May 03, 2018
Eating oily fish and fresh legumes delays the onset of natural menopause by around 3 years, shows a new published analysis of data from the UK Women's Cohort Study (UKWCS).
Higher intake of vitamin B6 and zinc were also associated with modestly delayed menopause.
But consuming refined pasta and rice was linked to an earlier natural menopause by 1.5 years, and likewise, vegetarian women had an earlier natural menopause than nonvegetarians.
The research, the first of its kind in UK women, was led by Yashvee Dunneram, MSc, from the University of Leeds, UK, and published online April 30 in the Journal of Epidemiology and Community Health.
"Our findings confirm that diet may be associated with the age at natural menopause," write Dunneram and colleagues, adding that the results have public health relevance because "age at natural menopause may have implications on future health outcomes."
"Health practitioners might thus also need to take into account the diet of women when dealing with menopause-related issues."
"A clear understanding of how diet affects the start of natural menopause will be very beneficial to those who may already be at risk, or have a family history, of certain complications related to menopause," study author Janet Cade, PhD, Professor of Nutritional Epidemiology and Public Health, also at the University of Leeds, added in a press release.
First Study on Relationship of Diet to Menopausal Age in UK Women
The average age of menopause in UK women is around 51 years. Early menopause has been linked to osteoporosis, depression, and cardiovascular and coronary disease, and those women who go through menopause later are at greater risk of breast, endometrial, and ovarian cancer, the authors note.
They point out that a number of causes for the relationship between age and start of menopause have been previously considered, such as genetic, behavioral, and environmental.
"But there are fewer studies that look at the impact of diet," Dunneram said in the statement.
"This study is the first to investigate the links between individual nutrients and a wide variety of food groups and age at natural menopause in a large cohort of British women."
Over 35,000 women participated in the prospective UKWCS study, and of these, 914 women aged 40 to 65 years who experienced a natural menopause over a 4-year follow-up were included in the current analysis.
Data collected at baseline and 4 years included demographics, weight history, physical activity, reproductive history (age at last period, number of periods in previous 12 months, use of hormone replacement therapy), anthropometric, and other health-related factors.
Self-reported quantities of 217 foodstuffs eaten daily were also recorded.
Participants included 38% vegetarians, and most women were married, parous, and of a professional or managerial class. Only 8% of women smoked, and mean alcohol consumption was around 1 unit/day. Median age at menopause was 51 years in women included in the analysis.
Antioxidant Properties of Foods Offer a Possible Explanation
After adjustment for confounders, high intake of oily fish was associated with delayed onset of natural menopause by 3.3 years/portion/day (99% CI, 0.8 to 5.8), and fresh legumes (such as peas, beans, lentils) by 0.9 years/portion/day (99% CI, 0.0 to 1.8).
Furthermore, a higher intake of vitamin B6 was associated with a delayed menopause of 0.6 years/mg/day (99% CI, 0.1 to 1.2) and zinc of 0.3 years/mg/day (99% CI, –0.0 to 0.6).
In contrast, refined pasta and rice were associated with an earlier menopause of –1.5 years/portion/day (99% CI, –2.8 to –0.2).
"Our results suggest that some food groups (oily fish, fresh legumes, refined pasta and rice) and specific nutrients are individually predictive of age at natural menopause," the authors say.
One possible explanation they propose is that oily fish intake (omega-3 fatty acid) can potentially improve antioxidant capacity, thereby offsetting the adverse effects of reactive oxygen species and decreasing follicle breakdown (follicular atresia), delaying the onset of natural menopause. The antioxidant properties of legumes are thought to have a similar effect on delaying menopause.
High refined-carbohydrate intake, however, is considered to increase insulin resistance, which in turn affects estrogen levels, causing the release of luteinizing hormone which triggers ovulation, and thereby may cause more cycles and rapid depletion of oocytes, leading to earlier menopause.
In explaining the findings as they relate to vegetarians, Dunneram and colleagues suggest that a vegetarian diet, which usually consists of a high fiber intake and no animal fat-containing foods, may affect luteinizing hormone levels, follicle stimulating hormone levels, and length of the menstrual cycle.
"Previous studies have demonstrated that high fiber and decreased fat intakes were both associated with a lower estrogen level, which may account for the earlier age at natural menopause among vegetarians," they observe, although they caution that vegetarian status was self-reported in this study.
The study was supported by a grant from the UK Medical Research Council. Cade is Director of Dietary Assessment Ltd.