Red Meat and Heart Health

Written by Dr. Steve Chaney on . Posted in Red Meat and Heart Health

Can Red Meat Be Part Of A Heart Healthy Diet?

Author: Dr. Stephen Chaney

 

What about red meat and heart health?

red meat and heart health studyIt is so confusing. One recent headline proclaimed “Plant-based foods decrease the risk of heart disease and cancer.”  Another headline read: “Including beef with the Mediterranean diet improves heart health.”  You are probably wondering which of these studies is correct. More importantly, you are probably wondering whether you should include more meat or less meat in your diet.

If you read the articles, you will find that the dueling headlines are deceptive. Both studies reached essentially the same conclusion. The first study (K.S. Petersen et al, Current Developments in Nutrition, 2017; 1:e001289 ) concluded that plant-based diets significantly decreased the risk of heart disease and diabetes. It also concluded that you can include small amounts of animal protein in a plant-based diet without losing its health benefits. The second study (L.E. O’Connor et al, American Journal of Clinical Nutrition, 108: 1-8, 2018 ) concluded that the Mediterranean diet, which is a primarily plant-based diet, significantly decreased the risk of heart disease and diabetes. It also concluded that you could include small amounts of lean, unprocessed red meat in the Mediterranean diet without losing its health benefits.

You might be wondering how it is possible to go from a study showing that small amounts of lean, unprocessed red meat did not reduce the heart-health benefits of the Mediterranean diet to a headline claiming: “Including Beef With A Mediterranean Diet Improves Heart Health.”  Did I mention that the study was funded by money from the beef industry and the headlines came from an online issue of Beef Magazine? That might explain it.

Let’s look at:

  • How the studies were designed.
  • The study results in detail.
  • What these studies mean for you.

 

How Were The Studies Done?

red meat heart health and heart diseaseStudy #1: The first study (K.S. Petersen et al, Current Developments in Nutrition, 2017; 1:e001289 ) was a systematic review of over 50 recent studies looking at the relative contribution of plant-based foods and animal products to healthy dietary patterns.

Study #2: The second study (L.E. O’Connor et al, American Journal of Clinical Nutrition, 108: 1-8, 2018 ) was, in the words of the authors, an investigator-blinded, randomized, crossover, controlled feeding trial. That is probably Greek to most of you, so let me explain.

  • A “controlled feeding study” is one in which subjects are given diets designed by dietitians to contain precise amounts of macronutrients and micronutrients. In this case, both diets were Mediterranean diets. One of the diets was the standard Mediterranean diet with 1 ounce/day of lean, processed red meat. This diet was referred to as Med-Control. The other diet was a version of the Mediterranean diet containing 2.47 ounces/day of red meat. It was referred to as Med-Red. (More about the design of these diets below). The diets were prepared for the subjects by the Indiana Clinical Research Center Bionutrition Facility at Purdue University. The subjects completed weekly menu check-off lists and met with staff weekly to monitor compliance.
  • A “crossover study” is one in which subjects are given one experimental diet, followed by a “washout period” when they consume their normal diet, followed by the second experimental diet. In this case both experimental diets were followed for 5 weeks and the washout period was 4 weeks. In this type of study each subject serves as their own control.
  • The term “randomized” simply means that some subjects consumed the Med-Control diet first and others consumed the Med-Red diet first.
  • The term “investigator-blinded” simply means the investigators did not know the order of the experimental diets each subject received. It is, of course, impossible to conduct a double-blind study when you are conducting a dietary intervention study, such as this one. The subjects know which diet they are consuming.

Other important features of the study were:

  • The study included 41 middle-aged (46±2 years), obese (BMI=30.5±0.6) adults from West Lafayette, Indiana.
  • Fasting blood samples were taken at entry into the study and during the last week of both experimental diets and the washout period. The investigators measured total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, ApoB, C-reactive protein, insulin, and blood glucose levels.
  • Blood pressure was also measured at the same times.

In interpreting the results of this study, it is important to know other features of the experimental diets. They are:

  • red meat heart health foodsOverall macronutrient composition was identical for the two diets. It was 40% carbohydrate, 22% protein, and 40% fat. In other words, it was nether low-carb nor low-fat. Instead it consisted of healthy carbs and healthy fats.
  • The differences between the two diets was almost entirely based on the relative amount of red meat and poultry in the diets. The Med-Control had more poultry and less red meat. The Med-Red had more red meat and less poultry.
  • The red meat was lean beef or pork tenderloin. The poultry was chicken or turkey breast (white meat with the skin removed prior to cooking). All meats were low in fat and cholesterol (˂10% total fat, ˂5% saturated fat, ˂95 mg cholesterol). In short, none of the subjects were eating juicy steaks and burgers or fried chicken.
  • Fish intake was the same on both diets (22% of protein intake) so that omega-3 intake was similar.
  • Nuts, seeds, and legumes (primarily soy) were the same on both diets (40% of protein intake). When you include grains and other plant protein sources, plant-based protein probably constituted almost 50% of total protein intake.
  • Both diets included the same amount of olive oil. The overall fat profile of the diet (7% saturated, 20% monounsaturated, and 13% polyunsaturated) was very healthy.
  • Both diets were rich in fruits and vegetables (4 servings/day of fruit and 7-8 servings/day of vegetables). This is much more than you would find in the typical American diet.
  • Both diets were composed primarily of whole grains. There was almost no sugar or refined grain in either diet. Again, this is very different from what most Americans eat.

 

Red Meat and Heart Health?

 

red meat and heart health dietsStudy #1: While the authors of this paper reviewed a variety of studies, I will focus on studies looking at the inclusion of red meat into otherwise healthy diets. For example, the authors reported on a recently published study looking at inclusion of 3 different levels (1 ounce/day, 4 ounces/day, and 5 ounces/day) of lean, red meat into the DASH diet, a diet specifically designed to reduce the risk of high blood pressure. That study showed:

  • Inclusion of up to 5 ounces/day of lean red meat did not reduce the effectiveness of the DASH diet at reducing heart disease risk factors. In fact, total and LDL cholesterol levels were slightly better than when red meat was limited to 1 ounce/day.
  • However, the authors noted that:
    • The DASH diet is already fairly high in animal protein. The increase in red meat consumption was achieved by replacing other animal protein sources in the diet.
    • These were very lean cuts of red meat. All 3 versions of the DASH diet were designed to limit saturated fat intake to ˂6% of total calories.
    • Plant protein was about 50% of total protein intake in all 3 diets.
    • All 3 diets eliminated “empty calorie” foods and provided lots of fruits and vegetables (8-10 servings/day).
    • All 3 diets included 4-5 cups of low fat dairy products.
  • The authors also noted that dietary intake was closely controlled in this study and that similar results might be difficult to achieve in a free-living setting. For example, they pointed out that previous studies have shown:
    • Higher meat consumption in the American population is associated with lower consumption of fruits, vegetables, legumes, nuts, seeds and soy products.

The authors concluded: “It is likely that consumption of animal products (excluding processed meats) at recommended amounts in the context of a dietary pattern that meets recommendations for fruits, vegetables, whole grains, nuts, seeds, and legumes, and does not exceed recommendations for added sugar, sodium, and saturated fat, may not adversely affect, and may benefit cardiometabolic risk [risk of heart disease and diabetes].”

The authors went on to say: “However, population adherence to these recommendations is markedly suboptimal. Therefore, improving intake patterns to align with dietary guidelines should be the focus of our efforts rather than engaging in debate about whether diets for cardiovascular disease prevention should be exclusively plant-based or include animal foods in recommended amounts.”

In case you think that was clear as mud, let me offer my translation: “Lean, unprocessed meat consumption does not increase the risk of heart disease or diabetes when consumed as part of an extremely healthy diet. However, the American diet is lousy. We should focus on eating a healthy diet rather than arguing about whether it should be completely plant-based or can include some meat.”

Study #2: This study found that:

  • red meat heart health vegetables fruitsTotal and LDL cholesterol decreased more with Med-Red Meat than with Med-Control. However, the authors noted that the Mediterranean diet has little effect on total and LDL cholesterol levels, so its effect on reducing heart disease risk must be due to other factors.
  • The other parameters (HDL cholesterol, ApoB, triglycerides, C-reactive protein, insulin and blood glucose levels) were essentially the same on the Med-Red and Med-Control diets. However, the Med-Control diet also had little effect on these parameters compared to the normal diet of the subjects in the study. That probably reflected the short duration (5 weeks) of the diet intervention phase. Much longer dietary interventions would be required to adequately assess the effectiveness of either the Mediterranean diet or the Mediterranean diet with red meat at reducing disease risk.
  • Once again, the Med-Red diet was a carefully controlled diet that featured:
    • Small amounts (2.5 ounces/day) of very lean (<10% fat, <5% saturated fat) red meat in place of very lean poultry with about 50% of the protein in the diet coming from plant sources.
    • Lots of fruits, vegetables, whole grains, nuts, seeds, legumes, omega-3-rich seafood, and olive oil.
    • Almost no sugar and refined carbs.
    • A very healthy fat profile (7% saturated, 20% monounsaturated, and 13% polyunsaturated fat).
  • In short, this diet was radically different from the typical American diet.

The authors concluded: “Adults who are overweight or obese can consume 2.5 ounces/day as lean and unprocessed beef and pork when adopting a Mediterranean Pattern to improve cardiometabolic disease [heart disease and diabetes] risk factors.”

The authors went on to say: “Our results support previous observational and experimental evidence which shows that unprocessed and/or lean red meat consumption does not increase the risk of developing cardiovascular [heart] disease…”

As discussed below, the second conclusion is not supported by the data. We need to remember that this study was funded by money from the beef industry.

What Does This Mean For You?

red meat heart health lean meatsThe beef industry and low carb enthusiasts are telling you that red meat consumption as part of a healthy diet is good for your heart. These claims are very misleading. That’s because most Americans assume that their diet is already healthy. In addition, some Americans are being misled into believing that low carb diets are healthy (As I document in my book, “Slaying The Food Myths” those claims are currently unproven). Finally, many Americans interpret these claims as telling them that the juicy steaks, burgers, and sausages they love are heart healthy. The reality is far different.

  • The studies the claims are based on looked at red meat consumption in the context of the heart healthy DASH and Mediterranean diets, not in the context of the typical American diet or low carb diets.
  • The only risk factors affected in most of the studies are total and LDL cholesterol, which have low reliability of predicting heart disease risk by themselves. Furthermore, they appear to have almost no effect on the heart healthy benefits of the Mediterranean diet. In addition, the studies have been too short (typically 5 weeks) to reliably assess the effect of red meat on other heart disease risk factors.
  • The effect of red meat on heart disease risk factors has been assessed in carefully controlled diets that feature:
    • Small amounts of very lean (<10% fat, <6% saturated fat), unprocessed red meat in place of very lean poultry with about 50% of the protein in the diet coming from plant sources.
    • Lots of fruits, vegetables, whole grains, nuts, seeds, legumes, omega-3-rich seafood, and vegetable oils.
    • Almost no sugar and refined carbs.
    • A very healthy fat profile (7% saturated, 20% monounsaturated, and 13% polyunsaturated fat).

The authors of one recent review accurately concluded: “It is likely that consumption of animal products (excluding processed meats) at recommended amounts in the context of a dietary pattern that meets recommendations for fruits, vegetables, whole grains, nuts, seeds, and legumes, and does not exceed recommendations for added sugar, sodium, and saturated fat, may not adversely affect, and may benefit cardiometabolic risk [risk of heart disease and diabetes]”.

How you extrapolate from that kind of conclusion to an unqualified claim that “Observational and experimental evidence shows that unprocessed and/or lean red meat consumption does not increase the risk of developing cardiovascular [heart] disease” is beyond me.

My summary would be: “Small amounts of lean, unprocessed meat do not appear to increase the risk of heart disease or diabetes when consumed as part of an extremely healthy plant-based diet. However, the American diet is lousy. Low carb diets leave out too many healthy foods. We should focus on eating a healthy diet [as defined above] rather than arguing about whether it should be low carb, low fat, completely plant-based or can include small amounts of lean, unprocessed meat.”

 

The Bottom Line

 

The beef industry and low carb enthusiasts are telling you that red meat consumption as part of a healthy diet is good for your heart. These claims are very misleading. That’s because most Americans assume that their diet is already healthy. In addition, some Americans are being misled into believing that low carb diets are healthy (As I document in my book, “Slaying The Food Myths” those claims are currently unproven). Finally, many Americans interpret these claims as telling them that the juicy steaks, burgers, and sausages they love are heart healthy. The reality is far different.

  • The studies the claims are based on looked at red meat consumption in the context of the heart healthy DASH and Mediterranean diets, not in the context of the typical American diet or low carb diets.
  • The only risk factors affected in most of the studies are total and LDL cholesterol, which have low reliability of predicting heart disease risk by themselves. In addition, they appear to have almost no effect on the heart healthy benefits of the Mediterranean diet. The studies have been too short (typically 5 weeks) to reliably assess the effect of red meat on other heart disease risk factors.
  • The effect of red meat on heart disease risk has been assessed in carefully controlled diets that feature:
    • Small amounts of very lean (<10% fat, <6% saturated fat), unprocessed red meat in place of very lean poultry with about 50% of the protein in the diet coming from plant sources.
    • Lots of fruits, vegetables, whole grains, nuts, seeds, legumes, omega-3-rich seafood, and vegetable oils.
    • Almost no sugar and refined carbs.
    • A very healthy fat profile (7% saturated, 20% monounsaturated, and 13% polyunsaturated fat).

The authors of one recent review accurately concluded: “It is likely that consumption of animal products (excluding processed meats) at recommended amounts in the context of a dietary pattern that meets recommendations for fruits, vegetables, whole grains, nuts, seeds, and legumes, and does not exceed recommendations for added sugar, sodium, and saturated fat, may not adversely affect, and may benefit cardiometabolic risk [risk of heart disease and diabetes].”

How you extrapolate from that kind of conclusion to an unqualified claim that “Observational and experimental evidence shows that unprocessed and/or lean red meat consumption does not increase the risk of developing cardiovascular [heart] disease” is beyond me.

My summary would be: “Small amounts of lean, unprocessed meat do not appear to increase the risk of heart disease or diabetes when consumed as part of an extremely healthy plant-based diet. However, the American diet is lousy. Low carb diets leave out too many healthy foods. We should focus on eating a healthy diet [as defined above] rather than arguing about whether it should be low carb, low fat, completely plant-based or can include small amounts of lean, unprocessed meat.”

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.

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Comments (1)

  • Nancy

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    Oh boy – this is very interesting information. I appreciate your opinions and hope you will continue to share with us.

    Reply

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Latest Article

Best Diet For Heart Disease Prevention

Posted July 9, 2019 by Dr. Steve Chaney

Are The American Heart Association’s Recommendations Correct?

Author: Dr. Stephen Chaney

 

What is the best diet for heart disease prevention? 

diet for heart disease preventionHeart disease is a killer. It continues to be the leading cause of death – both worldwide and in industrialized countries like the United States and the European Union. When we look at heart disease trends, it is a good news – bad news situation.

  • The good news is that heart disease deaths are continuing to decline in adults over 70.
  • The decline among senior citizens is attributed to improved treatment of heart disease and more seniors following heart-healthy diets.
  • The bad news is that heart disease deaths are starting to increase in younger adults, something I reported in an earlier issue, Heart Attacks Increasing in Young Women of “Health Tips From the Professor.”
  • The reason for the rise in heart disease deaths in young people is less clear. However, the obesity epidemic, junk and convenience foods, and the popularity of fad diets all likely play a role.

Everyone has a magic diet for reducing heart disease risk. The American Heart Association tells us to avoid fats, especially saturated fats. Vegans tell us to avoid animal protein. Paleo and keto enthusiasts tell us carbs are the problem. Who is correct?

Of course, we don’t eat fats, carbohydrates, or proteins. We eat foods. That is why a recent study (T Meier et al, European Journal of Epidemiology, 34: 37-45, 2019) is so important. It reported which foods increase and which decrease the risk of premature heart disease deaths.

How Was The Study Done?

diet for heart disease prevention studyThe authors of the current study analyzed data from the “Global Burden of Diseases (GBD) Study”, a major world-wide effort designed to estimate the portions of deaths caused by various risk factors.

The current study focused on the impact of 12 dietary risk factors on heart disease deaths between 1990 and 2016 for 51 countries in four regions (Western Europe, Central Europe, Eastern Europe, and Central Asia).

The dietary risk factors were:

  • Diets low in fiber, fruits, vegetables, legumes, nuts and seeds, polyunsaturated fatty acids, omega-3 fatty acids, and whole grains.
  • Diets high in sodium, processed meats, sugar-sweetened beverages, and trans fatty acids.

Saturated fat and meat were not explicitly included in the GBS Study data. However, diets low in polyunsaturated fats and omega-3 fats are likely high in saturated fats. Similarly, diets low in fruits, vegetables, whole grains, and legumes are likely higher in meats. The study also did not include dairy, and some recent studies suggest that some dairy foods may decrease heart disease risk.

For simplicity I will only consider the findings from Western Europe because their diet and heart disease death trends are similar to those in the United States.

 

Best Diet for Heart Disease Prevention?

plant-based diet bestThe study found that in 2016 (the last year for which data were available):

  • Dietary risk factors were responsible for 49.2% of heart disease deaths.
  • 6% of all diet-related heart disease deaths occurred in adults younger than 70, and that percentage has been increasing in recent years.

When they looked at the contribution of individual foods to diet related heart disease deaths, the percentages were:

  • Diets low in whole grains = 20.4%
  • Diets low in nuts and seeds = 16.2%
  • Diets low in fruits = 12.5%
  • Diets high in sodium = 12.0%
  • Diets low in omega-3s = 10.8%
  • strong heartDiets low in vegetables = 9.0%
  • Diets low in legumes = 7.0%
  • Diets low in fiber = 5.7%
  • Diets low in polyunsaturated fats = 3.7%
  • Diets high in processed meats = 1.6%
  • Diets high in trans fatty acids = 0.8%
  • Diets high in sugar-sweetened beverages = 0.1%

So, what is the best diet for heart disease prevention?

In short, this study concluded:

  • A primarily plant-based diet is the best protection against premature death due to heart disease.
  • All plant-based food groups (whole grains, nuts and seeds, fruits, vegetables, and legumes) play an important role in reducing heart disease deaths.
  • Meat was not included in the analysis, but it is likely that most people’s diets in this region of the world contained some meat. The most likely take-away is that meat does not affect heart disease risk in the context of a primarily plant-based diet.
  • Dairy was not included in the analysis either, but some studies suggest dairy, particularly fermented dairy foods, reduce heart disease risk.
  • Finally, the study concluded: “Compared to other…modifiable risk factors (physical inactivity, drug and alcohol abuse, tobacco smoking, obesity, etc.), an altered diet is the most effective means of preventing premature deaths from cardiovascular disease in Western Europe.”

While every study has its weaknesses, this study is consistent with multiple previous studies showing that primarily plant-based diets are best for reducing heart disease risk. You will find a more complete discussion of these studies in my book “Slaying The Food Myths.”

 

Are the American Heart Association’s Recommendations Correct?

With this study’s results in mind we can now ask whether the recommendations of the American Heart Association and other popular diets are correct. Are they likely to reduce heart disease deaths?

  • The American Heart Association Recommends a dietary pattern that emphasizes a variety of fruits and vegetables, whole grains, nuts and legumes, skinless poultry and fish, and low-fat dairy products. This study supports those recommendations.
  • This study also supports the heart-health benefits of the Mediterranean and DASH diets.
  • Meat and dairy were not explicitly considered in this study. Thus, the results of this study are also consistent with vegan and semi-vegetarian diets.
  • However, low carb diets like Paleo and keto eliminate some of the key food groups (whole grains, fruits, and legumes) that appear to be essential for reducing heart disease risk. 40% of the heart-health benefits in this study came from those 3 food groups. Thus, this study does not support claims that those two diets are heart-healthy long term.

 

The Bottom Line

 

Everyone has a magic diet for reducing heart disease risk. The American Heart Association tells us to avoid fats, especially saturated fats. Vegans tell us to avoid animal protein. Paleo and keto enthusiasts tell us carbs are the problem. Who is correct?

A recent study provides some important clues. It looked at dietary patterns associated with reduced risk of premature death from heart disease in Western Europe. The study concluded:

  • A primarily plant-based diet is the best protection against premature death due to heart disease.
  • All plant-based food groups (whole grains, nuts and seeds, fruits, vegetables, and legumes) play an important role in reducing heart disease deaths.
  • Meat did not appear to affect heart disease risk in the context of a primarily plant-based diet.
  • Dairy was not included in the analysis, but some studies suggest dairy, particularly fermented dairy foods, reduce heart disease risk.
  • Finally, the study concluded: “Compared to other…modifiable risk factors (physical inactivity, drug and alcohol abuse, tobacco smoking, obesity, etc.), an altered diet is the most effective means of preventing premature deaths from cardiovascular disease.”

While every study has its weaknesses, this study is consistent with multiple previous studies showing that primarily plant-based diets are best for reducing heart disease risk. You will find a more complete discussion of these studies in my book “Slaying The Food Myths.”

With this study’s results in mind we can now ask whether the recommendations of the American Heart Association and other popular diets are correct. Are they likely to reduce heart disease deaths?

  • The American Heart Association Recommends a dietary pattern that emphasizes a variety of fruits and vegetables, whole grains, nuts and legumes, skinless poultry and fish, and low-fat dairy products. This study supports those recommendations.
  • This study also supports the heart-health benefits of the Mediterranean and DASH diets.
  • Meat and dairy were not explicitly considered in this study. Thus, the results of this study are also consistent with vegan and semi-vegetarian diets.
  • However, low carb diets like Paleo and keto eliminate some of the key food groups (whole grains, fruits, and legumes) that appear to be essential for reducing heart disease risk. 40% of the heart-health benefits in this study came from those 3 food groups. Thus, this study does not support claims that those two diets are heart-healthy long term.

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.

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