is the foods that contain monounsaturated fats that make the difference, not the monounsaturated fats themselves. The oleic acid diet was only marginally better than the low fat diet at lowering total and LDL cholesterol.

This was the major conclusion of the authors of the study. Everything else was made up by the non-experts who write the articles that you see in the papers and on the internet. It is yet one more example of the headlines getting ahead of the science.

The authors admitted that we have no idea why avocados are more effective at lowering cholesterol than an equivalent amount of oleic acid. They speculated that it could be due to the high content of phytosterols in avocados. However, while the 114 mg of plant sterols in an avocado makes it an excellent source of plant sterols, it is far below the 2,000 mg of plant sterols that the NIH considers optimal for lowering cholesterol levels.

The authors also mentioned soluble fiber and specialized sugars in an avocado, but none of those was present in sufficient quantities to explain the cholesterol-lowering effect of avocados by itself. It is likely that all of those constituents plus others that we have not yet identified are what make avocados more effective than oleic acid at lowering cholesterol.

Question 1: Do We Really Want To Eat An Avocado a Day?

We need to keep in mind that a single avocado weighs in at around 234 calories. That is:

2.5 times the calories in an apple
4.7 times the calories in a peach or a cup of strawberries
5.7 times the calories in a half cup of blueberries
7.3 times the calories in a half cup of raspberries or blackberries

You get the point. What made this study so effective is that all three diets were designed to provide exactly the same number of calories so that nobody gained or lost weight. If you are thinking of adding an avocado a day to your diet, you are going to need to significantly cut back on calories somewhere else, or your weight gain will drive your cholesterol levels in the wrong direction.

Question 2: What Are The Long Term Implications of This Study?

The bottom line is that this and previous studies suggest that avocados should rightfully be included along with olive oil and nuts as healthy sources of monounsaturated fats that can help you lower cholesterol levels and may reduce your risk of heart disease.

However, we need to keep in mind that while a major clinical study has shown that adding either olive oil or nuts to your diet can reduce heart disease risk, we don’t have a comparable study showing that adding avocados to your diet will have the same benefit. It is plausible, but has not yet been demonstrated.

The Bottom Line

A recent clinical study has shown that eating an avocado a day was more effective at lowering bad cholesterol than adding an equivalent amount of the monounsaturated fat oleic acid to the diet. This suggests that it is the foods that contain the monounsaturated fats that make the difference, not the monounsaturated fats themselves.

This and previous studies suggest that avocados should rightfully be included along with olive oil and nuts as healthy sources of monounsaturated fats that can help you lower cholesterol levels and may reduce your risk of heart disease.

However, we need to keep in mind that while a major clinical study has shown that adding either olive oil or nuts to your diet can reduce heart disease risk, we don’t have a comparable study showing that adding avocados to your diet will have the same benefit. It is plausible, but has not yet been demonstrated.

You also need to keep in mind that a single avocado contains 234 calories. What made this study work so well is that each diet was carefully designed to provide exactly the same number of calories. If you are thinking of adding an avocado a day to your diet, you are going to need to significantly cut back on calories somewhere else, or your weight gain will drive your cholesterol levels in the wrong direction.

Finally, the American Heart Association Guidelines are to reduce saturated fats to no more than 6-7% of total calories. So while the low-carbohydrate, butter, bacon, and steak diet may give you temporary weight loss, it is definitely NOT recommended if you want to reduce your risk of heart disease. For more on this important topic, see my previous health tip “Are Saturated Fats Good For You?”

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

7 Easy Ways To Spot Fad Diets

December 30, 2014 by Dr. Steve Chaney

If It Sounds Too Good To Be True…

Author: Dr. Stephen Chaney

I think it was P. T. Barnum who said “There’s a Sucker Born Every Minute”. That’s particularly true in the diet world where hucksters seem to be all around us – especially this time of year.

You’ve seen the weight loss ads touting:

Pills or powders that suppress your appetite or magically prevent you from absorbing calories.

Fat burners that melt the pounds away.
New discoveries (juices, beans, foods) that make weight loss effortless.
The one simple thing you can do that will finally banish those extra pounds forever.

You already know that most of those ads can’t be true. You don’t want to be a sucker. But, the ads are so compelling:

Many of them quote “scientific studies” to “prove” that their product or program works.

Their testimonials feature people just like you getting fantastic results from their program. [You can do wonders with “computer enhanced” photographs.]
Many of those products are endorsed by well known doctors on their TV shows or blogs. [It is amazing what money can buy.]

So it is easy to ask yourself: “Could it be true?” “Could this work for me?”

Fortunately, the Federal Trade Commission (FTC) has stepped up to the plate to give you some guidance. Just in time for weight loss season, they have issued a list of seven claims that are in fact too good to be true. If you hear any of these claims, you should immediately recognize it as a fad diet and avoid it.

7 Easy Ways To Spot Fad Diets

Here are the seven statements in ads that the FTC considers as “red flags” for fad diets that should be avoided:

Causes weight loss of two pounds or more a week for a month or more without changing your diet and exercise routine.

Causes substantial weight loss no matter what or how much you eat.

Causes permanent weight loss without lifestyle change even after you stop using the product.

Blocks absorption of fat or calories to enable you to lose substantial weight.

Safely enables you to lose more than 3 pounds per week for more than 4 weeks.

Causes substantial weight loss for all users

Causes substantial weight loss by wearing a product on your body or rubbing it on your skin.

I’m sure you have heard some of these claims before. You may have actually been tempted to try the products or program. You should know that the FTC said that it considers these to be “Gut Check” claims that simply can’t be true.

The Bottom Line

There are no magical pills or potions that will make the pounds melt away. You need to change your diet, change your activity level and make significant lifestyle changes if you want to achieve long term weight control.

For more science-based health tips visit https://www.chaneyhealth.com/healthtips

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Do Diets Work?

December 16, 2014 by Dr. Steve Chaney

Obesity in America?

Author: Dr. Stephen Chaney

If you are like most Americans, you are either overweight yourself or have close friends and family who are overweight. That’s because 69% of Americans are currently overweight, and 36% of us are obese. Worldwide the latest estimates are that 1.5 billion adults are overweight or obese.

A new report, How The World Could Better Fight Obesity, estimates that obesity is a $2 trillion drain on the world’s economy. That is equivalent to the global cost of war & terrorism and of smoking – and is double the global costs of alcoholism and global warming!

If you are like most Americans you have tried a number of diets over the years. All of them promised that they had the “secret” to permanent weight loss. You lost some weight initially, but here you are a few years later weighing as much as ever.

You are probably beginning to wonder whether any diets work long term. According to the latest study, the answer may just be “no”.

Really, Do Diets Work?

This study (Atallah et al, Circulation Cardiovascular Quality and Outcomes, 7: 815-827, 2014) was a systemmatic review of all of the randomized controlled studies of the four most popular diet plans – Weight Watchers, Akins, Zone and South Beach.

In case, you are unfamiliar with these diets, here is their philosophy:

Weight watchers is a food, physical activity and behavior modification plan that utilizes a point system to control calorie intake and features weekly group sessions.
Atkins is based on very low carbohydrate intake, with unlimited fat and protein consumption.
South Beach is relatively low carbohydrate, high protein diet that focuses on low-glycemic index carbohydrates, lean proteins, and mono- and polyunsaturated fats.
Zone is a low carbohydrate diet that focuses on low-glycemic load carbohydrates, low-fat proteins and small amounts of good fats.

The investigators restricted their analysis to studies that were greater than 4 weeks in duration and either compared the diets to “usual care” or to each other. (The term usual care was not defined, but most likely refers to a physician giving the advice to eat less and exercise more).

Twenty six studies met their inclusion criteria. Fourteen of those studies were short-term (< 12 months) and 12 were long-term (>12 months). Of the long-term studies, 10 compared individual diet plans to usual care and 2 were head-to-head comparisons between the diet plans (1 of Atkins vs Weight Watchers vs Zone and 1 of Weight Watchers vs Zone vs control). The majority of participants in these studies were young, white, obese women. Their average age was 45 years and their average weight at the beginning of the studies was 200 pounds.

What Did This Study Show?

If you have struggled with your weight in the past, you probably won’t be surprised by the result of the study.

Short-term weight loss was similar for Atkins, Weight Watchers and Zone in the two head-to-head studies.
At 12 months, the 10 studies comparing individual diets to usual care (physician’s advice to eat less and exercise more) showed that only Weight Watchers was slightly more effective than usual care (physician’s advice to lose weight). The average weight loss at 12 months was 10 pounds for Weight Watchers and 7 pounds for usual care. That is a 3 pound difference for all of the additional effort and expense of Weight Watchers!
When they looked at the two head-to-head studies at 12 months, there was no significant differences between the diets. Average weight loss in these studies was 7 pounds for Weight Watchers, 7 pounds for Atkins, 5 pounds for Zone and 5 pounds for usual care. There was only one study comparing the South Beach diets with usual care. It was a study comparing the results with severely obese patients following gastric bypass surgery, and it also found no difference between the diet program and usual care. Based on hype about these diets, you were probably expecting more than a 5 to 7 pound weight loss 12 months later!
By 24 months 30-40% of the weight had been regained for the Atkins and Weight Watchers diets, which was comparable to the results for patients who were just told to eat less and exercise more. Not only was the weight loss modest, it also did not appear to be permanent.
Finally, many of the studies included in this review also looked at improvement in other health parameters such as HDL cholesterol levels, LDL cholesterol levels, triglycerides, blood pressure and blood sugar control. The Atkins diet gave slightly better results with HDL levels, triglyceride levels and blood pressure in the short-term studies, but there was no significant differences for any of these parameters in the long-term head-to-head studies. None of the diets were any healthier than the others.

The investigators concluded: “Our results suggest that all 4 diets are modestly efficacious for short-term weight loss, but that these benefits are not sustained long-term.

A similar study in 2005 compared the Weight Watchers, Jenny Craig and LA Weight Loss diets (Tsai et al, Annals of Internal Medicine, 142: 56-66, 2005) and concluded “…the evidence to support the use of major commercial and self-help weight loss programs is suboptimal”.

A Weight Loss Diet That Actually Works?

My personal recommendation for the initial weight loss is a high protein diet – one that provides about 30% of calories from healthy protein and moderate amounts of healthy carbohydrates and healthy fats. The protein should be high enough quality so that it provides 10-12 gram of the essential amino acid leucine because leucine specifically stimulates muscle growth. The combination of high protein and leucine preserves muscle mass while you are losing weight. That is important because it keeps your metabolic rate high without dangerous herbs or stimulants.

However, the high protein, high leucine diet is still just a diet. It is an excellent choice for the initial weight loss, but what about long-term weight control?

The authors of this study said: “Comprehensive lifestyle interventions aimed at curbing both adult and childhood obesity are urgently needed. Interventions that include dietary, behavioral and exercise components…may be better suited to [solve] the obesity epidemic.” I agree.

The Bottom Line:

Your suspicions are correct. Diets don’t work!

A recent systematic review of 26 randomized controlled clinical trials of the Weight Watchers, Atkins, Zone & South Beach diets compared to the usual standard of care (recommendations to eat less and exercise more) concluded:

1) Contrary to what the advertisements promise, after 12 months all four diets gave comparable and very modest (5-7 pounds) total weight loss. The results with the diets were not significantly different than for patients who were simply told to eat less and exercise more.

2) By 24 months 30-40% of the weight had already been regained.

3) A previous systematic review of the Weight Watchers, Jenny Craig, and LA Weight Loss diet programs came to a similar conclusion.

4) My personal recommendation for the initial weight loss is a diet that is high in protein and the amino acid leucine because that type of diet preserves muscle mass.

5) For permanent weight control the authors of the recent systematic review recommended comprehensive lifestyle interventions that include permanent changes in diet, behavior and exercise. I agree. Diets never work long term – lifestyle change does!

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Healthy Thanksgiving

November 25, 2014 by Dr. Steve Chaney

The Holidays Don’t Have To Be Unhealthy

Author: Dr. Stephen Chaney

While “Healthy Thanksgiving” doesn’t quite have the appeal of the more familiar “Happy Thanksgiving” greeting, I used it here to make the point that Thanksgiving dinner (and many other holiday meals) doesn’t have to be an unhealthy affair.

After all, there is a lot to like about the ingredients in Thanksgiving dinner. Turkey can be a healthy, low- fat meat, if prepared correctly. Sweet potatoes, yams, winter squash and pumpkin are all loaded with vitamin A and other important nutrients. And cranberries are a nutrition powerhouse.
Healthy Thanksgiving

Here are some healthy Thanksgiving ideas:

1) Skip the basting. Choose a plain bird and cook in a bag to seal in the moisture. Remove the skin before serving.

2) Refrigerate the turkey juices and skim off the hardened fat before making gravy and use a gravy cup that pours from the bottom to minimize fat.

3) Use ingredients like whole wheat bread, vegetables, fruits (cranberries, raisins, dates or apples), nuts and your favorite spices for the stuffing and bake it in the oven rather than in the turkey.

4) Serve your sweet potatoes or yams baked rather than candied and let your guests add butter to taste.

5) Use skim milk or buttermilk rather than whole milk and skip the butter for your mashed potatoes.

6) Give your meal gourmet appeal by cooking your green vegetables with garlic, nuts and herbs rather than creamy or fat-laden sauces.

7) Don’t serve the meal on your largest plates. By using smaller plates you ensure smaller portion size and even that second helping isn’t quite so damaging.

8) Use the Shaklee 180 meal replacement products for one or more meals the day before and/or after Thanksgiving so that your total caloric intake over the three day period is not excessive.

By now you have the idea. There are lots of little things that you can do to make your Thanksgiving dinner one that your waist and your heart will thank you for. Bon Appetit and have a Happy, Healthy Thanksgiving!

The Bottom Line

• If you make healthy food choices and choose your portion sizes wisely, you can make this a Healthy Thanksgiving as well as a Happy Thanksgiving.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Are There Health Benefits of Beetroot Juice for Athletes?

October 28, 2014 by Dr. Steve Chaney

Should You Add Beetroot Juice To Your Training Diet?

Author: Dr. Stephen Chaney

When I saw the headline “Beetroot Juice May Boost Aerobic Fitness For Swimmers” I did a double take. Could something as simple as eating more beets actually improve exercise performance? Are there real health benefits of beetroot juice for athletes? So I looked up recent papers on the topic. But, before I review those I should give you a little science behind the idea that beetroot juice might affect performance.

The Science Behind Beetroot Juice And Exercise

Nitric oxide is a colorless, odorless gas that serves as an important signaling molecule in the human body. Among its many beneficial effects is increased blood flow to muscle. This increased blood flow appears to be preferentially distributed to the type 2 muscle fibers which support moderate to high intensity exercise. Thus, nutrients that enhance nitric oxide levels might be expected to improve moderate to high intensity exercise.

There are two naturally occurring pathways for producing nitric oxide in the body. The first pathway utilizes arginine, an amino acid found in dietary protein. The second pathway utilizes nitrates, which are found in fruits and vegetables. The best dietary sources of nitrates are beetroot, spinach and other leafy green vegetables.

Arginine has been widely used in sports supplements for some time to enhance performance. However, clinical studies on arginine have been mixed, with some showing small enhancements in performance and others showing no significant effect. Most experts now think that the benefits of arginine are primarily seen with untrained or moderately trained athletes (people like you and me) – not for highly trained or elite athletes.

It is logical that natural sources of nitrates, such as beetroot juice, would have a similar beneficial effect on exercise, but it is only in the last couple of years that scientists have started to evaluate that possibility. I looked up six recent publications for this review.

Does Beetroot Juice Improve Exercise Performance?

Study # 1: In this study (Bailey et al, J. Appl. Physiol., 107: 1144-1155, 2009) untrained men (aged 19-38) were given beetroot juice or a placebo for 6 days and then put through a series moderate-intensity and severe-intensity step exercise tests on days 4-6. The amount of oxygen required to support the moderate intensity exercise was decreased by 19% in the beetroot juice group. For severe intensity exercise, the amount of oxygen needed to support the exercise was decreased by 23% and the time to exhaustion was increased by 16% in the beetroot juice group. Those effects were statistically significant.

Study # 2: In this study (Kelly et al, Am. J. Physiol. Regul. Integr. Comp. Physiol., 304: R73-83, 2013) untrained older adults (aged 60-70) were given beetroot juice or a placebo for 3 days and then put through a treadmill exercise test. Resting blood pressure and oxygen uptake kinetics during exercise were significantly improved in the beetroot group.

Study # 3: In this study (Breese et al, Am. J. Physiol. Regul. Integr. Comp. Physiol., 305: R1441-14505, 2013) physically active subjects were given beetroot juice or a placebo for 6 days and then put through a double step exercise protocol involving a transition from stationary to moderate intensity exercise followed immediately by a transition from moderate intensity to severe intensity exercise. No significant differences were observed between the beetroot juice group and the placebo group during the transition from stationary to moderate intensity exercise. However, for the transition from moderate intensity to high intensity exercise both efficiency of oxygen utilization and endurance were increased by 22% in the beetroot juice group.

Study # 4: In this study (Pinna et al, Nutrients, 6: 605-615, 2014) moderately trained male master swimmers were given beetroot juice for 6 days. Swimming tests were conducted at the beginning and end of the 6 day period. After 6 days of beetroot juice supplementation, the workload was increased by 6% and the energy cost was decreased by 12% when the swimmers were performing at their maximal capacity.

Studies # 5 & 6: These studies (Lanceley et al, British Journal of Sports Medicine, 47: doi: 10.1136/bjsports-2013-093073.8; Hoon et al, Int. J. Sports Physiol. Perform., 9: 615-620, 2014) were both done with highly trained athletes and no significant improvement in performance was observed. This is fully consistent with previous studies utilizing arginine supplements.

In short, these studies suggest that beetroot juice is similar to arginine supplements in that:

It improves exercise performance at moderate to severe exercise levels, but not at low exercise levels.

It improves exercise performance for untrained or moderately trained athletes, but not for highly trained athletes.

The effects are modest. However, you should keep in mind that even a 20% increase in endurance during high intensity exercise can result in a significant incremental increase in muscle mass if the exercise is repeated on a regular basis.

What Are The Strengths & Weaknesses Of These Studies?

Strengths: The strengths of these studies are:

Most of the studies were double-blind, placebo controlled studies

The studies were internally consistent and were consistent with previous studies done with arginine supplements.

Weaknesses: The weaknesses of these studies are:

The studies were all very small and were of short duration. Larger, longer term studies are needed to validate the results of these studies.

So, are there health benefits of beetroot juice for athletes?

The Bottom Line:

Nitrates and arginine are both converted to nitric oxide in the body, so it is plausible that they will have similar effects.

Arginine supplements have been around for years and appear to have a modest affect on exercise performance with untrained and moderately trained athletes, but not with highly trained athletes. This is most likely because one of the effects of training is to increase blood supply to the muscles. Thus, highly trained athletes already have enhanced blood flow to the muscles, and the effect of arginine supplementation on blood flow is less noticeable.

Nitrate supplements are just starting to be evaluated for their effects on exercise performance. Most of the research so far has been with beetroot juice, but the results should be similar for any naturally sourced nitrate supplement.

The clinical studies published so far suggest that nitrate supplements are similar to arginine supplements in that they have a modest effect on high intensity exercise in untrained and moderate trained athletes (people like most of us). They appear to have little or no effect for highly trained athletes. Thus, the effect of nitrate supplements on exercise appears to be very similar to the effect of arginine supplements on exercise.

Most of the studies performed to date have been small, short duration studies. They need to be validated by larger, longer term studies.

If the effects of nitrate supplementation published to date are accurate they should be most beneficial for weight training and high intensity exercise because even modest increases in exercise endurance can result in an incremental increase in muscle mass and strength over time.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Soy and Breast Cancer

October 7, 2014 by Dr. Steve Chaney

The Soy Controversy

Author: Dr. Stephen Chaney

Soy and breast cancer: the wars are heating up again. You may have seen the recent headlines saying: “Soy protein found to speed the growth of breast cancer!” “Eating soy may turn on genes linked to [breast] cancer growth!” “Women with breast cancer should avoid high soy diets!” It all sounds pretty scary.

If this is true, it is big news. In recent years the consensus in the scientific community has been that soy is not harmful for women with breast cancer, and that it might even be beneficial. However, some skeptics have never accepted that consensus view. Those skeptics are once again claiming that soy protein may be risky for women with breast cancer.

Let’s look at the study behind the recent headlines and see if it is compelling enough to challenge the prevailing consensus on the safety of soy for women with breast cancer.

Does Soy Protein Turn On Breast Cancer Growth Genes?

This study (Shike et al, Journal of the National Cancer Institute, Sep 4 2014, doi: 10.1093/jnci/dju 189) looked at 140 women (average age 56) with invasive breast cancer. They were randomly divided into two groups of 70 and either given soy protein or a placebo between the initial biopsy and the time that surgery was performed to remove the tumor (a period of 7 to 30 days). A second biopsy was obtained at the time of surgery.

The activity of a number of genes associated with breast cancer survival was measured in the two biopsy samples. The observation that made the headlines was:

For some of the women in the study the activity of several genes associated with breast cancer growth and survival was increased in the group consuming soy protein compared to the placebo group. The authors concluded: “These data raise concern that soy may exert a stimulatory effect on breast cancer in a subset of women.”

What Are The Limitations Of The Study?

The authors acknowledged the many limitations of the study, but the press has largely ignored them.

The increased activity of the cancer growth genes was only seen in 20% of the women studied. For 80% of the women studied soy protein consumption had no effect on the activity of genes associated with breast cancer growth and survival.

This effect was only seen for some of the genes associated with breast cancer growth and survival. Other breast cancer growth genes were not affected in any of the women enrolled in the study. The authors conceded that it was unknown whether these limited genetic changes would have any effect on tumor growth and survival.

There was no effect of soy consumption on actual tumor growth in any of the women studied.

This was a very short term study so it is not known whether these changes in gene expression would have continued if soy supplementation were continued for a longer period of time. There are numerous examples in the literature of initial changes in gene expression in response to a radical change in diet that disappear once the body becomes accustomed to the new diet.

There is absolutely no way of knowing if the observed changes in gene expression would actually affect clinical outcomes such as survival, response to chemotherapy or tumor recurrence.

Should Women With Breast Cancer Avoid Soy?

Even with all of the limitations listed above, if this were the only study to test the soy-breast cancer hypothesis, I and most other experts would probably be warning women with breast cancer to be very cautious about consuming soy.

However, as I discussed in a previous “Health Tips From the Professor” (https://www.chaneyhealth.com/healthtips/soy-and-breast-cancer-recurrence/) at least five clinical studies have been published on the effects of soy consumption on the recurrence of breast cancer in women who are breast cancer survivors, both in Chinese and American populations. The studies have shown either no effect of soy on breast cancer recurrence or a protective effect. None of them have shown any detrimental effects of soy consumption by breast cancer survivors.

A meta-analysis of all 5 studies was published last year (Chi et al, Asian Pac J Cancer Prev., 14: 2407-2412, 2013). This study combined the data from 11,206 breast cancer survivors in the US and China. Those with the highest soy consumption had a 23% decrease in recurrence and a 15% decrease in mortality from breast cancer.

Another meta-analysis of 18 clinical studies found that soy slightly decreases the risk of developing breast cancer in the first place (J Natl Cancer Inst, 98: 459-471, 2006). To date there is absolutely no clinical evidence that soy increases the risk of breast cancer.

The Bottom Line

What does this mean for you if you are a woman with breast cancer, a breast cancer survivor or someone who is concerned about your risk of developing breast cancer?

The study that has generated the recent headlines has so many limitations that I would not recommend any changes in soy consumption at present. It raises an interesting hypothesis that requires further study and validation. If this hypothesis holds up it may result in changes in dietary recommendations for a very small subset of women with invasive breast cancer.

There are many reasons to include soy protein foods as part of a healthy diet. Soy foods are one of the highest quality vegetable protein sources and provide a great alternative to many of the high fat, high cholesterol animal proteins in the American diet.

I personally feel that these studies are clear cut enough that women who are concerned about their breast cancer risk, women with breast cancer, and breast cancer survivors no longer need to fear soy protein as part of a healthy diet.

The responsible websites agree with this assessment. For example, WebMD and the American Institute for Cancer Research (AICR) both say that breast cancer survivors need no longer worry about eating moderate amounts of soy foods.

The irresponsible websites (I won’t name names, but you know who they are) are still warning breast cancer survivors to avoid soy completely. They are citing the latest study, with all of its limitations, as proof that they were right all along. As a scientist I really have a problem with people who are unwilling to change their opinions in the face of overwhelming scientific evidence to the contrary.

Finally, I want to emphasize that the published studies merely show that soy does not increase the risk of breast cancer and is safe to use for breast cancer survivors. None of those studies suggest that soy is an effective treatment for breast cancer. The protective effects of soy are modest at best. If you have breast cancer, consult with your physician about the best treatment options for you.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Is Alkaline Water Better For You?

September 16, 2014 by Dr. Steve Chaney

Facts About Water

Author: Dr. Stephen Chaney

Is alkaline water better for you? It’s bad enough that some people are paying a premium price for bottled water that isn’t required to be any better than tap water, but the latest fads appear to be things like “alkaline” water and “ionized” water. And these “super” waters come with a really hefty price tag.

If you believed the hype behind these products, you would think that they are revolutionary advances that will cure all sorts of ills. But the truth is these enticing claims are completely bogus. They contradict the basic laws of chemistry and biochemistry.

More importantly, there are no good quality clinical studies showing that they work!

What Is Alkaline Water?

Let’s start with alkaline water – but first a bit of background information.

Pure water has a pH of around 7, which is neutral. However, if the water is exposed to air for any length of time it picks up CO2 from the atmosphere. The CO2 dissolves in the water and is converted to carbonic acid making most sources of pure water slightly acidic.

On the other hand, if metal salts are dissolved in the water it generally becomes slightly alkaline.

Is Alkaline Water Better For You?

Here are some questions you might ask when deciphering if alkaline water is better for you than plain water:

1) What Are the Benefits of Drinking Alkaline Water?

In the 1930s Otto Warburg, one of the founders of modern biochemistry, showed that cancer cells were much more dependent on glucose (blood sugar) as an energy source than were most other cells in the body and that cancer cells metabolized glucose in a way that made the cancer cells very acidic.

That information languished for many years, but interest in the “Warburg Hypothesis” has been revived in recent years by studies showing that cancer cells can be selectively killed by limiting their source of glucose.

So, what are the benefits of drinking alkaline water? In theory, making the body more alkaline would also slow the growth of the cancer cells. There is some evidence to support that hypothesis, but the evidence is still relatively weak.

It is the same with the other proposed health benefits of alkalinizing the body. There is some evidence in the literature, but it is not yet convincing. As a scientist I’m keeping an open mind, but I’m not ready to “bet the farm” on it.

2) Can Alkaline Water Alkalinize the Body?

Here the answer is a clear cut NO! In fact, this hypothesis wins my “Flying Pig” award for the month!

The body has a very strong buffer system and some elaborate metabolic controls to maintain a near-constant neutral pH. More importantly, water is such a weak buffer that it has almost no effect on body pH!

Alkaline Foods

If you really want to alkalinize your body you can do that by eating more of the alkaline foods (most fruits, including citrus fruits, and most vegetables, peas, beans, lentils, seeds & nuts) and less of the acidic foods (grains, especially refined grains, meat, especially red meat, fish, poultry and eggs).

I’ve seen some experts recommend 60% alkaline foods and 40% acidic foods. I can’t vouch for the validity of that recommendation in terms of the benefits of alkalinizing the body, but there are lots of other good reasons to eat more fresh fruits and vegetables and less red meat and refined carbohydrates.

Is Ionized Water Beneficial?

Ionized water is an even sillier concept from a chemical point of view.

It is very difficult to ionize pure water and the ions that you do create quickly recombine to give you pure water again without any change in pH or physical properties.

If you add sodium chloride (table salt) to the water you can get electrolysis that creates a slightly alkaline pH at one electrode and a slightly acidic pH at the other electrode.

However, as soon as you turn off the current, these pH changes rapidly disappear. Even if you were somehow able to capture some of the alkaline or acidic water remember that water alone has almost no effect on body pH.

Never Underestimate The Placebo Effect

But, what about all of those glowing testimonials that you have heard?

You need to remember that the placebo effect is near 50% when it comes to pain or a feeling of well being.

You can’t repeal the laws of chemistry and biochemistry. Water is, after all, just water!

Good science trumps good testimonials any day. Never, never underestimate the placebo effect.

The Bottom Line

Don’t waste your money on alkaline water or ionized water. Water is a very poor buffer and has almost no effect on the pH of our bodies.

There may be some health benefits to keeping our bodies in a more alkaline state, but the best way to do that is to eat more alkaline foods and less acid foods (http://www.webmd.com/diet/alkaline-diets).

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Is There Hope for Alzheimer’s

August 26, 2014 by Dr. Steve Chaney

Preventing Cognitive Decline As We Age

Author: Dr. Stephen Chaney

As we age nothing is more terrifying than the word Alzheimer’s. For most of us the ultimate irony would be to spend a lifetime taking good care of our body, only to lose our mind. From time to time there are encouraging reports about the potential of low fat diets, diets rich in fruits and vegetables, B vitamins, omega-3 fatty acids, various herbs, and other natural approaches that might slow cognitive decline as we age.

Inevitably, it seems, those hopes are dashed by subsequent meta-analyses supposedly showing that each of those approaches is worthless. That wouldn’t be so bad if there were effective medications to slow cognitive decline and prevent Alzheimer’s, but there aren’t. The Alzheimer’s drugs on the market today simply have not been shown to be effective.

But, what if all of these studies were missing the mark by focusing on individual interventions? Perhaps we should be focusing a holistic approach instead.

The Power of Holistic Approaches

One of the examples of the power of a holistic approach that I love to use, because it really made an impression on me as a young scientist, occurred at an International Cancer Symposium I attended more than 30 years ago.

I attended a session in which an internally renowned expert was giving his talk on colon cancer. He said, “I can show you, unequivocally, that colon cancer risk is significantly decreased by a lifestyle that includes a high-fiber diet, a low-fat diet, adequate calcium, adequate B-vitamins, exercise and weight control. But I can’t show you that any one of them, by themselves, is effective.”

The question that came to me as I heard him speak was: “What’s the message that a responsible scientist or responsible health professional should be giving to their patients or the people that they’re advising?” You’ve heard experts saying: “Don’t worry about the fat” “Don’t worry about calcium.” “Don’t worry about B-vitamins.” “Don’t worry about fiber.” “None of them can be shown to decrease the risk of colon cancer.”

Is that the message that we should be giving people? Or should we really be saying what that doctor said many years ago – a lifestyle that includes all of those things significantly decreases the risk of colon cancer?

What about Alzheimer’s and cognitive decline? Could a holistic approach have an impact here as well?

Is There Hope For Alzheimer’s?

A study performed by Dr. Miia Kivipelto and colleagues at the Karolinska Insitute in Sweden and the National Institute for Health and Welfare in Helsinki, Finland suggests that a holistic approach may, in fact, be able to slow cognitive decline in older people.

Previous studies had suggested that exercise, a good diet, socialization and memory training might slow cognitive decline in the elderly, but, like all other individual interventions, the benefits of these interventions were not reproducible. Dr. Kivipelto and colleagues designed a clinical study that combined all of these interventions into a single holistic approach.

They started with 1,260 healthy adults aged 60-77 from Sweden and Finland and divided them into two groups. One group was enrolled in a holistic program involving exercise, a healthy diet, socialization and memory training. This group was closely monitored for compliance. The other group was just given general health advice – not unlike the advice you might expect to receive from your doctor.

Each group was given a memory test at the beginning of the study and a second memory test two years later. Both groups scored about the same on the first memory test. However, the group enrolled in the holistic program did considerably better on the second memory test than the control group who had just been given general health advice.

One of the lead investigators was quoted as saying: “These findings show that prevention is possible, and it may be good to start early [before the signs of cognitive decline become evident]. With so many negative trials of Alzheimer’s drugs reportedly lately, it’s good that we may have something that everyone can do now to lower their risk [of cognitive decline].”

Limitations of the Study

There are two big caveats for this study.

1) The study was too short to assess the effectiveness of this approach at reducing Alzheimer’s. The investigators plan to continue the study for 7 years. They hope that enough participants will have developed Alzheimer’s by then so they can accurately assess whether this approach is as effective at preventing Alzheimer’s as it is at preventing cognitive decline.

2) This study was recently presented at an Alzheimer’s Association International Conference. It has not yet undergone the rigorous peer review required for publication. Once the study has been published I will give you an update.

The Bottom Line

1) It has been very difficult to prove that individual interventions, whether they are natural or pharmaceutical, are effective at preventing cognitive decline and the onset of Alzheimer’s as we age.

2) However, a recent study suggests that a holistic approach that includes exercise, optimal nutrition, socialization and memory training may be effective at preventing cognitive decline in older adults.

3) Based on previously published individual studies, optimal nutrition probably includes:

A diet low in fat, especially saturated fat and trans fats

A diet with lots of fresh fruits and vegetables

Extra B vitamins, especially with high risk populations

Extra omega-3 fatty acids

4) Although not mentioned in this study, maintaining proper body weight is also an important part of a holistic approach to reducing the risk of cognitive decline. In a previous “Health Tips From the Professor” I shared data showing that obesity alone can cause a 3-fold increase in the risk of developing dementia.

5) The take home message should not be that each of the natural interventions is ineffective at preventing cognitive decline as we age. Rather, the message should be that a holistic approach that combines all of the natural interventions may be effective at preventing cognitive decline.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Nitric Oxide Benefits and Side Effects

August 19, 2014 by Dr. Steve Chaney

Reverse Heart Disease?

Author: Dr. Stephen Chaney

Nitric oxide has had a meteoric rise from obscurity to fame in just a few short years. It’s an amazing story. After all, nitric oxide is a colorless, odorless gas. Who could have known it was destined for greatness? In this article, we will discuss nitric oxide benefits and side effects.

Its rise to fame started in the 1980’s when scientists from several universities discovered that nitric oxide was an important regulator of numerous physiological processes. Just a few years later in 1992 Science magazine named it “Molecule of the Year”, a very prestigious honor. And, in 1998 three of its co-discoverers received the Nobel Prize for their ground-breaking research.

The Benefits of Nitric Oxide

Proven Benefits

Perhaps the most important benefit of nitric oxide is its role in maintaining the health of the endothelial cells that form the inner lining of our blood vessels. Nitric oxide reduces:

Platelet aggregation

Damage & inflammation of the endothelial cells

Oxidation of LDL cholesterol

Growth of smooth muscle cells.

This is important because these are the very physiological processes that, if left unchecked, can lead to atherosclerosis and disease of the cardiovascular system (Davignon and Ganz, Circulation, 109: 1127-1132, 2004; Tousoulis et al, Current Vascular Pharmacology, 10: 4-18, 2012).

However, the effect of nitric oxide that has gotten the most attention is its ability to relax the smooth muscle cells that surround our blood vessels. That leads to increased blood flow, which in turn decreases blood pressure, relieves angina, and even prevents erectile dysfunction (Davignon and Ganz, Circulation, 109: 1127-1132, 2004; Tousoulis et al, Current Vascular Pharmacology, 10: 4-18, 2012).

Possible Benefits

Many people with atherosclerosis, diabetes and hypertension (high blood pressure) have low nitric oxide levels. It’s not known whether this is a cause or a result of these diseases, but low nitric oxide levels certainly could contribute to the progression and health consequences of all three diseases. We already know that increasing nitric oxide levels can reduce high blood pressure. It is not yet known whether increasing nitric oxide levels could reduce or reverse heart disease and the effects of diabetes, but this is an area of active research.

Nitric oxide is a neurotransmitter and is thought to play a critical role in memory and learning. It also plays a critical role in immune function. In addition, it enhances the metabolic activity of mitochondria, which could enhance cellular metabolism. The physiological significance of these observations is unknown, but this is another area of active research

Finally, because nitric oxide stimulates blood flow, which should increase oxygen and nutrient delivery to active muscle, it has been suggested that nitric oxide supplements would improve sports performance. The results of clinical studies to test this hypothesis have been mixed. The latest research suggests that nitric oxide supplements may enhance performance in untrained or moderately trained subjects, but not in highly trained subjects (Bescoe et al, Sports Medicine, 42: 99-117, 2012). At last, a sports supplement for the common man!

Drugs That Affect Nitric Oxide Levels

Because nitric oxide has such powerful physiological effects, the pharmaceutical industry has been busy creating drugs that either increase nitric oxide levels or increase the biological effectiveness of nitric oxide. For example, these include drugs to treat angina, hypertension, pulmonary hypertension and erectile dysfunction.

These drugs are generally effective, but have some drawbacks, namely:

They have numerous side effects. For example, just listen to the Viagra or Cialis ads on TV.

Some of them lose their biological effectiveness over time, especially the angina medications.

Natural Approaches for Increasing Nitric Oxide Levels

There are two natural pathways for generating nitric oxide in the body.

1) The first pathway is an enzymatic process that oxidizes a nitrogen atom in the amino acid arginine to nitric oxide.

2) The second pathway is a non-enzymatic process in which naturally occurring nitrates and nitrites are reduced to nitric oxide either by bacteria in the mouth and intestine, or by naturally occurring antioxidants.

Arginine is found in proteins. The best protein sources of arginine are red meat, soy, crustaceans (crab, shrimp & lobster), nuts, spinach and lentils. In addition, you can find arginine supplements and arginine-enriched protein supplements.

The best natural sources of nitrates and nitrites are vegetables, especially spinach, beet root and arugula followed by green leafy vegetable and root vegetables in general. Vegetables provide about 80% of the nitrates and nitrites in the American diet.

Nitrates and nitrites do not appear to have the side effects of the nitic oxide producing drugs. This is probably because their effects on raising nitric oxide levels are slower and more modest, and they do not accumulate in the body.

Interestingly, conventionally grown vegetables are higher in nitrates than organically grown vegetables because of the use of inorganic, nitrate-containing fertilizers. However, that doesn’t mean that I recommend conventionally grown produce over organic produce. In last week’s “Health Tips From the Professor”, I reported that conventionally grown produce is 4-fold higher in pesticides.

Red meat and processed meats are also a minor source of nitrates and nitrites in the American diet because nitrates and nitrites are used as preservatives and coloring agents in those meats.

Are Nitrates and Nitrites Beneficial?

Until recently most of the focus has been on arginine as a natural source of nitric oxide. However, there are several lines of evidence suggesting that dietary sources of nitrates and nitrates can also provide the health benefits expected from nitric oxide.

For example, it has long been known that the DASH (Dietary Approaches to Stop Hypertension) diet is as effective as medications for lowering moderately elevated blood pressure. The DASH diet recommends 4-5 servings of vegetables per day, and recent studies have suggested that the nitrates found in those vegetables may play an important role in the blood pressure lowering effect of the DASH diet (Hord et al, American Journal of Clinical Nutrition, 90: 1-10, 2009; Lin et al, Journal of Nutrition and Metabolism, p 472396, 2012).

In addition, a recent meta-analysis of 16 clinical trials concluded that inorganic nitrate and beet root juice supplements lower blood pressure by modest amounts in healthy individuals (Siervo et al, Journal of Nutrition, 143: 818-826, 2013).

Are Nitrates and Nitrites Harmful?

There are two potential concerns around increasing dietary nitrate and nitrite intake.

1) The one you may have heard the most about is the concern that dietary nitrates and nitrites might increase cancer risk. That turns out to be mainly associated with the nitrates and nitrites added to meats because, in the intestine, nitrites can combine with amino acids to form cancer causing nitrosamines.

That does not appear to be a problem with vegetables because vitamin C and other naturally occurring antioxidants in the vegetables prevent nitrosamine formation. There is no cancer risk in consuming more vegetables.

2) The other concern is potential drug-nutrient interactions, especially drugs which also increase nitric oxide levels such as drugs for angina, hypertension, pulmonary hypertension and erectile dysfunction. This is because the combination of nitric oxide from nitrates in the diet and from the drugs has the potential to cause dangerously low blood pressure.

As a general precaution, if you are taking any medications I suggest consulting your doctor or pharmacist before increasing your dietary intake of nitrates and nitrites.

The Bottom Line

1) Nitric oxide plays an important role in keeping the endothelial lining of your blood vessels healthy, which is thought to reduce the risk of atherosclerosis.

2) Nitric oxide also relaxes the smooth muscle cells that surround our blood vessels. That increases blood flow and decreases blood pressure. The increased blood flow also decreases angina and erectile dysfunction.

3) Nitric oxide also may increase blood flow to active muscle cells. This has been reported to increase exercise efficiency and sports performance. This effect of nitric oxide appears to primarily affect untrained and moderately trained athletes, not highly trained athletes.

4) It has been suggested that nitric oxide may be useful for memory and learning, immune function, mitochondrial function and may reduce the risk of diabetes and heart disease. Research is currently going on to evaluate these hypotheses.

5) There are two natural sources of nitric oxide:

The amino acid arginine from proteins and supplements

Nitrates and nitrites from vegetables such as spinach, beet root and arugula and from supplements.

6) Foods (primarily vegetables) and supplements providing dietary nitrates have been shown to modestly lower blood pressure in healthy individuals. They are likely to provide the other benefits associated with nitric oxide as well, without the side effects associated with nitric oxide enhancing medications.

7) Nitrates and nitrites from vegetables are unlikely to increase cancer risk because vitamin C and other antioxidants from the vegetables prevent the conversion of nitrates and nitrites to nitrosamines.

8) If you are taking any medications, especially medications for angina, high blood pressure or erectile dysfunction, consult with your doctor or pharmacist before increasing your dietary nitrate intake.

9) High blood pressure is a silent killer. You should never substitute dietary nitrates for blood pressure medication. Always consult with your physician first. They may be willing to work with you to lower the amount of medication if appropriate. Finally, even if you don’t have high blood pressure, you should monitor your blood pressure on a regular basis. High blood pressure can sneak up on you without you realizing it.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.