Areas Of Study


Preliminary animal research has been investigating the potential benefit walnuts may have on a variety of cancers including breast, prostate, and colorectal cancer. A healthy eating pattern that includes a variety of plant-based foods such as vegetables, fruits, grains, oils, nuts and seeds, as well as protein and fat-free or low-fat dairy, is associated with a reduced risk of certain types of cancers, according to the Dietary Guidelines for Americans. Walnuts offer a variety of important nutrients, including good fats, making them an ideal ingredient for plant-based meals.

Learn more about walnuts and cancer research.


For many reasons, walnuts can be a nutritious food for people living with diabetes or metabolic syndrome.

More than 29 million Americans are living with diabetes and about 23 percent of adults are affected by metabolic syndrome.1,2 Individuals with diabetes or metabolic syndrome often have conditions such as high blood pressure, abnormal cholesterol, high triglycerides and obesity, which increase the risk for heart disease and stroke.

Walnuts are a heart-healthy food3 with more than 25 years of research showing how they may have beneficial effects on various factors related to heart health such as LDL (“bad”) and HDL (“good”) cholesterol, blood pressure, inflammation, and plaque formation. Walnuts can also easily be part of a healthy diet that won’t contribute to weight gain or hinder weight loss goals.4,5,6 Walnuts contain important nutrients, like omega-3 ALA (2.5 g/oz), protein (4 g/oz) and fiber (2 g/oz), so they can be eaten in place of less healthy choices to improve diet quality.

Gut Health

Research on the gut microbiome and its impact on health continues to grow. Scientists are finding that certain foods contribute to positive changes in the gut. Although there is still much to learn, studies suggest that walnuts may play a role in gut health including increasing the amount of beneficial bacteria in the gut.1,2,3,4

1 Byerley LO, Samuelson D, Blanchard E, et al. Changes in the Gut Microbial Communities Following Addition of Walnuts to the Diet. J Nutr Biochem. 2017;48:94-102. doi: 10.1016/j.jnutbio.2017.07.001.
2 Nakanishi M, Chen Y, Qendro V, et al. Effects of walnut consumption on colon carcinogenesis and microbial community structure. Cancer Prev Res (Phila). 2016;9(8):692-703. doi: 10.1158/1940-6207.
3 Holscher HD, Guetterman HM, Swanson KS, et al. Walnut Consumption Alters the Gastrointestinal Microbiota, Microbially Derived Secondary Bile Acids, and Health Markers in Healthy Adults: A Randomized Controlled Trial [published online ahead of print May 3, 2018]. J Nutr.
4 Bamberger C, Rossmeier A, Lechner K, et al. A Walnut-Enriched Diet Affects Gut Microbiome in Healthy Caucasian Subjects: A Randomized, Controlled Trial. Nutrients. 2018;10(2): 244. doi:10.3390/nu10020244.

Healthy Aging

The effects of aging can impact quality of life and the ability to maintain independence. Research on the role of diet on brain health continues to evolve.Limited evidence suggests that eating a diet containing a variety of vegetables, fruits, nuts, beans, and seafood during adulthood is associated with lower risk of age-related cognitive impairment, dementia, and Alzheimer’s disease.

Heart Health

Walnuts are a heart-healthy food1, certified through the American Heart Association’s Heart-Check program.2 Since 1993, published research has been investigating how eating walnuts affects various heart health markers such as LDL and HDL cholesterol, blood pressure, inflammation, endothelial function and plaque formation.

1 Supportive but not conclusive research shows that eating 1.5 ounces of walnuts per day, as part of a low saturated fat and low cholesterol diet, and not resulting in increased caloric intake may reduce the risk of coronary heart disease. One ounce of walnuts provides 18g of total fat, 2.5g of monounsaturated fat, 13g of polyunsaturated fat, including 2.5g of alpha-linolenic acid, the plant-based omega-3.
2 Heart-Check Certification does not apply to scientific research by an organization other than the American Heart Association, unless expressly stated.

Mediterranean Diet

Walnuts were a key component in the landmark PREDIMED study (PREvención con DIeta MEDiterránea, or Prevention with Mediterranean Diet) study. This research showed that a Mediterranean diet which includes nuts (primarily walnuts) or extra virgin olive oil, may reduce the risk for heart disease and stroke, compared to a low-fat diet.1 Study participants were older adults who lived in Spain and were at high risk for cardiovascular disease. More research is needed to understand the health benefits in other populations.

Reproductive Health

study of healthy young men (ages 21-35 years), who ate 2.5 ounces of walnuts per day, experienced positive shifts in sperm quality factors, including both motility (movement) and morphology (form).1 Consuming walnuts may have contributed to shifts in certain sperm quality factors in these healthy young men, but more research is needed to understand how these findings impact the broader male population, including men in fertility clinics. Watch this video to learn more about men’s reproductive health research.


Although walnuts contain dietary fat, they won’t necessarily make you gain body fat. Walnuts are predominantly made up of good fats, which play an important role in the diet. The Dietary Guidelines for Americans recommends shifting food choices from those high in saturated fats to those high in good unsaturated fats, like those found in walnuts.

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