Iron supplementation can cause a zinc deficiency—implications for anger and depression

Even borderline anemia due to mild iron deficiency has profound effects. But as this study recently published in the British Journal of Nutrition reveals, care must be taken to avoid creating a functional zinc deficiency even when iron supplementation is necessary. The authors begin by observing...

"Interventions to combat mild Fe deficiency in women of childbearing age may affect Zn nutriture."

Three groups of subjects with low iron were randomly assigned to one of three groups: dietary advice, a daily iron supplement and placebo. Their data showed that serum zinc increased in the dietary advice group (who ate more meat) and the placebo group. In the iron supplement group zinc decreased, leading to their conclusion:

"Zn status was not improved compared with placebo by an Fe-based dietary intervention. However, a daily moderate-dose Fe supplement with meals appeared to lower Zn status in these young adult women."

Among its many functions, zinc is involved in neurotransmitter production and the regulation of mood. This important study recently published in the European Journal of Clinical Nutrition begins with the observation...

"The relation of zinc (Zn) nutriture to brain development and function has been elucidated. The purpose of this study is to examine whether Zn supplementation improves mood states in young women."

The authors used a double-blind, randomized and placebo-controlled procedure to correlate psychological measures, somatic symptoms and serum zinc in two groups who took either a multivitamin or a multivitamin with zinc daily for 10 weeks. What did their data reveal?

"Women who took MV and Zn showed a significant reduction in anger–hostility score and depression–dejection score in the Profile of Moods State (POMS) and a significant increase in serum Zn concentration, whereas women who took only MV did not."

The authors summarized their findings by concluding:

"Our results suggest that Zn supplementation may be effective in reducing anger and depression."

It's easy to see the strong biological momentum to feeling angry and/or depressed around menstruation? Iron is a necessary co-factor for both serotonin and dopamine. Supplementing iron can reduce zinc status, also an important mood-regulating co-factor. Even without adding the hormonal component it's clear why so many women need help with this.