Nopal (Opuntia streptacantha), also known as prickly pear, is a member of the cactus family native to Mexico.

Nopal is used as a food, and the leaves, flowers, stems and fruit are all used. Broiled (not raw) stems, or extracts of Opuntia streptacantha have been used medicinally to lower blood glucose in Mexico and Central America.

Nopal contains mucopolysaccharide soluble fibers and phytochemicals, including pectin. These ingredients may slow carbohydrate absorption and decrease lipid absorption in the digestive tract.

Clinical studies of nopal are small and have mostly been published in Spanish, although abstracts are available in English.

One trial, published in a 1988 issue of Diabetes Care (vol. 11, issue 1, pp. 63-66), was done with three groups of type 2 patients in Mexico who were treated with diet alone or in combination with sulfonylureas. Oral medications were discontinued 72 hours before nopal was administered. After a 12- hour fast, one group of 16 patients received 500 grams of broiled nopal stems; a second group of 10 received only 400 ml of water; and a third group of six received three tests: one with 500 grams of broiled nopal stems, a second with 400 ml of water and a third with 500 grams of broiled zucchini.

Subjects had blood drawn at 60, 120 and 180 minutes after receiving the nopal, water or zucchini.

The nopal group had a significant decline from 222 mg/dl fasting to 203, 198 and 183 mg/dl, respectively, at 60, 120 and 180 minutes after receiving the treatment. This group also experienced a significant decrease in blood insulin levels. Researchers speculate that this points toward a nopal effect of increased insulin sensitivity. Larger studies need to be conducted.

Q: Is it true that cactus can improve my diabetes?

A: Nopal, nopales or prickly pear cactus is a food commonly eaten in the Southwestern United States. It is primarily used as a vegetable in Mexican and Central American cultures, but there is some preliminary evidence that it may help lower blood glucose and cholesterol. The most common side effect of nopal is mild gastrointestinal upset.

The major side effects of nopal

• Mild diarrhea
• Nausea
• Sensation of abdominal fullness
• Increased stool volume

Precautions for Patients

Nopal may help lower blood glucose when it is cooked or taken as a dietary supplement. The raw stems do not lower blood glucose.

Nopal contains fiber and pectin, which may decrease carbohydrate absorption. There are no long-term studies evaluating nopal for diabetes treatment. It is a benign agent when consumed as a food; however, it has not been studied as an oral extract in pregnant or lactating women and should therefore not be used by these groups of individuals.