Dairy, Diabetes, and Your Heart
Published Mar 29, 2016
My wife’s grandfather passed away two weeks ago. At 94, he’d lived an amazing life. He grew up in a family that owned large areas of land 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. His legacy is left through his family, and through the many people he touched with small acts of kindness. He was a loving man of few words, but when we spoke, the words he chose were always uplifting.
He lived his long, active life on a diet rich in meat and dairy products, which we’re often advised to avoid for heart health.
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. 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.
When I see patients in the clinic, one of the first things they mention when we discuss diet is that they intend to cut out all dairy products. Because nutritional guidelines often recommend a low-fat diet, most people believe this means they should consume less dairy fat.
But is this a good idea? Are milk, cheese, butter, and other dairy products really harmful to your health, and should you avoid them? Personal experience and new clinical research sheds light on this question.
The Facts on Dairy Products and Your Health
First, whole-fat or low-fat dairy products have not been associated with an increase in heart disease risk factors when they’re consumed in moderation, shows a study review published in October 2013 in PLOS One.
Second, dairy products have not been linked to an increased risk of coronary artery disease or death related to coronary artery disease or other heart conditions, as noted in a review published in January 2011 in The American Journal of Clinical Nutrition.
In addition, evidence suggests that, to the contrary, eating dairy comes with health benefits. For example, a relatively low-fat dairy product, yogurt, and a relatively high-fat dairy product, cheese, may both lower your risk of diabetes, a strong risk factor for heart disease.
One of the challenges in understanding these studies is that researchers depend on people reporting how much cheese, milk, yogurt, and other dairy products they eat. This can be very difficult to remember when you’re eating a variable diet. As a result, the findings of these studies may not be as accurate as we would like them to be. Also, what you think is a normal portion of food may be very different from what I think is normal.
I learned that lesson early while in residency training, when I asked a woman in her early nineties if she drank any alcohol.
She said, “Just a small amount to help me go to bed at night.”
That was what I reported to my supervising doctor. When he asked her the same question, he also asked how much was “just a small amount.”
She promptly told him she drank a pint of whiskey each night.
Dairy and Diabetes: The Surprising Link
When it comes to eating dairy fats, and determining how much is just right, we have helpful screening tests. When our bodies break up dairy fats, the fats form unique fatty acids called pentadecanoic acid, heptadecanoic acid, and trans-palmitoleic acid. We don’t naturally make these fatty acids — we only get them from our diet. If we truly want to understand the potential benefits or risks of dairy fats on our diet, the answer may be in measuring body levels of these fatty acids to see if they’re risk markers for disease.
In a study published in December 2014 in The American Journal of Clinical Nutrition, researchers from Tufts and Harvard universities in Boston looked to see if high levels of fatty acids from a diet rich in dairy products were associated with a risk of diabetes. Among the 3,499 male and female research participants, the average age was 65, about 50 percent were overweight or obese, 25 percent had high blood pressure, and 33 percent had high cholesterol. Their average daily dairy consumption was two servings, of which 45 percent was whole-fat, and 55 percent low-fat.
These people were carefully followed for an average of 15 years. The researchers separated the study group into four categories based on the amount of circulating fatty acids in their blood from dairy consumption, essentially separating them by their daily intake of dairy fats.
The research team found that in people with the highest dairy consumption, compared to those with the lowest, there was a significantly lower risk of diabetes: The risk was 44 to 52 percent lower depending on which fatty acid marker was studied. The researchers also found that those who ate more dairy products weighed similar amounts (measuring body mass index, or BMI) compared to those who ate less dairy.
How Fats Can Be Good for Your Heart
I’ve written columns previously that discussed the fact that fats themselves are not necessarily harmful to your health, as evidence shows:
- Fats from eating a daily avocado can significantly lower your bad cholesterol.
- Saturated fats, or fats that are saturated with hydrogen, are typically solid at room temperature and are found in meat and animal products like beef, lamb, butter, cheese, and high-fat dairy products. They’re also found in cocoa butter, palm oil, and coconut oil, though some research has shown that coconut oil offers heart health benefits.
- And fats from multiple types of nuts have very profound benefits in lowering high blood pressure, weight, cholesterol, diabetes risk, and heart disease risk and progression.
This newest study adds to the list of positive health effects of fats.
Dairy products and dairy fats are not inherently bad for most of us. The Tufts-Harvard study shows the opposite: that dairy products like cheese, yogurt, milk, butter, and my favorite, ice cream, may be healthy — and in fact can lower risk of diabetes.
But don’t go overboard. One finding in the study suggests caution, because some people may gain weight eating too much dairy. Height and weight were self-reported, so researchers don’t know the precise risk of weight gain, though they note that eating some dairy products, such as yogurt, has been associated with gaining less weight in other studies.
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.
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 latest study teaches us more about why he did so well for so long.