Pineapple is a tropical fruit widely available in most grocery stores and produce markets. It is rich in manganese and contains plenty of copper, fiber and vitamins B-1, B-6 and C. While these nutrients are important to health, it is the bromelain present in pineapple juice that gives the fruit its anti-inflammatory properties.
Pineapple's high bromelain content is believed to be responsible for the fruit's numerous health benefits. Bromelain is an extract of the fruit and stem of pineapple. Cysteine proteinases, enzymes that digest proteins, may provide most of bromelain's anti-inflammatory benefits. These anti-inflammatory effects stem partly from bromelain's ability to reduce levels of thromboxane A2 and prostaglandin E2, hormone-like substances associated with blood vessel constriction, blood clotting and the modulation of inflammation. Bromelain may also decrease secretion of cytokine and chemokine, two immunoregulatory proteins secreted by immune system cells, according to Memorial Sloan-Kettering Cancer Center.
Pineapple juice may reduce inflammation associated with arthritis and other joint disorders, and reduce the swelling of soft-tissue injuries. The bromelain in pineapple juice may also ease inflammation in digestive disorders, such as ulcerative colitis and Crohn's disease, according to a study published in the 2008 issue of "Clinical Immunology." Moreover, Germany's Commission E has approved bromelain as a treatment for sinusitis when used in conjunction with other therapies.
Drugs.com notes that the usual daily dose of bromelain is three or four doses of 40 milligrams, or about two standard-size slices of pineapple. Commercial preparations of bromelain are available in tablet, capsule and liquid form, but because these products contain mostly stem bromelain, the dosing is different. Most manufacturers of bromelain supplements recommend taking 500 milligrams to 1,000 milligrams per day.
Never begin treatment with bromelain or any other supplement without first consulting your doctor. Bromelain may increase heart rate, cause vomiting or diarrhea, or trigger allergic reactions in some people. Additionally, the American Cancer Society warns that some women taking bromelain may experience increased menstrual bleeding and that anyone with kidney disease, liver disease, high blood pressure or a bleeding disorder should use bromelain cautiously and under a doctor's supervision.