Milk & Heart Disease: What Scientifc Evidence Tells Us
Milk is an essential component of my delicious Indian masala chai I drink every morning. Milk enhances the flavor and provides important nutrients such as calcium and vitamin D. Knowing how well milk pairs with various foods and beverages, I was surprised to learn that milk consumption has been steadily declining from 28.6 gallons per person per year in 1975 to 20.9 gallons per person per year in 2010.
In fact, many people do not get the recommended three daily servings of milk and dairy products. Some even choose this eating pattern on purpose because they falsely believe that dairy foods are not good for them. Thus, I wanted to examine milk consumption and its impact on cardiovascular disease (CVD) since it is a major public health concern.
As you may know, about 735,000 Americans have a heart attack annually and about 610,000 people die from heart disease every year, according to the Centers for Disease Control and Prevention (CDC). Given these overwhelming statistics and that diet is one factor associated with heart disease, as health and wellness professionals, we need to address how different foods may impact CVD.
Science Behind Milk and Heart Disease
Several studies have examined the effect of the dairy food group as whole (cheese, yogurt, and milk grouped together) on CVD in adults with the overall results indicating that consumption of these dairy foods is associated with reduced risk of CVD. While these results are promising, the impact of milk cannot be isolated because it was not examined separately. A limited number of studies designed to only focus on milk exist:
- A 2004 observational study of 2,403 adult men from South Wales concluded there was no evidence that higher milk consumption (more than 1 pint/day) increased the risk of ischemic heart disease, compared to those who consumed no milk.
- A meta-analysis providing evidence from 10 observational studies concluded that milk consumption at the highest levels was associated with a small reduction in heart disease and that these studies provide no convincing evidence that milk is harmful to cardiovascular health.
It is important to note that observational studies show an association, not causation; therefore, they are a starting point for nutrition research. In order to provide more evidence for future recommendations, we need to look at multiple, replicable intervention studies, like this one:
- A small randomized intervention trial in 14 healthy people in Japan indicated that those who drank 500 mL of fat-free milk daily for two weeks had reduced cholesterol levels, while those who drank whole milk showed no significant difference.
As an aspiring Registered Dietitian Nutritionist, I feel that I can now better educate my future patients about the health benefits of milk. In fact, the 2010 Dietary Guidelines Advisory Committee (DGAC) pointed out that moderate evidence indicates that consumption of milk and milk products is associated with reduced risk of CVD in adults. Based on the current scientific evidence, milk may not have adverse effects on CVD and due to milk’s diverse and rich nutrient content, people can fulfill their three daily-recommended servings of dairy by incorporating milk as part of a nutritious eating plan.
After evaluating the literature on milk, it is critical to note that the body of evidence in this area needs further exploring, including large-scale randomized controlled trials in both healthy individuals and those with CVD. Do you work with people on a regular basis who are concerned about their heart health? Do you have any advice for those of us who don’t? I’d love to hear your thoughts!