Natural Foods Merchandiser

Science Beat

Low Vitamin C Intake Increases Chance of Pregnancy Complication
Women with low intakes of vitamin C before and during pregnancy have an increased risk of preterm delivery compared with women taking higher amounts, according to a new study in the American Journal of Obstetrics and Gynecology (2003:189;519?25).

The normal time from conception to birth is between 37 and 41 weeks, so births that occur less than 37 weeks after conception are considered preterm. There are several known causes of preterm delivery but premature rupture of the membranes is the most common.

Rupture of the membranes of the fetal sac normally occurs early in labor. When it precedes the onset of labor by more than one hour, it is known as PROM and is associated with 30 percent to 40 percent of preterm deliveries. Several nutrients, including magnesium, copper and vitamin C, are important for maintaining the strength of the membranes. Previous studies have found that low levels of vitamin C in maternal blood and amniotic fluid can contribute to weaker membranes.

The current study analyzed the vitamin C intake and pregnancy outcomes for 2,064 women who entered the study between 24 and 29 weeks past conception. They answered questions about their dietary habits, lifestyle habits and supplement use both before and during pregnancy. Vitamin C intake was calculated based on these answers. The average total vitamin C intake among the participants was 124 mg per day before conception and 251 mg per day in the second trimester. Women with vitamin C intake in the 10th percentile or lower had an average total intake of 24 mg per day before conception and 112 mg per day in the second trimester.

Women in the 10th percentile or lower for vitamin C intake either before or during pregnancy were found to have a significantly increased risk of preterm delivery due to PROM, compared with women with higher intake; the greatest increase in risk, however, was found in women whose intake was low both before and during pregnancy.

The results of this study suggest that very low intake of vitamin C is associated with increased risk of preterm births due to PROM. Moreover, they suggest that the amount and cost of supplemental vitamin C needed to reduce the risk of preterm delivery due to PROM would be minimal. Further studies are needed to confirm this relationship and to identify the effect of higher intake of vitamin C on pregnancy outcomes.

Selenium Reduces Prostate Cancer Risk
Men with high selenium intake are less likely to develop prostate cancer than men with low selenium intake, reports a new study published in Cancer Epidemiology, Biomarkers and Prevention (2003:12;866?71).

Selenium is a trace mineral that plays a role in a critical antioxidant pathway in the body. It is also important for normal immune function and might have a direct toxic effect on cancer cells. Selenium is found in wheat germ, Brazil nuts, barley, wheat bran, garlic and some other grains and vegetables.

More than 15 percent of U.S. men will develop prostate cancer in their lifetimes, and more than 3 percent will die from it. A number of U.S. studies have found that men with low intake of selenium have a higher risk of prostate cancer than men with high intake of selenium, suggesting that selenium might have a protective role. In addition, one controlled trial found that people given 200 mcg of supplemental selenium per day (in the form of high-selenium yeast) for seven years had a 50 percent lower risk of death from cancer, including prostate cancer, than people given placebo.

In the current study, 1,733 men in the Netherlands were observed for about six years. Participants answered a dietary questionnaire at the beginning of the study to assess their intake of antioxidants and other nutrients. Selenium levels were measured in toenail clippings, which were collected from participants at the beginning of the study and during each year of follow-up. The risk of developing prostate cancer was found to be 31 percent lower in men with high toenail selenium levels compared with those whose toenail selenium levels were low. The protective effect of selenium was found to be more pronounced in men whose intake of other antioxidants, especially vitamin C and beta-cryptoxanthin (a carotenoid), was low.

The results of this study are consistent with those of studies performed in the United States showing that high selenium intake reduces prostate cancer risk. Clinical trials to measure the potential preventive effect of selenium supplementation on prostate cancer risk, and to identify optimal amounts, are currently under way.

Maureen Williams, N.D., received her doctorate of naturopathic medicine from Bastyr University in Seattle, Wash. She has a private practice in Quechee, Vt.
Copyright ? 2003 Healthnotes Inc.

Natural Foods Merchandiser volume XXV/number 1/p. 56

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