[慢速VOA] 你对维生素D了解多少(1)[080722]
Among Vitamins, D Seems Short for 'Does a Lot' (1/2)
Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lead to problems such as rickets, a deformity mainly found in children. Osteoporosis, the thinning of bone, is a common problem as people, especially women, get older.
But more and more research is suggesting that vitamin D might also help prevent many diseases.The easiest way to get vitamin D is from sunlight. The sun's ultraviolet rays react with skin cells to produce vitamin D. But many people worry about getting skin cancer and skin damage from the sun. As a result they cover their skin or wear sunblock or stay out of the sun.
Also, darker skinned people produce less vitamin D than lighter skinned people. Production also decreases in older people and those living in northern areas that get less sunlight.Not many foods naturally contain vitamin D. Foods high in this vitamin include oily fish such as salmon, tuna and mackerel, and fish liver oils.
Boston University researchers reported last year that farmed salmon had only about one-fourth as much vitamin D as wild salmon.
