Vitamin D is naturally present in a few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet (UV) rays from sunlight strike the skin and trigger vitamin D synthesis.
Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth and muscles healthy.
Vitamin D has other roles in the body, including reduction of inflammation as well as modulation of such processes as cell growth, neuromuscular and immune function, and glucose metabolism.
Without sufficient vitamin D, bones can become thin, brittle, or misshapen
Together with calcium, vitamin D also helps protect older adults from osteoporosis.
Few foods naturally contain vitamin D. The flesh of fatty fish (such as trout, salmon, tuna, and mackerel) and fish liver oils are among the best sources
Should I take a vitamin D supplement? (Advice for adults and children over 4 years old)
During the autumn and winter, you need to get vitamin D from your diet because the sun is not strong enough for the body to make vitamin D.
But since it’s difficult for people to get enough vitamin D from food alone, everyone (including pregnant and breastfeeding women) should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter.