Nickel is an essential trace mineral found in the body. Human and animal tests show that nickel may be a factor in hormone, lipid, and membrane metabolism. It is an activator of some enzymes and may also be involved in glucose metabolism. Significant amounts are found in DNA and RNA, and nickel may possibly act as a stabilizer of these nucleic acids.
Nickel is a by-product of many industries; it is found in heating fuel, cigarette smoke, and car exhaust. Seafood, cereals, grains, seeds, beans, and vegetables are food sources of nickel.
Absorption and Storage
The amount of nickel actually absorbed by the intestine is small. Most of it passes into the urine or feces. The kidneys appear to regulate the amount of nickel retained or excreted from the body.
Daily dietary intake from food varies with the soil content of nickel; estimates range from several micro-grams to several hundred milligrams.
Nickel can be toxic to humans if levels are high. Excessive levels can occur in people who experience myocardial infarction, stroke, uterine cancer, burns, and toxemia of pregnancy.
Nickel is particularly toxic when combined with carbon monoxide, producing nickel carbonyl. This element is a result of many industrial processes. It is also a component of cigarette smoke. Studies on rats revealed that the amount of nickel capable of causing lung cancer can be obtained from 15 ciga¬rettes smoked per day over a period of 1 year.
In animals, nickel toxicity results in pigmentation changes, leg swelling, dermatitis, and fat and oxygen depletion of the liver. Nickel accumulates in the liver, bone, and aorta. It may cause lung cancer in humans. Symptoms of nickel poisoning are headache, vertigo, nausea, vomiting, chest pain, and coughing.
Deficiency Effects and Symptoms
A deficiency can result from cirrhosis of the liver, chronic kidney failure, excessive sweating, intestinal malabsorption, and stress. Iron-deficiency anemia may also be aggravated.