Vitamin D

Vitamin D Sources and Functions

All of the vitamins work together to keep you healthy and feeling good. Here is a summary of the role of Vitamin D, a fat-soluble vitamin, in your good health.

What it does Promotes healthy bone growth and density; Helps balance blood calcium levels; Part of healthy immune function
Daily needs (AI#) [Infants: 10 µg or 400 IU]
[Children: 15 µg or 600 IU]
[Men: 15-20 µg* or 600-800 IU ]
[Women: 15-20µg* or 600-800 IU]
[Pregnant: 15 µg or 600 IU]
[Lactating: 15 µg or 600 IU]
Not enough Rickets in children, Soft bones, back pain and leg pain in adults; Osteoporosis
Too Much High blood calcium level; calcification of soft tissues(Upper Limit established by USDA for infants, 0-6 months is 25 µg or 1,000 IU, infants, 6-12 months is 37.5 µg or 1,500 IU, children, 1-3 years is 62.5 µg or 2,500 IU, children 4-8 years is 75 µg oe 3,000 IU, and children 9-13 years and adults is 100 µg or 4,000 IU.)
Foods Sunlight, Fortified dairy products and cereals, Liver, Eggs, Salmon, Sardines, Mackerel, Fish oil

# Vitamin D needs are based in Adequate Intake “AI”, the amount the average healthy person consumes. There is not enough scientific evidence to establish an RDA. These amounts are based on getting Vitamin D from diet alone and not from the sun.
*The higher level of Vitamin D is for adults 71 years and older.

Let the sun shine

Vitamin D is the only vitamin (some say it is really a hormone) that is not necessarily something you need to get from your diet. Sunlight on your skin activates a precursor that manufactures Vitamin D. However, if you live in northern climates or have very dark skin, it may be more difficult for you to get enough sunshine. In that case, you will need to get Vitamin D from your diet.

Those most affected by Vitamin D deficiency are children living in poverty and the elderly. In developed countries, rickets (Vitamin D deficiency in children) is uncommon. However, infants who are breast fed by mothers who don’t get enough sunshine or Vitamin D fortified foods may become deficient.


Caveat for Vitamin D Sources and Functions: Of all the vitamins, Vitamin D is the most likely to become toxic if taken in large doses. Too much Vitamin D can cause calcification of the soft tissues of the body.


The older you are, the more at risk you are

The elderly are at risk because with advancing age, the body becomes less able to manufacture Vitamin D. In addition, older people tend to stay out of the sun or to use sunscreen. Vegans and vegetarians that do not live in sunny climates or include fortified products in their diets, are also at risk for Vitamin D deficiency.

Testing is the best way to know whether you need to supplement with Vitamin D.

Because of the potential toxicity of Vitamin D supplements, it is a good idea to have your doctor test your levels before taking too much of this fat soluble vitamin.  Once you know what your number is, you can make a better decision about what you need to be healthy.

Protecting more than your bones

Although Vitamin D is mostly known for its role in promoting healthy bones, recent studies have shown that it may have a protective influence against some types of cancer and some autoimmune diseases. There is also some research that shows that Vitamin D helps protect against viruses such as respiratory flu.


Interesting Fact about Vitamin D Sources and Functions: Although many health experts recommend that you wear sunscreen to protect yourself from the harmful rays of the sun, sunscreens with SPF of 8 and above also block the ability of your body to produce Vitamin D from the very same sunlight. It seems we are always trying to balance the harmful effects with the beneficial effects.

Some health experts suggest that you spend ten to fifteen to twenty minutes in the sun each day without wearing sunscreen. Dark-skinned people will require as much as an hour each day of sunshine to achieve the same effect and very fair-skinned people require less.  Keep in mind that the idea is not to get a sunburn, but merely to get enough sun to allow your body to produce adequate Vitamin D.


Click here to go from Healthy Eating Vitamins 9 - Vitamin D Sources and Functions page to Calcium page.