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Walnuts FAQs

Are walnuts genetically modified?

California-grown walnuts are not genetically modified.

The California walnut industry understands consumer concerns regarding genetically modified foods. Therefore, we work closely with the University of California’s walnut breeding program to release new walnut varieties for planting that have been developed through conventional breeding methods. The California Walnut Board does not anticipate production of genetically modified walnuts in California in the foreseeable future.

Can walnuts be eaten when monitoring weight?

Research has suggested that health benefits from eating walnuts do not come at the expense of weight gain¹. However, large and longer-term studies are needed to address the effects of walnut consumption on CVD risk and body weight. Portion control is also important when monitoring weight. The recommended portion size for walnuts is 1 ounce, or 1/4 cup. Check our Wellness Weight page for published research, recipe ideas, and more.

¹Banel DK, Hu FB. Effects of walnut consumption on blood lipids and other cardiovascular risk factors: a meta-analysis and systematic review. Am J Clin Nutr. 2009;90(1):56-63. doi: 10.3945/​ajcn.2009.27457.

What is the DASH Diet and does it include walnuts?

The Dietary Approaches to Stop Hypertension diet–known at the DASH diet–is an eating program that was developed through research sponsored by the U.S. National Institute of Health (NIH) that is aimed at reducing blood pressure and cholesterol. It includes eating fruits and vegetables, low-fat or non-fat dairy, nuts (including walnuts), and whole grains. It includes high fiber and low to moderate fat, and is rich in potassium, calcium and magnesium. Recent DASH studies have shown benefits of lowering sodium intake on blood pressure. Not only have studies shown that eating walnuts is associated with improved blood pressure and cholesterol levels, walnuts are naturally sodium-free and thus are a perfect food for those following the DASH diet guidelines.

What exactly is the Mediterranean Diet?

The Mediterranean Diet is actually comprised of many diet patterns that hail from various countries surrounding the Mediterranean Sea. According to the American Heart Association, the common Mediterranean dietary pattern has these characteristics:

  • High consumption of fruits, vegetables, bread and other cereals, potatoes, beans, nuts and seeds.

  • Olive oil is an important monounsaturated fat source.

  • Dairy products, fish and poultry are consumed in low to moderate amounts, and little red meat is eaten.

  • Eggs are consumed up to four times a week.

  • Wine is consumed in low to moderate amounts—up to one five-ounce glass of wine per day for women and up to two five-ounce glasses for men.

  • Walnuts are a traditional component in this dietary pattern. Research has suggested that this is a heart-healthy pattern of eating.

  • PREDIMED is a landmark Spanish study that has been investigating specific benefits of this eating style. Preliminary published findings have found that consuming Mediterranean ingredients, including walnuts, is linked to heart health benefits including lowering LDL (“bad”) cholesterol and inflammatory markers.

Where do walnuts fit into the 2015 USDA Dietary Guidelines?

The 2015 Dietary Guidelines encourage a shift from current eating patterns to a healthy eating pattern that includes nutrient-dense foods and beverages in place of less healthy choices. Among other things, a healthy eating pattern includes a variety of protein foods, including nuts and seeds along with seafood, lean meats and poultry, eggs, legumes and soy products. The Guidelines also emphasize the importance of reducing saturated fats intake to less than 10 percent of calories per day and shifting food choices from those high in saturated fats to those high in polyunsaturated fats. Consuming walnuts can help you meet these guidelines. In addition to providing polyunsaturated fat (13 grams per ounce), which includes an excellent source of alpha-linolenic acid (ALA), the plant-based form of omega-3 fatty acids (2.5 grams per ounce), a serving of walnuts (1 oz), as part of a healthy diet, provides protein (4 grams per ounce) and are naturally sodium and cholesterol free. Looking for new ways to include walnuts on your plate? Check out our recipe section.

Does heating affect the nutrient content of walnuts?

The nutrient profile of walnuts changes insignificantly when roasted, toasted or baked for short periods of time. For information on the proper way to toast walnuts, see How to Toast Walnuts.

Are all omega-3 fatty acids the same?

No, they are not. There are three main omega-3 fatty