By "pumpkins," we mean common large pumpkins, as well as smaller members of the pumpkin family with orange or deep yellow flesh such as butternut squash, acorn squash, winter squash, spaghetti squash, harlequin squash, Hokkaido pumpkins, red kuri squash, and other small orange squashes. Pumpkins contain hypoglycemic substances that may improve diabetes. Pumpkins and pumpkin seeds have components such as squalene, beta-carotene, alpha-carotene, and various tocopherols with suspected or demonstrated cancer fighting properties. Pumpkin polysaccharide has been shown to possess significant cytoprotective effect and antioxidative activity.
Dietary intake of pumpkin was found to be protective against head and neck cancer in one Eastern European study. Studies have found that those with very low plasma levels of alpha-carotene and beta-carotene are at a higher risk of gastric cancer. Intake of orange and yellow vegetables may also be protective against prostate cancer and non-Hodgkin lymphoma. However, one Japanese study that found a reduced risk of lung cancer in males with frequent consumption of raw and green vegetables, fruit and milk, found an increased risk of lung cancer associated with the consumption of carrots, pumpkins, eggs and coffee.
Breast cancer-related effects of eating pumpkins
Most of the population-based breast cancer studies performed to date that specifically included pumpkins were conducted in Japan (since pumpkin consumption is higher there than in the U.S. or Europe). One Japanese study found that consuming vegetables (specifically including pumpkins) reduced the risk of gastric, breast, lung and colorectal cancer, regardless of the family history of cancer. Another Japanese study found reductions in breast cancer risk associated with high intakes of green-yellow vegetables (green leafy vegetables, carrots and pumpkins) among both premenopausal and postmenopausal women.
Pumpkin flesh and seeds should be eaten cooked or roasted, not raw. One study found that raw pumpkin juice increased chromosomal damage in bone marrow cells of experimental rats treated with a carcinogen whereas boiled pumpkin juice significantly suppressed it.
Pumpkin seeds and pumpkin seed oil are rich sources of phytoestrogens and cucurbitacin E. One study found that pumpkin seed oil supplementation prevented changes in plasma lipids and blood pressure associated with inadequate estrogen availability in experimental rats that had their ovaries removed. Cucurbitacin E has been shown to inhibit triple negative breast cancer metastasis in the laboratory by suppressing cell migration and invasion. On the other hand, pumpkin seeds also contains relatively high levels of copper, which has been shown to increase angiogenesis and metastasis of breast cancer.
Below are links to recent studies concerning this food. For a more complete list of studies, please click on pumpkin.