SAN FRANCISCO – Here’s potential bad news for everyone who dines on skim milk and non-fat yogurt:
The findings aren’t conclusive. Still, researchers found that “among whites and African- Americans, the whole milk/high-fat dairy pattern had a protective effect on the risk of metabolic syndrome,” said epidemiologist and study lead author Dale Hardy, PhD, of Morehouse School of Medicine, in an interview. She presented the study findings at the scientific sessions of the American Diabetes Association.
Hardy launched her research as part of a project that’s examining relationships between diet, genes, type 2 diabetes, and cardiovascular diseases in whites and African-Americans.
According to a 2017 study, an estimated 34% of adults in the U.S. from 2007-2012 had MetS, defined as the presence of at least 3 of these factors – elevated waist circumference, elevated triglycerides, reduced high-density lipoprotein cholesterol, high blood pressure, and elevated fasting blood glucose ().
MetS is linked to higher rates of a variety of ills, including cardiovascular disease, kidney disease, and early death.
For the new study, Dr. Hardy and colleagues examined data from the Atherosclerosis Risk in Communities study (1987-1998) and food questionnaires (1987 and 1993). There were 9,778 white participants and 2,922 African-American participants.
Subjects with diets higher in whole milk/high-fat dairy diets were significantly less likely to develop MetS per 5-unit increase at risk ratio (RR) =.96 (0.90-1.00), for whites and RR = .81 (0.72-0.90), for African-Americans.
But whites with skim milk/low-fat dairy diets had significantly higher risks of MetS per 5-unit increase at RR = 1.11 (1.06-1.17). There was also a higher risk for African-Americans but it was not statistically significant.
There was an even bigger bump in significant risk for those with diets higher in red and processed meat per 5-unit increase at RR = 1.17 (1.12-1.23), for whites and RR=1.16 (1.08-1.25), for African-Americans.
The researchers also found evidence that whole milk/high-fat dairy diets had an even greater protective effect in whites when genetic risk was present.
What’s going on? “Maybe the fat in the [dairy] foods is holding back glucose absorption and decreasing the risk for MetS over time,” Hardy said. “This fat is different from the animal fats from meats. Fat from dairy has a shorter molecular structure chain compared to the hard animal fats. Hard animal fats are more dangerous in terms of increasing the risk of type 2 diabetes and cardiovascular diseases.”
The dairy fat, Hardy said, could also be lowering insulin secretion.
So should everyone embrace whole milk and high-fat yogurt and cottage cheese? Hardy isn’t ready to offer this advice. “I don’t think that high-fat diary per se should be recommended as a miracle food to manage or prevent MetS,” she said. “I believe that the macronutrient composition of the meals and the day’s intake should be a more important feature of the diet. In addition, frequent exercise should be recommended to manage MetS.”
More analysis of the data is ongoing, Hardy said, and her team has found signs that diets higher in nuts and peanut butter are protective against MetS in whites.
The study was funded by the National Heart, Lung, and Blood Institute. The study authors had no relevant disclosures.
SOURCE: Hardy, D. et al. 2019 ADA annual meeting Abstract 1458-P.