Walnuts have long been hailed as a healthy diet staple, and it's clear to see why. This tree nut is a fantastic source of nutrients that can help lower your blood pressure, support brain health, benefit the digestive system and much more.
Most of the walnuts in the United States are harvested in the Central Valley of California. They make a versatile and nutrient-boosting addition to meals but can also stand on their own as a hearty snack.
Walnut Nutrition Facts
One ounce of walnuts (about 14 walnut halves) is equal to a single serving. One ounce of walnuts contains:
- Calories: 186
- Total fat: 18.5 g
- Cholesterol: 0 mg
- Sodium: 0.6 mg
- Total carbs: 3.9 g
- Dietary fiber: 1.9 g
- Sugar: 0.7 g
- Added sugar: 0 g
- Protein: 4.3 g
- Total fat: One ounce of walnuts has 18.5 grams of total fat, which includes 13.3 grams of polyunsaturated fat, 2.5 grams of monounsaturated fat, 1.7 grams of saturated fat and 0 grams of trans fat.
- Carbohydrates: One ounce of walnuts has 3.9 grams of carbs, which includes 1.9 grams of fiber and 0.7 grams of naturally occurring sugars.
- Protein: One ounce of walnuts has 4.3 grams of protein.
Vitamins, Minerals and Other Micronutrients
- Copper: 50% of your Daily Value (DV)
- Manganese: 42% DV
- Magnesium: 11% DV
- Vitamin B6: 9% DV
- Vitamin B1: 8% DV
- Zinc: 8% DV
- Vitamin B9: 7%
- Iron: 5% DV
- Potassium: 3% DV
- Selenium: 3% DV
- One ounce of walnuts is not a good source of calcium (2% DV) or choline (2%).
How Do Walnuts Compare to Other Common Tree Nuts?
Based on a 1-oz. serving, raw
Health Benefits of Walnuts
Walnuts are a powerhouse nut and part of a nutritious diet. The healthy fats, fiber and antioxidants in walnuts may benefit your health in a number of ways, from lowering heart disease risk to boosting brain health.
1. Walnuts Are Linked to Lower Blood Pressure
"Even more than other nuts, walnuts appear to exert powerful benefits on controlling diastolic blood pressure and other markers of cardiovascular wellness," says Bethany Doerfler, RDN, a clinical research dietitian at Northwestern Medicine. "Diastolic blood pressure is a really important cardiovascular marker because it measures the pressure in the blood vessels when the heart is resting."
Although it's not fully known why walnuts have such positive effects on blood pressure, there may be a combination of factors at play: "It's likely due to the way gut bacteria feed off the fiber and other innate nutrients in walnuts to produce anti-inflammatory compounds," Doerfler says. "Nuts like walnuts also contain compounds such as plant sterols, soluble fiber and phenolic compounds, which can directly lower cholesterol and work as antioxidants."
"We have enough evidence now to suggest that what's good for the blood vessels and heart is also good for the brain. Walnuts exert their benefit on brain and heart health, not just because of their healthy fats, but also because of their direct ability to reduce blood pressure and modify gut bacteria."
Nuts and seeds like walnuts are part of the DASH (Dietary Approaches to Stop Hypertension) diet, which emphasizes vegetables, fruits and low-fat dairy foods, and calls for four to five servings of nuts, seeds and legumes per week.
When researchers compared the effects of three heart-healthy diets based on the DASH diet — one focusing on carbohydrates, another emphasizing protein and the third emphasizing unsaturated fat — all three lowered blood pressure and improved cholesterol, but those focusing on protein and unsaturated fat did so the best, according to Harvard Health Publishing. Protein and unsaturated fats are two nutrients found in walnuts.
"This research showed that dietary patterns can positively improve all cardiometabolic risk factors, and the daily addition of fruits and nuts like walnuts was a cornerstone to how researchers built the sample menus," Doerfler says.
2. They're Linked to Better Brain Health
Eating walnuts are linked to preventing brain damage and may even improve cognition. "We have enough evidence now to suggest that what's good for the blood vessels and heart is also good for the brain," Doerfler says. "Walnuts exert their benefit on brain and heart health, not just because of their healthy fats, but also because of their direct ability to reduce blood pressure and modify gut bacteria."
Walnuts contain alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid. "Walnuts are a really important way to get polyunsaturated fats, including omega-3 fatty acids," Doerfler says. "They have more omega-3 fatty acids than any other nut or legume."
Not only are walnuts high in ALA but they also contain more polyphenolic compounds (a type of antioxidant) than any other nut. Both alpha-linolenic acid and polyphenolic compounds are considered important brain foods that may help reduce oxidative stress and inflammation that lead to cognitive decline, according to the American Society for Nutrition. This, in turn, means they could benefit cognition.
Eating more walnuts was observed to increase adults' performance on cognitive tests, regardless of their age, a December 2014 study published in The Journal of Nutrition, Health and Aging found. It's important to note that the research was funded by the California Walnut Council, but the findings are still important as this was the first large representative study to analyze walnut intake and cognition and to include all available cognitive data across the National Health and Nutrition Examination Survey (NHANES) research program.
Whether you eat walnuts alone or with other foods, their unique blend of compounds will help you to better absorb healthy nutrients. “Walnuts in the diet can be great stand-alone nutrition, but they can also act as a power booster to other healthy foods,” Doerfler says. “Because of the healthy fats in walnuts, they could help you better absorb vitamin D or antioxidants found in foods like berries.”
3. Walnuts Can Benefit the Digestive System
It was once thought that people with diverticula (small, pouch-like structures that can form in the colon's muscular wall) should avoid nuts and seeds, but experts now know it's not necessarily the case for everyone. What's more, nuts like walnuts provide the fiber that's important for gut health and maintaining regularity, according to Harvard Health Publishing.
"It's possible that people with digestive issues will really benefit from the fiber in walnuts, but I often advise people to make sure they're chewing them well or puréeing them into recipes," Doerfler says. "That way, you are modifying the fiber so your gut has less mechanical chopping to do, and access to the nutrients in food is optimized."
The magnesium in walnuts can also help keep you regular. "Walnuts are one of the richest plant-based sources of magnesium, which can prevent constipation by helping the muscles of intestines contract," Doerfler says.
How Many Walnuts Should You Eat Per Day?
One serving of walnuts (about 14 walnut halves) contains 186 calories. If you stick to the serving size, that calorie count shouldn’t deter you from eating walnuts. “They’re one of the more calorie-dense nuts, but those are the calories from natural fat, fiber and protein that we want,” Doerfler says.
4. They May Have Potential to Lower Cancer Risk
Ongoing research is investigating the link between walnuts and cancer prevention.
Evidence has been mixed, but emerging research shows that walnuts have the potential to contribute to a cancer-preventive diet through the synergy of numerous compounds such as melatonin, ellagitannins and gamma-tocopherol. All of these compounds may work together to lower oxidative stress, inflammation and gene expression that can result in cancer, according to the American Institute for Cancer Research.
Overall, swapping the typical Western diet (which is high in red meat, refined grains and high-fat dairy products like butter) with a plant-based diet that includes nuts like walnuts is associated with a lower risk of cancer.
"The research for diet and cancer right now is very focused on dietary patterns, and eating a Western diet particularly increases your risk of solid organ cancers, such as breast, colon, esophageal and stomach cancers," Doerfler says. "Conversely, eating a more plant-based diet that revolves around plant-based proteins and fats is protective against cancer."
Walnut Health Risks
Allergy to tree nuts such as walnuts affects an estimated 0.5 to 1 percent of the population in the United States, and is one of the eight most common types of food allergies, according to the American Academy of Allergy, Asthma & Immunology (AAAAI).
If you're allergic to one tree nut, it doesn't mean you'll be allergic to all of them, but some are closely related (like walnuts and pecans, or cashews and pistachios) and may cause similar reactions. Talk to an allergist to assess your risk: Tree nut reactions can be severe and may include life-threatening anaphylaxis, so it's important to always have epinephrine with you if you have a tree nut allergy, according to the AAAAI.
High-fiber foods like walnuts may affect the absorption of thyroid drugs such as levothyroxine. You may need to take your medication at a different time of day than when you would normally eat walnuts — say, at bedtime rather than at breakfast, per Consumer Reports.
If you have questions or concerns about when to take your medication, talk to your doctor.
Walnut Preparation and Useful Tips
Walnuts are harvested in the fall, but can be found year-round in grocery stores. Follow these tips to store and prepare them as part of a snack or meal.
Opt for whole, plain varieties. Many packaged nuts come with added sodium, sugar or other ingredients, so it's best to look for plain raw or roasted walnuts. If you'd like, add your own herbs or spices such as thyme or cinnamon.
Walnuts are also found in a number of protein and granola bars, but opt for whole walnuts if possible.
"In bars, you might have preservatives, added sugars, refined grains or even sugar alcohols and other artificial sweeteners that can disrupt your healthy gut bacteria," Doerfler says. "It's best to eat whole foods. When you look for real foods that are satisfying and beneficial for your entire body, nuts are a natural inclusion — and walnuts, in particular, are an all-star."
Store in a cool place. Proper storage is important for walnuts, as warm temperatures can cause their healthy fats to go rancid, according to Michigan State University Extension.
Walnuts are no longer fresh if they are shriveled or rubbery, or if they have an odor similar to paint thinner, per Michigan State University.
Walnuts tend to absorb odors, so store them away from other foods with strong scents, such as onions — preferably in an airtight container. Store shelled or unshelled walnuts in a cool, dry place. They’ll stay fresh for up to three months in the refrigerator, or up to one year in the freezer.
Use them to add texture to recipes. Walnuts are often sprinkled into oatmeal or added to trail mix, but their texture can also make them a unique ingredient in sauces or sautés.
"Walnuts can be a nice meat substitute in dishes when they're puréed," Doerfler says. "You can finely mince or purée walnuts with mushrooms, cauliflower, canned diced tomatoes and herbs to make a high-fiber, high-protein pasta sauce."
Alternatives to Walnuts
Walnuts have a rich nutrient profile that may help improve your blood pressure. They contain a number of antioxidants, which can boost your brain health and lower your risk of cancer. The fiber and magnesium in walnuts can also benefit digestive health.
For similar health benefits, you can swap walnuts for other tree nuts such as:
As with all nuts, it's important to eat walnuts in moderation — because they're calorically dense, they may lead to weight gain if eaten in excess.
- My Food Data: "Walnuts"
- My Food Data: "Almonds"
- My Food Data: "Pecans"
- My Food Data: "Cashews (Raw)"
- My Food Data: "Macadamia Nuts"
- National Heart, Lung, and Blood Institute: "DASH Eating Plan"
- Mayo Clinic: "DASH diet: Healthy eating to lower your blood pressure"
- Harvard Health Publishing: "Information about the OmniHeart diets"
- Mayo Clinic: "High blood pressure dangers: Hypertension's effects on your body"
- Johns Hopkins Medicine: "The Brain-Gut Connection"
- American Society for Nutrition: "Can walnut consumption benefit brain health?"
- Springer Nature: "A cross sectional study of the association between walnut consumption and cognitive function among adult us populations represented in NHANES"
- Harvard Health Publishing: "Avoiding nuts and seeds for better gut health? You shouldn’t"
- American Institute for Cancer Research: "Walnuts"
- American Academy of Allergy, Asthma & Immunology: "Everything You Need to Know About Tree Nut Allergy"
- Consumer Reports: "Food and Drug Interactions You Need to Know About"
- Michigan State University Extension: "Preserving fresh walnuts to maintain nutritional content"