Vitamin B in food, but not supplements, may decrease risk of PMS

Women who eat foods rich in B vitamins thiamine and riboflavin, such as spinach and fortified cereal, lower their risk of premenstrual syndrome (PMS), but women who rely on supplements for B vitamin intake don’t reap comparable benefits, according to a new study.

The case-control study, nested within the Nurses’ Health Study II cohort, examined the diets of more than 3,000 women using food surveys completed by the women 3 times over 10 years. During that period, 1,057 women developed moderate to severe symptoms of PMS, including anxiety, depression, irritability, fatigue, abdominal pain, and bloating. Intake of thiamine and riboflavin from food was inversely associated with PMS.

“We observed a significantly lower risk of PMS (P<.001) in women with high intakes of thiamine and riboflavin from food sources only,” the authors write. “Intake of B vitamins from supplements was not associated with a lower risk of PMS.” Further, the researchers did not observe a significant association between PMS and dietary intake of niacin, vitamin B₆, folate, or vitamin B₁₂.

To experience a benefit, women had to consume higher amounts of thiamine and riboflavin than those recommended by the Institute of Medicine (1.1 mg a day of each nutrient). Among those who reported eating about 1.9 mg of thiamine per day, approximately 2 in 5 developed PMS, compared with 3 in 5 women who ate 1.2 mg per day. Rates of PMS were the same for women who ate 2.5 mg of riboflavin per day compared with women who ate 1.4 mg.

Diet may offer an alternative to treating PMS with birth control pills or antidepressants, which can have side effects, the authors note.

The study published online February 23 in the American Journal of Clinical Nutrition.