A 30-year-old woman records her average daily intake of vitamin X as 8 mg. The RDA is 10 mg and the AI is not established for this vitamin; the UL is 40 mg. How should she interpret her intake relative to nutritional guidance?

• A. Because her intake is below the UL, it is considered safe and therefore adequate for all physiological needs, and no dietary changes are necessary.
• B. Her intake of 8 mg is irrelevant because RDAs apply only to children, and adults should use UL values exclusively to determine adequacy.
• C. Her intake is below the RDA and may be inadequate for nearly all people; she should aim to increase intake from foods and consult guidance if she remains below the RDA long term.
• D. Since an AI does not exist for this vitamin she is automatically considered deficient regardless of intake and must begin high-dose supplementation immediately to reach a presumed adequate level.

Answer: (C)