People are used to the idea that you can become deficient in vitamins and minerals if you don’t eat the right foods. They’re often surprised to find out, though, that you can also become deficient in a vitamin that doesn’t necessarily require you to eat anything. The human body can meet its Vitamin D needs through exposure to sunlight, but many individuals spend so much time indoors and wearing sunscreen that they don’t get enough of it. There are also large portions of the United States, and the rest of the world, that are far enough from the equator that the sun available is inadequate for much of the year.
Fortunately, this is a fairly easy and safe vitamin to supplement. Scientists believe that humans probably need somewhere in the range of 400 to 4,000 IU of it each day if they’re not getting exposure to good summer sunlight. There’s often a little bit in products like milk, but most individuals can benefit from some supplementation. The most obvious problem associated with deficiency is weak bones, but there is also some reason to believe that mental health, the ability so sleep well, and the likelihood of getting cancer may all be impacted by the available amount of this nutrient.
The side effects of vitamin d are generally not a concern, because the amounts found in normal supplements are far less than what the human body can produce on its own, given a little sunlight. It’s pretty typical for a person to be able to produce around 10,000 IUs of it in just half an hour in the sun, so quantities well beyond the recommended daily allowance can be tolerated without any difficulty. In rare cases, particularly where someone takes 50,000 IUs or more a day for months on end, there can be a buildup of calcium in the blood that leads to symptoms like appetite loss and vomiting.
Vitamin D is notable for being a nutrient that is absolutely crucial, fairly easy to get or supplement, and exceptionally safe. Anyone following a reasonable supplementation routine should have no need to worry about side effects or taking too much, and the positive effects of having enough of it seem to affect the functioning of virtually every system in the human body.