From The Desk Of Clarence Bass
“People who had the most dairy fat in their diet had about 50 percent lower risk of diabetes…Our research indicates that the national policy should be neutral about dairy fat, until we learn more.” Dariush Mozaffarian, MD, DrPH, Dean, Friedman School of Nutrition Science and Policy, Tufts University, Boston, NPR Morning Edition, April 18, 2016
“These results suggest that dairy fat is not an optimal type of fat in our diet [and] strongly support existing recommendations to choose mainly unsaturated fats from vegetable oils, nuts, seeds, avocados, and some oily fish for a heart-healthy diet.” Dr. Frank B. Hu, Harvard T. H. Chan School of Public Health, Nutrition Source, October 25, 2016
Milk in the Middle
Some foods are clearly beneficial, some are clearly harmful—and others are in the middle, good in some ways and not so good in others. Based on current research, whole Milk (along with eggs and poultry) is at the bottom of the beneficial group—roughly in the middle of the Benefit-Harm continuum.
Tufts Professor Dariush Mozaffarian, MD, DrPH, is perhaps the most articulate spokesperson for an evidence-based focus on food quality and overall diet patterns, rather than deficiencies and single isolated nutrients. Professor Richard Winett, PhD, whose 45-year career has been devoted to the study of health behavior, wrote recently that he has not seen anything to match Dr. Mozaffarian’s “Authoritative Review: Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity.” Circulation, 2016; 133: 187-225. “This review with its integration of 405 references is by far the most sophisticated review I have ever read and studied,” Winett wrote. Master Trainer, August, 2016
Mozaffarian’s image of the continuum of foods from “Benefit” to “Harm” does a superb job of capturing what we now know about healthy eating. It should be posted on refrigerators across America.
The following is Mozaffarian’s summary assessment of milk, cheese, and yogurt:
In sum, dairy products represent a diverse class of foods, with complex effects that vary by specific product type and with emerging mechanistic pathways that appear to include influences of fermentation and probiotics. No long-term studies support harms, and emerging evidence suggests some potential benefits, of dairy fat or high-fat dairy foods such as cheese. Together these findings provide little support for the prevailing recommendations for dairy intake that are based largely on calcium and vitamin D contents, rather than complete cardiometabolic effects; that emphasize low-fat dairy based on theorized influences on obesity and CHD, rather than empirical evidence; or that consider dairy as a single category, rather than separately evaluating different dairy foods. The current science supports consuming more yogurt and possibly cheese; with the choice between low-fat versus whole-fat being personal preference, pending further investigation. This new evidence also calls for substantial further investment in research on cardiometabolic effects of dairy foods, including relevant components and molecular mechanisms.
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Tufts University and Harvard seem to be at the heart of the evolving view of dairy products.
Most Harvard researchers are apparently okay with the current Dietary Guidelines for Americans, which limit saturated fat intake to 10 percent, and recommend low-fat dairy products. Tufts Professor Dariush Mozaffarian, on the other hand, is uncomfortable with the restrictions. "I am conservative about setting national dietary guidelines. While evidence remains insufficient to definitively recommend only whole-fat dairy, it certainly is robust enough not to recommend only low-fat dairy," Mozaffarian told CBS News.
Let’s look at two studies reported after Mozaffarian’s comprehensive review which help to sort out the complex nature of dairy foods. One looks at the impact of dairy products on diabetes risk and the other focuses on heart health.
Dr. Mozaffarian is the senior author of the first study, but is not involved in the other study. Harvard Professor Frank B. Hu is involved in both studies, as a co-author of the first study and senior researcher in the second study. Well-known Harvard Professor Walter Willett is also a co-author of both studies.
Diary Fat Associated with Lower Diabetes Risk
A comprehensive review of two studies that followed 3,333 adults for over two decades showed that those with the most diary fat biomarkers in their blood had a 46 percent lower risk of diabetes compared to those with the least. The study, led by Mohammad Y. Yakoob, was published March 22, 2016, in the journal Circulation.
The study does not prove a cause and effect, but it builds on a body of evidence suggesting that dairy fat may have protective effects, both in cutting the risk of diabetes and in helping people control body weight.
For example, a study reported in the January, 2016, journal Nutrition found that full-fat dairy foods are infrequently associated with the components of metabolic syndrome (abdominal obesity, high blood pressure, low HDL cholesterol, high triglycerides, and high blood sugar) in middle-aged and older adults. The more full-fat dairy products people consume the less likely they are to have these problems. “Dietary recommendations to avoid full-fat dairy intake are not supported by our findings,” Drehmer et al concluded.
A strength of the Yakoob study was that it assessed circulating blood biomarkers rather than self-reported consumption of dairy products.
Interestingly, the researchers found no other studies that identified harms of whole-fat dairy for diabetics.
“Our findings highlight [the] need to better understand potential health effects of dairy fat,” the researchers concluded.
With all the new evidence that challenges the low-fat-is-best orthodoxy, Dr. Mozaffarian told NPR Morning Edition that it may be time to reconsider the National School Lunch Program rules, which allow only skim and low-fat milk.
"Our research indicates that the national policy should be neutral about dairy fat, until we learn more," says Mozaffarian.
Good—and Bad—News for Heart Health
Researchers from the Harvard T.H. Chan School of Public Health and Huazhong University, Wuhan, China followed more than 43,000 men and 177,000 women in three studies over several decades to assess the relationship between dairy fat and heart disease. Dairy fat and other fat intakes were assessed every four years with the use of food-frequency questionnaires. During the course of the study, 14,815 cases of fatal and nonfatal heart disease and stroke cases were documented.
The good news is that, compared to an equivalent amount of energy from carbohydrates (excluding fruit and vegetables), various foods including full-fat dairy milk, yogurt, butter, cheeses, and cream were not found to increase heart disease risk. However, it is important to note that these dairy foods were not found to decrease risk either. The risk was essentially neutral, not effecting CVD one way or the other.
Keep in mind that the low-fat dairy foods recommended by the current guidelines are often eaten with refined carbohydrates and sugars. It’s likely that full-fat dairy foods discourage consumption of refined carbohydrates and sugars—a good thing in anybody’s book.
What did predict risk of cardiovascular disease was fat trade offs. When dairy fat was replaced with the same amount of calories from vegetable fat or polyunsaturated fat, the risk of cardiovascular disease dropped by 10% and 24%, respectively. Furthermore, replacing the same amount of calories from dairy fat with healthful carbohydrates from whole grains was associated with a 28% lower risk of cardiovascular disease. (Again, it seems likely that full-fat dairy foods discourage consumption of unhealthy carbohydrates.)
Replacing dairy fat with other types of animal fat, such as from red meat, predicted a modest 6% higher risk of cardiovascular disease.
“The replacement of animal fats, including dairy fat, with vegetable sources of fats and PUFAs may reduce risk of CVD,” the researchers concluded. “Whether the food matrix may modify the effect of dairy fat on health outcomes warrants further investigation.”
Food matrix refers to surrounding substances independent of dairy fat content. “For example, the LDL-cholesterol-raising effect of dairy fat in cheese was less than that of butter at comparable intakes of total fat and saturated fat,” the researchers wrote in the “Discussion” portion of their report. “Regular consumption of yogurt was associated with lower risk of type 2 diabetes,” they added.
The study was published August 24, 2016, in The American Journal of Clinical Nutrition.
“These results suggest that dairy fat is not an optimal type of fat in our diets. Although one can enjoy moderate amounts of full-fat dairy such as cheese, a healthy diet pattern tends to be plant-based and low in saturated fat,” senior author Frank Hu told the Harvard Nutrition Source. “These results strongly support existing recommendations to choose mainly unsaturated fats from vegetable oils, nuts, seeds, avocados, and some oily fish for a heart-healthy diet.”
In terms of specific dairy products, Hu does not recommend regular consumption of full-fat milk or eating a lot of cheese, which is often paired with processed meats and refined flour in the form of hamburgers and pizza. Instead, small amounts of cheese can be consumed as a snack with fruits or whole-grain crackers. Among the range of dairy products, yogurt appears to have more health benefits. A cup of plain yogurt with nuts or fresh fruit for flavor and texture makes for a satisfying breakfast or healthy snack.
Clearly, a lot depends on one’s overall diet pattern and lifestyle.
Words of Wisdom
How things have changed. I grew up believing that fat intake should be limited in any way possible; that fat made you fat. My father used to counsel his patients not to eat any fat they could see; still probably pretty good advice.
Dr. Mozaffarian’s food chart shows how dietary fat now spans the spectrum from good to bad. Nuts and fish are at the very top and industrial trans fats are at the bottom. Vegetable oils and yogurt are near the top and processed meats are near the bottom. Cheese and milk are just over the midline and butter is just below.
Now, the task becomes integrating the new findings into everyday living. I found advice that rings true on Explore Everyday Health in a piece by T. Jared Bunch, MD, titled Diary, Diabetes, and Your Heart.
I’ll capsulize it here and you can look to the entire article for full details. (See the link below)
Dr. Bunch’s exemplar is his wife’s grandfather who passed away at 94, after spending his life on large ranch he owned near Farmington, New Mexico, and Durango, Colorado. He served as a pilot in World War II, married a wonderful woman, and had seven children. His wife died in her late fifties of ovarian cancer, and he lived another 40 years alone as a widower. He worked hard his entire life and continued to farm and ranch into his nineties.
He lived his long and meaningful life on a diet rich in meat and dairy products.
“The first few years I knew him, I think my wife’s grandfather had whole milk and a steak for at least two of his daily meals,” Bunch writes. “You’d think that such a diet could be harmful, but he remained independent in his home, still working, until a stroke suddenly took his life.”
What does Dr. Bunch take away from this remarkable man’s example?
He tells patients that in moderation dairy fat is not likely to increase heart disease and may actually reduce the risk of diabetes—citing numerous studies which he details.
The key, he says, is moderation.
So as with all things in life, moderation is a good thing. Eat dairy, but don’t eat so much that you gain weight. Your diet still needs to be primarily comprised of whole foods such as fruits, nuts, vegetables, and heart-healthy oils like olive oil. That way, you’ll feel full and eat less high-calorie foods.
In closing, he comes back to his wife’s grandfather for a message rarely stressed.
Grandfather left a lasting lesson by his life example. He enjoyed his dairy products while also working hard his entire life. He awoke each day with a purpose. He remained slender and active into his nineties. Perhaps this…teaches us more about why he did so well for so long.
As promised, here’s the link to Dr. Bunch’s wisdom filled article: http://healthaverage.com/columns/jared-bunch-rhythm-of-life/daily-consumption-of-dairy-products-can-lower-risk-of-diabetes/index.htm
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I’m comfortable with my decision to switch from skim milk to organic whole milk and yogurt—in the context of a diet heavily weighted in plant foods, regular exercise, weight control, and purposeful living.
See also my article Rethinking Saturated Fats: http://www.cbass.com/rethinking_saturated_fats.htm
January 1, 2017
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