What happens to your body if you eat a handful of walnuts every day?

Early autumn marks the time when Fresh Walnuts hit the market. The freshwalnut kernels at this time are rich in moisture, crisp, and sweet, making them highly sought after by people of all ages. Many walnut lovers even consider walnuts a year-round essential nut, eating a handful daily. So, what subtle changes can occur in your body if you consistently eat a handful of walnuts daily? What are the health benefits of regularly eating walnuts compared to those who don't? A growing number of studies are finding that those who consistently eat a handful of walnuts daily will gradually experience these five health benefits...

1.A handful of walnuts a day improves sleep quality. In August 2025, a clinical study published in the journal Food & Function found that consuming 40 grams (a small handful) of walnuts daily with dinner can regulate melatonin metabolism, significantly increase melatonin metabolite levels, and significantly improve overall sleep quality. This study also provides scientific evidence for walnuts as a natural sleep aid.

2.The study included 76 healthy young adults with an average age of 24 years old, and divided them into a "walnut-eating group" and a "non-walnut-eating group." The "walnut-eating group" consumed 40 grams of walnuts at dinner every day, while the control group completely avoided nuts for 8 weeks. Analysis of sleep quality found that people who ate walnuts for dinner fell asleep faster (significantly shortened the latency to fall asleep), had higher overall sleep quality scores, and significantly reduced daytime sleepiness and improved sleep efficiency. ①2. A handful of walnuts a day can reduce systemic inflammation. Many people know the dangers of long-term chronic inflammation in the body, such as weakened immunity, accelerated aging, and increased risk of cancer. In April 2025, a study published in the journal Cancer Prevention Research found that eating walnuts daily can help increase urolithin A levels and reduce systemic inflammation.

The study recruited 47 healthy adults aged 50-65 and had them consume 56 grams of peeled walnuts daily for three weeks. The results showed that walnut consumption significantly increased urolithin A levels, which in turn reduced systemic inflammation. For example, participants with higher urolithin A levels had significantly lower levels of multiple inflammatory markers and a downward trend in tumor necrosis factor-α levels.

In other words, people who regularly eat walnuts may have lower levels of chronic inflammation throughout the body. 3. A handful of walnuts a day reduces the risk of colorectal cancer. The study published in the journal Cancer Prevention Research found that daily walnut consumption not only reduces systemic inflammation but also has a direct, positive impact on immune cells within colon polyps, thereby inhibiting the development of colorectal cancer. YaNiu collected blood, urine, and fecal samples from participants and analyzed the effects of walnut consumption on urolithin A, inflammatory markers, and polyp tissue. The results showed that by increasing urolithin A levels in the body, it has a positive impact on immune cells within colon polyps, thereby inhibiting the development of colorectal cancer. ②

4.A handful of walnuts a day improves brain cognition. It's often said that "eating walnuts nourishes the brain," but do they really do? A February 2025 study published in the journal Food & Function found that consuming walnuts at breakfast improves executive function reaction time throughout the day and has a delayed protective effect on memory, impacting cognitive function.

In 2023, a study published in the Lancet journal eClinicalMedicine conducted a six-month randomized controlled nutritional trial on 771 healthy adolescents aged 11 to 16. The study found that adolescents who ate 30 grams of walnuts per day had enhanced attention function, and those with symptoms of attention deficit hyperactivity disorder had significant improvements. At the same time, functions related to fluid intelligence (perception, memory, calculation speed, reasoning ability, etc.) also increased. ④5. A handful of walnuts a day improves microvascular function. After eating walnuts for one month, their blood vessels changed. A study published in the Journal of Nutritional Biochemistry in 2015 stated that consuming 40 grams of walnuts daily for four consecutive weeks can effectively improve the microvascular function of the subjects. Studies have confirmed that the intake of fatty acids in walnuts can effectively promote the production of plasma epoxides, thereby improving microvascular function.