High intake of vitamin A increases risk of osteoporosis
High intake of vitamin A leads to reduced bone density and increases the risk of bone fractures and osteoporosis, according to Swedish researchers.
In the first part of the study, researchers measured the bone density of 175 women, aged from 28 to 74. The women were asked to record everything they ate over a typical week and the vitamin A content was calculated.
The results showed that women whose vitamin A intake was more than 1500 mcg per day, bone density was 6 to 14 per cent lower than women whose intake was less than 500 mcg per day.
In another part of the study, the researchers compared the vitamin A content of the diets of 247 women who had suffered hip fractures with that of 873 women who had not suffered fractures. They found that women whose intake was over 1500 mcg per day had double the risk of fracture compared to women whose intake was less than 500 mcg per day.
Diets in northern Europe tend to be higher in vitamin A than those in other areas and the risk of osteoporotic fractures is the highest in the world. People in northern areas often eat large amounts of cod liver oil which is high in vitamin D and vitamin A. Previous research has shown that very high doses of vitamin A cause fractures in animals and some forms of vitamin A may stimulate cells that break down bone.
