Nutrition Overview

Nutrition is essential for maintaining good health, and it plays an important role in the prevention of certain diseases. Malnutrition, which encompasses undernutrition, micronutrient deficiency or excess, and diet-related conditions such as obesity,¹ remains a serious public health concern in the United States.^{2 , 3} The Food and Nutrition Board of the National Academies of Sciences, Engineering, and Medicine has established a comprehensive series of nutrient reference values called the Dietary Reference Intakes; these values include Recommended Dietary Allowances (RDA) and Tolerable Upper Intake Levels.^{4 , 5}

The nutritional needs for women change across their life course. Pregnant women require higher intakes of certain nutrients than nonpregnant women to support both their health and fetal development. For example, folate is involved in cell division and nucleic acid synthesis, and studies have reported that women who do not have adequate folate intakes have a higher risk of giving birth to infants with neural tube defects (e.g., anencephaly, spina bifida).^{6 , 7} Neural tube defects occur during the early stages of pregnancy, often before a woman knows she is pregnant; therefore, obtaining adequate amounts of folic acid, a form of folate, during the periconceptional period is critical for reducing the risk of these defects.⁶ Because it can be difficult to consume the necessary amount of folic acid from diet alone, several organizations, including the U.S. Preventive Services Task Force and the Centers for Disease Control and Prevention, recommend that women who are capable of becoming pregnant take a daily supplement that contains at least 400 mcg of folic acid.^{8 , 9} The RDA for folate also increases during pregnancy. Other nutrients that have higher intake recommendations during pregnancy include iodine, vitamin B6, vitamin B12, iron, magnesium, zinc, and omega-3 fatty acids.¹⁰ Conversely, excessive intakes of certain nutrients (e.g., preformed vitamin A) can be harmful during pregnancy.¹⁰

Increasing the intakes of certain nutrients may also help mitigate some of the effects of lower estrogen levels during perimenopause and menopause. Notably, the RDA for calcium increases from 1,000 mg for younger women to 1,200 mg for women over 50 to reduce bone loss and the risk of osteoporosis after menopause.¹¹ Vitamin D also plays an important role in bone health and reducing the risk of osteoporosis. The vitamin D RDA increases from 15 mcg to 20 mcg after age 70.¹²

The absorption of nutrients can also be affected by certain disorders. Celiac disease, which is predominately diagnosed in women, is an autoimmune disorder that causes damage to the lining of the small intestine. This damage impairs the absorption of certain nutrients, including folate, vitamin B12, and iron. As a result, malnutrition is a potential long-term effect of celiac disease; the combination of nutritional deficits and inflammation may explain why celiac disease has also been associated with infertility and pregnancy loss.¹³ Eating disorders, such as anorexia nervosa and bulimia nervosa, are also more common in girls and women than in boys and men, and these conditions can make it difficult for an individual to meet their nutritional needs and cause long-term effects on health.¹⁴

Research is ongoing in the field of nutrition and women’s health. One active area of research is evaluating the effects of diet and nutrition on the gut microbiome, which can play a role in the development of a number of disorders. These include certain cancers, such as breast cancer.¹⁵

A study supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) found that low levels of vitamin D during the first trimester of pregnancy increased the risk of preterm birth. A secondary analysis of data from a prospective cohort study revealed that, among 351 nulliparous women, those who had serum levels of 25-hydroxyvitamin D that were less than 40 nmol/L during weeks 6 to 13 of pregnancy had a risk of delivering a preterm infant that was 4.35 times higher than women with serum levels of 80 nmol/L or more during the same timeframe. In addition, infant length at birth also increased with higher maternal levels of vitamin D during the first trimester.¹⁶

The Office of Nutrition Research coordinates and supports research initiatives on nutrition across NIH. These initiatives include the clinical research conducted by several branches of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), such as the Digestive Disease Branch and the Diabetes, Endocrinology, and Obesity Branch.