All nutrients are essential, of course, but women have three particular factors that make some nutrients particularly important: pregnancy and lactation, menstruation, and menopause. Women need more of certain nutrients during those times, for a variety of reasons.
Because iron is lost during menstruation, women with particularly heavy periods–or low intake–could find that they need to get more in their diets or through supplements. As well, because blood volume increases during pregnancy women need extra iron then as well.
Due to the effects of menopause, women are five times more likely than men to develop osteoporosis, which is associated with a higher risk of fractures. The USDA recommends that women older than 50, or who have gone through menopause, get in 1,000 mg of calcium each day. Consider a vitamin D supplement as well, as that vitamin helps with calcium absorption.
Folic acid is important for pregnant women in particular because supplementation is associated with a reduced risk of birth defects like spina bifida. It is recommended that pregnant women and those considering becoming pregnant supplement with additional folic acid (also called vitamin B9), because the nutrient is important in the very early stages of pregnancy.
Women also need more vitamin B12 while pregnant and lactating, to support the needs of the growing fetus and their increased blood capacity. This vitamin is found in either fortified foods or animal-based proteins. If you aren’t eating much of those foods, for whatever reason–perhaps you are vegetarian or cannot handle certain foods because of morning sickness–consider a supplement to ensure you’re meeting your needs.