Harvard Health Content API

Almost 80 million Americans don’t have low vitamin D levels after all, an expert group says. The new, lower guidelines on vitamin D come from the Institute of Medicine. This is an independent group that provides research-based advice on medical care. Current guidelines don’t agree on what blood level of vitamin D is too low. For example, the Endocrine Society says that people should have at least 30 nanograms of vitamin D per milliliter of blood (ng/ml). Anyone with lower levels may need vitamin D pills, the group says. The new Institute of Medicine guidelines say that 20 ng/ml is enough. An estimated 78.7 million American have levels between 20 and 30. The new study included more than 15,000 adults. Information about them came from a major health survey. This was compared with a national death registry.

A study of diabetics has been stopped early because an intensive diet and exercise program did not reduce their risk of heart attack or stroke. Adults with type 2 diabetes have twice the risk of these problems as other adults. The study included 5,145 overweight or obese adults with type 2 diabetes. They were randomly divided into 2 groups. One group followed a strict diet. People were limited to 1,200 to 1,800 calories a day. They also did 175 minutes a week of moderate exercise. The other group just received general diabetes education and support. People in the first group lost about 10% of their weight at first. They kept off about 5% for at least 4 years. Other research has shown that a 5% weight loss can reduce factors that affect heart and stroke risk. People in the second group lost about 1% of their weight. After 11 years, U.S.

American boys, like girls, may be entering puberty earlier than they did 30 to 40 years ago, a new study finds. Based on prior research, doctors have considered 11½ to be the average age of puberty for boys. In the new study, the average was about 10 for whites and Hispanics. The average was 9 for blacks, about 2 years earlier than prior studies showed. The new study was based on exams of more than 4,000 boys. Their ages ranged from 6 to 16. Doctors in 41 states recorded information during well-child visits. They took note of pubic hair, genital size and testicle size. Growth of testicles is considered the first sign of puberty for boys. Other research has shown that puberty in girls is starting sooner. This may lead to a higher risk of breast cancer. It’s unclear why early puberty may be happening in boys, researchers said.