That was the question of a large study conducted by Harvard University. They looked at the eating habits of over 200,000 people for up to 30 years. In particular, they measured the intake of fat from dairy foods and then looked to see who got heart disease or suffered a stroke. When they divided dairy fat intake into quintiles they found no increase in cardiovascular disease (CVD) from a low intake of dairy fat (Q1, 3% of calories) to a high intake (Q5, 9% of calories).
However, as they looked at replacing dairy fat with plant fats, they saw a marked decrease in risk. They compared the risk of CVD when 5% of the calories from dairy fat were replaced with other fats. Here is what they found:
- Vegetable fats, when replacing dairy fat, reduced the risk of CVD by 10%
- n-6 polyunsaturated fat reduced risk by 25%
- Other animal fats (meats) raised CVD risk by 6%
- n-3 alpha-linoleic fatty acid (ALA) reduced risk
by 14% (replacing only 0.3% of calories)
- n-3 EPA and DHA reduced risk by 11%
When they replaced 5% of calories of dairy fat with refined carbohydrates (refined grains and cereals, and sugars) they saw no decrease in risk – it stayed the same. However, when they replaced 5% of calories from dairy fat with whole grains, the risk of CVD dropped by 28%.
Thus, dairy fat is healthier than fat from meats, but less healthy than plant fats, and no healthier than an equal intake of calories from added sugar and refined grains. Whole grains, however, reduced risk significantly when replacing dairy fat.
The authors concluded, “These results support current recommendations to replace animal fats, including dairy fat, with vegetable sources of fats and polyunsaturated fat (both n-6 and n-3) in the prevention of cardiovascular disease.”
Examples of healthier choices than high fat dairy would be soy milk which is high in polys and n-3 fatty acid (ALA), soy yogurt, tofu, nuts, whole grains, and vegetable fats high in polyunsaturated fats. To use low fat dairy but include refined grains and foods high in added sugar, a common practice today, didn’t show any health benefit.
Reference: American Journal of Clinical Nutrition 2016;104:1209-1217
Written by Don Hall, DrPH, CHES, Dec. 8, 2016