Post by Joann on Nov 5, 2007 11:04:17 GMT -5
Diet and Exercise May Help Prevent Ovulation-Linked Infertility
This is the very first time to my knowledge that a mainstream, med report associates better diet with fertility.
Note positive correlation with high fat dairy!
By Judith Groch, Senior Writer, MedPage Today
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco
November 02, 2007
BOSTON, Nov. 2 -- Following a so-called fertility diet and exercising may promote fecundity in otherwise healthy women with an ovulatory disorder, researchers here reported.
Action Points
• Explain to interested patients that in this observational study following a healthy diet and exercising reduced the risk of infertility caused by an ovulatory disorder.
• Tell patients that these results need to be reproduced in large randomized trials, but these lifestyle practices are consistent with an overall healthy lifestyle.
Women who followed a combination of five or more lifestyle factors, especially dietary changes, had a more than 80% reduction in their risk of ovulatory infertility compared with those who undertook none of these changes, Jorge Chavarro, M.D., and Walter Willett, M.D., of the Harvard School of Public Health, and colleagues, reported in the Nov. 1 issue of Obstetrics & Gynecology.
Surprisingly, the researchers noted, high fertility scores were related to consuming more high-fat dairy products versus low-fat products, for which they had no obvious explanation.
Drs. Chavarro and Willett are co-authors of a book called The Fertility Diet: Groundbreaking Research Reveals Natural Ways to Boost Ovulation & Improve Your Chances of Getting Pregnant, scheduled for publication next month.
The study involved 17,544 married women from the Nurses' Health Study II, none with a history of infertility, who were trying to become pregnant or became pregnant. The women were followed for eight years, and there were 3,209 incident reports of infertility for any cause. There were 416 women reporting ovulatory disorder infertility.
Dietary information was collected in 1991 and 1995, using a validated food-frequency questionnaire. The team devised a scoring system for dietary and lifestyle factors based on data previously related to lower ovulatory disorder infertility.
Among these factors were the ratio of monounsaturated to trans fats in diet; protein consumption (from animals or vegetable); carbohydrate consumption (including fiber intake and dietary glycemic index); dairy consumption (low-fat and high-fat); iron consumption, multivitamin use; body mass index; and physical activity.
He adjusted relative risk of ovulatory disorder infertility comparing women in the highest quintile of the fertility diet score with women in the lowest quintile, found that the high-quintile women had a 66% reduced risk of ovulatory disorder infertility (relative risk 0.34, 95% confidence interval 0.23- 0.48; P for trend 0.001).
This inverse relation was similar in subgroups defined by women's age, parity, and body weight.
A combination of five or more low-risk lifestyle factors, including diet, weight control, and physical activity was associated with a 69% lower risk of ovulatory disorder infertility.
The risk of ovulatory infertility decreased with increasing number of low-risk lifestyle habits followed, the researchers said.
For example, compared with women who did not follow any of these habits, women following one of the habits had a 30% lower risk of infertility (P=0.02).
The risk of ovulatory infertility was lower for each additional low-risk lifestyle habit followed, up to an 84% lower risk for women following five or more habits, the researchers said.
Time spent in vigorous physical activity was unrelated to overall infertility or infertility because of ovulatory disorders. However, when BMI, which is partly determined by physical activity, was removed from the model, women who exercised vigorously for 30 minutes or more each day had a slightly lower risk of ovulation infertility (RR 0.78, CI 0.58-1.05).
These finding were similar for different subgroups of women regardless of age and whether they had been pregnant in the past, the researchers said.
These results suggest that the majority of infertility cases caused by ovulation disorders are preventable through modification of diet and lifestyle. The proportion of cases potentially preventable by following this strategy could be even higher in the general population because the prevalence of obesity was lower in this cohort (10%) than among comparable women in the general U.S. populations (29%), they said.
Because this dietary pattern favors low-glycemic foods while limiting the intake of nutrients that may increase insulin resistance, such as trans fatty acids, these results are also consistent with the overall hypothesis that glucose homeostasis and insulin sensitivity are important determinants of ovulatory function and fertility in otherwise healthy women, Dr. Chavarro and colleagues wrote.
Important study limitations, the investigators said, included the fact that it was not a cohort of women known to be trying to conceive, although the cohort was restricted to married women whose pregnancies were more likely to be intentional.
Also, imperfect measurement of diet and physical activity, and other factors might have influenced the findings. Because this was an observational study, the possibility of confounding factors remains.
Although large randomized trials are needed to reproduce these findings, this study suggests that women with ovulatory disorders trying to get pregnant should consider these lifestyle practices because they are consistent with an overall healthy lifestyle and may also help them conceive, the researchers concluded.
Drs. Chavarro and Willett reported no potential conflicts of interest. The book by Drs. Chavarro and Willett, written with Patrick Skerrett, is to be published by McGraw-Hill/Harvard Health Publications.
Primary source: Obstetrics & Gynecology
Source reference:
Chavarro JE, et al "Diet and Lifestyle in the Prevention of Ovulatory Disorder Infertility"Obstet Gynecol 2007; 110: 1050-1058.