Vitamin Supplements

Diagnosis

Diagnosis for mild vitamin and mineral deficiencies is technically complex and may be open to variation among laboratories. There are two distinct methods of biochemical diagnosis of vitamin deficiencies. One method involve examining vitamins (or their metabolites) in blood, urine, or tissue samples. These levels are compared with a population reference range for the nutrient, which, as described earlier, may or may not reflect the nutrient needs of HIV-infected people.

The other method of diagnosis involves loading tests of vitamins and tests of enzymatic function. While these tests do not need population reference ranges, and are considered more reliable by some, they are routinely available. The acute phase response (APR) may also affect observed vitamin levels. The APR is a set of metabolic changes, induced by cytokines such as Interleukin-6 (IL-6) and Tumor Necrosis Factor (TNF), which naturally occur in response to infection, cancer, or inflammation. Observed nutrient may be considerably altered during the APR because they are sequestered in intracellular compartments. Whether deficiencies observed during the APR are functional or just signs of altered vitamin metabolism and circulation is unknown. Hair analysis is a method of diagnosis used by some physicians and alternative health practitioners. However, hair analysis is not an established, validated method for clinical practice. It is primarily a research tool and may have some use detecting heavy metal poisoning in populations. Hair analysis is not reliable for individual nutrient analysis for several reasons. Vitamin and mineral levels in hair have not been correlated to the clinical or biochemical condition in the body. Hair care products and other environmental factors may also impact vitamin and mineral levels in hair. Furthermore, some reports suggest that hair analysis laboratories are not standardized, with wide variation among them. At its worst, some authors suggest that hair analysis is more a marketing tool than a method of diagnosis. In some cases, even healthy people are told to purchase many types of vitamin supplements based on hair analysis diagnosis of "deficiency."

* High Vitamin Content is due to fortification
Adapted from The Vitamins, by Gerald F. Coombs Jr. New York. The Academic Press, 1992.