According to a study published by the American Medical Association,
people who are deficient in vitamin D, which is produced naturally from
exposure to the sun, may be susceptible “to a range of conditions,
including bone health, cancer, cardiovascular disease, glucose
intolerance, high blood pressure, some infectious diseases, multiple
sclerosis, and type 2 diabetes mellitus.”

While it would be an over-simplification to suggest that sunshine
alone can prevent these diseases, research indicates that the “sunshine
vitamin” can greatly enhance our ability to prevent them. Additionally,
numerous studies have shown that an increase in vitamin D, whether from
the sun or in supplement form, may actually reduce the risk of breast
cancer, chronic pain in women, and even mortality.

What is Vitamin D?

Technically vitamin D is not a “vitamin,” but is in a class by itself. Its metabolic product, calcitriol, is actually a secosteroid hormone
that targets over 1000 genes in the human body. Vitamin D is a
fat-soluble “vitamin” that helps the body absorb and maintain normal
blood levels of calcium and phosphorus. Fat-soluble vitamins are stored
in the bodys fatty tissue. . There are three sources of vitamin D:
natural sunlight, fortification of dietary foods, particularly dairy
products and some cereals, and oily fish. Vitamin D is made in the skin
when exposed to natural sunlight.

What about Harmful UV Rays?

Interestingly, research suggests that our concerns about skin
cancer may actually be exaggerated and that most Americans, especially
African Americans, need more exposure to the sunshine to benefit from
the valuable vitamin D that it helps to produce.

Additionally, it is not necessary to spend hours in the sun to
benefit. In fact, most scientists agree that 15 – 20 minutes, a few
times a week during warmer months is sufficient. It is best to take in
the morning or late afternoon sun, when the atmosphere filters our some
of the UV radiation. The use of sun blockers can inhibit the production
of vitamin D, so it is advisable to soak in your 20 minutes of sunshine
before putting on the sun blocker.

Can Too Much Sun Produce Too Much Vitamin D?

Not to worry. The human body is truly awe-inspiring! The sunshine
will actually destroy excess vitamin D in the skin after it reaches
20,000 units. So under normal conditions, an overdose from the sun is
not possible.

However, if you are combining sunshine with vitamin D supplements,
caution is warranted. Too much vitamin D can make the intestines absorb
too much calcium. This may cause high levels of calcium in the blood
and lead to calcium deposits in soft tissues such as the heart and
lungs. This can reduce their ability to function.

When Sunshine is Not Enough

So we need sunshine, but winter is just around the corner! Do you
really have to bask in the winter’s sun to get your daily supply of
nature’s “sunshine vitamin”? The idea is probably not very appealing to
you. We are just naturally drawn to warm, cozy places in the
wintertime…a cup of hot chocolate or tea, a good book, and a warm
fire.

Well, there’s good news and bad news. The winter’s sun in most of
North America is not strong enough to trigger the chemical reaction in
your skin that converts vitamin D to its active form. The bad news…
this could mean that most of us are probably vitamin D deficient during
these cold months. So when sunshine isn’t enough, it’s time to go to
the vitamin store and pick up a supply of vitamin D supplements.

Recommended Daily Allowance

It is important to note that Vitamin D is included in most
multi-vitamins, usually in strengths from 50 IU to 1,000 IU. Remember
to check this out before deciding on the IU values you will purchase.

The Adequate Intake (AI) levels established by the U.S. Institute
of Medicine of the National Academy of Sciences are: 200 IU
(International Units) daily for all individuals (males, female,
pregnant/lactating women) under the age of 50 years-old.

For all individuals from 50-70 years-old, 400 IU daily is recommended.

After 70 years of age the skin is unable to convert vitamin D efficiently, so a higher dosage of 600 IU daily is suggested.

There has been much debate over whether the current recommended
adequate levels are sufficient to meet physiological needs,
particularly for individuals deprived of regular sun exposure. The
upper limit (UL) for vitamin D has been recommended as 2,000 IU daily
due to toxicities that can occur when taken in higher doses.

New guidelines from the American Academy of Pediatrics call for
doubling the recommended daily dosage to 400 IU (International Units)
per day, beginning in the first few days of life, for lasting health
benefits.

Clearly adequate intake of vitamin D is essential to good health,
however, given it’s potential toxicity we recommend that you consult
your healthcare provider before starting this or any new therapy.