The idea that a link between diet and heart disease exists has been around for a while, but it was just after the seminal Seven Countries Studies of A.Keys that importance between fatty acid composition of the diet for cardiovascular disease was highlighted. One of the most important take-home messages of this study was that an increased intake of saturated fatty acids (SFA) was associated with an increased heart-disease risk.
Despite the important findings of this very large observational study and others, there are some discrepancies that make nutrition science difficult to critically appraise. Many of these studies have looked at the effect of single fatty acids and not the overall diet. And unfortunately, we don’t eat isolated nutrients, we eat FOODS.
Dairy is a clear example that we should move away from this perspective.
Theoretically, dairy, a food group high in SFA, increases the risk of cardiovascular disease.
Concretely, a large and robust body of evidence indicates that full-fat dairy isn’t linked with an increased risk of heart disease. Some types of dairy products are even associated with a decreased risk. (French paradox?!)
How can this be?
There are several potential reasons by which dairy intake may have this controversial effect.
Dairy products are a rich source of:
- minerals [such as calcium, potassium and magnesium]
- vitamin [both fat-soluble and water-soluble]
- protein [such as whey and casein]
Cheese contains many of these important nutrients in concentrated form. Milk from ruminant animals contains a large proportion of some beneficial fermented metabolites, called short chain fatty acids. Fermented dairy products (cheese, yoghurt, kefir) also contain several beneficial microorganisms, called probiotics.
Furthermore, there is evidence to suggest that the complex matrix of dairy foods as a whole rather than just individual components may be as important to improving heart health. Indeed, it is thought that fats in milk and other products are contained within a spherical structure known as the milk fat globule membrane. This can have an effect on the way these fats are absorbed and utilised. It can also explain why butter, that has less fats within this structure, doesn’t have the same beneficial effect.
Collectively all of these nutrient sources and characteristics may have a favourable effect on our heart health and highlight the idea that the link between food and health is not that straightforward if science gives us findings based on constituent nutrients, the evidence so far does not support current recommendations to choose lower fat dairy over full-fat dairy!