How does pumpkin seed work as a dietary supplement?

Overview

The familiar Halloween pumpkin is a member of the squash family, native to North and Central America. The seeds of the pumpkin were used medicinally in Native American medicine, primarily for the treatment of kidney, bladder, and digestive problems. From 1863 to 1936, the United States Pharmacopoeia listed pumpkin seeds as a treatment for intestinal parasites.

Uses and Applications

Pumpkin seed oil has become popular today as a treatment for prostate enlargement (benign prostatic hyperplasia, or BPH), and it was approved for this use in 1985 by Germany’s Commission E. However, there is no meaningful evidence that pumpkin seed is helpful for this condition. Only double-blind, placebo-controlled studies can prove a treatment effective, and none have been reported for pumpkin seed oil alone. However, two such studies evaluated a combination product containing pumpkin seed oil and the herb saw palmetto.

These studies did suggest benefit with the combination product, but because saw palmetto is thought to be effective for BPH, it is not clear whether pumpkin seed oil made any additional contribution. The only reported study on pumpkin seed oil alone lacked a placebo group, and for this reason its results prove little. (BPH is a condition that responds greatly to the power of suggestion, so it could have been assumed, even before conducting this trial, that people given pumpkin seed oil would show improvement.)

In highly preliminary research, pumpkin seed or its constituent cucurbitin has shown some activity against intestinal parasites. These studies, however, can only be regarded as preliminary investigations of a traditional use; they were not designed in such a way that they could prove effectiveness.

Two studies performed in Thailand hint that pumpkin seed snacks might help prevent kidney stones among children at high risk for developing them. However, this research looked only at chemical changes in the urine suggestive of a possible preventive effect, not at actual reduction of stones. Furthermore, the design of the studies did not reach modern standards.

Dosage

In studies, the dose of pumpkin seed oil used for the treatment of BPH was 160 milligrams three times daily. For the prevention of kidney stones, the dose of pumpkin seed snack tried was 5 to 10 grams per day.

Safety Issues

As a widely eaten food, pumpkin seeds are presumed to be safe (though there have been cases in which incompletely chewed seeds have lodged in the esophagus). There are no known or suspected safety risks with pumpkin seed oil.

Bibliography

Caili, F., S. Huan, and L. Quanhong. “A Review on Pharmacological Activities and Utilization Technologies of Pumpkin.” Plant Foods for Human Nutrition 61 (2006): 73-80.

Naghii, M. R., and M. Mofid. “Impact of Daily Consumption of Iron Fortified Ready-to-eat Cereal and Pumpkin Seed Kernels (Cucurbita pepo) on Serum Iron in Adult Women.” Biofactors 30 (2007): 19-26.

Suphiphat, V., et al. “The Effect of Pumpkin Seeds Snack on Inhibitors and Promoters of Urolithiasis in Thai Adolescents.” Journal of the Medical Association of Thailand 76 (1993): 487-493.