The clean eating challenge that BIG athletes are doing right now is very similar to Whole 30 with one major exception, dairy is allowed and encouraged. Why? Fortified dairy is one of the most nutrient dense foods, naturally rich in protein, carbohydrates, and calcium and supplemented with Vitamin D, it is one of the few food sources containing this vitamin that has a clear role in bone health and a growing recognition that is may have a role in muscle strength. It may not seem relevant to worry about muscle strength if you are participating in CrossFit, but after age 30, adults lose 3-5% muscle mass and strength per decade.
Looking at active and inactive levels of Vitamin D in the blood, British researchers found that the active form of Vitamin D is associated with leaner bodies, and possibly more muscle strength, whereas higher levels of inactive Vitamin D were associated with bodies that had a higher percentage of body fat. Other, previous research studies have also connected higher inactive Vitamin D levels with lack of muscle strength. This research contributes to a greater understanding of the forms of Vitamin D and their role in the body and demonstrates why further research is needed to understand these associations (not cause and effect) and the mechanisms of action for better Vitamin D guidance.
Produced by the skin, Vitamin D is often referred to as the sunshine vitamin, and 15 minutes of mid-day sun without sunscreen is recommended with sunscreen applied after that because of the risk of skin cancer. Food sources of Vitamin D, other than fortified dairy, are fatty fish, egg yolks, and fortified cereals. Cholecalciferol (Vitamin D3) supplement is also possible and is the best form recommended at 800-1000 IU per day (100% RDA). You learn more about Vitamin D here.
Questions about the nutrition challenge or other nutrition topics?
I will be available after the following classes.
- Tuesday, Feb. 28, 4:30 pm
- Thursday, March 2, 9:30 am
- Saturday, March 4, 9:30 am
Happy and healthful eating,
Donna G. Pertel, MEd, RD, LDN
Want more information about whether your whey protein supplement contains Vitamin D? Contact me at firstname.lastname@example.org.