Three nutrients come up again and again when it comes to women’s health, and each has a different story.

Iron is lost through menstruation, and needs rise during pregnancy. Women who eat little red meat, including many vegetarians, are at higher risk of low levels. Symptoms like fatigue, breathlessness and pale skin overlap with many other conditions, so get a blood test (including ferritin) before supplementing. Too much iron causes constipation and can be harmful in people with haemochromatosis.

Folate is essential for preventing neural tube defects. Australian guidelines recommend women planning a pregnancy take 400 micrograms of folic acid daily from at least a month before conception through the first three months. Some women, such as those with certain health conditions or a prior affected pregnancy, need a higher dose from their doctor.

Vitamin B12 is found almost exclusively in animal foods, so vegans need a supplement or fortified foods. Absorption can also be reduced by metformin, long-term acid-reducing medication and some gut conditions.

Food comes first: lean meat, legumes, leafy greens, eggs, dairy and fortified cereals cover a lot of ground. Pairing plant-based iron with vitamin C improves absorption.

Bottom line: Test, don’t guess. A simple blood test can show which nutrient, if any, you actually need.