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Vitamin D, how much?

Vitamin D plays many roles in producing optimal health, both our physical and our mental health. Most people know that we need vitamin D to help absorb calcium into our teeth and bones to make them strong. But did you know that Vit D is also important for our immune system, our muscle strength and mood?

Since Vitamin D is produced by our bodies when sunlight hits our skin, why is it that after being in the sun during the summer, often we find that our Vit D levels don’t improve very much?

There are several good reasons why:

1. When we bathe within 12 hours of sunshine, we wash off most of the Vit D, it takes from 12-24 hours to absorb it from the skin.

2. Without adequate magnesium, Vit D is not absorbed readily, and it is not utilized in the body as well either

3. The darker our skin, the less efficient it is in producing Vit D. Interestingly, people with black skin may produce less Vit D but seem to need less of it to have the same benefits.

What is the best natural source of Vit D? Cod liver oil! Not only does it have Vit D, but it also has Vit A and omega 3 fatty acids. One tablespoon a day is all it takes. Remember, Vit D is a fat-soluble nutrient so it must be taken with meals that have some kind of oil or fat to get the maximal absorption.

How much Vit D? There has been much debate over the optimal dose of Vit D. Numbers ranging from 200 units to 5,000 units a day have been proposed. Studies conducted regarding serum levels of Vit D and associated health revealed that levels above 50 ng/ml put some people at risk for increased falls, sub-optimal bone density and increased mortality. This means that if we take too much, we can expect fewer benefits and even some side effects.

The bottom line is, Vit D is essential, and we should be taking it regularly. Even breast-fed babies need it because Vit D is not transferred through the breast milk.

So how much Vit D should we be taking to get the most benefit?

According to the Food and Nutrition Board of the Institute of Medicine in 2010 the upper limits of Vitamin D supplementation are as follows:


0 to 6 mo

1,000 IU (25 µg)

6 to 12 mo

1,500 IU (38 µg)


1–3 y

2,500 IU (63 µg)

4–8 y

3,000 IU (75 µg)


9–13 y and older

4,000 IU (100 µg)


9–13 y

4,000 IU (100 µg)

Pregnancy and Lactation

4,000 IU (100 µg)

NOTE: IU = International Unit.

What about magnesium? The best source of magnesium is Magnesium Citrate. For young children, start with 100 – 200 mg. If you take too much, your bowels will tell you. You will get loose stools or even mild diarrhea. So just lower the dose. Adults typically need 400-1000 mg a day. It will improve bowel function, energy, mood, bone density, and overall sense of well-being.

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