If you menstruate

Every entry whose writeup carries a note for if you menstruate. The note is the entry’s own — follow it for the full context. See this in the planner →

Supplements

• CalciumCalcium and iron compete for the same absorption pathway, so a calcium supplement taken with an iron-rich meal works against you. Separate them by a couple of hours.
• FeverfewTraditionally used to bring on menstruation, which is the flip side of the pregnancy caution.
• Folate (B9)Neural tube defects form in the first few weeks, usually before a pregnancy is confirmed. That is why the 400 mcg recommendation is written for anyone who could become pregnant, not from the point of a positive test.
• IronMonthly blood loss roughly doubles the requirement — 18 mg against 8 mg — and iron deficiency is the most common nutrient deficiency in this group worldwide. Heavy periods push it higher again. Test ferritin first rather than treating the symptoms, because fatigue and breathlessness are non-specific and this is one of the few supplements where guessing wrong does harm.
• Vitamin CTaken with an iron-rich meal it markedly increases how much non-haem iron you absorb, which matters more here than in almost any other group.
• Vitex (Chasteberry)Its main studied group — PMS and cyclical breast pain.

Movement

• RunningEndurance runners who menstruate are the group where iron deficiency shows up most often, through a combination of menstrual loss, foot-strike haemolysis and sweat losses. Worth a ferritin test if training is going badly, before assuming it is fitness.

Other situations