Vitamin D and the Sun - What to do?

 

Years ago, before the discovery of vitamin D, children with rickets were given sunbaths because sunlight had been found to heal them.  Regular play in sunlight was also encouraged for all growing children to prevent rickets.

 

Giving daily doses of cod-liver oil was found to cure rickets and to prevent it. 

 

In the 17^th century, Glisson and Whistler described a childhood disease of bone causing deformity, such as "bow legs." It was called rickets (Greek rachitis = inflammation of the spine) and was found to respond to sunlight, so afflicted children were encouraged to take "sun baths."  Later all children living in temperate climes were encouraged to enjoy sunny outdoor air in bathing clothes as this was found to prevent rickets.

 

Later, doses of cod-liver oil cured rickets, and daily doses were given to children as prophylaxis.  In 1919, Sir Edward Mellanby studied puppies and proved conclusively that rickets was nutritional, and responded to a vitamin present in cod-liver oil. 

 

Vitamin A was known to exist in cod-liver oil, but Mellanby described a different chemical.  In 1922 McCollum isolated a second vitamin from cod-liver oil: vitamin D.  At the same time, research on skin led to an explanation of how ultraviolet rays prevent rickets.

 

In human beings, skin exposed to sunlight converts 7-dehydrocholesterol into vitamin D_{3 .}  So vitamin D can be made in the skin and absorbed from animal products taken in the diet.

 

How much per day?  Nutritional authorities recommend 400 IU per child or adult per day.  It prevents rickets, and helps keep the bones of women over 30 strong, and is helpful in older men as well. In adults, it prevents osteomalacia, a softening of the bones associated with bone pain.  Osteoporosis also responds to vitamin D.

 

The typical American diet contains 100 IU vitamin D per day.

 

Levels of vitamin D can be measured in the blood:

 

Severe deficiency: 0 to 14.9 ng/ml

 

Mild deficiency: 15.0 to 31.9 ng/ml

 

Optimal: 32.0 to 100.0 ng/ml

 

Toxicity possible: >100.00 ng/ml

 

Best sources of vitamin D in the diet include herring, sardines, salmon, tuna and other cold-water fishes.  Dairy products, especially fortified milk, butter, cheese, eggs, and fortified cereals, orange juice, etc.  Mushrooms exposed to sunlight or other UV source make vitamin D and make another source if they're just in from Cancun!

 

Concern about solar skin damage, including premature wrinkling and development of skin cancers, including melanomas, has led to reduced skin exposure to the sun, and hence less conversion of precursors to vitamin D.

 

Reductions in fat and cholesterol intake and use of lipid-lowering agents potentially reduce vitamin D intake, absorption and substrate for conversion.  These factors contribute to the decline in body levels of vitamin D in Americans.  Dietary awareness and modifications can correct this.  A plethora of supplements containing vitamin D in various forms and combinations exists.

 

Vitamin D has a steroid or cholesterol-based molecular structure, and like all steroid hormones, enters the human cell nucleus and up- or down-regulates cell functions, influencing all the cells of the body.  Widespread studies associating vitamin D deficiency with a litany of diseases and disorders has paralleled the discovery of large comparison groups low in vitamin D:

 

Coronary artery disease

Aging

Cancer (prostate, colon, breast, leukemia, squamous cell skin cancers of the head and neck, basal cell skin cancers)

Systemic lupus erythematosus

Type 1diabetes

Organ transplant rejection

Multiple sclerosis

Hypertension

Tuberculosis

Periodontitis

Chronic pain syndromes

Seasonal affective disorder

Peripheral artery disease

Cognitive impairment

Memory loss and foggy brain

Psoriasis

 

 

 

On the other side, vitamin D is fat soluble, and can build up in human fat stores and cause toxicity.  US Dietary References list the tolerable Upper Intake Level (UL) of vitamin D for children and adults as 2000 IU /d, but various levels can be easily found-400 IU should be the target per day, unless a physician has ordered otherwise.

 

A mild sunburn, 2-sided, like on a tanning bed, produces up to 25,000 IU of vitamin D!

 

Remember, deficiency of vitamin D results in impaired bone mineralization, leading to softening of bones and rickets in children, osteomalacia in adults, and helps treat osteoporosis.

 

 

References: Scope Manual on Nutrition 1972:pp 83-84.

 

 

 

 

 

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Notes: References: Scope Manual on Nutrition 1972:pp 83-84. http://en.wikipedia.org/wiki/Vitamin_D#Role_in_cancer_prevention_and_recovery

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EditText of this page (last edited November 16, 2009)