Whole-Fat Dairy Foods: Exploring the Evolving Science
Health professionals practice evidence-based medicine, but nutrition is an evolving science. Just after an edition of the Dietary Guidelines for Americans (DGA) is released, the Advisory Committee begins the process of re-evaluation. This shows that we can’t account for all we’re learning about nutrition and health. It can be frustrating to wait on recommendations to catch up with the latest science.
Before the release of the 2015-2020 DGA, we were talking about whole-fat dairy foods and cardiovascular disease (CVD). Today, we’re still talking about their place in a healthy diet and hoping the upcoming editions of the DGA consider all the new and emerging research on milk fat.
Why all this focus on whole fat? Because we’re finding it may be possible to be a little more flexible.
Shifting Fat Focus
For 30 years, the DGA have recommended limiting saturated fat intake, due to its associations with heart disease and stroke risk, related to the original diet-heart hypothesis and the idea that saturated fat increases LDL cholesterol. The 2015-2020 DGA recommend less than 10 percent of daily calories from saturated fat for a healthy eating pattern. The American Heart Association (AHA) agrees, currently recommending a reduction in saturated fat to 5-6 percent of daily calories for individuals with elevated LDL cholesterol.
These recommendations could change. Observational evidence over the last 10 years indicates that saturated fat may not be directly associated with CVD risk. The story is much more complex than that: With dairy, it isn’t solely about fat content. Dairy foods play a beneficial role in cardiovascular and metabolic health, recognized by the Dietary Guidelines Advisory Committees in both 2010 and 2015 – much of that due to calcium, magnesium and potassium acting together to lower blood pressure.
Calcium from dairy has additional benefits: A recent study found that higher calcium intake obtained from food, not from dietary supplements, was associated with decreased risk of atherosclerosis and coronary artery calcification (CAC).
Other highlights from recent studies:
- A systematic review found that eating dairy foods had favorable or neutral associations with cardiovascular-related clinical outcomes.
- A meta-analysis found that eating dairy foods may be associated with reduced risks of CVD, though additional research was recommended to fully understand potential dose-response patterns.
- Another meta-analysis found that eating dairy foods was significantly and inversely associated with the risks of CVD and stroke. Dairy foods had this effect regardless of fat content.
- When whole-fat dairy foods were incorporated into the popular DASH diet, participants maintained the cardiovascular benefits.
- A small randomized crossover study found that drinking about 2 cups of whole milk for three weeks as part of participants’ habitual diets did not negatively impact markers of CVD or Type 2 diabetes, as compared to drinking fat-free milk.
Dairy Fat Is Unique
As more research comes out about dairy and cardiovascular health, it’s natural to question how dairy fats differ from other saturated fats, and what other evidence could begin to help explain some of these research findings. Dairy fat is unique and complex, containing over 400 different types of fatty acids.
- Among the saturated fatty acids, dairy fat contains short-, medium- and long-chain fatty acids from four to 18 carbons in length.
- All these fats have different biological effects that contribute to the complexity of our favorite dairy foods.
- Dairy foods also contain additional components – such as protein, vitamins, minerals and bioactive compounds – that may modulate the effects of dairy fat on CVD biomarkers and risk.
Additionally, much of the emerging scientific evidence points to the need to examine disease endpoints – not just saturated fat intake as it relates to LDL cholesterol – indicating that this biomarker may not always be the best predictor of CVD risk.
The tide may be changing when it comes to our recommendations for whole-fat dairy foods, specifically as part of a balanced diet. For now, it may be time to just embrace the flavor, texture and deliciousness that dairy brings. We eat to live, but we should also enjoy what we choose to eat. I’ll raise my glass of whole-fat milk to all the great taste and great nutrition dairy provides all of us.