N-Acetyl-Cysteine
This is an altered form of the amino acid cystine, which is commonly found in food and synthesized by the body. NAC helps break down mucus. Double blind research has found that NAC supplements improved symptoms in individuals with bronchitis. NAC also helps the body synthesize glutathione (see nutritional info), protects the body from acetaminophen toxicity and is used at very high levels in hospitals for that purpose. Cysteine, the amino acid from which NAC is derived, is found in most high protein foods. NAC is not found in the diet, it must be derived from cysteine. NAC is being used for bronchitis, chronic obstructive pulmonary disease, emphysema, gastritis and HIV support. Preliminary evidence shows that intravenous injections of NAC may significantly improve kidney function and survival rates iun hepatorenal syndrome, an almost invariably fatal form of kidney failure.

Niacin
See Vitamin B3

Nickel
Nickel is trace mineral that may be thought of in connection to skin allergies or dermatitis from jewelry, eyeglass frames or dental material, however of the approximately 10 mg in the body, significant concentrations of nickel are found in RNA and DNA where it interacts with these nucleic acids. Most of plasma nickel is a constituent of the circulating proteins nickeloplasmin and albumin, and it is also thought to be a factor in hormone, lipid and cell membrane metabolism. Insulin response is increased after ingesting nickel, which may be related to its activation of enzymes associated with the breakdown or utilization of glucose.