It has been estimated that 1 billion people world-wide are vitamin D deficient or insufficient.

Without vitamin D only about 10-15 percent of dietary calcium and about 60 percent of phosphorus is absorbed by the body. This is directly related to bone mineral density which is responsible for osteoporosis and fractures, as well as muscle strength and falls in adults.

Effects of vitamin D deficiencies

• In utero and childhood, vitamin D deficiency may cause growth retardation, skeletal deformities and increase risk of hip fractures later in life.
  
• In adults, vitamin D deficiency may precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases.
• Studies have shown people living at higher latitudes (where the angle of the sun's rays are unable to sufficiently produce adequate amounts of vitamin D in the skin) are more likely to develop and die of Hodgkin's lymphoma, colon, pancreatic, prostate, ovarian, breast and other cancers.
• Prospective and retrospective epidemiologic studies have also shown an association between low levels of vitamin D and an increased risk for Type 1 diabetes, multiple sclerosis, Crohn's disease, hypertension and cardiovascular disease.

Food Sources of vitamin D

In the 1930s, a vitamin D deficiency disease called rickets was a major public health problem in the United States so a milk fortification program was implemented nearly eliminating this disorder.

Although milk is fortified with vitamin D, dairy products made from milk, such as cheese and ice creams, are generally not fortified with vitamin D. There are only a few foods that are good sources of vitamin D, like fatty cold-water fish and fortified foods, which include breakfast cereals and some juices in addition to milk, but you’d have to eat an awful lot to raise your blood levels so vitamin D supplements are often recommended unless you are exposed to sunlight on your skin regularly.

Table 1: Selected food sources of vitamin D

Sun Exposure as a Vitamin D Source

Exposing yourself to sunlight is the most important source of vitamin D because sunlight is far more likely to provide you with your vitamin D requirement than food is.  UV rays from the sun trigger vitamin D production in your skin.^13-14  Lights from your home are not strong enough to produce vitamin D.

There are variables however that may limit the amount your body can produce through this option. Variabales include;

• Season,
  
• Gographic latitude,
  
• Time of day,
  
• Cloud cover,
  
• Pollutants/smog, and
• Sunscreen

Obviously any point of north of Boston is worse.  Complete cloud cover halves the energy of UV rays, and shade reduces it by 60%.  Industrial pollution also filters sun exposure and may contribute to the development of rickets if you have insufficient dietary intake of vitamin D.¹⁵

Sunscreens with a sun protection factor (SPF) of 8 or greater will block UV rays that produce vitamin D.   An initial exposure to sunlight of 10 to15 minutes allows you adequate time for Vitamin D synthesis and should be followed by application of a sunscreen with an SPF of at least 15 to protect the skin.  Ten to fifteen minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen is usually sufficient to provide adequate vitamin D.¹⁴  If you have limited sun exposure it is very important that you include good sources of vitamin D in your diet or supplement with AlgaeCal® Plus.

Vitamin D Supplements

The National Institutes of Health indicates Vitamin D may have benefit for some forms of Cancer, Osteoporosis, Alzheimer's, Crohn’s Disease and other maladies.

Many calcium pills contain about 200 IU of vitamin D, so a multivitamin and three calcium pills would get you to 1,000 IU. For women, that’s not a bad way to go. For men, it may be risky because of the possible link between high calcium intake and prostate cancer.

That leaves vitamin D pills. A daily 1,000-IU supplement should take care of your minimum needs. If your multivitamin contains some vitamin D, but less than 1,000 IU, you can take a separate vitamin D supplement to make up the difference.

What is the Recommended Intake for Vitamin D?

The recommended dietary intake of vitamin D goes up as people age, from 200 IU daily for ages 19 to 50, to 400 IU for ages 51 to 70, and 600 IU for those 71 and older. However, most experts recommend getting at least 1,000 IU of vitamin D per day.

The National Institutes of Health indicates Vitamin D may have benefit for some forms of Cancer, Osteoporosis, Alzheimer's, Crohn’s Disease and other maladies^.

If you avoid the sun, live in the northern latitudes, are elderly, or have darker skin, you might benefit from even more vitamin D. Recent science is showing that levels above the Adequate Intake may provide better health.  For example, professor Robert Heaney has reported in April 2006 in the Journal of Nutrition his study showing an additional 2600 IU/day of oral vitamin D3 should be given to older women. Vieth reported in the American Journal of Clinical Nutrition a recommendation of 4000 IU per day for adults.  He also showed that levels of 10,000 IU per day were normal from body exposure to the sun and the only published vitamin D toxicity was at levels exceeding 40,000 IU/day.

Daily Adequate Intake of Vitamin D

What is the Best Form of Vitamin D Supplement?

In a 2006 article appearing in the American Journal of Clinical Nutrition¹⁸ points out that vitamin D2, the synthetic variety used for fortification of milk and foods, is inferior to the natural form, vitamin D3 for several reasons.  Many studies suggest D2 should not be regarded as a nutrient suitable for supplementation or fortification.

Authors Goldberg, and Cantorna, show it is very important to take adequate calcium and magnesium along with vitamin D3 supplementation as the three balance each other.

More Vitamin D May Be Better!

Recent science is showing that levels above the Adequate Intake may provide better health.  For example, professor Robert Heaney has reported in April 2006 in the Journal of Nutrition his study showing an additional 2600 IU/day of oral vitamin D3 should be given to older women.¹⁵

Vieth reported in the American Journal of Clinical Nutrition a recommendation of 4000 IU per day for adults.¹⁶  He also showed that levels of 10,000 IU per day were normal from body exposure to the sun and the only published vitamin D toxicity was at levels exceeding 40,000 IU/day.

The National Institutes of Health indicates Vitamin D may have benefit for some forms of Cancer, Osteoporosis, Alzheimers, Chron’s Disease and other maladies.¹⁷

It seems more studies are warranted on proper vitamin D levels.  Given that vitamin D3 is safe at very high levels and may provide extraordinary benefits with no known risk, we recommend individuals get reasonable sun exposure, eat foods rich in vitamin D, and supplement with AlgaeCal Plus.