Like many people who have a background in nutrition, I can remember some of the very first things I learned in my early nutrition courses. For example, in a lesson on micronutrients (i.e., vitamins and minerals), I learned there are two main types of vitamins: fat soluble and water soluble. The fat soluble vitamins are vitamins A, D, E and K, and not much has changed since then; vitamins A, D, E and K are still fat soluble. This is a chemical property that will not change.
What has evolved over time is our knowledge of nutrition, like our understanding of dietary fat. Back in our early nutrition courses, while I learned about the need for some fat in the diet for overall health, I also remember learning about the virtues of a low-fat diet, and that the best thing we could do for our health was to limit fat consumption. This, however, appears to be changing as we learn more and more about fat and various fatty acids. We now understand that fat likely is not as taboo as it has been made out to be in more recent years, even the saturated fat found in dairy foods.
This is part of what makes nutrition science so fascinating. Sometimes things we thought we knew change, and things we hypothesize sometimes prove to be wrong. But when this happens, new and exciting opportunities may arise.
This is exactly what happened in a study by nutrition scientists at The Ohio State University that was sponsored by National Dairy Council. In keeping with the idea of fat-soluble vitamins and a renewed appreciation for the role of dairy fat in our diet, researchers hypothesized that vitamin E, being a fat-soluble vitamin, would be more easily absorbed when consumed with dairy fat. In order to test this the researchers studied 20 participants (10 healthy and 10 with metabolic syndrome, a group known to have reduced levels of vitamin E).
The results of the study were unexpected. While it was confirmed that individuals with metabolic syndrome in fact have reduced levels of vitamin E absorption, there was no effect of dairy fat on vitamin E absorption. It simply didn’t matter what fat level of milk participants drank, the fat did not have an effect on vitamin E. However, the researchers performed additional experiments on milk and vitamin E using a system that simulates human digestion. In these further experiments the researchers determined that drinking milk, regardless of fat content, actually enhances vitamin E absorption! This was certainly an unexpected finding given the hypothesis before the study of a potential benefit of fat consumption. The mechanism of action behind why milk and its non-fat constituents enhances vitamin E bioavailability is not clear and requires more research.
This is a great example of scientific research that starts out with one hypothesis but leads to unexpected, almost surprising results. To be sure, these results need to be replicated with additional research and more follow up is needed to determine just what it is about milk that may drive this effect, but certainly this discovery indicates that there may be more to milk than just its nutrients. While milk intrinsically provides nine essential nutrients, it may be that drinking milk could enhance the bioavailability of other non-dairy nutrients when consumed together, and this may be one more reason to encourage your clients to reach for milk with their meals.