Walnuts are a healthy nut chock-full of essential nutrients such as omega-3 fatty acids and antioxidants. They’re also easy to incorporate into your diet.
To say that walnuts are a nutritious food is a bit of an understatement.
Walnuts provide healthy fats, fiber, vitamins, and minerals — and that’s just the beginning of how they may support your health.
In fact, there’s so much interest in this one nut that scientists and industry experts have gathered annually for the past 50 years at the University of California, Davis, for a walnut conference to discuss the latest walnut health research.
Here are 10 science-based health benefits of walnuts.
Rich in antioxidants
Walnuts have greater antioxidant activity than any other common nut. This activity comes from vitamin E, melatonin, and plant compounds called polyphenols, which are found in particularly large amounts in the papery skin of walnuts. A 2022 study in healthy adults over age 60 showed that eating a walnut-rich meal reduced the participants’ levels of LDL (bad) cholesterol. If LDL cholesterol builds up in your arteries, it can cause atherosclerosis.
Super plant source of omega-3s
Walnuts are significantly higher in omega-3 fatty acids than any other nut, providing 2.5 grams (g) per 1-ounce (oz) serving. Omega-3 fats from plants, including walnuts, is called alpha-linolenic acid (ALA). It’s an essential fat, which means you have to get it from your diet. According to the Institute of Medicine, an adequate intake of ALA is 1.6 g per day for men and 1.1 g per day for women. A single serving of walnuts meets this guideline. Studies suggest that increased dietary levels of ALA may lower the risk of cardiovascular conditions such as heart disease and arrhythmia.
Promote a healthy gut
Studies suggest that if your gut is rich in health-promoting bacteria and other microbes (your gut microbiota), you’re more likely to have a healthy gut and good overall health. An unhealthy composition of gut microbiota can contribute to inflammation and disease in your gut and elsewhere in your body, increasing your risk of obesity, heart disease, and cancer. What you eat can significantly influence the makeup of your microbiota. Eating walnuts may be one way to support the health of your microbiota and your gut. In a 2018 study, 194 healthy adults ate 1.5 oz (43 g) of walnuts every day for 8 weeks. At the end, they showed an increase in beneficial bacteria compared to a period of not eating walnuts. This included an increase in bacteria that produce butyrate, a fat that nourishes your gut and promotes gut health.
May reduce risk of some cancers
Animal and a few human studies suggest that eating walnuts may reduce your risk of certain cancers, including breast, prostate, and colorectal cancer. As noted earlier, walnuts are rich in polyphenols called ellagitannins. Certain gut microbes can convert these to compounds called urolithins. Urolithins can have anti-inflammatory properties in your gut, which may be one way that eating walnuts helps protect against colorectal cancer. These anti-inflammatory actions could also help protect against other cancers. What’s more, urolithins have hormone-like properties that enable them to block hormone receptors in your body. This may help reduce your risk of hormone-related cancers, especially breast and prostate cancers. But more human studies are needed to determine the effects of eating walnuts on the risk of these and other cancers.
Support weight management
Walnuts are calorie-dense, but a small 2016 study suggests that your body absorbs 21% less energy from them than would be expected based on their nutrients. What’s more, eating walnuts may help regulate your appetite. A well-controlled study in 10 people with obesity found that drinking a smoothie made with about 1.75 oz (48 g) of walnuts once per day for 5 days decreased the participants’ appetite and hunger. This was in comparison to a placebo drink equal in calories and nutrients. Additionally, after 5 days of consuming the walnut smoothies, brain scans showed that the participants had increased activation in a region of the brain that helped them resist highly tempting food cues, such as cake and french fries. Even though larger and longer-term studies are needed, this provides some initial insight into how walnuts may help regulate appetite and weight.
May help lower blood pressure
High blood pressure is a major risk factor for heart disease and stroke. A small 2019 study suggests that eating walnuts may help lower blood pressure, including in people with high blood pressure. Additionally, the authors of a 2019 research review examined the effects of a Mediterranean diet, which often involves consumption of walnuts and other nuts. They concluded that following the Mediterranean diet may help lower blood pressure in some people. This suggests that nuts may slightly improve the blood pressure benefits of a heart-healthy diet. Even small differences in blood pressure are thought to have a big impact on your risk of heart disease.
Support healthy aging
As you age, good physical functioning is essential for maintaining your mobility and independence. One thing that may help you maintain your physical abilities is healthy eating habits. In an observational study involving more than 50,000 women over 18 years, scientists found that those with the healthiest diets had a 13% lower risk of physical impairment. Walnuts were among the foods that made the strongest contribution to a healthy diet. Though relatively high in calories, walnuts are packed with essential vitamins, minerals, fiber, fats, and plant compounds that may help support good physical functioning as you age.
Support reproductive health in people with sperm
Typical Western diets — high in processed foods, sugar, and refined grains — have been linked to reduced sperm function. Eating walnuts may help support sperm health and male fertility. In a 2012 study involving 117 healthy young men, participants who ate 2.5 oz (75 g) of walnuts per day for 3 months as part of a Western-style diet had improved sperm shape, vitality and motility compared to those who did not eat nuts. Animal research suggests that eating walnuts may help protect sperm by reducing oxidative damage in their membranes. Further studies are needed to learn more about these benefits. But if you have concerns about fertility and sperm function, eating walnuts is a simple thing to try.
Improve blood fat levels
Elevated levels of LDL (bad) cholesterol and triglycerides have long been linked to an increased heart disease risk. Regularly eating walnuts has been consistently shown to decrease cholesterol levels. In a small 2017 study in healthy adults, eating 1.5 oz (43 g) of walnuts daily for 8 weeks produced a 5% decrease in total cholesterol, LDL cholesterol, and triglycerides compared to not eating walnuts. The walnut eaters also had nearly a 6% decrease in apolipoprotein B, which is an indicator of how many LDL particles are in your blood. Elevated apolipoprotein B is a major risk factor for heart disease.
Widely available and easy to add to your diet
You can find walnuts in any grocery store. Check for raw walnuts in the baking aisle, roasted walnuts in the nut aisle, and cold-pressed walnut oil in the specialty oils section. It’s helpful to understand how to convert the serving sizes used in studies so that you know how your portion sizes compare. The following servings are essentially equivalent, providing about 190 calories each: Though it’s simplest to eat walnuts one by one as a snack, there are plenty of tasty ways to use them in dishes.
