Don’t you love it when the foods you eat to nourish your body also have functional benefits that go beyond supplying energy and nutrition? It sounds a little “nutty,” but eating walnuts may help you manage stress a bit better. We know walnuts are a nutrient-dense snack, but can they also help you stay calm? That’s what a study suggests. Specifically, this study found that eating walnuts helps manage the impact that stress has on the cardiovascular system. When you’re under physical or emotional stress, your heart rate speeds up, your blood pressure rises, and your cardiovascular system is forced to work harder. Over time, these stress reactions increase the risk of developing heart disease.
Walnuts May Modify the Body’s Stress Response
The participants in the study were 22 healthy adults with high LDL-cholesterol. The subjects were assigned to one of three diets, each containing a similar number of calories. One was the typical American diet. The second was a typical American diet that included 1.3 ounces of walnuts and a tablespoon of walnut oil. A third diet was similar to the second but also included flaxseed oil.
On these diets, the researchers followed the participants’ blood pressure. In addition, they measured their blood pressure response to stress. In this case, the stress was forcing their foot into a bucket of ice-cold water. Ouch! They were also asked to make an impromptu public speech as they measured their stress response. What they found was the participants who consumed the walnuts and walnut oil had significantly lower blood pressure AND their blood pressures didn’t rise as much in response to the stress of the ice-cold bucket of water or the pressure of making a speech.
What about flaxseed? Adding flaxseed oil didn’t enhance the stress reductive benefits beyond what the walnut diet offered, but it was linked with a reduction in C-reactive protein (CRP), a marker of whole- body inflammation. Other research shows that nuts, in general, are linked with a reduction in inflammatory markers, including C-reaction protein.
How many walnuts would you need to eat to get these perks? Based on the research, a handful of walnuts should do the job. The participants in the study ate the equivalent of 18 walnut halves or 9 whole walnuts per day. That’s manageable!
Are Walnuts a Mood Enhancer?
Another way munching on walnuts may help with stress is by providing a mood pick-me-up. A study published in the journal Nutrients suggests that walnuts may have mood-enhancing benefits. In the study, 64 college students were assigned to a diet that contained walnuts or a placebo diet without walnuts. The students ate each diet for 8 weeks at different times with a 6-week wash-out period in between. During the study, the researchers monitored the mood of the participants using mood assessment tools. What they found was the students experienced an improvement in their mood and mental state while on the diet that contained walnuts.
What is the Active Ingredients in Walnuts That Explain These Findings?
When researchers look at the health benefits of walnuts, they often focus on their omega-3 content. The omega-3’s in walnuts are short-chain omega-3’s, in contrast to the long-chain omega-3’s in fish oil and fatty fish. It isn’t clear whether short-chain omega-3’s have identical benefits to their long-chain cousins, but research shows they likely do have health perks. In fact, previous research shows, alpha-linolenic acid (ALA), the main omega-3 in walnuts improves blood vessel function and the ability of a blood vessel to dilate. This may explain how walnuts reduce the cardiovascular response to stress, for example, when you have to give an unexpected public speech! Previous research also suggests that these healthy fats reduce inflammation inside the blood vessel wall – all good things for the health of your heart and how it responds to stress.
It’s less clear how walnuts might enhance mood. However, walnuts are shaped like brains for a reason! Studies suggest that compounds in walnuts may slow brain aging. This may be partially mediated by the omega-3’s in walnuts, but also the polyphenols that you get when you bite into a handful of walnuts. Research shows that the polyphenols in walnuts may improve communication between nerve cells and help reduce the formation of misfolded, damaged proteins that are characteristic of people with some forms of dementia.
What are polyphenols? They’re a diverse group of compounds with antioxidant and anti-inflammatory activity. We know that oxidative stress and inflammation play a role in brain aging and that the brain generates lots of free radicals due to its high metabolic demands. In fact, brain activity accounts for 20% of your daily resting metabolic rate! So, eating a handful of walnuts each day may be good for brain health and your mood!
Other Functional Chemicals in Walnuts
Walnuts are a powerhouse of compounds with potential biological activity. Along with polyphenols, they contain various tannins, flavonoids, carotenoids, sulfur compounds, and melatonin, the hormone responsible for regulating the sleep-wake cycle. Plus, they’re rich in vitamin E, folate, and a variety of minerals. In addition, you get modest amounts of plant-based protein and fiber when you munch on nuts, including a fiber-like substance called pectin that helps with appetite control. As mentioned, nut consumption is linked with a reduction in inflammatory markers as well.
Eat Your Walnuts!
Unless you’re allergic to tree nuts, walnuts are a healthful addition to the diet. Chop them up and add them to hot breakfast cereal, such as steel-cut oats in the morning. They add a delicious bit of crunch to a garden salad. If you’re looking for a cooking oil that handles high temperatures well, walnut oil fits the bill. You can even make or buy walnut butter as a substitute for peanut butter! Plus, a study found that walnuts have twice the antioxidants than other common tree nuts do. So, enjoy!
References:
J Am Coll Nutr. 2010 Dec; 29(6): 595–603.
Nutrients. 2016 Nov; 8(11): 668.
Indian Heart Journal. Volume 70, Issue 4, July–August 2018, Pages 497-501.
J Nutr. 2014 Apr;144(4 Suppl):561S-566S.
Live Science. “Health Nut: Walnuts Offer Huge Amount of Antioxidants”
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