What Does Research Say About the Health of Eating Meat?

Meat and Vegetables

We are badly in need of a study that compares good vegetarian to good meat-containing diets using quality foods, with high vegetable content and good quality fats in both diets. Too often vegetarians are compared to a standard American population, health-conscious vegans are compared to non-health conscious omnivores and studies on omnivores with low meat diets are extrapolated to suggest that a diet with no animal food altogether may be superior. The study should isolate the effects of gluten from other starchy foods and meats from fish.There was a study in the 1970s that supposed a loss of bone (measured by urinary calcium excretion) with a diet high in meat.  The study lasted two weeks and subsequent studies showed that no loss occurred after two weeks, so that the effect might be transitional.  But urinary calcium excretion may not come at the cost of bone.  Additional studies by Kerstetter and Insogna demonstrated that there is higher absorption in the intestine and net calcium increases with high protein in the elderly. Kerstetter also demonstrated using tracers that the calcium in the urine from bone goes -down- while calcium from absorption goes up.

In fact other studies indicate that the phytates in legumes, traditionally consumed by vegetarians or vegans can lock up minerals necessary for bones.   Fermentation, and to a lesser extent, cooking can reduce the anti-nutrient effect of legumes, and isoflavones in the beans may help counteract the phytic acid.

Grain based vegetarian diets contribute to hyperinsulinemia (high blood insulin) which causes the excretion of magnesium and calcium in the urine and can increase osteoporosis.  This applies to omnivores who have high carbohydrate content as well.  Fat taken with carbohydrates helps minimize the effects of insulin spikes, and meat eaters do tend to have more dietary fat.  So while some vegetarians may be at risk from low fat/high grain diets it is not exclusive to vegetarians

This seems contradicted by the results of a 1972 study that matched 25 lacto-ovo vegetarians with omnivores of the same age and gender showed lower bone density in the omnivores.  However:

  1. Finger bone density determinations through absorptiometry or X-ray are highly subject to error
  2. The study was not double blind, increasing the subjectivity of measurement
  3. While the subjects were matched for age and gender, they were not matched for body composition, smoking, sugar, coffee and alcohol consumption or for health consciousness
  4. British lacto-ovo vegetarians tend to have high dairy calcium and to have good health habits
  5. The sample size was quite small

A 1974 study found that Inuit had lower bone density than similar Caucasians and attributed it to their meat rich diet.  However Weston Price had earlier found people such as the Massai and the Inuit who subsist primarily on meat to have healthier teeth and dental arches than groups subsisting primarily on vegetable foods.  And skeletal studies of pre-Columbian Native Americans found height, bone density and dental health higher in people with traditionally high meat diets.  Diets had changed by 1974, so the issue might well have been the introduction of sugars and other modern foods.

In 1986 Dr. Herta Spencer noted that the major animal and human studies that correlated calcium loss with high protein diets used isolated, fractionated amino acids from milk or eggs which lacked fat soluble vitamins and also have crosslinked dehydrated proteins.

  1. Vitamin D, which was missing, is necessary to assimilate calcium in bones
  2. Oil soluble vitamins A, D, K and E are also important to bone formation
  3. Her  1983 studies had shown that when protein is given as meat, subjects do not show any increase in calcium excreted, or any significant change in serum calcium, even over a long period.

A low carbohydrate diet is often conflated with a high meat diet, although one can be a low carbohydrate vegetarian. A grain-based diet is often conflated with a vegetarian diet although vegetarians can have a tuber and root based diet.

Vegetables are good for everyone

A recent study in the New England Journal of Medicine compared diets with different amounts of fats, protein or carbohydrates and concluded that none was different in weight loss over 2 years. This has been used to target Atkins-type carnivorous diets since it is easier to have a low carbohydrate diet with meats. However closer attention to the data showed:

  1. There was no low carbohydrate diet. The purported low carb diet had 135 grams of carbohydrates, more than twice the amount usually recommended for low carbohydrate, high protein diets.
  2. Nevertheless, the lowest carbohydrate diet showed superior blood lipids despite higher fats and probably more animal fats
  3. The quality of the foods was not regulated- there were breads, industrially processed meat which has different fat profiles, low nutrient density foods. Only macronutrients differed.
  4. While people with the higher fat tended to eat more meat, there were no strictly vegetarian controls. Thus the study tells us nothing about the value of a vegetarian diet versus an omnivorous diet.

What of diets that were more explicitly testing vegetarians against omnivores? A 1994 study in the British Medical Journal purported to show that vegetarians had 40% less cancer, heart disease and lower mortality however:

  1. Vegetarians were drawn from the Vegetarian Society and society members chose the meat eaters, so selection was not random
  2. More of those in the vegetarian group were females, who live longer
  3. More of the omnivores were male, and in the age range where heart disease is more prevalent
  4. The average age of the vegetarian group was younger
  5. The diets were quite different, aside from absence of meat so the information would not show benefits from the absence of meat
Seventh Day Adventist Cooking Class

A famous 1984 study of Seventh Day Adventists, who do not eat meat, showed that they had lower cancer and heart disease rates than the population at large.

  1. The population at large included people not interested in health, with poor exercise habits, junk food, little spiritual focus and loose social cohesion. The Seventh Day Adventist group did not.
  2. The authors of the study concluded that the results did not justify vegetarianism saying ‘ We hope that no-one will take data from this report and use it to say “Food A lowers or food B raises mortality risk”.’
  3. Mormons in Utah who eat considerable quantities of meat have similar low mortality, cancer and heart attack rates. Both groups are close knit, interested in health, and have a strong spiritual bent.

A study by Neal Bernard, involving 99 people with Type 2 diabetes found that they did three times better in controlling blood sugar on a low fat vegan diet than the American Diabetes Diet which includes meat.

  1. The American Diabetes diet has high levels of carbohydrates, around 135 grams, and too low levels of vegetables
  2. The vegan diet was essentially lowfat Atkins without meat and dairy. It allowed a half cup of grain a day and depended on low glycemic vegetables and fruit. This was fewer carbohydrates than the ADA diet.
  3. The conclusion of the study says: “Both diets were associated with sustained reductions in weight and plasma lipid concentrations. In an analysis controlling for medication changes, a low-fat vegan diet appeared to improve glycemia and plasma lipids more than did conventional diabetes diet recommendations. Whether the observed differences provide clinical benefit for the macro- or microvascular complications of diabetes remains to be established.”
Soy

The China Study purported to show that vegetarians were healthier but totally misrepresented the data.  See Denise Minger’s articles, cited below where she ran the raw data (available online) and removed confounding variables, getting significantly different information.

  1. Sugar, soluble carbohydrates, and fiber all had correlations with cancer mortality about seven times the magnitude of that with animal protein
  2. Both total fat and fat as a percentage of calories were both negatively correlated with cancer mortality
  3. Meat eaters in China tend to be better off and may be more urban than those with low amounts of animal foods.  They are known to also eat more sugar and wheat which may be independent factors rather than the meat.
  4. Fish eating provinces in China have high rates of contamination with hepatitis B and shistosomiasis which are independent variables for cancer and do not necessarily apply to uncontaminated sources.
  5. The same data also shows living in a hot climate is highly correlated with low cancer. This exceeds the effect of animal protein by over 700% and may be correlated with low Vitamin D status
  6. When the data didn’t show correlations between diet and actual disease, Campbell used proxy factors like cholesterol levels to assume that disease was affected.  This matters because for instance shistosomiasis raises cholesterol independently of diet.
  7. And of course, correlation is not causation.  Not even the regressions that Minger ran on the raw China Study data show causation, although they do filter out some confounding factors. The data raises questions that should be studied in clinical trials.  But it is imperative to fairly and accurately present the data, which is not done in Campbell’s book.

A study by Cho, et. al. showed that women in the Nurses Study who had the highest fat intake had the lowest cancer rates. This was purported to show that an Atkins-type diet was unhealthy, but the data differed significantly from the conclusions.

  1. Women who ate the most fat, the 5th quintile, had lower cancer rates than those who ate less fat (3rd and 4th quintiles.)
  2. Those with very low animal fat intake had the lowest cancer rates.
  3. The cancer rates in all quintiles was less than 1%, with rates between 0.68%-0.88% so differences are not really significant
  4. Similar studies do not differentiate saturated fat intake from vegetable sources which is more dangerous than from animal saturated fats which may have very different effects.

There have been a variety of ethnographic studies that try to look at vegetarian versus omnivorous diets. (There are no ethnographic studies of vegans since there are no vegan traditional diets.) These often are not of sufficient rigor to show such a comparison.  Epidemological studies don’t prove causation, but they may suggest associations that can later be tested.

Massai

The Kenyan Maasai and the Kikuyu, live in the same country, climate, and the environment. The Maasai, were wholly carnivorous, drinking only the blood and milk of their cattle, and were tall, slim, healthy and long-lived. The Kikuyu, were wholly vegetarian, with stunted growth, high rates of disease, more visceral fat and shorter lives. Since the 1960s the Kikuyu have increased animal protein and are healthier while the Massai have incorporated corn and beans and now have more disease according to a 1996 study.

A similar study of the Inuit showed that the Inuit of Baffin Island and Greenland who ate a diet primarily of fish and meat had better health than the omnivorous Inuit of Lapland. However the latter tribe was adopting a western diet with junk food so the study does not prove anything other than that modern western diets are less healthy than fish and meat diets.

Other comparisons such as the higher rate of diabetes in Indian vegetarians versus Chinese omnivores have too many variables to consider them as useful. There are similar studies comparing vegetarian South Indians to omnivorous people in the north of India, and while the latter have better health, they also have different environments, cultures and ethnicity.

While there is no conclusive data that eating meat is harmful, there is significant evidence that eating poor quality food does impact health.  The majority of studies that compare vegetarians to omnivores do not select omnivores with similar interests in healthy lifestyles.  A study that looks at exercise, variety of vegetable consumption, high quality food, and degree of knowledge about health might find very different results.  There is ample evidence that a paleloithic diet which is low in gluten and grains and high in vegetables and quality meats is healthy.  Comparing such a diet to a vegetarian diet might yield more meaningful results.

Sources below

Sources:

Insogna, K., Kerstetter, J. E., et al.  Optimizing bone health in older adults: the importance of dietary proteinAging health. 2010 Jun 1;6(3):345-357.

Kerstetter, J. E., et al.The effect of dietary protein on intestinal calcium absorption in rats.Endocrinology. 2010 Mar;151(3):1071-8. Epub 2010 Feb 10.

Viadel B, Barberá R, Farré R.Calcium, iron and zinc uptakes by Caco-2 cells from white beans and effect of cooking.Int J Food Sci Nutr. 2006 May-Jun;57(3-4):190-7.

Urbano, G. et. al. The role of phytic acid in legumes: antinutrient or beneficial function? J Physiol Biochem. 2000 Sep;56(3):283-94.

Sally Fallon and Mary Enig.  Dem Bones: Do High Protein Diets Cause Bone Loss? 1999

Frey R Ellis, et al, “Incidence of osteoporosis in vegetarians and omnivores” American Journal of Clinical Nutrition, June 1972, 25:555-558

Richard B Mazess and Warren Mather, “Bone mineral content of North Alaskan Eskimos” American Journal of Clinical Nutrition, September 1974 2:916-925

Nutrition and Physical Degeneration by Weston A. Price and Price-Pottenger Nutrition Foundation (Jan 31, 2008)

Susan J. Whiting, et. al.  “Dietary Protein, Phosphorus and Potassium Are Beneficial to Bone Mineral Density in Adult Men Consuming Adequate Dietary Calcium ”
Journal of the American College of Nutrition, Vol. 21, No. 5, 402-409 (2002).

Herta Spencer and Lois Kramer, “Factors contributing to osteoporosis”, Journal of Nutrition, 1986 116:316-319

Herta Spencer and Lois Kramer, “Further studies of the effect of a high protein diet as meat on calcium metabolism”, American Journal of Clinical Nutrition, June 1983 37 (6):924-929

Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates

Thorogood M., Mann J., Appleby P., McPherson K.. Risk of death from cancer and ischaemic heart disease in meat and non-meat eaters . Br Med J . 1994; 308: 1667-70.

Association between reported diet and all-cause mortality: 21-year follow-up on 27,530 7th Day Adventists . Am J Epidem 1984; 119 (5): 775.

Egold B., Laskar J., Wolf S., Putvin L.. The Roseto effect: a 50-year comparison of mortality rates. Am J Public Health 1992; 82: 1089-92

Mortality, Biochemistry, Diet and Lifestyle in Rural China: Geographic Study of the Characteristics of 69 Counties in Mainland China and 16 Areas in Taiwan by Junshi Chen, Richard Peto, Wen-Harn Pan, and Bo-Qui Liu (Mar 16, 2006)

The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss and Long-term Health by T. Colin Campbell, Thomas M. Campbell II, Howard Lyman, and John Robbins (Jun 1, 2006)

Eunyoung Cho, Donna Spiegelman, David J. Hunter, Wendy Y. Chen, Meir J. Stampfer, Graham A. Colditz, Walter C. Willett Premenopausal Fat Intake and Risk of Breast Cancer. J Natl Cancer Inst 2003;95:1079-85

Animal Fats Don’t Cause Breast Cancer.

Pauletto P, et al. Blood pressure and atherogenic lipoprotein profiles of fish-diet and vegetarian villagers in Tanzania: the Lugalawa Study. Lancet 1996; 348: 784-8.

McClellan W. S., Du Bois E. F.. Prolonged meat diets with a study of kidney function and ketosis. J Biol Chem 1930; 87: 651-668.

McCarrison, Sir Robert (with Sinclair, Dr. H. M.). Nutrition and Health . Faber & Faber, London, 1953

Minger, Denise.  The China Study:  Fact or Fallacy? See also her other 11 articles tagged “China Study”

See Also:

The China Study Misrepresents Data: Does Not Support a Vegan Diet

Vitamin D Prevents Cancer, Type 1 Diabetes, Cancer, Heart Attack and Pain

Is A Vegetarian Diet Healthier Than An Omnivorous Diet?

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3 thoughts on “What Does Research Say About the Health of Eating Meat?”

  1. To whom it may concern,
    Your article, although informative, is rife with many factual misrepresentations and conclusions that are supportive not of the scientific outcomes of an overwhelming majority of the studies done but of your own ideas and beliefs. Throughout your article you repeatedly highlight one study and try to use that to discard thousands of other studies that demonstrate a strong association/link between a diet rich in animal protein and a higher incidence of heart disease (number one killer in America) diabetes (the new epidemic) cancer and a myriad of other so called Western Diseases. Your advocacy against a mainly vegetarian diet is alarming to say the least. In your “article” above you state that Campbell misrepresented the facts from the study called Mortality, Biochemistry, Diet and Lifestyle. This is a striking statement as Campbell is one of the MAIN authors of this book. Under what authority can you make this type of opinion statement? Is this the official position of Junshi Chen? One other highlight, your example, on the study of pre-columbian indians having more bone density due to the fact that they consumed meat. Did you ever consider HOW indians had to get their meat? I can guarantee you that hunting for days on end, a reduced calorie intake, a consumption of raw vegetables and an overall higher physical lifestyle counteracted any of the detrimental effects of the leaching of calcium from the bones compensating for the increased acidity of the body.
    Your conclusions are dangerous, your method of deduction is sloppy at best and the fact that you purport yourself to be an authority in the medical field is alarming. The American population as a whole is uninformed and your biased opinions about the true nature of health and well being do not help those who are uninformed. In fact, they do the exact opposite. On a personal note, 6-months ago, I began limiting my animal protein to less than 15% of my total calorie intake. My B.P. was in the hypertension range and is now in the normal range. My cholesterol has dropped to below 160 from over 200 and I have lost 20 pounds. Perhaps, I can also encourage you to look at your dietary habits, as you know a high Body Mass Index is proven to contribute to a myriad of health problems.

  2. Eric,

    One of the truisms about scientific studies is that you need to look at the actual data and the groups compared instead of the executive summaries, which is what tends to be reported in the popular press. It unfortunately is not uncommon for data to contradict what is the purported conclusion. This is especially true where a researcher has an axe to grind, as Campbell, who has a long history of pushing a dangerous vegan diet,did.

    If you look at the data table I posted from the China Study (click through to the China Study article I wrote) you will realize that his correlations for meat and cancer were lower than his correlations for carbohydrates and cancer. So how does this vilify meat?

    And when he looked at people who were healthy eating a low meat diet, he drew the erroneous conclusion that a no meat diet was healthier. It is entirely possible to be well-nourished on a low meat or vegetarian diet with animal products other than meat. But aside from a vegan fast, which can be useful to balance years of excess, a vegan diet does not support long term health or reproduction. I see vegan or low-protein vegetarian infertility patients all the time who respond to adding meat in their diet.

    A vegan diet, which is not what you engaged in yourself, is deficient in DHA, B-12, butryic acid, vitamin D, and the ability to assimilate minerals that use animal fats in their absorption. You often see osteoporosis in young vegan women, even athletes, because their excessively low cholesterol (well below 150) is not there to make hormones (cholesterol is the building block of hormones). There are many vegan women who cease menstruating and cannot make sufficient hormones to carry a pregnancy.

    If you don’t compare equivalent groups, you don’t prove what your study sets out to. So the 1974 British study showed that high-dairy vegetarians had stronger bones than an undifferentiated group of non-vegetarians including those who lived on beer and junk food and sat on the couch watching television all day. Rather biases the result, don’t you think?

    The 1994 study compared younger vegetarian, mostly women to older omnivorous, mostly men, and was not randomly selected. So how does that tell you anything about whether it was the meat or the age and gender?

    The Seventh Day Adventist study compared to the Mormon study shows that a group interest in health in the context of strong community and spiritual practice produces health whether or not there is meat in the diet.

    We simply have no studies whatsoever that compare the results of health-conscious vegetarians with health-conscious omnivores, and if someone wants to design one they should have subgroups that are free of glutenous grains, unfermented soy and which look at the kinds of meats consumed.

    There is indeed no medical consensus that a diet without meat is superior, or that would form the nutritional policy of the nations or organizations that study nutrition. There is a consensus that eating a diet with a variety of healthy vegetables, nutritionally dense foods like blueberries, wild fish or yellow squashes, good fats and quality (non-industrially farmed) meats and eggs will support health. And exercise and other components of a healthy lifestyle also make a difference.

    I do believe, in accordance with the traditions of Chinese medicine and Ayurveda and recent research on bio-individuality, that one size does not fit all. Different constitutional types and different genders do better on different diets. It is not just the macronutrients- there are specific foods that make a difference. I don’t think D’Adamo’s blood type diet is quite there yet either- it probably isn’t all about blood and we don’t easily test tissues. Mercola’s metabolic type diet attempts to do it, but seems short on the prescriptive end. I have found a paleolithic diet has a balance that can be adapted for different people and which seems to exclude a number of problematic foods.

    On a personal note, after a disastrous “healthy” vegetarian diet which caused bloating and weight gain, I was advised by Annemarie Colbin that I would probably do better on fish and vegetables. I started limiting my carbohydrates to 60 grams a day, foreswearing grains and sugar altogether and lost 30 pounds. I did not restrict animal protein except to limit it to humanely-raised meat or wild game. My cholesterol was never high but it improved, and my triglycerides dropped over a hundred points. My blood sugar dropped 50 points on average (although patients with higher blood sugar, in the 300s, have dropped to a non-medicated 100 on this diet.) And while fat cells acquired during my pregnancies will never disappear (they can only shrink), it is clear to me that a low grain Paleolithic type diet will make my life healthier and can do the same for others.

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