By Joseph E. Scherger, MD, MPH

Core Faculty, Eisenhower Health Family Medicine Residency Program, Eisenhower Health Center, La Quinta, CA; Clinical Professor, Keck School of Medicine, University of Southern California, Los Angeles

Dr. Scherger reports no financial relationships relevant to this field of study.

SYNOPSIS: An investigation of the Framingham Offspring Study revealed a higher intake of dietary flavonoids found in plants is associated with modest slowing of age-related dementia.

SOURCE: Shishtar E, Rogers GT, Blumberg JB, et al. Long-term dietary flavonoid intake and change in cognitive function in the Framingham Offspring Cohort. Public Health Nutr 2020;23:1576-1588.

The Framingham Offspring Study, part of the original Framingham Heart Study, began in 1971 when researchers started following 5,124 men and women who were children of the original cohort and their partners. Shishtar et al used data from the Framingham Offspring Study to determine if there is any connection between long-term intake of dietary flavonoids and a decline in cognitive function over a follow-up period of up to 15 years.

A total of 1,779 subjects ≥ age 45 years and free of dementia had attended at least two of the last three Framingham Offspring Study exams. Subjects were well-educated, reported engaging in light physical activity, and were overweight (average body mass index, 27.8 kg/m2). The authors controlled for other variables, such as smoking and comorbidities. Subjects completed at least four validated food frequency questionnaires, which researchers used to learn more about long-term flavonoid intake. This intake was separated into four groups: 15th, 30th, median, and 60th percentiles.

Over a median follow-up of 11.8 years, the authors observed “nominally significant trends” toward a slower decline in cognitive function among those who consumed more flavonoids. Despite these trends, the authors stopped short of concluding there was a clear, direct link between consuming more flavonoids and slowing cognitive decline.

COMMENTARY

Flavonoids are a group of foods found in certain plants. The food frequency questionnaires used in this study included a list of 126 foods. Flavonoids were divided into recognized groups, including berries, citrus fruits (including orange juice), apples, pears, strawberries, and red wine. These foods feature antioxidant properties and can scavenge cellular breakdown products. Recent evidence shows flavonoids exert favorable cognitive effects by protecting neurons from neurotoxins and combating neuroinflammation.1,2

The popular American diet, loaded with excess processed carbohydrates, leads to obesity, prediabetes, and type 2 diabetes — and it certainly does no one any favors when it comes to cognition. One-third of Americans ≥ age 85 years are afflicted with Alzheimer’s disease; one in three seniors die with some form of dementia.3 A growing collection of recent work suggests better nutrition and modified lifestyle factors could prevent and even reverse cognitive decline.4,5 Nutrition science, such as the work carried out by Shishtar et al, may be life-saving for the brain.

REFERENCES

  1. Spencer JPE. Flavonoids: Modulators of brain function? Br J Nutr 2008;99:ES60-ES77.
  2. Vauzour D. Dietary polyphenols as modulators of brain functions: biological actions and molecular mechanisms underpinning their beneficial effects. Oxid Med Cell Longev 2012;2012:914273.
  3. Alzheimers.net. 2019 Alzheimer’s statistics.
  4. Bredesen DE. Reversal of cognitive decline: A novel therapeutic program. Aging 2014;6:707-717.
  5. Sherzai D, Sherzai A. The Alzheimer’s Solution: A Breakthrough Program to Prevent and Reverse the Symptoms of Cognitive Decline at Every Age. HarperCollins; 2017.