Nutraceuticals and nootropics for anti-aging

Rival dermatology factions intensify their cat-fight over Vitamin D and sun exposure.

Last year, Boston University professor Michael Holick was pressured to resign from his position in the Dermatology Department because he had written a book recommending exposure of the skin to the sun as a way to boost vitamin D levels in the body. There was no question about the fact that sunshine does cause the body to make vitamin D, or the fact that many people are deficient in vitamin D because they avoid the sun. The point of contention was simply that dermatologists had been telling people for years to avoid sun exposure because it can cause skin cancer, and the concept had become a dogma of the dermatology profession.

Now, a year later, many dermatologists are changing sides in this controversy — and recent research seems to support Holick’s view that the risks of UV-induced skin cancer are far outweighed by the risks of cancer and osteoporosis caused by vitamin D deficiency.

On the face of it, this debate would seem to be unnecessary — after all, vitamin D supplements are easily obtained, and can provide a source of vitamin D that requires no sun exposure at all. The subject, however, is a little more complicated than that — there are several forms of vitamin D that are used as supplements or drugs, and not all of them are equivalent in bioavailability, effectiveness, or safety.

Many vitamin D supplements contain a substance called ‘vitamin D2’ or ‘ergocalciferol’. In the body, D2 is converted to D3 (‘cholecalciferol’) in the liver, which in turn is converted in the kidneys to calcitriol, the active form of vitamin D. Thus: D2 -> D3 -> calcitriol. Unfortunately, various factors can alter the efficiency of absorption and conversion along this pathway. Furthermore, it is possible to get too much vitamin D and suffer toxic effects from it. Why not simply avoid these complications by taking calcitriol itself as a supplement? The reason seems to be that government regulatory agencies such as the U.S. Food and Drug Administration has defined calcitriol to be a drug rather than a supplement, and so it is only available by prescription. (It is a very powerful substance, and the effective dosage would be extremely small. While taking calcitriol directly would make it easier to obtain an adequate amount, it would also reduce the body’s ability to compensate for overdosages. Therefore, a case can be made for calcitriol supplementation being riskier than D2 or D3 in some respects.)

In view of these constraints, the best available choice for vitamin D supplementation would be vitamin D3 (cholecalciferol).

The importance of maintaining adequate vitamin D levels in the body is strongly supported by recent research, which is mainly focused on two aspects:

• prevention of cancer progression and metastasis, for a wide spectrum of cancers
• strengthening of bone, prevention of fractures.

The optimum dosage range for vitamin D3 appears to be between 800 i.u./day (20 micrograms/day) and 2400 i.u./day (60 micrograms/day). Using larger doses than this is to invite disruptions in calcium metabolism.

Link to news article:

Vitamin D research turning sunscreen wisdom on head

Links to abstracts of research reports:

The epidemiology of vitamin D and cancer incidence and mortality: A review (United States).

Plasma vitamin D metabolites and risk of colorectal cancer in women.

Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials.

The high prevalence of inadequate serum vitamin D levels and implications for bone health.

Osteoporosis: the role of micronutrients.

Links to good reviews on the subject of vitamin D:

Review of vitamin D chemistry from the Merck Manual

Review of vitamin D usage from PDR Health

Review of vitamin D by Colorado State University

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LifeLink carries Vitamin D3 in its Platform multi-vitamin and -mineral product.