Have you noticed how walnuts are shaped like a brain? It’s no coincidence! It should come as no surprise that this crunchy tree nut is beneficial for brain health. Of all the tree nuts, walnuts are richest in omega-3s, a type of fat linked with brain health. Although the omega-3s in walnuts are in the short-chain fatty acid form, your body can convert a portion to the long-chain form that’s beneficial for brain health.
Plus, studies reveal that English walnuts contain polyphenols that reduce brain inflammation and improve communication between nerve cells. Some research suggests these polyphenols may boost the building of new nerve cells too. In addition, eating them often could mitigate some effects of aging on the brain. Some studies show that older animals that eat walnuts enjoy improvements in brain function, memory and motor function. That’s enough to make you want to grab some walnuts!
But walnuts may benefit other parts of your body too. Let’s look at two other organs that may benefit from a walnut-rich diet.
Gut Health
Can walnuts keep your gut healthy? We know that the gut microbiome, the home to trillions of friendly gut bacteria, is command central for digestive and immune health. 70% of your immune system lies in your gut and the bacteria that make their home there modify its function. Here’s the good news. Munching on walnuts may help seed your gut with even more gut-friendly bacteria. That’s because walnuts may increase the population of “good guys” in the gut.
In one study, researchers took fecal samples from overweight and obese individuals who consumed one of three diets:
- One that included polyunsaturated fats but no walnuts
- One that included whole walnuts
- One that included the same fats in walnuts without whole walnuts
The whole walnut diet boosted the quantity of gut bacteria that protect the lining of the gut. In addition, another study found that consuming walnuts increased the number of bacteria in the gut that produce butyrate, a compound that keeps the lining of the colon healthy. Studies suggest that butyrate has anti-inflammatory properties and may lower the risk of colon cancer.
Another way in which walnuts could lower the risk of colon cancer is related to their impact on bile acids. When you have high levels of secondary bile acids in your gut, it damages the cells that line the colon and this can lead to inflammation and, potentially, cancer. Research shows that foods like walnuts reduce secondary bile acids and their negative effects on the gut.
How many of these crunchy nuts do you need? Studies suggest that you need not eat a lot of walnuts to get gut health benefits. A handful is sufficient. For example, 42 grams of walnut halves per day increased the quantity of several species of bacteria in the gut that have health benefits. Plus, walnuts, with their healthy fat and fiber, are satiating.
Heart Health
Walnuts may benefit one of the hardest working and most important organs in your body, your heart. For example, the combination of healthy fats, fiber, and polyphenols in walnuts help lower LDL-cholesterol, the elevation of which are linked with cardiovascular disease.
One study published in Nutrition Journal found that walnuts reduce the oxidation of LDL-cholesterol, a process that speeds up the risk of cardiovascular disease. The benefits may stem from the antioxidant polyphenols in walnuts and the vitamin E they contain. Oxidative stress and inflammation play a key role in damaging the walls of arteries and promoting cardiovascular disease. Plus, research finds that a diet rich in walnuts enriches the gut with species of bacteria, such as Eubacterium eligens, that reduce several markers of cardiovascular risk such as cholesterol and blood pressure.
If you have high blood pressure, skip the chips and munch on walnuts. Scientists from Penn State University point out that the main omega-3 in walnuts is alpha-linolenic acid. (ALA). Research finds that foods rich in ALA may help lower blood pressure. However, other components in this crunchy nut may play a role, including the polyphenols and fiber.
In a study, subjects who ate a diet rich in whole walnuts experienced a reduction in central blood pressure, the pressure in the arteries as blood moves toward the heart. In contrast, they didn’t have the same benefits when they ate a diet with the fats in walnuts without the other components such as the fiber and polyphenols.
The team assessed all the participants for cardiovascular risk factors at the end of each diet period. From these data, the researchers found that the heart health of participants from all three groups improved to some extent. Therefore, the greatest benefits would come from eating whole walnuts. There’s a lot more in a walnut than just fat!
The Bottom Line
Walnuts are shaped like a brain and good for your brain too. However, they’re also healthy for your gut and heart. Although nuts are high in calories, studies find that you only absorb about 80% of the calories and fat from nuts. The other 20% travels through your digestive tract without being absorbed. There’s so much you can do with walnuts too:
- Chop up walnuts and add to hot porridge in the morning
- Add chopped walnuts to salads
- Stir walnuts into your next container of yogurt
- Add them to baked goods
- Add walnuts to quinoa bowls
- Buy walnut butter instead of peanut butter
- Enjoy dark chocolate covered walnuts as a snack
- Keep a jar on your desk to snack on
Walnuts are a great replacement for other carb-heavy and processed snacks. Enjoy the health benefits they offer!
References:
- The Journal of Nutrition, 2019; DOI: 10.1093/jn/nxz289.
- J Nutr. 2014 Apr;144(4 Suppl):561S-566S. doi: 10.3945/jn.113.184838. Epub 2014 Feb 5.
- Am J Clin Nutr. 2009;89Suppl:1602S–6S.
- Science Daily. “Walnuts impact gut microbiome and improve health”
- Holscher HD, Guetterman HM, Swanson KS, et al. Walnut Consumption Alters the Gastrointestinal Microbiota, Microbially Derived Secondary Bile Acids, and Health Markers in Healthy Adults: A Randomized Controlled Trial. J Nutr. 2018;148(6):861–867. doi:10.1093/jn/nxy004.
- Medical News Today. “Eat walnuts to lower blood pressure, new study suggests”
- Nutr J. 2014 Jan 10;13:4. doi: 10.1186/1475-2891-13-4.
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