|
Growth In A Bottle
Can one find the positive effects of human growth hormone (hGH) injections—weight and fat loss; muscle, strength and endurance gains; and improved skin—in a pill? None of the available hGH products appears to have been the focus of well-designed, placebo-controlled research.
The one exception is a study on an oral homeopathic hGH preparation, which was produced through recombinant gene technology by Biomed Comm (the company's principal was also the study's lead investigator).1 Researchers found this hGH preparation decreases body weight and increases muscle mass. However, its effects on body fat and water retention were not reported in the study.
Neither the potential drawbacks of hGH injections, such as impaired carbohydrate metabolism, nor its potentially favorable effects on blood cholesterol, were reported.
One concern with hGH use is possible tumour growth promotion. Increasing levels of the hormone IGF-1 may increase breast cancer risk in premenopausal women.2 More rigorous research is needed to examine the efficacy and long-term effects of oral hGH products.
Tocotrienol Action
Vitamin E contains various substances, including alpha-tocopherols and tocotrienols. The polyunsaturated forms of tocopherol are found in rice bran, palm oil and cranberry seeds. These natural antioxidants appear to influence blood cholesterol metabolism in much the same way as statin drugs do.3
Researchers in several human studies have found that tocotrienols do not always lower blood cholesterol.4,5 The most recent studies, however, suggest that a proprietary tocotrienol derived from rice bran extract can improve blood lipids when combined with a low-cholesterol and reduced-fat diet, even in conjunction with statin drug use.6,7 The tocotrienols and statin drugs work synergistically for a better outcome.
The safety of long-term tocotrienol use is unknown. In a recent animal toxicology study, researchers found that liver function and blood-cell profiles could be altered with tocotrienol supplementation.8
Genistein: A Long-Term Solution?
Isoflavones, including genistein, are abundant in soy and red clover and are widely used to help treat menopausal symptoms and reduce breast cancer risk. Isoflavones, which exert mild estrogenlike effects, are classified as phytoestrogens.
Despite the growing popularity of isoflavones for treating these conditions, there is little convincing evidence supporting long-term safety, efficacy, or lack of adverse effects in treating women with breast cancer or those at risk.9 Animal studies show either a preventive effect against chemical-induced breast cancer10 or a promoting effect among animals with implanted human breast cancer cells.11
The doses that have been used in animal studies are comparable to approximately two standard servings of soy products per day, or 6.25g soy protein.
In a human study, 84 premenopausal women who received 45mg isoflavones for 14 days prior to breast surgery experienced a mild estrogenic effect, helping prevent the effects of lowered estrogen levels on normal breast tissue.12
One area of human research that needs more exploration is the interaction between tamoxifen and isoflavone-rich products when both are used by breast cancer survivors. In a recent study of human breast cancer cells, researchers found a positive interaction between the drug and the plant estrogen.13
Anthony Almada, BSc, MSc, is a nutrition and exercise biochemist and has collaborated on more than 50 university-based clinical trials. He is the co-founder of EAS and founder and chief scientific officer of IMAGINutrition.
References
1. Brewitt B, et al. Homeopathic human growth hormone for physiologic and psychologic health: three double-blind placebo-controlled studies. Altern Compl Ther 1999;5:373-85.
2. Campbell MJ, et al. IGF status is altered by tamoxifen in patients with breast cancer. J Clin Pathol Mol Pathol 2001;54:307-10.
3. Parker RA, et al. Tocotrienols regulate cholesterol production in mammalian cells by post-transcriptional suppression of 3-hydroxy-3-methylglutaryl coenzymeA reductase. J Biol Chem 1993;268:11230-8.
4. Mensink RP, et al. A vitamin E concentrate rich in tocotrienols had no effect on serum lipids, lipoproteins, or platelet function in men with mildly elevated serum lipid concentrations. Am J Clin Nutr 1999;69:213-9.
5. O'Byrne DS, et al. Studies of LDL oxidation following alpha-, gamma-, or delta-tocotrienyl acetate supplementation of hypercholesterolemic humans. Free Radical Biol Med 2000;29:834-45.
6. Qureshi AA, et al. Novel tocotrienols of rice bran modulate cardiovascular disease risk parameters of hypercholesterolemic humans. J Nutr Biochem 1997;8:290-8.
7. Qureshi AA, et al. Synergistic effect of tocotrienol-rich fraction (TRF25) of rice bran and lovastatin on lipid parameters in hypercholesterolemic humans. J Nutr Biochem 2001;12:318-29.
8. Nakamura H, et al. Oral toxicity of a tocotrienol preparation in rats. Food Chem Toxicol 2001;39:799-805.
9. Messina MJ, Loprinzi CL. Soy for breast cancer survivors: a critical review of the literature. J Nutr 2001;131(Suppl):3095S-108S.
10. Shao ZM, et al. Genistein exerts multiple suppressive effects on human breast carcinoma cells. Cancer Res 1998;58:4851-7.
11. Ju YH, et al. Physiological concentrations of dietary genistein dose-dependently stimulate growth of estrogen-dependent human breast cancer (MCF-7) tumors implanted in athymic nude mice. J Nutr 2001;131:2957-62.
12. Hargreaves DF, et al. Two-week dietary soy supplementation has an estrogenic effect on normal premenopausal breast. J Clin Endocrinol Metab 1999;84:4017-24.
13. Tanos V, et al. Synergistic inhibitory effects of genistein and tamoxifen on human dysplastic and malignant epithelial breast cells in vitro. Eur J Obstet Gynecol Reprod Biol (in press).
|
