July 20, 2023/Nutrition

The Health Benefits of Walnuts

Packed with healthy fats and antioxidants, walnuts can help with heart, brain and gut health

Shelled walnut cracked for eating in foreground with a bowl of walnuts in background.

Making a bag of trail mix? Make sure to include a heaping serving of walnuts. They’re full of nutrients like omega-3 fats, fiber and antioxidants, and can help lower heart disease and boost your brain function.


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“The health benefits of walnuts are impressively broad,” says Amber Sommer, RD, LD. “They definitely deserve a place in your diet. They’re well-known for their healthy fats, and they also have benefits you might not know about, such as improving your gut microbiome.”

So, what exactly are the health benefits of walnuts? Here are the many reasons to eat these wrinkly, brain-shaped nuts.

1. Omega-3s and antioxidants for heart health

Nuts in general are a healthy food choice. What makes walnuts a particularly good option? Walnuts boast several nutrients — including antioxidants and healthy fats like omega-3s — making them part of heart-healthy diets such as the Mediterranean diet. Here are some of the ways walnuts are good for your heart:

Lower cholesterol

A meta-analysis research paper, where researchers review and analyze previous studies, suggests that walnuts may help lower cholesterol.

Adding walnuts to your diet regularly may lower your:

Even better, the research shows that participants who added walnuts to their diets reaped the cholesterol benefits without gaining weight.

Help prevent heart disease

Walnuts are high in alpha-linolenic acid (ALA), a type of omega-3 fat — one of the healthy types of fat. Research shows that eating foods rich in ALA can have an impressive impact on your heart disease risk. For each gram of ALA you eat per day, you lower your risk of dying from heart disease by 10%. Walnuts contain about 2.5 grams of ALA per 1-ounce serving.

Walnuts seem to benefit everyone’s heart, but people with Type 2 diabetes especially should take note. Those who eat five servings of tree nuts per week have a lower risk of heart disease. A serving is about 12 to 14 walnut halves or 1/4 cup. If you want to eyeball it, it’s about the amount that fits in the palm of your hand.

Tree nuts include:

Help prevent atherosclerosis

In addition to healthy omega-3s, walnuts are packed with other antioxidants, including polyphenols and vitamin E.

A small study that included 16 adults found that the antioxidants in walnuts fought the oxidative stress caused by LDL (“bad”) cholesterol. Oxidative stress happens when there are too many free radicals in your body. Antioxidants cancel out the free radicals.

This process benefits your heart health because when LDL cholesterol builds up on your artery walls, it leads to damage and atherosclerosis. Atherosclerosis is when your arteries become harder and narrower, says Sommer. “Atherosclerosis leads to heart problems such as heart attacks and coronary artery disease.”

2. Nutrients to fight inflammation

Oxidative stress also contributes to inflammation in your body, which can be a driving force behind a scary list of chronic illnesses and even cancer.

“Walnuts contain several antioxidants, including ALAs, the amino acid arginine, polyphenols and magnesium,” notes Sommer. “These make walnuts an antioxidant powerhouse that helps fight inflammation.”


3. More beneficial bacteria for gut health

Your gut microbiome includes all of the microbes in your intestines, and the types and amounts of bacteria living there can affect your health. “The microbes in your gut play a role in inflammation, digestion and how well your immune system works. Your microbiome can even affect your mental health,” says Sommer.

Surprisingly, research shows walnuts can improve your gut health. In a trial, 96 adults ate 1.5 ounces of walnuts daily for eight weeks and then switched to a no-walnut diet. The other 98 adults in the study started with no walnuts and then added 1.5 ounces per day to their diets. Both groups had more beneficial gut bacteria during the time they were eating walnuts.

4. Polyphenols for lower cancer risk

In some studies, walnuts appear to reduce the risk of some cancers. These include:

Researchers believe this protective effect may be due to polyphenols, which are powerful antioxidants.

5. Healthy fats and antioxidants for better brain function

The omega-3s and other antioxidants in walnuts are also great for your brain health. Healthy fats, polyphenols and vitamin E may help reduce or prevent inflammation and oxidative damage in your brain. But a research review shows this effect in non-human trials, so the results need to be confirmed by human research.

The same review included evidence suggesting that a diet with walnuts may improve brain function in older adults — including memory and mental processing speed. The review also discussed several studies indicating that many nutrients in walnuts may help decrease the risk of dementia, Alzheimer’s disease and other neurodegenerative diseases.

Walnut nutrition facts

A serving of walnuts, about 1 ounce or 12 to 14 halves, offers:

A serving also provides about 10% of the iron and 14% of the magnesium adults need each day.

Don’t overdo it

The health benefits of eating walnuts are many, but Sommer notes one small caution. “Walnuts, like all nuts, are high in calories. If you’re concerned about calorie intake or weight gain, be aware of your serving sizes. Stick to a single serving of nuts per day or several times a week.”

Sommer also suggests choosing raw, unsalted walnuts to maximize the health benefits. Walnuts are good any time of day or night, from your breakfast oatmeal to this unique, refreshing salad to sides and desserts. And of course, they’re also delicious plain (or in your trail mix) making them a great on-the-go snack.


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