Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lead to problems like rickets and osteoporosis. Rickets is a deformity mainly found in children. Osteoporosis is the thinning of bone, a common problem as people, especially women, get older. Studies in recent years have suggested that vitamin D may also have other uses. Studies have shown that low levels of D may increase the risk of heart attacks in men and deaths from some cancers.
Other studies have shown that people with rheumatic diseases often have low levels of D. The easiest way to get vitamin D is from sunlight. The ultraviolet rays react with skin cells to produce the vitamin. But many people worry about skin cancer and skin damage from the sun. So 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 with high levels include oily fish such as salmon, tuna and mackerel, and fish liver oils. Boston University researchers reported in two thousand seven that farmed salmon had a lot less vitamin D than wild salmon.
Small amounts of D are found in beef liver, cheese and egg yolks. And some people take dietary supplements containing the vitamin. But most of the D in the American diet comes from foods like milk with the vitamin added. These days, more doctors are testing for vitamin D levels in their patients. But as research continues, some experts worry that if people take too much D, it might act as a poison. Also, skin doctors warn people to be careful with sun exposure because of the risk of skin cancer. How much vitamin D does a healthy person need? Nutrition experts who advise the American government set the current recommendations in nineteen ninety-seven.
The daily amount is two hundred international units from birth through age fifty. Then it rises to four hundred I.U.s through age seventy, and six hundred for those seventy-one and older. But some groups say these amounts are not high enough. The nutrition experts are taking another look at how much vitamin D and calcium people should get. The Institute of Medicine of the National Academies expects to release a report by this coming May. And thats the VOA Special English Health Report.
Words in This Story
rickets – n. a disease which children who do not have enough vitamin D can suffer from, in which the bones become soft and not shaped correctly
osteoporosis – n. a disease that causes the bones to become weaker and easily broken
deformity – n. the situation in which a part of the body has not developed in the normal way or with the normal shape
osteoporosis – n. a disease that causes the bones to become weaker and easily broken
rheumatic – adj. relating to inflammation of muscles, joints, heart valves, or other parts of the body
ultraviolet – adj. (abbreviation UV) Ultraviolet light has a wavelength that is after the violet (= light purple) end of the range of colours that can be seen by humans.
Light of this type causes the skin to become darker in the sun
salmon – n. a medium-sized silver-coloured fish that lives in the sea or rivers and swims up rivers to produce its eggs. Its pink flesh is eaten as a food
tuna – n. a large fish that lives in warm seas
mackerel – n. a sea fish with a strong taste, often used as food
liver – n. a large organ in the body that cleans the blood and produces bile, or this organ from an animal used as meat
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