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Taking selenium in pills may correct a deficit. But too much can be risky, a new study suggests. Much of the difference may depend on where people live and what they eat. Selenium levels in soil, and the food grown there, vary from place to place. The new study reviewed recent research on selenium. Low levels in the blood have been linked with a higher risk of death from all causes and from cancer. Selenium deficiency also has been linked with poor immune function and a greater risk of dementia. But too much selenium can be harmful, research suggests. High blood levels have been linked with a greater risk of type 2 diabetes. Other research has linked high selenium with increases in skin rashes, hair loss and skin cancers other than melanoma. The new review of research found that blood levels of selenium vary greatly by region. They tend to be high in North America.

People with stable heart disease do just as well with medicines as with stenting to open clogged arteries, a new evidence review finds. The study focused on stable angina. This is chest pain that occurs during exercise or stress, but not at other times. It is caused by deposits in coronary arteries that limit blood flow. Many Americans are treated with angioplasty. A tiny balloon is blown up inside the artery to crush the blockage. Usually a tube called a stent is put in to keep the artery open. The new review put together results from 8 prior studies. They included 7,229 people with stable angina. They were randomly assigned to receive stenting plus standard heart medicines or medicines alone. Researchers kept track of them for an average of 4 years. About 9% of each group died. About 8.9% of the stent group and 8.1% of the medicine group had nonfatal heart attacks.