two hands holding a bowl of walnuts

The history of walnuts can be traced back to ancient Persia, where they were once meant for royalty. Eventually, walnuts made their way to California where they were listed in the state's top 10 agricultural commodities of 2021.

Walnuts have been considered valuable throughout history, but why? We might find the answer by looking at the nutritional benefits of walnuts.

Although walnuts are high in calories, they are also extremely nutritious with a variety of health benefits:

1. Heart health

Walnuts are a great source of alpha-linolenic acid (ALA), an omega-3 fatty acid that is important for reducing inflammation. In fact, it is the only nut significantly high in these omega-3 fatty acids. Their anti-inflammatory compounds may reduce the risk of heart disease.

Learn 8 ways to reduce your risk of heart disease

2. Brain health

Studies have shown that the antioxidants and anti-inflammatory polyphenols (compounds) found in walnuts may improve brain function and slow mental decline that occurs with aging. Cognitive functions include your memory and ability to think.

Explore other foods for brain health and how you can keep your mind sharp

3. Gut health

Bacteria and microbes in your intestines and gut are also essential to your health. Research shows walnuts can improve gut health. In a clinical trial, adults who ate walnuts every day had healthier gut bacteria.

4. Cancer prevention

Microbes in your gut take compounds found in walnuts and produce urolithin compounds. These urolithins may help lower risk for certain cancers. Research is still being done to fully understand walnuts' potential role in cancer prevention.

How many walnuts should I eat?

The 2020-2025 Dietary Guidelines for Americans recommends about 5 ounces of nuts, seeds and soy products per week for a 2,000 calorie diet. One serving (1 ounce) contains 2 grams of fiber, 4 grams of protein, 18 grams of fat, and about 190 calories.

What nutrients do walnuts contain?

Although walnuts are high in calories, they are also high in nutrients. The healthy unsaturated fats in walnuts keep you feeling full for longer.

Recent research suggests that the way fat is stored in walnuts prevents your body from holding onto all the calories. One study found that even though an ounce of walnut has 190 calories, only about 145 are usable.

Walnuts also give you some of the iron and magnesium you need – about 10-14% of your daily needs.

What are the best ways to eat walnuts?

To maximize the health benefits, look for raw, unsalted walnuts. You can eat them alone as a snack or add them to your oatmeal in the morning. While walnuts have plenty of health benefits, it's still important to not overeat.

Volunteer for walnut research

Walnuts are jam-packed with beneficial compounds as described above, but there is still more to learn. Understanding the other potential health effects of walnuts can provide us with more accurate information about who would benefit from consuming them and how they can help contribute to a balanced and nutritious diet.

The UCD Steinberg Lab is trying to crack the shell on the workings of walnuts. Researchers are looking at how walnuts may provide benefits to your gut and cholesterol levels. Measuring the effects of walnut consumption on cholesterol levels can further help us understand what role these nuts potentially play in lowering risk for heart disease.

If this research sounds interesting to you, consider volunteering to participate in their research study. They are looking to recruit men and postmenopausal women ages 45-70. There are some additional requirements for participation. The study will take about 10 weeks and includes four 30-minute visits to the UC Davis campus in Davis, Calif.

Get more information on this study and how you can participate

This blog was written by UC Davis undergraduate Amaya Nerb and reviewed by UC Davis Health registered dietitian Marie Barone.