Did you know that vitamin D deficiency is a common source of muscle pain and weakness, and that vitamin D deficiency is relatively common in modern cultures? One medical journal has published studies showing the prevalence of marginal to serious vitamin D deficiency among young adults to be 23% to 43%!
The marketing of milk has made most people aware that vitamin D is an important component of bone health. Over the past few years, a few research papers have called the attention of health care professionals to the role of vitamin D in muscle function, and to the fact that a high percentage of nonspecific musculoskeletal pain cases can be attributed to vitamin D deficiencies. A number of studies are finding that vitamin D supplementation improves muscle function as well.
However, most of the vitamin D needed by humans does not come from diet. Exposure to sunlight causes people to synthesize 80 to 90% of the vitamin D the body needs. In the summer, the body stores vitamin D in adipose tissue for use through the winter. Urban societies spend more time indoors, and this may contribute to the prevalence of vitamin D deficiency. Of course, reducing sun exposure decreases the risk of skin cancer, so these two opposing concerns must be balanced.
Despite the fact that most our vitamin D comes from that synthesized based on sun exposure, diet does help. Various research studies have found supplementation and diet modifications to create important improvements in groups of people with deficiency related conditions. In addition to foods that have been supplemented with vitamin D, foods rich in vitamin D include:
- Mushrooms (150 to 168 IU): microwaving reduces vitamin D in mushrooms
- Ocean fish (Atlantic raw herring = 2061 IU)
- Freshwater fish (wild catfish = 1053 IU)
- Tofu (Vitasoy brand = 581 IU)
- Eggs (26 IU per whole egg with 25 of that in the yolk)