What Does Vitamin D Do?

There's been a lot of good news about vitamin D recently, but what does vitamin D do?

Vitamin D is actually a fat-soluble prohormone, and there are several forms of vitamin D. The two primary forms are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is made by plants. Vitamin D3 is made by humans when skin is exposed to ultraviolet B (UVB) rays from sunlight.

It's well known that vitamin D helps the body absorb calcium and maintain proper blood levels of calcium and phosphorus, thereby helping bones and teeth stay strong and healthy. But recent research indicates vitamin D does much more than that.

There's a growing body of evidence that vitamin D may be helpful in the prevention and treatment of certain cancers, heart disease, high blood pressure, diabetes, fibromyalgia, multiple sclerosis, rheumatoid arthritis, chronic pain and obesity. It also looks like vitamin D helps strengthen the immune system.

While there's growing excitement about vitamin D's promise, there's no agreement yet on how much you need. The Institute of Medicine currently recommends 600 IU daily for infants through adults age 70, and 800 IU after age 70. But many scientists and health experts believe that this amount is too low and recommend as much as 2,000 IU to 3,000 IU of vitamin D per day.

But how much vitamin D is too much? Excess vitamin D can cause problems such as nausea, vomiting and weakness. The exact long-term safe dose of vitamin D is not known. The Institute of Medicine's tolerable upper intake level for vitamin D for children and adults is 4,000 IU per day, but some scientists and health experts think that it should be higher.

Most people don't have to worry about getting too much vitamin D, but instead have to worry about getting too little. Vitamin D deficiency is a common problem. Some studies have shown that more than three out of every four Americans now have vitamin D levels below what is believed to be necessary for optimal health.

Here are the three ways to increase your vitamin D:

1. Sunlight

Several factors influence the sun's ability to produce vitamin D, such as the time of day, the time of year, the latitude in which you live, and your skin pigmentation and age. A general guideline for increasing vitamin D is to get 15 minutes of sun at the peak of the day (11 a.m. to 3 p.m.) to the face, neck and arms three times a week.

2. Food

Very few foods naturally contain vitamin D. Fatty fish (salmon, sardines, mackerel, tuna etc.) are some of the best sources. Some foods, such as milk, juices and breakfast cereals, are fortified with vitamin D.

3. Supplements

Vitamin D supplements are a reliable and safe source of vitamin D. Many experts recommend choosing a supplement that contains vitamin D3 instead of vitamin D2. This is because some studies suggest that vitamin D3 is more potent, is better absorbed, and is more beneficial to human health than vitamin D2.

In conclusion, vitamin D is an important nutrient and you need to make sure that you get enough vitamin D every day.

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