Women who eat diets rich in iron (particularly from plant-based sources such as leafy vegetables and beans) are about 1/3 less likely to develop PMS than those who eat less iron. Now researchers have found that ingesting higher levels of zinc also help reduce PMS, although they can’t say why as yet. Still, many believe that deficiencies of the mineral may be linked to mood-related symptoms like depression and possibly menstrual cramps.
“A range of minerals is important for menstrual cycle health and for pre-menstrual syndrome,” stated study lead author Elizabeth Bertone-Johnson an associate professor of epidemiology at UMass Amherst. “Women should eat a balanced diet, and if they’re not getting enough nutrients from the foods they eat, they should take a multi-vitamin,” she added.
According to Bertone-Johnson, researchers think that higher levels of iron might reduce the pain and emotional symptoms of PMS by raising levels of serotonin, although they aren’t certain. Low levels of serotonin are known to play a significant role in clinical depression.
To conduct their study, Bertone-Johnson and her team reviewed three sets of food frequency questionnaires collected over a 10-year period from more than 3,000 American women, ages 25 to 42. All the women were enrolled in the ongoing Nurses’ Health Study II, which is exploring the influence of diet and lifestyle on women’s health.
They then compared the mineral intakes from food as well as supplements for nearly 1,060 women who had been diagnosed with PMS against those of roughly 1,970 women who had few if any PMS symptoms. Other factors linked to PMS, such as a woman’s age, weight, pregnancy history, use of oral contraceptives and her smoking and exercise habits were also taken into consideration.
However, not all forms of dietary iron are the same. It was primarily the iron found in plant foods and in supplements, non-heme iron, that reduced a woman’s chances of developing PMS. The heme iron coming from animal sources, such as red meat and poultry, did not have the same effect.
Bertone-Johnson suspects that non-heme iron had a stronger relationship with PMS because it’s easier to eat a diet rich in plant and supplement sources. For example, 3/4 of a cup of fortified cereal has 18 mg of non-heme iron, and a cup of lentil or beans has between 3 and 7 mg. But a 3-ounce serving of beef has only 2 to 3 mg of heme iron, so you would need to eat a large serving of beef to meet your daily iron needs, which is not advisable considering its saturated fat content.
Readers interested in reading the full study can find it in online in this week’s issue of the American Journal of Epidemiology.