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Dear Dietitian - What are functional foods

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PICT Leanne McCrate Dear Dietitian
Leanne McCrate, RDN, LD

Dear Dietitian,

I enjoyed your column on functional foods and heart health. I eat healthy and exercise regularly. I’ve also read about functional foods that are good for your brain. What is your opinion?


Dear Ken,

Functional foods have gained popularity in Western cultures due to scientific discoveries that connect certain dietary factors to disease. For example, there is a link between a diet high in saturated fat and heart disease. Conversely, when saturated fats are replaced with unsaturated fats in a diet low in cholesterol, the risk of heart disease decreases.


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A functional food is one that has a potentially positive effect on health beyond basic nutrition. Many of the same foods that aid in heart health are also good for your brain. Listed below are foods that may help prevent mental decline.

  • Walnuts—While all nuts are good sources of monounsaturated fats, walnuts contain an 
  • Omega-3 fatty acid, alpha-linolenic acid, which lowers blood pressure. This action            
  • helps the heart and brain (1).
  • Flavonoids found in dark chocolate, red wine, and green tea have shown improvement 
  • in cognitive function of older adults (2).
  • Choline—an organic compound found in egg yolks, chicken, and veal may help   
  • slow mental decline (3).
  • Mushrooms—In a study of more than 1,000 participants, mushrooms were linked to a 
  • decrease in mild cognitive decline. Types of mushrooms included in the study include 
  • shitake, golden, oyster, and white button (4).
  • Green, leafy vegetables, such as spinach, kale, broccoli, and turnip greens, contain antioxidants lutein, folate, and beta carotene that protect the brain from damaging

free radicals, thereby possibly slowing mental decline.

It is important to note that studies on functional foods are limited. Much of the research has been conducted on rodents or in a laboratory. These studies are considered pre-clinical, and the same results cannot be predicted in humans. That said, the foods listed above are healthy as they provide fiber, vitamins, minerals, and other essential nutrients. 

Until next time, be healthy!

Dear Dietitian


  1. Foods linked to better brainpower. Harvard Health Publishing. Retrieved from
  2. Letenneur L, Proust-Lima C, Le Gouge A, Dartigues JF, Barberger-Gateau P. Flavonoid; Intake and cognitive decline over a 10-year period. Am J Epidemiol. 2007;165:1364-1371.
  3. McCann JC, Hudes M, Ames BN. An overview of evidence for a causal relationship between dietary availability of choline during development and cognitive function in offspring. Neurosci Biobehav Rev. 2006;30:696-712.
  4. Lei Feng, Irwin Kee-Mun Cheah, Maisie Mei-Xi Ng, Jialiang Li, Sue Mei Chan, Su Lin Lim, Rathi Mahendran, Ee-Heok Kua, Barry Halliwill. The association between mushroom Consumption and Mild Cognitive Impairment: a community-based cross-sectional study in Singapore. Journal of Alzheimer’s Disease, 2019;1. DOI:  10.3233/JAD-180959.
Leanne McCrate, RDN, LD, is an award-winning dietitian based in St. Louis, MO. Her mission is to educate consumers on sound, scientifically-based nutrition. Do you have a nutrition question? Email her today at Dear Dietitian does not endorse any products, health programs, or diet plans.