Printer Friendly Tell a Friend

I saw a news article recently about vitamin D being an anti-cancer vitamin.

Q:I saw a news article recently about vitamin D being an anti-cancer vitamin. Is there much truth in this idea, or is it just wishful thinking? If vitamin D really is an anti-cancer vitamin, what is the best dosage to use?

A:Yes, Vitamin D really is a cancer-prevention vitamin, and it appears to be a very good one. Vitamin D is also an excellent bone-strength enhancer. Let us look at the evidence for both of these claims.

Vitamin D as a cancer preventative

This vitamin came to the attention of cancer researchers in the 1950s but little was done to explore its potential in therapy or prevention. In the 1980s it was noted that colon cancer rates are lower when vitamin D consumption is higher.13 But again, the gears of medicine ground along so slowly that another ten years passed before the medical world began to take the association seriously.

More recently there has been a rapidly growing interest in the use of vitamin D as a cancer treatment and preventative.4,5,6,7,8,9 Research during the past decade has shown that vitamin D can inhibit the proliferation of a wide variety of cell types.9 According to one reviewer, this “antiproliferative action makes [vitamin D] a possible therapeutic tool to treat … different types of cancer.”6 For example, a 2006 review of vitamin D treatment of prostate cancer reported that the vitamin “showed significant antineoplastic activity in pre-clinical models of prostate cancer and many other tumor types.”10 A recent compilation of statistics from clinical trials revealed that “an impaired vitamin D status is associated with a 20-30% increased breast cancer incidence and 10-20% increased mortality.”7 The clinical data that supports these conclusions was collected from studies that used relatively low doses of vitamin D — typically less than 1000 i.u. per day.

In 2000, researchers at Creighton University began a four-year clinical trial to test the anti-cancer and anti-osteoporosis effects of a vitamin D supplement combined with calcium. Some of the subjects received the active supplement (1100 i.u./day of vitamin D3 plus 1400-1500 mg/day of calcium), and others received a placebo. This long-overdue experiment, ‘the Creighton Study’, showed startling results: a 77% reduction in overall cancer risk.1

Vitamin D as a bone strengthener

Vitamin D’s history of use as a bone strengthener goes back at least to the 1920s, although people have used it unwittingly since ancient times, inasmuch as they learned to avoid getting vitamin D deficiency diseases by eating certain foods or by spending time in the sun — fish, eggs, butter, and beef are dietary sources of this vitamin, and sunlight stimulates its production in the skin. There are many vitamin D deficiency diseases, the most famous of which are rickets and osteoporosis.

The Creighton Study showed that for those subjects who received the active supplement (1100 i.u./day of vitamin D3, combined with 1400-1500 mg/day of calcium), their Bone Mineral Density rose — whereas for those who received the placebo, their BMD fell.2

Supplement industry responds quickly to discoveries

Unlike the medical world, the supplement world responds quickly to research successes. Within a few months of the announcement of the Creighton Study’s results, higher-dosage vitamin D3 products appeared on the supplement market. Among these were two new products from LifeLink: Formula CS Plus and D3ZO.

  • Formula CS Plus replicates the formula used in the Creighton Study, but with added ingredients to increase its effectiveness for preventing cancer and increasing bone strength.
  • D3ZO is a very high potency vitamin D3 supplement that relies purely on D3 and Zinc Orotate for its anti-cancer and bone-strengthening effects.

In contrast to the supplement industry’s rapid response to the discoveries about vitamin D3, the medical establishment remains in its typical foot-dragging mode. For example, the NIH (U.S. National Institutes of Health) admits that experts are now advocating vitamin D dosages in the thousands of i.u./day, yet the NIH itself continues to advocate vitamin D consumption at only 200-600 i.u./day, and falsely suggests to readers that doses higher than 2000 i.u./day may be toxic.14

Vitamin D3

The optimum amount of vitamin D3 consumption undoubtedly differs from person to person, and certainly depends also on what condition one hopes to alter — for example, the best dosage for cancer prevention may not be the same as that for bone strength. In any case, the optimum amount is not really known for any condition. We do know, from the Creighton Study, that 1100 i.u. per day is better than 400 i.u., and that experts are leaning toward considerably higher doses than 1100 i.u. One prominent researcher suggests 10,000 i.u./day.3 Some supplement companies are offering vitamin D3 products containing as much as 50,000 i.u. per capsule. LifeLink settled on 4000 i.u. for Formula CS Plus in order to enhance the formula without going too far beyond the parameters shown to be effective in the Creighton Study. And 25,000 i.u. per capsule was chosen for the high-potency D3ZO product because this is half the dosage for which safety data have been collected.

Good overviews of vitamin D can be found at Wikipedia11 and at the University of California at Riverside12 — however, the dosages suggested in these reviews are obsolete.

Side effects of vitamin D supplementation

No serious side effects were observed during the Creighton Study.1 Theoretically, an excess of vitamin D could lead to ‘hypercalcemia’ — too much calcium in the blood, causing one to feel lethargic. In that case, the supplement would be working too well at making calcium bioavailable and one should try reducing the dose.


Disclaimer: The information provided in this “Ask Dr. Zarkov” article contains no medical advice whatsoever — it contains biological information. Nothing in the article constitutes an effort to persuade readers to use, or not to use, this biological information as a basis for action.

To get our newsletter please enter your email address in the box below and press 'Subscribe' button.