研究：大多数维生素片没什么用

Vitamin and mineral supplements are a staple in many people's diets, but there is increasing evidence to suggest the most popular ones are essentially useless.

维生素和矿物质补充剂是许多人日常膳食中的固定组成部分，但越来越多的证据表明，最受欢迎的一些维生素补充剂其实都没什么用。

A new systematic review of data and trials published between January 2012 and October 2017 found that many popular multivitamins - as well as vitamin C, vitamin D, and calcium supplements - had no real advantage to people's health and that there was no evidence taking them reduced the risk of cardiovascular disease, heart attack, stroke, or early death.

The study, published in the Journal of the American College of Cardiology, was led by researchers at St. Michael's Hospital and the University of Toronto.

"We were surprised to find so few positive effects of the most common supplements that people consume," said Dr. David Jenkins, the lead author of the study.

"Our review found that if you want to use multivitamins, vitamin D, calcium or vitamin C, it does no harm – but there is no apparent advantage either."

There were, however, a few apparently advantageous supplements. Folic acid and B vitamins with folic acid may reduce the risk of cardiovascular disease and stroke, the study found.

Niacin (a form of vitamin B3) and antioxidants, meanwhile, were associated with a higher risk of death by any cause, albeit a very small increase.