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A Healthful Diet in Childhood Linked to Starting Menstrual Periods Later, Regardless of BMI or Height

Eating a healthful diet in childhood is linked to a later onset of menstruation in girls compared with those who consumed a less healthful diet, according to a new study published in Human Reproduction.

The findings remained unaltered by the girls' BMI or height, both of which have been associated with the earlier onset of periods.

The study has implications for health in later life as it is well known that women who started their periods at an early age may be at higher risk for diabetes, obesity, breast cancer, and diseases of the heart and blood vessels.

Holly Harris, MPH, ScD, an associate professor at the Fred Hutchinson Cancer Center in Seattle, who led the study, explains: "I think our findings highlight the need for all children and adolescents to have access to healthful meal options, and the importance of school breakfasts and lunches being based on evidence-based guidelines."

The findings come from a large, prospective study of more than 7,500 children, aged 9 to 14, who were enrolled in the US Growing Up Today Study in two waves, 1996 and 2004. The researchers followed them through to 2001 and 2008, respectively.

For the first time, the researchers investigated the link between specific diets and the age that periods first started (menarche). They are also the first to examine whether BMI might have a modifying effect on the association between diet and age of menarche. Previous studies have only looked at BMI as a confounding factor when analyzing results.

Harris says: "In previous work that we had conducted in the Nurses' Health Study II—an ongoing prospective cohort—we observed a higher risk of breast cancer among people who consumed an inflammatory-promoting diet during adolescence and early adulthood. Following these results, we were interested in understanding whether earlier life dietary intake might influence breast cancer through impact on risk factors for breast cancer that occur between early life and breast cancer, such as age at menarche. This led to the current study, where we examined the impact of dietary patterns on age at menarche."

Before their periods started, the children completed questionnaires about their diet when they joined the study and then every one to three years thereafter. They also reported their age when their first period started.

The researchers assessed the girls' diets against two established dietary patterns: the Alternative Healthy Eating Index (AHEI), and the Empirical Dietary Inflammatory Pattern (EDIP). The AHEI awards more points for healthier foods—such as vegetables, legumes, and whole grains—and fewer points to unhealthful foods like red and processed meats, trans fats, and salt. The EDIP scores diets in a way that reflects their overall potential for causing inflammation in the body. Foods linked to greater inflammation include red and processed meat, refined grains, and high-energy drinks.

A total of 6,992 girls—93% of the whole group—had their first period during the study. Analysis of data from the questionnaires showed that the 20% of girls with the highest AHEI score and who, therefore, had the healthiest diets, were 8% less likely to have their first period within the next month compared with the 20% of girls who had the lowest AHEI score. The 20% of participants with the highest EDIP score, which meant they had the most inflammatory diet, were 15% more likely to have their first period in the next month compared with the 20% who had the lowest EDIP score.

Harris explains: "We observed that these two dietary patterns were associated with age at menarche, indicating that a healthier diet was linked to menstrual periods starting at an older age. Importantly, these results were independent of BMI and height, demonstrating the importance of a healthful diet regardless of body size. As earlier age at menarche is associated with multiple later life outcomes, including higher risk of diabetes, obesity, cardiovascular disease, and breast cancer, this may be an important period for trying to reduce the risk of these chronic diseases."

The researchers believe that these results suggest the type of food eaten by girls during childhood and adolescence, and its impact on inflammation, may be what is influencing the time of menarche, rather than height and BMI.

"As this is the first study to look at these specific dietary patterns, it’s important to examine the association in other populations. It also highlights that eating a healthful diet, which we know is associated with chronic disease outcomes in later life, could also have benefits in adolescence. Generally, eating fruits, vegetables, whole grains, fatty fish, nuts and legumes, and polyunsaturated fatty acids—while limiting intake of red and processed meats, refined grains, sugar-sweetened beverages, and added salt—benefits everyone, regardless of age," Harris says.

The researchers now plan to look at childhood and adolescence dietary patterns and body size to see how they may relate to characteristics of menstrual cycles in adulthood.

Source: European Society of Human Reproduction and Embryology