Final answer:
Folate (C) is the specific nutrient that most pregnant women cannot meet solely through diet and may require supplementation, with a minimum intake of 400 µg/day recommended to prevent neural tube defects in the fetus.
Step-by-step explanation:
Most of a pregnant woman's nutrient needs indeed can be met by consuming a healthful, balanced diet, but folate (C) is a specific nutrient of concern. The Food and Nutrition Board of the Institute of Medicine recommends that all women who might become pregnant consume at least 400 µg/day of folate from supplements or fortified foods. This recommendation is in place because folate is crucial for the prevention of neural tube defects (NTDs) in the developing fetus, and the body's demand for this B vitamin significantly increases during pregnancy.
While pregnant, the body requires additional nutrients, including iron, calcium, folic acid, and omega-3 fatty acids. Although a balanced diet is critical, some nutrients, especially folate and iron, are difficult to obtain in adequate quantities from diet alone. A balanced diet provides essential nutrients needed to maintain proper bodily functions, plus the vitamins and minerals to support good health and reproductive capability.