Posts Tagged ‘red meat’

Does Grilled Meat Increase Prostate Cancer Risk?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

Author: Dr. Stephen Chaney

 Want Cancer With That Burger?

 backyard-bbq

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.

how-you-can-reduce-cancer-risk

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?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues, Supplements and Health

Carnitine: Dr. Jekyl or Mr. Hyde?

Author: Dr. Stephen Chaney

Heart HealthIt’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?

fatty steakLet’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?

Heart AttackThe 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.

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Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, 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.

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