Pistachio nuts are a good source of monounsaturated fatty acids such as oleic acid. Pistachios also contain resveratrol and several proanthocyanidins), as well as copper, and soluble fiber. Pistachio components have been shown to have high antioxidant activity. Pistachios are a rich source of beta-sitosterol, which competes with the absorption of cholesterol from food, helping to lower cholesterol. Consumption of pistachio nuts is also associated with lower levels of inflammatory markers. These qualities may account for an observed inverse relationship between pistachio nut consumption and cardiovascular and diabetes risk factors. Frequent nut consumption (including pistachios) is associated with a reduced risk of gallstone disease in men.
Breast cancer-related effects of eating pistachio nuts
Although pistachio nuts are assumed to share at least some of the favorable characteristics of other tree nuts such as walnuts with respect to breast cancer, there is little specific evidence to recommend pistachio consumption for reducing breast cancer risk.
The U.S. is the world's second largest producer of pistachio nuts (most are grown in California), whereas Iran is the largest producer. Turkey, Syria, and China also produce significant volumes. Pistachios typically are infected to some extent with molds that produce aflatoxins, which are mutagenic, carcinogenic and teratogenic and cause immuno-suppression in humans. Aflatoxin B1 has been shown to cause liver cancer, especially in hepatitis B-positive individuals. While U.S. pistachio nuts generally contain very low levels of aflatoxins, non-U.S. pistachios sometimes contain unacceptably high levels. Dangerous levels have been reported in pistachio nuts from Iran and Morocco (note that, officially, the U.S. does not import pistachios from Iran). Pistachio nuts normally are dried soon after harvest to minimize shell staining and decay and to ensure safety. Pistachio nuts sold without the shell are much more likely to have a high level of contamination than pistachios sold in the shell. To maximize safety, select U.S. pistachio nuts in the shell that have not been dyed red (the dye itself is not healthy and is sometimes used to cover up stains). Avoid eating any pistachios with stained or missing shells, that have a sour taste, or any signs of mold, excessive moisture or insect damage.
The aflatoxin problem described in the paragraph above is not related to the salmonella-related recall of pistachios and pistachio-containing products from the 2008 crop of Setton Pistachio Inc., of Terra Bella, California. The Setton Pistachio products were contaminated with salmonella strains matching strains found in several people who became ill after consuming them. Although salmonella contamination of pistachios has not been a widespread problem, the Setton Pistachio outbreak prompted the FDA to announce in April 2009 that it intended to examine current pistachio industry practices and to issue more guidance on measures to be taken to prevent salmonella contamination.
Since most pistachios are sold roasted and salted, those who are concerned about their intake of sodium should seek out pistachios with no added salt.
Below are links to recent studies concerning this food. For a more complete list of studies, please click on pistachio nut.