Life Extension Magazine®

Walnuts rich in polyphenol compounds for brain health


Walnuts’ unique nutrient composition works to combat heart disease, cancer, and cognitive decline—and even boosts the creation of new brain cells.

Scientifically reviewed by: Holli Ryan, RD, LD/N, in March 2021. Written by: Laurie Mathena.

Walnuts are one of the healthiest nuts you can eat. These brain-shaped nuts contain a unique composition of nutrients not commonly found in other whole foods.

This is one reason why this superfood has been shown to help combat cognitive decline, heart disease, cancer, and more.

Brain Health

Walnuts contain polyphenol compounds that not only reduce oxidation and inflammation in the brain, but also improve signaling between brain cells and increase neurogenesis (the creation of new brain cells).1

In a study of mice with Alzheimer’s disease, giving them the human equivalent of a handful of walnuts daily led to enhanced memory and learning skills, superior motor development, and reduced anxiety. The authors concluded that, “Dietary supplementation with walnuts may have a beneficial effect in reducing the risk, delaying the onset, slowing the progression of, or preventing AD [Alzheimer’s disease].”2

In another study, researchers concluded that eating foods like walnuts may increase “health span” while enhancing cognitive and motor function in aging.3

Heart Protection

Walnuts have beneficial effects against numerous underlying factors contributing to heart disease.

A meta-analysis was conducted, reviewing 26 clinical trials involving 1,059 people. It found that, compared to people who didn’t eat walnuts, people who ate walnuts on a regular basis had modestly lower total cholesterol (3.25% reduction), lower LDL cholesterol (3.73% reduction), and lower triglycerides (5.52% reduction).4 This study also found that eating walnuts did not increase body weight.

Cancer Prevention

Walnuts have been shown to have properties that act against numerous types of cancer. A Harvard Medical School study found that diets containing walnuts could slow the growth of colorectal tumors in mice.5

Similar results have been found with breast cancer. In a mouse study, mice that ate walnuts every day were less likely to develop breast cancer. And in the mice that did develop breast cancer, the tumors were smaller and slower-growing. Adding walnuts to their diet also slowed the growth of prostate, colon, and renal cancers.6

The best way to consume walnuts is with the skin on, as about 90% of the phenols from walnuts are found in the skin.


  1. J Nutr. 2014 Apr;144(4 Suppl):561s-6s.
  2. J Alzheimers Dis. 2014;42(4):1397-405.
  3. J Nutr. 2009 Sep;139(9):1813s-7s.
  4. The American Journal of Clinical Nutrition. 2018;108(1):174-87.
  5. J Nutr Biochem. 2015 Jul;26(7):776-83.
  6. J Nutr. 2014 Apr;144(4 Suppl):555s-60s.