When it comes to vitamins and minerals, more is always better, right?
Not exactly. While it may be enticing to reach for that vitamin-C packed drink when feeling under the weather, your body can’t actually process it all. And a balanced diet typically carries enough B, C, and E vitamins to keep your body running smoothly.
But there is growing evidence that there could be one vitamin worth getting with the help of supplements: vitamin D.
Though how much of this vitamin the body is actually able to use is still up for debate, it’s difficult to get much vitamin D from food. Especially if a person is deficient in vitamin D, a supplement can help get to the recommended daily amount.
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. It’s also used by our muscles for movement and by our immune system to fight infections.
Studies have found that people who consistently took vitamin D supplements lived longer, on average, than those who did not take them. Other studies suggest vitamin D is also helpful in protecting bone health.
And now, even more evidence suggests it could help prevent acute respiratory tract infections, which include things like colds, the flu and sinus infections. A meta-analysis released Wednesday in The BMJ reviewed 25 randomised controlled trials that looked at whether the risk of contracting one of these infections decreased among those who took vitamin D supplements.
It found that for those taking supplements either daily or weekly, the risk of getting at least one acute respiratory tract infection was reduced. That was especially the case in people who were deficient in vitamin D.
“What we found is that those with the lowest vitamin D levels experienced the greatest benefit from supplementation,” Dr. Adrian Martineau, study author and a professor of respiratory infection and immunity at Queen Mary University of London, told NPR. Their risk of infection decreased by half.
How to get more vitamin D
Exposure to the sun helps us produce vitamin D, but it’s also found in fatty fish like salmon and tuna. There are small amounts of the vitamin in beef liver, cheese, and egg yolks as well.
Since vitamin D is not found in too many foods, it’s often added to milk, breakfast cereal, and orange juice.
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.
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. The
National Institutes of Health recommends 600 IU per day (or 15 mcg).
Just don’t go too far. 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. Luckily, your body knows how to regulate how much vitamin D it makes, so you won’t get too high a dose from sitting in the sun.
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