Animal studies with Se-garlic

According to much research and documentation over the past six years, Se-enriched garlic contains cancer preventive properties. Several researchers conducted a study of long-term versus short-term dosage in mammary cancer prevention in the rat. These scientists discovered that a short-term (one month) exposure to Se-garlic in rats, implemented immediately following the carcinogenic insult (DMBA), could prevent subsequent mammary tumor development that usually occurs months later.

The findings suggested that immediate selenium treatment truly did produce a positive impact on the rats following exposure to carcinogenic sources. In fact, a one-month administration produced the same results as Se treatment for five months. However, Se administration 13 weeks after a carcinogenic exposure generated no impact on the growth or number of mammary tumors developing.

In another study, scientists examined whether the selenium in Se-enriched garlic was responsible for the cancer prevention, as opposed to other compounds found in the garlic itself.

It is yet unknown why transformed cells in the early stages of carcinogenesis express more sensitivity to selenium intervention than those in the late stage. One theory suggests that Se-garlic, partly through the action of MSC, blocks clonal expansion and/or alters clonal selection of transformed cells. It may do so by inducing apoptosis and by interfering with the cell cycle transit.

Human intervention studies

Unfortunately, very few human trials have been conducted to measure the effect of selenium supplementation on the incidence of cancer.

Funded by the National Cancer Institute in 1983, Larry Clark and other cancer researchers (Clark et al. 1996) conducted a randomized controlled trial to determine whether selenium supplementation would affect the incidence of carcinoma of the skin.

The researchers introduced a 200 *g dose of Se as high-Se brewer's yeast or a placebo yeast. The blinded phase of the study concluded early due to secondary endpoint findings.

While scientists found no significant difference between placebo and selenium for the primary indication of skin carcinomas, significant differences became evident for secondary endpoints of total cancer mortality, total cancer incidence and the incidences of lung, prostate and colorectal cancers (Clark et al. 1996, Combs et al. 1997). In other words, introduction of selenium produced important results regarding cancer incidence and mortality.

Total cancer incidence recorded at 37% lower with a 50% reduction in cancer mortality in the Se group. The researchers cautiously determined that supplemental selenium might reduce the incidence and mortality of cancer and further recommended an independent trial for confirmation.

Not all studies show a correlation between selenium levels and cancer incidence. One study of 60,000 nurses compared levels of selenium in toenail clippings and cancer incidence without finding any apparent benefit in higher selenium levels (Garland et al. 1995).

Clinical trial collaboration: City of Hope and Integrated BioPharma

A phase one human clinical trial nears the horizon, as Integrated BioPharma Inc. (INB) and the City of Hope Cancer Center recently entered into a collaborative research and development agreement. The study will scrutinize PhytoSel™, INB's plant-derived form of selenium, and its ability to assuage the side effects of two chemotherapy drugs.

Expected to begin in early 2006, the study will last one year as scientists work to determine if high doses of PhytoSel™ might lessen the chemo drugs' side effects, like mucositis, diarrhea and lowered blood counts. If this form of selenium proves successful, doctors might then administer greater doses of chemotherapy with fewer side effects, ultimately achieving more effective cancer treatments.

Sources:

Block, E. (1996) In: Phytochemicals in Cancer Prevention and Treatment. Plenum Press, New York, pp. 155-167.

Brown and Shrift (1982) Biol. Rev 57: 59-84.

Cameron (1980) Sci. Proc. Royal Dublin Soc. 2: 231-233.

Clark et al. (1996) J. Am. Med. Assoc. 276:1957-63.

Combs, et al. (1997) Biomed Environ Sci 10:227-234.

El-Bayoumy, K. (1991) In: Cancer Principles and Practice of Oncology, 4th Edn. J.B. Lippincott, Philadelphia, PA. pp.1-15.

Garland, et al. (1995) J. Natl Cancer Inst 87:497-505.

Ge, et al. (1996) Anal. Commun. 33:279-281.

Ip and Ganther (1992a) In: Cancer Chemoprevention pp. 479-488. Boca Raton FL. CRC Press.

Ip and Ganther (1992b) Carcinogenesis 13:1167-1170.

Ip and Hayes (1989) Carcinogenesis 10:921-925.

Ip and Lisk (1993) Nutrition and Cancer 20:129-137.

National Research Council (1989). Food and Nutrition Board, Recommended Dietary Allowances.10th ed. Washington, DC National Academy Press.

National Research Council (1980) Food and Nutrition board. Recommended Dietary Allowances. 9th ed. Washington, DC National Academy Press.

Poirier, K.A. (1994) In: Risk Assessment of Essential elements. Washington, DS: ILSI Press. 5)