GLOSSARY

Vitamin D Status Table

NASEM interpretation of serum 25-hydroxyvitamin D as summarized by NIH ODS; this is not a universal athlete performance target.

Vitamin D Status Vitamin D status assessed with an appropriate clinical method and interpretation, rather than inferred solely from reported sun exposure.

Nutrient status reflects intake, absorption, distribution, stores, losses and physiological demand. A normal blood concentration may not exclude depleted stores, while an abnormal result can have non-nutritional causes. Calcium in blood, for example, does not directly measure dietary calcium adequacy or skeletal reserves. Different nutrients require different assessment strategies. Select tests for a defined clinical question and interpret them with symptoms, diet, relevant disease and sampling conditions instead of ordering a broad panel and assuming every number is a performance target.

A recovery biomarker quantitatively relates to intake or expenditure under a specified balance model, whereas a concentration biomarker is influenced by absorption, metabolism and other factors. Predictive biomarkers use a calibrated relationship that may depend on the studied population. Distinguish intake biomarkers from markers of tissue status, function or disease. Blood, urine and tissue measurements answer different questions. Sampling conditions, recent exercise, hydration and inflammation can affect interpretation; no single biomarker provides a complete nutritional assessment or proves the cause of poor performance.

An adequate diet provides sufficient energy and essential nutrients while fitting health needs. A high score for variety or a healthy food label cannot independently demonstrate adequacy. Review what is actually eaten, including foods excluded and suitable replacements. Athletes can consume many vegetables yet still lack enough energy or carbohydrate for training. Assess the overall pattern, distribution and relevant nutrient risks rather than assuming that a single food or supplement makes the entire diet balanced.