Nutrition Q and A
with Linda White, M.D.
Question:
What do you know about remedies for vitiligo?
Answer:
Vitiligo is a skin condition that results in unpigmented white patches of skin. For unknown reasons, melanocytes, the pigment-producing cells in the skin, disappear from affected areas. One theory is that the body develops antibodies to its own melanocytes and destroys them.
Compared with healthy people, those with vitiligo often have diminished blood levels of folic acid and vitamins B12 and C. In a study of only eight patients, vitamin B12 shots and oral doses of folic acid and vitamin C significantly repigmented subjects' skin without side effects.1 A subsequent study treated 100 vitiligo patients with 10 mg folic acid and 2 mg vitamin B12 daily for three to six months. Definite repigmentation occurred in 52 patients, including 37 who exposed their skin to summer sun and six who used UVB lamps. Repigmentation was most evident on sun-exposed areas. In addition, vitiligo stopped spreading in 64 percent of the patients. The authors recommended that further studies investigate ideal vitamin dosages, UV exposure and treatment time.2
Free radical damage may play a role in this condition. Compared with normal cells, vitiligo melanocytes seem to have an antioxidant imbalance—they have normal superoxide dismutase but lower catalase and Co-Q10 and higher vitamin E levels than other cells.3 Blood levels of these antioxidants, however, seem to be normal.4 Although studies have yet to confirm these results, the preliminary data suggest that applying creams and lotions containing antioxidants such as vitamin C, carotenes, ginkgo (Ginkgo biloba) and green tea (Camellia sinensis) might be helpful.
Question:
What can I tell customers about gamma-oryzanol and menopausal symptoms?
Answer:
Gamma-oryzanol occurs naturally in grains and other foods, and commercial products isolate it from rice bran oil. Chemically, it's a mixture of ferulic acid esters.
Two uncontrolled studies have investigated the use of gamma-oryzanol for menopause. A Japanese study in the 1960s gave 13 women who had hysterectomies, also called surgical menopause, 100 mg gamma-oryzanol three times daily for 38 days and found that it halved menopausal symptoms such as hot flashes in more than 67 percent of the women.5 In a later Japanese study, 40 perimenopausal women received 300 mg gamma-oryzanol daily for four to eight weeks. Ninety percent of the women improved and 40 percent experienced "excellent effectiveness" in reducing menopausal symptoms.
In addition, women in this study with pre-existing high cholesterol significantly reduced their total cholesterol and triglyceride levels and increased their high density lipoprotein (HDL) cholesterol levels. Oxidation of these blood fats was also significantly reduced. No side effects were reported.6
Regarding the supplement's effect on blood fats, a range of other human and animal studies show that rice bran oil can lower blood cholesterol levels.7 Animal studies show that gamma-oryzanol significantly lowers several blood lipids, decreases cholesterol absorption and actually reduces aortic fatty streaks.8 And when added to a high-cholesterol diet, gamma-oryzanol significantly inhibits platelet aggregation—a plus for preventing heart attacks and strokes.9 It's also a potent antioxidant. One test-tube study found that gamma-oryzanol was more than four times as effective at stopping tissue oxidation than vitamin E.10
Question:
I've heard that calcium lowers the risk of colon cancer. Do studies back this up?
Answer:
Yes. Population studies have found that people who consume more calcium have a significantly reduced risk of colon and rectal cancer.11 In a randomized, double-blind trial, 930 patients with a recent history of a colon tumor took either 3 g calcium carbonate (1,200 mg elemental calcium) or placebo daily. Follow-up colonoscopies at one and four years indicated the calcium group was 24 percent less likely to have recurrent tumors—a risk reduction deemed moderate, yet still significant.12
Scientists have proposed that calcium binds bile acids in the bowel, thus inhibiting their carcinogenic effects. Animal studies show that dietary calcium supplementation protects against other types of colon cancer carcinogens as well.13
Linda B. White, M.D., is a freelance writer and editor and the co-author of Kids, Herbs and Health (Interweave Press, 1999).
References
1. Montes LF, et al. Folic acid and vitamin B12 in vitiligo: a nutritional approach. Cutis 1992;50:39-42.
2. Juhlin L, Olsson MJ. Improvement of vitiligo after oral treatment with vitamin B12 and folic acid and the importance of sun exposure. Acta Derm Venereol 1997;77:460-2.
3. Maresca V, et al. Increased sensitivity to peroxidative agents a possible pathogenic factor of melanocyte damage in vitiligo. J Invest Dermatol 1997;109(3):310-3.
4. Picardo M, et al. Antioxidant status in the blood of patients with active vitiligo. Pigment Cell Res 1994;7:110-5.
5. Murase Y, Iishima H. Clinical studies of oral administration of gamma-oryzanol on climacteric complaints and its syndrome. Obstet Gynecol Prac 1963;12:147-9.
6. Ishihara M, et al. Clinical effect of gamma-oryzanol on climacteric disturbance on serum lipid peroxides. Nippon Sanka Fujinka Gakkai Zasshi 1982 Feb;34(2):243-51.
7. Sugano M, Tsuji E. Rice bran oil and cholesterol metabolism. J Nutr 1997 Mar;127(3):521S-24S.
8. Rong N, et al. Oryzanol decreases cholesterol absorption and aortic fatty streaks in hamsters. Lipids 1997;32(3):303-9.
9. Seetharamaiah GS, et al. Influence of oryzanol on platelet aggregation in rats. J Nutr Sci Vitaminol (Tokyo) 1990 Jun; 36(3):291-7.
10. Hiramitsu T, Armstrong D. Preventive effect of antioxidants on lipid peroxidation in the retina. Ophthalmic Res 1991; 23(4):196-203.
11. Marcus PM, Newcomb PA. The association of calcium and vitamin D and colon and rectal cancer in Wisconsin women. Int J Epidemiol 1998;27:788-93.
12. Baron JA, et al. Calcium supplement for the prevention of colorectal adenomas. N Engl J Med 1999;340:1101-7.
13. Vinas-Salas J. Calcium inhibits colon carcinogenesis in an experimental model in the rat. Eur J Cancer 1998;32:1941-5.
