Review finds vitamin D could prevent significant number of cancers

[Guest guest]

Review finds vitamin D could prevent significant number of cancers

In a review that will appear in the February 2006 issue of The American

Journal of Public Health vitamin D researcher F. Holick and

colleagues concluded that improved vitamin D status could significantly

cut the risk of colon, breast, ovarian and prostate cancer. A previous

review conducted by the team, published in the October 2005 Journal of

Steroid Biochemistry and Molecular Biology found that consuming 1000

international units (IU) or more of vitamin D per day cut the risk of

colon cancer in half.

The team reviewed 63 studies of oral intake or serum levels of vitamin D

as related to the risk of cancer published between January 1966 and

December 2004. The majority revealed a protective effect for the

vitamin. The authors attribute vitamin D & rsquo;s benefits to its

abilities to inhibit the formation of new blood vessels by tumors,

stimulate mutual adherence of cells, and enhance intercellular

communication. They also note that having higher serum vitamin D levels

is associated with reduced proliferation of high-risk epithelial cells

in the colon and that the vitamin helps prevent breast epithelial cell

mitosis.

The authors observed that vitamin D doses of up to 1000 IU per day are

unlikely to produce toxicity and comment that this dose would be

consistent with maintaining serum vitamin D levels at or above 30

nanograms per milliliter. Serum levels of vitamin D lower than 30 ng/mL

have been associated with double the risk of colon cancer than that

experienced by individuals with higher levels.

The review concludes that Supplemental vitamin D intake could address

the high prevalence of vitamin D deficiency in the United States... The

cost of a daily dose of vitamin D3 (1000 IU) is less than 5 cents, which

could be balanced against the high human and economic costs of treating

cancer attributable to insufficiency of vitamin D. & rdquo;

Coauthor Cedric F. Garland, who is a professor at the University of

California, San Diego School of Medicine & rsquo;s Department of Family

and Preventive Medicine, commented, & ldquo;A preponderance of evidence,

from the best observational studies the medical world has to offer,

gathered over 25 years, has led to the conclusion that public health

action is needed. Primary prevention of these cancers has largely been

neglected, but we now have proof that the incidence of colon, breast,

and ovarian cancer can be reduced dramatically by increasing the

public's intake of vitamin D. "

" Many people are deficient in vitamin D, & rdquo; he added. & ldquo;A glass

of milk, for example, has only 100 IU. Other foods, such as orange

juice, yogurt and cheese, are now beginning to be fortified, but you

have to work fairly hard to reach 1,000 IU a day. Sun exposure has its

own concerns and limitations . . . The easiest and most reliable way of

getting the appropriate amount is from food and a daily supplement.

Protocol

Colorectal cancer

In a population-based case-control study of 105 cases of colorectal

adenoma, serum concentrations of vitamin A were significantly inversely

related to the risk of colorectal adenoma when cases were compared with

the control group. The risk of developing colorectal adenomas was found

to be reduced in those with high vitamin A levels (Breuer-Katschinski et

al. 2001).

Retinol, retinoic acid, and beta-carotene (in nanomolar concentrations)

block stimulation of protein kinase C (PKC), which when stimulated has

been shown to increase tumor activity in the colon. It has been

suggested that beta-carotene could be useful in the prevention and

treatment of colorectal cancer (Kahl-Rainer et al. 1994), as

beta-carotene has been shown to down-regulate growth factors which

contribute towards proliferation of premalignant cells. Combined,

vitamin A and vitamin D3 have been shown to inhibit tumor-induced

angiogenesis (Majewski et al. 1996).

Convincing evidence is available showing that dietary calcium and

vitamin D impede the development of colonic carcinogenesis (Lamprecht et

al. 2001). Calcium supplementation and vitamin D both appear to have

antineoplastic effects in the large bowel; they appear to act together

to reduce the risk of colorectal adenoma recurrence (Grau et al. 2003).

Additionally, dietary vitamin D3 impedes the neoplastic process in

murine large intestine (Mokady et al. 2000) and vitamin D3 has

demonstrated the ability to inhibit liver cancer cell growth

(Alvarez-Dolado et al. 1999; Majewski et al. 1996).

http://www.lef.org/protocols/prtcl-148.shtml