Steve Chaney

Do Omega-3 Fatty Acids Cause Prostate Cancer?

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Fish, Fish Oils And Prostate Cancer

Author: Dr. Stephen Chaney

Pure Fish OilMy phone has been ringing off the hook. My email in-box is full. It seems that everyone wants to know if the headlines about omega-3 fatty acids and prostate cancer are true.

In case you have just gotten back from a vacation on some deserted island with no newspapers and no internet, let me bring you up to date. The headlines are saying things like “Fish Oils May Increase Your Risk of Prostate Cancer” and “Latest Study Links Fish Oils to Prostate Cancer”.

Once again, it seems like just when you’ve figured out which foods that are good for you, someone tells you they could actually kill you. It’s no wonder so many of you have been asking me to cut through the hype and put this latest study in perspective.

What the study actually says:

As usual, let me start with the study itself (Brasky et al., Journal of the National Cancer Institute, doi: 10.1093/jnci/djt174). On the surface, it appears to be a reasonably well designed study, and the conclusions were dramatic. They reported that subjects with high levels of omega-3 fatty acids in their blood were 43% more likely to develop prostate cancer, 44% more likely to develop low grade prostate cancer, and 71% more likely to develop high grade prostate cancer compared to those with low levels of omega-3 fatty acids in their blood.

The flaws in the study:

Case closed you might be tempted to say. However, once you dig a little deeper, the study does have two important weaknesses.

1)     It used data from another study that was designed for a totally different purpose. They went back and analyzed blood samples from a previous study that was actually designed to measure the association between vitamin E and selenium intake and prostate cancer. That’s a scientific no-no.  Let me explain why.

If they had designed a study to investigate the association between omega-3 fatty acids and prostate cancer, they probably would have selected participants with a wide range of omega-3 fatty acids in their blood at the beginning of the study. The subjects in this study actually had a very narrow range of omega-3 fatty acids in their bloodstream.

They also would probably have done a diet analysis and found out whether the subject’s omega-3 fatty acids were coming from fish or fish oil supplements. They might have even asked whether the omega-3 fatty acids were from farm-raised fish or inexpensive fish oil supplements known to be contaminated with PCBs. This study collected none of these data.

2)     This is a single study, and individual studies often provide misleading results. For example, if you examine their data closely, it looks like heavy drinkers and smokers might have a decreased risk of prostate cancer. I think that’s unlikely, but weird associations like that often pop up in individual studies.

What do you find when you look at other studies?

Expert scientists aren’t swayed by individual studies. We prefer to look at the “big picture” that emerges when you combine the results of many studies. For example, a meta-analysis of 24 studies with 461,402 subjects (Symanski et al, American Journal of Clinical Nutrition, 92: 1223-1233, 2010) found no association between fish consumption and prostate cancer risk.

Individual studies ranged from a 61% decrease in risk to a 77% increase in risk, but the overall effect was zero! Even more importantly, fish consumption decreased prostate cancer deaths by 63%.

The Bottom Line:

1)     Don’t panic. Don’t change what you are doing based on the latest sensational headlines. This study has been way overblown. We have come to expect sensational headlines and hype from journalists and bloggers because that’s how they get people to read what they write.

However, I find the comment from the senior author that “We’ve shown once again that use of nutritional supplements may be harmful” to be very irresponsible, especially since they have no data showing that anyone in their study actually used fish oil supplements.

2)     The benefits of assuring optimal omega-3 fatty acid intake clearly overshadow the risks. Omega-3 fatty acids have been shown to lower triglycerides and blood pressure, reduce inflammation and depression, and may even help prevent dementia.

3)     This study does raise a caution flag, but I would not recommend reducing your omega-3 fatty acid intake on the basis of these data alone – especially since most published studies show no increased risk of prostate cancer. There are much better designed studies underway that should clearly show an increase in prostate cancer risk if it is a real effect. I will monitor those studies closely and keep you abreast of any new developments.

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.

Omega-3 Fatty Acid Deficiency And ADHD: Do The Effects Worsen From Generation to Generation

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The Seventh Generation Revisited

Author: Dr. Stephen Chaney

Angry boy portraitDo the effects of omega-3 fatty acid deficiency on ADHD get worse from one generation to the next?

When I was a young man I read an article called “The Seventh Generation” in Organic Gardening magazine. That article was based on the old Indian admonition to consider the effects of everything we do on the seventh generation of our descendents.

The article was written before the environmental movement had co-opted the seventh generation concept. It was also written at a time when the food industry and the public had really started buying into the “better living through chemistry” concept. Processed foods, fast foods and artificial ingredients had just started to replace real foods in the American diet.

The author envisioned a world in which, if we continued to eat nutrient depleted foods, each generation would be sicker than the previous generation until by the seventh generation our descendents would live miserable, sickly, shortened lives – and nobody would know why.

That article made a powerful impression on me. I always like to keep my mind open to new ideas, especially ideas that challenge my preconceived thinking.

So I asked myself “Could it be true? Could eating nutrient depleted foods actually make each generation sicker than the previous generation?”

The author did not have the foresight to predict the obesity epidemic, so he did not envision a world in which we might live sicker, shorter lives in as little as one or two generations.

In addition the author was not a scientist, and his whole premise seemed scientifically implausible at the time. In those days we thought of DNA as the sole determinant of our genetic potential and as something that could not be influenced by our environment. Now we know the DNA and the proteins that coat the DNA can be influenced by the foods we eat and other environmental factors – and that those changes can be passed down from generation to generation. This has lead to a whole new scientific discipline called epigenetics.

Could it be true?

All of that leads me to this week’s article (Bondi et al, Biological Psychiatry, doi:10.1016/j.biosych.2013.06.007). Let me start by pointing out that this is an animal study. It was done with rats. I usually base my health tips on human clinical trials, but it is simply not possible to do multi-generation studies in humans.

The authors hypothesized that omega-3 fatty acid deficiency could be associated with psychiatric disorders such as ADHD, autism, schizophrenia and depression. They based this hypothesis on the known role of omega-3 fatty acids in both brain development and maintenance of normal brain function. They also pointed to numerous clinical studies showing that omega-3 fatty acids could either prevent or reduce the severity of these diseases in humans.

They focused on adolescent rats as well as adult rats because these diseases frequently emerge, and are sometimes more severe, during the adolescent years in humans. Finally, they included second generation rats in the study because the change in our food supply that created an excess of omega-6 fatty acids and a deficiency of omega-3 fatty acids started in the 1960s and 1970s. They reasoned that if the effect of omega-3 deficiency is multigenerational it would be more severe in today’s human adolescents. As I said before, you can’t do multigenerational studies in humans, but you can do them in rats.

They separated litters of rat pups from omega-3 sufficient parents into two groups. One group was fed a diet sufficient in omega-3 fatty acids, and the second group was fed an identical diet except that it was deficient in omega-3 fatty acids. When the omega-3 sufficient group reached adulthood, they were mated and their offspring were continued on the same omega-3 sufficient diet. Similarly, when the omega-3 deficient group reached adulthood, they were mated and their offspring were raised on the same omega-3 deficient diet.

They put each group of rats through a series of behavioral tests when they were adolescents and again when they were adults. It is beyond my expertise to analyze the validity of rat behavioral assays, but the authors claim that the tests they employed were good measures of behavioral traits in human that would be classified as hyperactivity, anxiety, attention deficit disorder and reduced behavioral flexibility. [If you have adolescents in your household, some of those behaviors may sound awfully familiar].

The results were thought provoking. They found little evidence that omega-3 fatty acid deficiency triggered these behaviors in the first generation rats. However, they found strong evidence that omega-3 fatty acid deficiency triggered each of those behaviors in the second generation rats – and the effect was much stronger in the adolescent rats than in the adult rats.

The Bottom Line

At the present time, it isn’t possible to predict the significance of this study for you. This is a single study. And, it is an animal study. It could mean nothing, or it could mean everything.

We do know that the incidence of ADHD in US children has increased by 38% from 2003 to 2012 – and nobody really knows why. We also know that some studies have shown that the American diet is often deficient in omega-3 fatty acids. These same studies have suggested that providing adequate amounts of omega-3 fatty acids in the diet may prevent or reduce the symptoms of ADHD.

I’m a hard-nosed scientist. So I’m not going to be one of those bloggers who writes sensational headlines claiming that omega-3 fatty acid deficiency, or some other nutritional factor, is the cause of our skyrocketing rates of ADHD.

But, it is enough to make you wonder “What if? Could it be true?”

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.

Can Soft Drinks Cause Heart Disease?

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Put Down That Soda

Author: Dr. Stephen Chaney

 soda-drink-300x181Can Soft Drinks Cause Heart Disease? For today’s “Health Tip” I’m going to paraphrase a quote from your some of your favorite action flicks: “Put down that soda and back away and nobody gets hurt.”

You see, the news about soft drinks keeps getting worse and worse! You’ve probably already heard that soft drink consumption leads to weight gain, pre-diabetes and possibly even diabetes because calories in liquid form do not affect appetite to the same extent as calories in solid form.

Soft Drink Consumption increases the risk of heart attack and stroke in women:

As if that weren’t bad enough, three recent studies suggest that soft drinks consumption is also associated with increased risk of heart attacks and stroke.

The first study looked at sweetened beverage consumption and risk of coronary heart disease in women (Fung et al, Am. J. Clin. Nutr., 89: 1037-1042, 2009).

This study followed 88,520 women enrolled in the Nurses Health Study for 24 years. Consumption of sugar-sweetened beverages (either sodas or non-carbonated sugar-sweetened beverages such as Hawaiian Punch, lemonade and other non-carbonated fruit drinks) was assessed from food-frequency questionnaires administered 7 times during the 24 years. And the total incidence of coronary events (both fatal and non-fatal) was recorded.

The results were striking. When they compared women who consumed as little as one sugar-sweetened beverage per day with women who consumed those beverages less than once per month, the increased risk of coronary heart disease was 23%. And when they compared women who consumed more than two sugar-sweetened beverage per day with women who consumed those beverages less than once per month, the increased risk of coronary heart disease was a whopping 35%.

Sodas are just as harmful for men:

And, in case you guys thought you were off the hook, a study has just been published showing similar results in men (de Koning et al, Circulation, March 12, 2012, Epub ahead of print). This study was a 22 year follow up of 42,883 men enrolled in the Men’s Health Professional study. The study design and results were very similar to the ones obtained previously in the Nurses Health Study except that this study did not distinguish between subjects consuming one sugar sweetened beverage a day and those consuming more than one each day.

When they compared men who consumed one or more sugar sweetened beverage a day to men who never consumed sugar-sweetened beverages, the increased risk of coronary heart disease was 20%.

Diet sodas are just as bad as regular sodas:

 Finally, you may be saying that this information doesn’t apply to you because you only consume diet sodas or artificially sweetened non-carbonated beverages.

Unfortunately, you may not be off the hook either!

Another study published in January 2012 reported that diet soft drink consumption is also associated with increased risk of coronary heart disease – including strokes (Gardener et al, J. Gen. Intern. Med., DOI: 10.1007/sl11606-011-1968-2). This study followed 2564 men and women enrolled in the Northern Manhattan Study for 10 years.

The people in this study who consumed more than one diet soda or artificially sweetened beverage/day were 43% more likely to have a vascular event (heart attack or stroke) then the people consuming less than one diet beverage/month. This study is in line with previous studies showing that diet soda consumption is associated with increased risk of pre-diabetes and type 2 diabetes.

And, as I have pointed out in my previous “Health Tips”, there is no convincing evidence that diet sodas actually help prevent weight gain. Sure there are several published studies showing that when dietitians supervise the diets of the study participants, you can achieve weight loss by substituting diet beverages for sugar containing beverages.

However, two major studies have shown that when you look at free-living populations, consumption of diet beverages is associated with just as much weight gain as consumption of sugar containing beverages (Dhingra et al, Circulation,116: 480-488, 2007; Fowler et al,

Obesity, 16:1894-1900, 2008). Apparently, without a dietitian looking over our shoulder, we manage to make up for those lost calories somewhere else!

The Bottom Line:

So what’s the bottom line for you?

You should be aware that these studies just look at associations – not cause and effect – and they can be skewed by the characteristics of the study populations. For example, there were some striking inconsistencies between the 3 studies I cited that are likely due to differences in the population groups that they sampled. However, despite some differences from one study to the next, the weight of accumulating evidence seems to suggest that sodas – both sugar containing and diet – are really not good for us.

So it’s back to my original advice: “Just put down that soda and nobody gets hurt.” Water is sounding better and better!

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.

Can Obesity Affect Your Sex Drive?

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A Big, Fat Problem With Testosterone

Author: Dr. Stephen Chaney

 Obese_Man-300x225Can Obesity Affect Your Sex Drive? While millions of American women are on a diet at any one time, many men just ignore those extra pounds. Things like heart disease, cancer and diabetes seem to be much more distant threats to us. The male ego also allows us to stand in front of a mirror, pot belly and all, and visualize ourselves as we were in our college years.

However, you can’t turn on the TV nowadays without seeing ads for medications to prevent erectile dysfunction and allow you to be ready “when the moment is right.”  Similar ads seem to find their way into our email inbox.  That appears to be a topic of much more relevance to most of us.

What if obesity caused erectile dysfunction? Would that get your attention?

That is why a recent study in the Journal of Clinical Endocrinology and Metabolism should be of great interest to all of us. This study looked at 1700 men of all weights and showed that weight gain of 30 pounds lowered testosterone levels as much as if the men had aged 10 years.

Low testosterone levels in men lead to depression, loss of muscle mass and bone density, feminization, and loss of sexual drive and performance.

The Bottom Line:

So guys, if you are not motivated to lose those extra pounds by how you look or by the increased risk of heart disease, cancer & diabetes, now you have yet another reason to shed those extra pounds.

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.

Can Exercise Help You Live Longer?

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Run Long And Prosper

Author: Dr. Stephen Chaney

Man running Can Exercise Help You Live Longer? In my past “Tips” I have talked about how hard it is to prove the value of individual lifestyle changes for improving our longevity – whether we are talking about more exercise, lower fat diets or individual nutritional supplements. Most studies have too few subjects and last too short a time to show any significant effect.

That’s why the study I’m featuring this week is so remarkable. The study was designed to answer the question of whether exercise can actually help people live longer. Many studies have tried to answer that question. But what was remarkable about the study was the number of people enrolled in the study and how long the study lasted.

Let’s look at the study (Byberg et al, British Journal of Sports Medicine, 43: 482-489, 2009) in detail. The study enrolled 2,204 men aged 50 from the city of Uppsala Sweden in 1970-1973 and followed the men for 35 years! At the beginning of the study the participants completed a survey on leisure time physical activity and were categorized into low, medium or high activity groups.

Participants were re-examined at ages 55, 60, 70, 77, and 82 years and changes in physical activity were recorded. Other information, such as body mass index, blood pressure, cholesterol levels, smoking status and alcohol use, was also collected at each survey. And, of course, the researches recorded how many of the initial participants were still living at each of those ages.

After adjusting for other risk factors (obesity, smoking, excess alcohol consumption, elevated cholesterol or blood pressure), the researchers found that men who reported high levels of physical activity from age 50 lived 2.3 years longer than sedentary men and 1.1 years longer than men who reported medium levels of physical activity.

They also looked at what happened to men who started at low or medium levels of activity and increased their exercise level during the study. After 5 years of increased activity there was no apparent benefit. But after 10 years of increased activity the risk of dying had been reduced just as much as if they had always been exercising at that level!

I find that last finding particularly significant because most studies of this type last 5 years or less. If this study had been concluded at the end of 5 years, you might be tempted to say “Why bother. If I haven’t exercised before, there’s no point in starting now.” But, this study did last more than five years – so the conclusion was completely different.

The Bottom Line:

So, what are the take-home lessons from this study?

1) We’ve known for years that exercise reduces the risks of several types of diseases and improves the quality of life. This study clearly shows that exercise also helps us live longer.

2) And, if you haven’t exercised before, it’s never too late to start. Just don’t expect instantaneous results.

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.

Household Cleaners And Asthma: Is There A Link?

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Do Toxic Homes Cause Asthma?

Author: Dr. Stephen Chaney

AsthmaEverybody is going green. Biodegradable cleaners are finally in fashion. But did you realize that many of the cleaners that you buy in the supermarket – and some of the biodegradable cleaners that you buy in the health food store – release toxic fumes in your home that can adversely affect the health of you and your children?

For this week’s story, I’m going to focus on just one aspect of this topic – household chemical exposure and childhood asthma.

Let me start with a bit of background information: The prevalence of childhood asthma increased 74% between 1980 and 1994 and has continued to increase in the years since.

The causes of this rapid increase in asthma prevalence are likely to be complex, but evidence has accumulated in recent years that some of the increase may be caused by early exposure to toxic chemical fumes in the home.

Are household cleaners becoming more toxic?

The American consumer keeps demanding cleaners that work better. It’s considered a big plus if they require no effort and are easy to use. Don’t bother with messy liquids and pastes – just spray it on. And manufacturers have been willing to oblige by adding ever more exotic chemicals to household cleaners and putting them in aerosol spray cans. And of course no one opens their windows any more. That would be wasting energy and contributing to global warming.

The result is that these toxic chemicals accumulate in the air that we breathe in our own homes. In fact, the Environmental Protection Agency has stated that the air inside our homes is often more polluted than in Los Angeles or New York on a smoggy day.

What do the studies show?

A number of studies have pointed to an association between these toxic household fumes and childhood asthma, but I’d like to focus on one particularly good study on this topic that was published recently in the European Respiratory Journal (31: 547-554, 2008).

This study measured the household chemical exposure of 7,162 pregnant women in England and looked at the incidence of asthma in their children at age 8.5 years. A maternal composite household chemical exposure (CHCE) score was derived by measuring the pregnant mother’s exposure to a number of common household products known to contain toxic chemicals.

The household products used most frequently were disinfectants (87.4%), bleach (84.8%), aerosols (71.7%), air fresheners (68%), window cleaners (60.5%), carpet cleaners (35.3%) and pesticides/insecticides (21.2%). (For information on the toxic chemicals in these and other common household products visit: http://www.householdproducts.nlm.nih.gov/products.htm)

Asthma was quantified based on persistent wheezing (reported by the parents) and several lung function tests that were administered at age 8.5 years. To make sure that the asthma was not caused by simple allergies the children were also given a skin prick test against a panel of 6 common childhood allergens (house dust mites, cats, mixed grass, mixed nuts, peanuts and milk). The study also controlled for confounding variables such as exposure to tobacco smoke, damp housing, pets in the home and maternal history of asthma. In short, this was a very large and particularly well controlled study.

And the results were clear. Higher household chemical exposure during pregnancy was associated with a 41% increase in childhood asthma in children with no known allergies.

The Bottom Line:

What does that mean to you and me? It means that it is not enough to select household cleaners that are safe for the environment. We also need to select products that we use in our homes on the basis of their safety for us and our family – not just on the basis of cost and convenience.

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.

Welcome to Health Tips from the Professor

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My goal is to keep you abreast of the latest developments in health, nutrition and fitness. I will cut through the sensational headlines and hype to let you know what health information you can trust. I will provide you with this information in a straight-forward manner so that you can apply it to your personal health goals.

 

I know you have access to an endless stream of health information on the internet, much of which is inaccurate and misleading.  What makes my e-newsletter unique is I evaluate every published article and health claim with the objective eye of a trained scientist. I separate fact from fiction. And, I do so without hype or bias.

 

I will be starting delivery of “Health Tips from the Professor” in just a few short weeks. In the meantime if what I will be providing sounds like the type of information you would like to be receiving on a regular basis, please go ahead and subscribe. This would also be a great time to let me know what information you would like to see in the coming months by going to ….

 

To Your Good Health

 

Stephen G. Chaney, PhD

Health Tips From The Professor