Cobalt

Hair may be used for monitoring excess exposure to cobalt (Co). However, hair is occasionally contaminated by external Co from some hair treatments. If an individual’s hair has been treated with permanent solutions, dyes, or bleach, the Co levels may not be indicative of body Co accumulation.

The primary clinical manifestations of chronic Co toxicity include weight loss, pulmonary syndrome, allergy, nausea, cardiomyopathy, electrolyte imbalance, hematological disorders, and thyroid lesion.

The dietary content of Co is highly variable and depends upon types of foods eaten, geographical location, and type of soil. Toxicity has been noted with ingestion of 250-400 mg/day. Recent animal studies indicate that excess Co can cause marked impairment of myocardial metabolism that results in metabolic acidosis.

Hair analysis cannot be used to assess vitamin B-12 status. Appropriate tests for determination of B-12 status are the measurement of urine levels of methylmalonic acid (elevated with B-12 coenzyme deficiency/dysfunction), quantitative blood assay for vitamin B-12, and urine amino acids analysis (several metabolic steps require vitamin B-12).

One can not determine vitamin B-12 status by use of hair analysis, and the clinical significance of low hair Cobalt (Co) levels is not known. Hair is analyzed for Co primarily for detection of excessive intake of the potentially toxic element.

There is little evidence that Co has an essential function in humans other than as an obligatory constituent of the vitamin B-12 molecule. Humans absorb Co as inorganic Co and as vitamin B-12; the body pools of each fluctuate independently. Humans cannot convert inorganic Co to vitamin B-12.

The dietary content of Co is highly variable, depending upon types of foods eaten, geographical location and type of soil. Vegetarians often have lower Co levels than meat eaters.

Appropriate tests for determination of vitamin B-12 status are the measurement of urine levels of methylmalonic acid (elevated with vitamin B-12 coenzyme deficiency/dysfunction), a quantitative blood assay for vitamin B-12, a urine amino acids analysis (several metabolic steps require vitamin B-12), and diet analysis.

Hair may be used for monitoring excess exposure to cobalt (Co). However, hair is occasionally contaminated by external Co from some hair treatments. If an individual’s hair has been treated with permanent solutions, dyes, or bleach, the Co levels may not be indicative of body Co accumulation.

Humans absorb Co both as inorganic Co and as vitamin B-12; the body pools of each fluctuate independently. Humans cannot convert inorganic Co to vitamin B-12, and vitamin B-12 provides the only documented function of Co in humans. Thus, a high hair Co level does not mean that vitamin B-12 levels are high or even adequate.