A. Alice H. Lichtenstein, DSc, director of the Cardiovascular Nutrition Laboratory at the Human Nutrition Research Center on Aging (HNRCA) and executive editor of Tufts Health & Nutrition Letter, answers:
“Some nut proponents say raw are healthier than roasted, and some say the opposite. The fact is that there are pros and cons to each, and either kind is a good choice—so long as they aren’t covered in a lot of salt or sugar, and as long as they are used to replace less healthy choices.
Nutrients: According to the USDA food database, the difference in vitamin and mineral content among oil-roasted, dry roasted, and raw cashews is so small as to be inconsequential in the context of an overall dietary pattern.
Anti-nutrients: So-called ‘anti-nutrients’ are compounds that block the body from absorbing nutrients such as calcium and iron. Raw nuts may contain a higher level of ‘anti-nutrients’ than roasted, but the difference in absorbable nutrients will not make a significant impact in the context of an overall healthy diet.
Microorganisms: Raw nuts have caused outbreaks of food poisoning due to Salmonella bacteria, and peanuts can harbor fungi that produce disease-causing compounds called aflatoxins. Roasting, blanching, or steaming will create enough heat to kill bacteria and roasting reduces levels of aflatoxins. (The FDA carefully monitors peanut products, and no outbreak of human illness caused by aflatoxins has been reported in the U.S. to date.)
Carcinogens: The roasting process can cause the formation of chemicals called acrylamides. In animal studies, at high levels of intake, these compounds have been associated with kidney, ovarian, and endometrial cancers. However, these levels cannot be achieved by eating nuts.
“Nuts are a source of heart-healthy unsaturated fats, as well as fiber, vitamin E, and magnesium—which are nutrients of concern for many U.S. adults. Consuming any kind of nuts instead of refined-carbohydrate choices like chips, pretzels, crackers, or croutons is a health-promoting choice. (See the July 2020 issue for more information.)”