Walnuts (Juglans regia) are tree nuts that contain many vitamins, minerals, fiber, and polyphenols. While all nuts are nutrient-dense, walnuts have more plant-based omega-3 fatty acids, an essential polyunsaturated fat that has been studied for its role in reducing inflammation, heart health, brain health, and more.
Learn more about why walnuts are so healthy, walnut nutrition facts, how to eat them, who should avoid them, and more.
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Walnuts' Benefits: What Makes Them So Healthy?
Walnuts contain a variety of nutrients that are beneficial to your health. Walnuts are a rich source of micronutrients, vitamin B6, magnesium, melatonin, copper, and manganese. They also contain plant-based protein, fiber, omega-3 fatty acids, and other powerful plant-based compounds. Although all nuts are nutrient-dense, walnuts contain the highest omega-3 fatty acids.
Heart Disease
A walnut-rich diet may reduce levels of low-density lipoprotein (LDL) cholesterol (considered bad cholesterol). Researchers found that eating about half a cup of raw, pieced walnuts daily can significantly reduce LDL cholesterol.
Another review examined evidence of walnut consumption on cardiovascular risk factors, including cholesterol, triglycerides (a type of fat in the blood), blood pressure, and weight. Participants had high cholesterol, type 2 diabetes, metabolic syndrome, and experienced overweight or obesity.
Researchers found reductions in levels of LDL, triglycerides, and apolipoprotein B compared to control diets, including low-fat or Mediterranean diets (mainly consisting of vegetables and fruits, whole grains, healthy fats like olive oil, and legumes like beans, lentils, and peas).
Gut Health
Walnuts may contribute to gut health by having a positive impact on the gut microbiome, which consists of microorganisms in the digestive system.
One study found eating walnuts daily over eight weeks significantly enhanced probiotic- and butyric acid–producing bacterial species in the gut, which are important components in gut health. Participants self-reported food records and were asked to reduce their intake of fats and carbohydrates.
More research is needed since the study relied on self-reporting rather than clinical observation. This makes it hard to know what other foods participants consumed and how the nutrients in those foods played a role in their gut health.
Brain Health
Studies have evaluated the effects of walnut consumption and mood, cognitive performance, and memory improvements. In two clinical trials, healthy adults on a Mediterranean diet supplemented with mixed nuts (walnuts, hazelnuts, and almonds) daily showed better cognitive function than the control group on a low-fat diet.
Walnut consumption has also been evaluated for its use in preventing and slowing down the progression of diseases such as Alzheimer's disease and Parkinson's disease.
Another study evaluated women's health in their late 50s and found that those who ate at least two servings of walnuts per week were likelier to age healthfully (no chronic diseases) than those who do not eat walnuts.
Cancer
Walnuts are encouraged to be consumed regularly in a cancer-prevention eating plan. Reduced risk of colorectal and endometrial cancers has been linked to eating about 1 ounce of walnuts (about seven walnuts) daily.
Walnuts also contain specific nutrients (ellagitannins, melatonin, and gamma-tocopherol), which may reduce oxidative stress, inflammation, and gene expression that can lead to cancer. However, more research is needed.
Diabetes
Walnuts are low in carbohydrates and contain polyunsaturated fat, fiber, and protein, three nutrients that can increase feelings of fullness and help reduce blood sugar from rising too quickly. Including these nutrients in your diet may also contribute to a reduced risk of diabetes.
Researchers followed nearly 138,000 women over 10 years and found that those who ate two or more 1-ounce servings of walnuts per week were 24% less likely to develop diabetes than those who ate fewer or no walnuts. Notably, the women who ate more nuts also tended to be leaner, which may be a factor in diabetes prevention.
Other promising research on walnuts includes reducing triglycerides in people with metabolic syndrome and increasing sperm quality and motility (movement) in males.
Varieties of Walnuts
English or Persian walnuts are the most common walnuts produced in the United States. Black walnuts are also available. According to some reports, there are over 37 varieties of English walnuts available from growers in California.
Walnut Servings: Nutrition Breakdown
A single serving of walnuts is about seven whole walnuts, which is equal to 12–14 halves, 1 ounce, or one handful.
Nutrition information in grams (g), milligrams (mg), and micrograms (mcg) for 1 ounce (28g) of walnuts (about seven English walnuts or 14 halves) includes:
Who Shouldn't Eat Walnuts?
People who are allergic to nuts should not eat walnuts. Children 4 years and younger should avoid all seeds and nuts, including walnuts, to prevent choking.
How to Eat Walnuts
Walnuts are a very versatile food. They can be consumed raw and eaten as a snack, used in grain dishes, chopped and added to salads, as a protein topper, and in desserts.
You can prepare them in a variety of ways, too, which include:
Summary
Walnuts are a nutritious addition to most eating plans. Their positive impact on health is associated with their robust nutrient profile, including omega-3 fatty acids, fiber, vitamins, minerals, and other plant-based compounds. Some of the benefits of walnuts include improving heart, brain, and gut health. Because they can be a choking hazard, children under the age of 4 should avoid walnuts. People with nut allergies should not eat walnuts.
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