cobalamin, cyanocobalamin, hydroxocobalamin

Cobalt is a hard, gray metal element. It's part of vitamin B-12. This vitamin is essential for making red blood cells (erythropoiesis). It also maintains the nervous system.

Cobalt is in the body only as part of vitamin B-12.

Cobalt has some of the same jobs as manganese and zinc. It can replace manganese in activating several enzymes. These are called biochemical reaction activators. It can also replace zinc in some biochemical reactions.

Cobalt is also part of the biotin-dependent Krebs cycle. This is the process that the body uses to break down sugars into energy.

As part of B-12, cobalt is used to prevent pernicious anemia. It's also needed to keep the nervous system working well.

There are no claims based on cobalt as a single element.

As part of supplements, cobalt is measured in micrograms (mcg). The average adult intake of cobalt is 5 to 8 mcg a day. A safe Recommended Dietary Allowance for cobalt hasn't been set yet.

Trace amounts of cobalt are found in most foods. Foods high in vitamin B-12 are the only source of cobalt used by the body.

It's best to take cobalt as part of vitamin B-12.

If you have a cobalt deficiency, this also means you have a vitamin B-12 deficiency. Anemia is a main cause of a cobalt and vitamin B-12 deficiency. This is the case with pernicious anemia. Symptoms can include numbness, severe tiredness (fatigue), and tingling in your hands and feet. Over time, the condition also leads to decreased nerve function.

Cobalt is toxic to the heart muscle. It can cause heart muscle disease (toxic cardiomyopathy) after too much exposure.

An increase in red blood cells (polycythemia) may be a symptom of too much cobalt. Not treating this issue can cause congestive heart failure.

Too much intake of cobalt may cause enlargement of the thyroid gland (goiter). It can also reduce the activity of the thyroid. Cobalt may also increase blood sugar levels.

Since cobalt is a key part of vitamin B-12, people with Leber syndrome, a rare eye condition, should not take it without talking to their doctors. Some forms of vitamin B-12 may lead to vision loss in people with this issue.

If you are pregnant or breastfeeding, talk with your doctor before taking any supplements.

There are no known food or medicine interactions with cobalt.

There have been reports of high levels of cobalt in people who had hip replacements that used metal-on-metal devices. Symptoms of a higher level of cobalt in the blood are:

• Fatigue.
• Weakness.
• Peripheral neuropathy.
• Hearing loss.
• Visual loss.
• Cognitive decline.
• Cardiomyopathy.
• Hypothyroidism.