Is Red Meat Healthy For You?

January 28, 2020 by Dr. Steve Chaney

Why Is Red Meat So Controversial?

The American Heart Association, the American Cancer Society, the World Health Organization and other organizations have been telling us for years that diets high in red meat are likely to increase our risk of chronic diseases. If you are like most Americans, you have been trying to cut back on red meat.

However, the latest headlines are saying things like: “Red meat is actually good for you” and “Most adults don’t need to cut back on red meat for their health”. Where did those headlines come from?

A group calling itself the Nutritional Recommendations Consortium (NutriRECS) has reviewed the scientific literature and said: “The evidence is too weak to justify telling individuals to eat less beef and pork.” They have issued guidelines (BC Johnston et al, Annals of Internal Medicine, 171: 756-764, 2019) saying that adults really don’t need to change the amounts of red meat they are eating.

As you can imagine, that has proven to be a controversial recommendation. Many of the top experts in the field have questioned the validity of the study and have condemned the guidelines as misleading.

However, most of you don’t care about arguments between the experts. Your questions are: “What does this study mean to me?” Is everything I have been told about red meat wrong?” “Is red meat healthy after all? Can I really eat as much as I want?”

Why Is Red Meat So Controversial?

If you are confused by the latest headlines, it’s not your fault. Over the past few decades you have been bombarded by conflicting headlines about red meat. One month it is bad for you. The next month it is good for you. It is fair to ask: “Why is red meat so controversial? Why is it so confusing?”

Perhaps the best way to answer those questions is to review the scientific critique of the latest guidelines saying we can eat as much red meat as we want and then look at the authors’ rebuttal.

The best summary of the scientific critique of these guidelines is a WebMD Health News report. Let me cover a few of the most important criticisms:

#1: The NutriRECS group was not backed by any major health, government, or scientific organizations. The members of this group self-nominated themselves as gurus of nutritional recommendations. In an earlier publication they concluded that the evidence was too weak to justify telling individuals to eat less sugar. But in that review they stopped short of recommending that adults could eat as much sugar as they wanted.

#2: The review left out 15 important studies showing that diets high in red meat are associated with increased disease risk. If those studies had been included in the analysis, the link between meat consumption and disease would have been much stronger. Even worse, the omitted studies met the author’s stated criteria for inclusion in their analysis. No reason was given for omitting those studies. This suggests author bias.

#3: The authors used an assessment method that prioritizes evidence from randomized controlled trials and downgrades evidence from association studies. As a result, multiple association studies showing red and processed meat consumption increases disease risk were discounted, and a few randomized controlled clinical trials giving inconsistent results dominated their analysis.

Let me state for the record that my research career was devoted to cancer drug development. I am a big proponent of the value of randomized controlled trials when they are appropriate.

· Randomized controlled trial are perfect for determining the effectiveness of new drugs. In this context it is appropriate. In a drug trial it is easy to design a randomized, placebo-controlled clinical trial. In addition, every participant already has the disease. If a drug has a benefit, it is apparent in a very short time.

· However, randomized controlled trials are not optimal for dietary studies. In the first place, it is impossible to design a placebo or have a “blinded study”. People know what they are eating. In addition, diseases like heart disease, cancer, and diabetes take decades to develop. You can’t keep people on specific diets for decades.

· In addition, because randomized controlled trials are short, they can only measure the effect of diet on disease markers like LDL cholesterol. These disease markers are imperfect predictors of disease outcomes. I will discuss this in more detail next week.

· Consequently, most of the major studies in nutrition research are “association studies” where the investigators ask people what they customarily eat and look at the association of those dietary practices with disease outcomes. These studies aren’t perfect, but they represent the best tool we have for determining the influence of diet on disease outcomes.

#4: The authors included people’s attitudes about eating meat in their analysis. Because many meat eaters stated they would be unwilling to give up meat, the authors downgraded the association between meat consumption and disease risk.

· That really had the outside experts scratching their heads. They agreed that people’s attitudes should be considered in discussions about how to implement health guidelines. However, they were unanimously opposed to the idea that people’s opinions should be a factor in crafting health guidelines.

#5: The authors ignored the environmental impact of meat consumption. As I indicated in a previous issue of “Health Tips From the Professor”, this should be a major consideration when choosing your diet.

#6: The authors may have been influenced by the beef industry. The NutriRECS group stated that the Agriculture and Life Sciences (AgriLife) program at Texas A&M provided generous support for their study. While that sound innocuous, the AgriLife program receives financial support from the “Texas Beef Checkoff Program”, which is a meat industry marketing program paid for by cattle ranchers.

#7: The beef industry influenced the studies the authors relied on in their review. The beef industry supports randomized controlled clinical trials on red meat and influences the outcome of those studies in ways that minimize the health effects of red meat consumption. I will give some examples of this next week. Unfortunately, these are the studies the NutriRECS group relied on for their recommendations.

What Did The Authors Say About Their Guidelines?

Because I like to provide a balanced evaluation of nutrition controversies, it is only fair that I summarize the authors argument for their recommendations. However, I will add my commentary. Here is a summary of their arguments.

#1: Nutritional recommendations should be based on sound science. In principle, this is something that everyone agrees on. However, as I noted above randomized controlled trials are not always the best scientific approach for studying the health effects of diet.

My comment: In matters of public health it is better to be safe than sorry. Simply put, it is better to warn people about probable dangers to their health rather than waiting decades for certainty. Smoking is a perfect example. The Surgeon General warned the US public about the dangers of smoking long before the evidence was conclusive.

Smoking is also an example of how industry tries to influence scientific opinion. The tobacco industry supported and influenced research on smoking. Industry funded research tended to minimize the dangers of smoking. Next week I will show how the meat industry is doing the same concerning the dangers of red meat.

#2: It is difficult to get good dietary information in association studies. That is because most association studies ask people what they have eaten over the past few decades. There are two problems with that.

1) Most people have enough trouble remembering what they ate yesterday. Remembering what they ate 10 or 20 years ago is problematic.

2) People listen to the news and often change their diets based on what they hear. What they are eating today may not resemble what they ate 10 years ago.

My comment: That is a legitimate point. However, in recent years the best association studies have started collection dietary information at the start, the mid-point, and the end of the study. I agree we need more of those studies.

#3: The authors claim they found no statistically significant link between meat consumption and risk of heart disease, diabetes, or cancer in a dozen randomized controlled trials that had enrolled about 54 000 participants.

My comment: That statement is highly misleading. One of those studies had 48,835 participants. That study wasn’t even designed to measure the effect of red meat consumption. It was designed to measure the health effects of low fat versus high fat diets. The difference in red meat consumption between the two groups was only 1.4 servings per day, a 20% difference. Even with that small difference in red meat consumption, there was about a 2% reduction in some heart disease outcomes, which the authors considered insignificant.

That leaves 11 studies with only 5,165 participants, which averages out to 470 participants per study. Those studies had too few participants to provide any meaningful estimate of the effect of red meat on health outcomes.

In addition, the meat industry influenced the design of some of those studies to further minimize the effect of red meat on health outcomes, something I will discuss next week.

#4: The authors found a slight effect of red meat consumption on heart disease and cancer deaths in association studies, but said the decrease was too small to recommend that people change their diet.

My comment: This represents the folly of looking at any single food or single nutrient rather than the whole diet. We need to take a holistic approach and ask questions like: “What are they replacing red meat with? What does their overall diet look like?

For example, let’s look at what happens when you reduce saturated fats, something I discussed in a previous issue (https://www.chaneyhealth.com/healthtips/are-saturated-fats-bad-for-you/) of “Health Tips From the Professor”. When you replace saturated fats with:

· Trans fats, your heart disease risk increases by 5%.

· Refined carbohydrates and sugars (the kind of carbohydrates in the typical American diet), your heart disease risk increases slightly.

· Complex carbohydrates (whole grains, fruits and vegetables), your heart disease risk decreases by 9%.

· Monounsaturated fats (olive oil & peanut oil), your heart disease risk decreases by 15%.

· Polyunsaturated fats (vegetable oil & fish oil), your heart disease risk decreases by 25%.

· Unsaturated fats in the context of a primarily plant-based diet like the Mediterranean diet, your heart disease risk decreases by 47%.

While we don’t have such precise numbers for red meat, we do have enough evidence to know that the situation with red meat is similar.

· Replacing high-fat red meat with low-fat red meat or white meat in the context of a typical American diet will probably have only a modest effect on disease risk.

· Replacing red meat with plant protein in the context of a typical American diet (think Impossible Burgers or the equivalent at your local Fast Food restaurant) will also probably have only a modest effect on disease risk.

· Replacing red meat with white meat or plant protein in the context of a primarily plant-based diet is likely to significantly reduce disease risk.

Is Red Meat Healthy For You?

Let’s return to the question I posed at the beginning of this article: “Is red meat healthy for you?” In the context of headlines saying: “Red meat is actually good for you”, the answer is a clear No!

· The saturated fat in red meat is associated with increased heart disease risk.

· However, it’s not just saturated fat. Other components of red meat are associated with increased risk of heart disease and cancer. I will discuss those next week.

There are simply too many studies that show an association between red meat consumption and disease risk to give red meat a clean bill of health. We can’t say red meat is healthy with any confidence.

However, that doesn’t mean we need to eliminate red meat from our diet. The health risks of red meat are determined by the type of red meat consumed, the amount of red meat consumed, and the overall composition of our diet. So:

· If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat is probably not healthy.

· However, if you are thinking of 2-3 ounces of lean steak in a vegetable stir fry or a green salad, red meat may be healthy.

Of course, one question I am frequently asked is “What about grass fed beef? Is it healthier than conventionally raised beef?” I will answer that question next week.

The Bottom Line

A group calling itself the Nutritional Recommendations Consortium (NutriRECS) recently reviewed the scientific literature and said: “The evidence is too weak to justify telling individuals to eat less beef and pork.” They then issued guidelines saying that adults really don’t need to change the amounts of red meat they are eating.

When you examine the pros and cons carefully, it becomes clear that the NutriRECS group:

1) Put too little emphasis on association studies with hundreds of thousands of participants showing a link between red meat consumption and increased risk of heart disease and cancer.

2) Put too much emphasis on very small randomized controlled trials that had no possibility of evaluating the effect of red meat consumption on disease risk. In part, that is because many of the randomized controlled trials were funded and influenced by the meat industry, something I will discuss next week.

3) Did not ask what the red meat was replaced with or look at red meat consumption in the context of the overall diet.

Based on what we currently know:

1) Replacing high-fat red meat with low-fat red meat or white meat in the context of a typical American diet will probably have only a modest effect on disease risk.

2) Replacing red meat with plant protein in the context of a typical American diet (think Impossible Burgers or the equivalent at your local Fast Food restaurant) will also probably have only a minor effect on disease risk.

3) Replacing red meat with white meat or plant protein in the context of a primarily plant-based diet is likely to significantly reduce disease risk.

That means:

1) If you are thinking in terms of a juicy 8-ounce steak with a baked potato and sour cream, red meat is probably not healthy.

2) However, if you are thinking of 2-3 ounces of lean steak in a vegetable stir fry or a green salad, red meat may be healthy.

Of course, one question I am frequently asked is “What about grass fed beef? Is it healthier than conventionally raised beef?” I will answer that question next week. Stay tuned.

For more details, read the article above.

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.

Does Grilled Meat Increase Prostate Cancer Risk?

July 5, 2014July 1, 2014 by Dr. Steve Chaney

Author: Dr. Stephen Chaney

Want Cancer With That Burger?

Its summer and you have most likely already visited a backyard bbq. One question that you probably won’t hear from your host or hostess is “Would you like some cancer with that burger?” But, perhaps that is exactly the question that they should be asking.

You probably already knew that red meat consumption may increase your risk of cancer. But, did you know that grilling that red meat may increase your risk of cancer even more?

You probably didn’t really want to know that when fat from the meat hits the hot coals, carcinogens form that are deposited on the meat.

You probably also didn’t want to know that when you cook meat to high temperatures the amino acids in the meat combine to form cancer causing substances.

And you really didn’t want to know that a recent study showed that people who consume well-done red meat were 60% more likely to develop advanced pancreatic cancer.

Does Grilled Meat Increase Prostate Cancer Risk?

This study compared 531 people ages 40-79 who had recently been diagnosed with advanced prostate cancer with 527 matched controls. Both groups were asked about their dietary intake of meats, usual meat cooking methods and doneness of the meat.

The results were quite striking:

Increased consumption of hamburgers was associated with a 79% increased risk of advanced prostate cancer.

Increased consumption of processed meat was associated with a 57% increased risk of advanced prostate cancer.

Grilled red meat was associated with a 63% increased risk of advanced prostate cancer.

Well done red meat was associated with a 52% increased risk of advanced prostate cancer.

However, those percentages are a little bit difficult to compare, because “increased consumption” was defined relative to what the usual consumption or cooking practice was. So put another way, weekly consumption of…

3 or more servings of red meat or…

1.5 or more servings of processed meat or…

1 or more servings of grilled or well done red meat…

…were associated with a 50% increased risk of advanced prostate cancer.

In contrast, consumption of white meat was not associated with increased cancer risk, no matter what the cooking method was used.

Is It Possible To Enjoy Your Cookouts Without Increasing Cancer Risk?

Our local newspaper recently carried some tips by Dr. Denise Snyder from the Duke University School of Nursing in Durham, NC on how you could reduce the risk of giving your guests cancer the next time you are the chef at your backyard bbq.

Here are her suggestions:

Grill fruits and vegetables instead of meat. That was her idea, not mine. My editorial comment would be that grilling white meat (fish or chicken) is also OK.

Use the lowest temperature that will cook your food thoroughly and keep the grill rack as high as possible.

Use a meat thermometer so that you can make sure that as soon as the meat is thoroughly cooked you remove it from the grill. We usually overcook the meat to make sure that it is done.

Shorten your grill time by microwaving the meat first, using thinner leaner cuts of meat or cutting up the meat and making kabobs.

Trim as much fat from the meat as possible before you cook it.

Line your grill rack with aluminum foil poked with holes. This allows the fat to drip down but minimizes the exposure of the meat to the carcinogens formed when the fat hits the coals.

Marinate your meats before grilling. That has been shown to reduce the formation of cancer causing chemicals.

And, of course, avoid processed meats like hot dogs and sausage completely because they have been shown to increase the risk of cancer and diabetes (British Journal of Cancer, 106: 603-607, 2012; American Journal of Clinical Nutrition, doi: 10.3945/ajcn.111.018978, 2011) no matter how they are cooked.

So here’s to a healthier backyard bbq. Bon appétit!

The Bottom Line

1) You already knew that red meat and processed meats may increase your risk of cancer, but how you cook your red meat also matters. Grilling your meat and/or cooking it until it is well done appear to significantly increase your risk of developing advanced prostate cancer.

2) In contrast, consumption of white meat was not associated with increased cancer risk, no matter what the cooking method was used.

3) I’ve included several tips on how you can reduce the cancer risk associated with grilling red meats in the article above so you can enjoy both your cookouts and your health.

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.

Does Carnitine Increase Heart Disease Risk?

April 8, 2014 by Dr. Steve Chaney

Carnitine: Dr. Jekyl or Mr. Hyde?

Author: Dr. Stephen Chaney

It’s both interesting and confusing when one Journal article appears talking about the dangers of a particular supplement and just a couple of weeks later another article appears talking about the benefits of that same supplement – especially when the conclusions of both articles are misrepresented in the media.

But that’s exactly what has just occurred with the supplement L-carnitine. Media reports of the first article trumpeted the headline “Cleveland Clinic study links L-carnitine to increased risk of heart disease”. Media reports of the second article featured the headline “Mayo Clinic review links L-carnitine to multiple health heart benefits”. As you might suspect, neither headline was completely accurate. So let me help you sort out the confusion about L-carnitine and heart health

What is Carnitine?

But first let me give you a little bit of background about L-carnitine. L-Carnitine is an essential part of the transport system that allows fatty acids to enter the mitochondria where they can be oxidized and generate energy. So it is an essential nutrient for any cell that has mitochondria and utilizes fatty acids as an energy source.

L-carnitine is particularly important for muscle cells, and the hardest working muscle cells in our body are those that pump blood through our hearts. So when we think of L-carnitine we should think of heart health first.

But that doesn’t mean that L-carnitine is an essential nutrient. In fact, our bodies generally make all of the L-carnitine that we need. There are some metabolic diseases that can prevent us from making L-carnitine or utilizing L-carnitine efficiently. People with those diseases benefit from L-carnitine supplementation, but those diseases are exceedingly rare.

There is some evidence that supplemental L-carnitine may be of benefit in individuals suffering from congestive heart failure and other diseases characterized by weakened heart muscles. Other than that there is little evidence that supplemental L-carnitine is beneficial for healthy individuals.

Does Carnitine Increase Heart Disease Risk?

Let’s look at the first study (Koeth et al, Nature Medicine, doi:10.1038/nm.3145, April 7, 2013) – the one that purportedly linked L-carnitine to increase risk of heart disease. The authors were trying to gain a better understanding of the well-established link between red meat consumption and cardiovascular disease risk. The classical explanation of this link has been the saturated fat and cholesterol content of the red meat.

However, several recent studies have questioned whether saturated fat and cholesterol actually increase the risk of cardiovascular disease (see last week’s article “Are Saturated Fats Good For You?”)

Since red meat is also high in L-carnitine, the authors hypothesized that it might be the L-carnitine or a metabolite of the L-carnitine that was associated with increased risk of heart disease in people consuming red meat.

The authors honed in on a metabolite of L-carnitine called trimethylamine-N-oxide or TMAO that is produced by bacteria in the intestine and had been previously shown to accelerate atherosclerosis in mice. They developed what they called an L-carnitine challenge. Basically, they gave their subjects an 8 ounce sirloin steak, which contains about 180 mg of L-carnitine, and measured levels of L-carnitine and TMAO in the blood one hour later and the urine 24 hours later. [I’m guessing they didn’t have much trouble finding volunteers for that study.]

When the subjects were omnivores (meaning meat eaters) they found a significant increase in both L-carnitine and TMAO in their blood and urine following the L-carnitine challenge. When they put the same subjects on broad-spectrum antibiotics for a week to wipe out their intestinal bacteria and repeated the L-carnitine challenge, they found an increase in L-carnitine but no increase in TMAO. This simply confirmed that the intestinal bacteria were required for the conversion of L-carnitine to TMAO.

Finally, because previous studies have shown that omnivores and vegetarians have very different populations of intestinal bacteria, they repeated their L-carnitine challenge in a group of vegans and found that consumption of the same 8 ounce sirloin steak by the vegans did not result in any significant increase in TMAO in either their blood or urine.

Armed with this information, the authors measured L-carnitine and TMAO concentrations in the fasting blood of 2595 patients undergoing cardiac evaluation in the Cleveland Clinic. They used an established protocol to assess the three-year risk for major adverse cardiac events in the patients they examined. They observed a significant association between L-carnitine levels and cardiovascular event risks, but only in subjects who also had high blood levels of TMAO.

Now it’s time to compare what the headlines said to what the study actually showed. The headlines said “L-carnitine linked to increased risk of heart disease”. What the study actually showed was that there were two things that were required to increase the risk of heart disease – L-carnitine and a population of intestinal bacteria that converted the L-carnitine to TMAO.

The major source of L-carnitine in the American diet is red meat, and habitual red meat consumption is required to support a population of intestinal bacteria that is capable of converting L-carnitine to TMAO. So the headlines should have read “red meat consumption linked to increased risk of heart disease”. But, of course, that’s old news. It doesn’t sell subscriptions.

Does Carnitine Decrease Heart Disease Risk?

The second study (DiNicolantonio et al, Mayo Clinic Proceedings, dx.doi.org/10.1016/j.mayocp.2013.02.007) was a meta-analysis. It reviewed 13 clinical studies involving 3629 people who had already had heart attacks and were given L-carnitine or a placebo after the heart attack.

In evaluating the results of this study it is useful to remember that a heart attack generally kills some of the heart muscle and weakens some of the surviving heart muscle. When the data from all of the studies was combined the authors reported a 27% reduction in all cause mortality, a 65% reduction in arrhythmias, and a 40% reduction in angina. However, there was no reduction in a second heart attack or the development of heart failure.

So perhaps the headlines describing this study were a little closer to being on target, but they failed to mention that these effects were only seen in people who had already suffered a heart attack and had weakened heart muscles. They also failed to mention that there was no decreased risk of a second heart attack or congestive heart failure.

The Bottom Line:

1) The first study should be considered preliminary. It needs to be confirmed by other studies. If it is true, it is not ground breaking. It merely gives us a fuller understanding of why red meat consumption may be linked to increased risk of heart disease and gives you yet another reason to minimize red meat consumption.

The study does raise the possibility that use of L-carnitine supplements may increase your risk of heart disease if you eat red meat on a regular basis, and that this same risk may not be associated with L-carnitine supplementation if you are a vegan. But the study did not directly test that hypothesis, and much more research is required before I would give it any weight.

2) The second study suggests that if you have already had a heart attack, you may want to consult with your physician about whether L-carnitine supplementation might be of benefit. Once again, this study is not ground breaking. We already knew that L-carnitine supplementation was helpful for people with weakened heart muscle. This study merely confirmed that.

Contrary to what the headlines suggested, this study provides no guidance about whether L-carnitine supplementation has any heart health benefits in people without pre-existing heart disease – and the bulk of existing literature suggests that it does not.

3) Finally, I realize that the major use of L-carnitine in the US market is in sports supplements purported to increase strength and endurance. The literature on that is decidedly mixed, but that’s another subject for another 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.