A healthy diet has long been linked to a reduced risk of various health conditions, including heart disease and certain cancers.
Recent research adds to the growing body of evidence that maintaining a varied, plant-rich diet can also decrease the risk of cognitive decline and dementia in later life. The findings suggest an unhealthy diet is strongly associated with lower cognitive abilities.
In contrast, a high-quality diet during youth and middle age helps maintain brain health as you age. Adopting healthy eating habits at any age can improve your chances of staying mentally sharp as you age.
The Impact of Diet on Cognitive Health
Numerous studies have shown that a diet rich in plants and low in salt, saturated fats, and processed foods benefits overall health, including brain health.
Diets such as the Mediterranean, DASH, and MIND diets, which emphasize fruits, vegetables, whole grains, and healthy fats, have been associated with a reduced risk of cardiovascular disease, diabetes, and cancer.
Research presented at NUTRITION 2024, the annual meeting of the American Society for Nutrition, provides further evidence that healthy eating throughout life is crucial for maintaining cognitive function as we age.
This study suggests that the earlier people adopt healthy eating patterns, the more likely they are to stay mentally sharp into old age.
Study Overview
The study collected data from 3,059 individuals over seven decades. All participants were born in March 1946 and enrolled as children in the Medical Research Council’s National Survey of Health and Development in the United Kingdom.
Over 75 years, participants completed questionnaires and tests on diet, cognition, general health, and other factors.
Researchers assessed participants’ dietary intakes at five-time points between the ages of 4 and 63 using recall and food diaries.
They also measured cognitive ability at seven-time points between ages 8 and 69. Group-based trajectory modeling was used to investigate the relationship between diet and cognition.
Findings on Diet and Cognitive Decline
The researchers used the 2020 Healthy Eating Index (HEI) from the U.S. Department of Agriculture Health and Nutrition Service to assess the quality of the participants’ diets.
Higher intakes of foods such as fruits, vegetables, whole grains, protein, dairy, and seafood increased HEI scores, while higher intakes of refined grains, sugar, sodium, and saturated fats reduced scores.
The study found a strong association between diet quality over time and cognitive trajectory. Participants who retained high cognitive abilities into older age tended to eat more of the index’s high-scoring foods and less of the low-scoring ones.
Specifically, 47% of participants with the lowest-quality diets were in the lowest cognitive trajectory, whereas 48% of those with the highest-quality diets were in the highest cognitive trajectory.
Early Life Diet and Later Life Cognitive Function
The study also found that differences in childhood diet quality influenced later-life dietary patterns. This suggests that early-life dietary intakes may influence our dietary decisions later in life, and the cumulative effects of diet over time are linked with the progression of our global cognitive abilities.
However, improving diet later in life can still benefit, suggesting that adopting healthier eating habits is never too late.
Mechanisms Behind Diet and Cognitive Health
Diets shown to have health benefits include a high intake of fruits, vegetables, and whole grains, combined with low consumption of sugars, saturated fats, and processed foods.
These nutrients protect brain cells from damage related to oxidative stress, support brain structure and function, and maintain a healthy vascular system, which helps promote healthy blood flow to the brain.
The Mediterranean, DASH, and MIND diets provide a high intake of polyphenols and plant compounds that can help protect against the development of chronic health conditions such as certain forms of cancer, cardiovascular disease, diabetes, osteoporosis, and neurodegenerative diseases.
Polyphenols are antioxidants that combat cell damage and have anti-inflammatory and neuroprotective effects.
Dietary Recommendations for Brain Health
To support cognitive health, experts recommend the following dietary habits:
- Eat various colorful fruits and vegetables: Aim for at least six colors daily.
- Consume a serving of leafy greens daily.
- Include whole grains, nuts, seeds, beans, and seafood.
- Use olive oil as your primary cooking fat.
- Limit red meat, cheese, butter, refined grains, sweets, pastries, and fried or fast food intake.
Wrap up
A first-of-its-kind study tracked dietary information and cognitive ability in more than 3,000 individuals across seven decades.
The findings suggest that those with higher-quality diets also had better cognitive outcomes over time than those with unhealthy diets.
This highlights the importance of adopting healthy eating habits early in life to support and maintain mental health throughout the lifespan. A diet rich in fruits, vegetables, whole grains, and healthy fats is crucial for brain health and can help prevent cognitive decline as we age.
