Copy of article in Nutrition and Cancer 2000; 36:238–41
July 13,
2000
From a press release
TORONTO -- A phytosterol, Beta-Sitosterol (SIT), identified in peanuts and
peanut products, has been shown to inhibit cancer growth, as well as to protect
against heart disease. Exciting new research published last week in Nutrition
and Cancer, (Vol. 36, No. 2), suggests this compound may inhibit cancer and may
help protect against heart disease.
Simply stated, phytosterols are natural chemicals found in plants. The most
common forms are Beta-sitosterol, Campesterol, and Stigmasterol, which are found
in high concentrations in some legumes, such as peanuts, plant oils and seeds.
Researchers at the State University of New York at Buffalo examined the SIT
content of several peanut products. They found that snack peanuts contain 160 mg
SIT/100 gm and regular peanut butter contains 157 mg SIT/100 gm. Peanut oil
contains approximately 198 mg SIT/100 gm, and is a good source of SIT. In fact,
refined peanut oil contains 38 per cent more protective SIT than refined (pure)
olive oil.
Dr. Atif Awad, co-investigator of the study and professor of nutrition at the
State University of New York at Buffalo said, "Studies from our laboratory and
others suggest that plant sterol consumption offers protection from colon,
breast and prostate cancer. Therefore, identifying peanuts and its products such
as peanut butter, oil and flour as good sources of SIT may provide major health
benefits."
Phytosterols and the Cancer Connection
Several theories regarding the mechanism of action of phytosterols as a
protective factor include inhibiting of cell division, stimulating death of
tumour cells and modifying some of the hormones that are essential to tumour
growth.
In another study by Dr. Awad, recently published in anti-cancer Research, mice
with human cancer tumours were fed either a phytosterol diet or a cholesterol
diet. Tumour size in animals fed the phytosterols was 33%
smaller and had 20% fewer shifts of cancer cells to lymph
nodes and lungs than in the cholesterol diet group. The article concludes, "Phytosterols,
which can be easily incorporated into our diet, may offer a relatively simple
and practical means for retarding growth and metastases of breast cancer cells."