Vitamin D overuse - anything above that 4,000 IU/day limit, or almost seven times the recommended daily amount - has been linked with symptoms like vomiting, constipation, weakness, and weight loss, and it's almost always because of overused supplements. The National Institutes of Health recommends 600 IU per day (or 15 mcg). The suggested daily dose of vitamin D for most healthy adults is 600 IU (the measurement tool for fat-soluble vitamins), of which a serving of milk has about 25% of the daily amount. There is a debate about whether supplements are the right choice for everyone, but it does seem that those who are deficient could stand to benefit from adding a supplement to their existing diet. Since vitamin D is not found in too many foods, it's often added to milk, breakfast cereal, and orange juice. There are small amounts of the vitamin in beef liver, cheese, and egg yolks as well.
Their risk of infection decreased by half.Įxposure to the sun helps us produce vitamin D, but it's also found in fatty fish like salmon and tuna. Adrian Martineau, study author and a professor of respiratory infection and immunity at Queen Mary University of London, told NPR. "What we found is that those with the lowest vitamin D levels experienced the greatest benefit from supplementation," Dr. That was especially the case in people who were deficient in vitamin D. It found that for those taking supplements either daily or weekly, the risk of getting at least one acute respiratory tract infection was reduced.
A meta-analysis released Wednesday in The BMJ reviewed 25 randomized controlled trials that looked at whether the risk of contracting one of these infections decreased among those who took vitamin D supplements. Other studies suggest vitamin D is also helpful in protecting bone health.Īnd now, even more evidence suggests it could help prevent acute respiratory tract infections, which include things like colds, the flu and sinus infections.
Studies have found that people who consistently took vitamin D supplements lived longer, on average, than those who did not take them. It's also used by our muscles for movement and by our immune system to fight infections. Technically, two different vitamins - D2, which mainly comes from supplements and food, and D3, which comes from the sun - the fat-soluble vitamin D works in our bodies to help build up bone strength.