The Harvard T.H. Chan School of Public Health conducted a study aimed to answer the question: Is there one best diet for optimal brain health? Harvard Study: 6 Diets Improve Long-Term Brain Health. This study, published in February in JAMA Neurology, indicates that there are numerous ways to eat healthily that support cognitive function and longevity. The study’s authors show that the consistent use of multiple healthy eating habits will significantly help preserve cognitive function (memory and attention) throughout life.

Overview of the Harvard Research Study

The study will use data collected from three large longitudinal cohort research studies (159347 subjects, 82.6% female) with participants aged 44 (mean) at baseline. As such, this is the first study to examine the association between six established healthy dietary patterns, including DASH (Dietary Approaches to Stop Hypertension), in a formalized, structured manner. The dietary patterns emphasize consuming less processed and/or added sugars, more whole foods, more plant-based and/or protein sources, and less dietary sodium. Harvard Study: 6 Diets Improve Long-Term Brain Health.

Six Healthy Diets Examined in the Study

The nutrition research study focused on the six major types of dietary patterns that have been connected to good health:

  • Diets rich in fruits, vegetables, whole grains, and low sodium (DASH Diet)
  • Mediterranean style of eating.
  • Diets with an emphasis on plant sources of food
  • Diets whose primary intent is to reduce inflammation
  • Diets providing a balanced intake of all food types
  • Hybrid healthy eating interactions and models

All six of these diets also share a common feature: higher consumption of natural foods and fewer or no processed/refined foods. Harvard Study: 6 Diets Improve Long-Term Brain Health.

6 Diets Improve Long-Term Brain Health

Key Findings: Strong Link Between Diet and Brain Function

All six diet types were positively associated with participants’ performance on cognitive evaluations administered later in life. The DASH Diet resulted in the strongest cognitive performance among participants, which meant reduced cognitive decline.

Individuals who adhered closely to the DASH diet had a 41% lower risk of self-reported cognitive decline compared with those who did not adhere closely to it. Cognitive function evaluations also showed that individuals with a healthy nutritional pattern performed better on both memory and attention throughout their lives. Harvard Study: 6 Diets Improve Long-Term Brain Health.

Importance of Midlife Nutrition

One of the more important findings in this study is the impact nutrition plays during midlife (ages 45 to 54 years). Subjects who had healthy nutritional habits at that time demonstrated greater longevity of brain protection than those who did not have healthy nutritional habits. This signifies that the earlier people have a healthy nutritional foundation, the greater the impact on health and function throughout their lives. Harvard Study: 6 Diets Improve Long-Term Brain Health.

How Healthy Diets Protect the Brain

Various mechanisms by which nutrient-dense diets promote brain health were identified by the researcher(s):

  • Decreased inflammation of the brain and body.
  • Better flow of blood and other materials to the heart and cardiovascular system.
  • Enhanced functioning and communication of neurons in our brains.
  • Reduced risk of diseases and conditions such as hypertension and diabetes.
  • Neutralize free radicals through the consumption of antioxidants, thereby protecting and facilitating the function of brain cells.

The cumulative effect of these mechanisms ultimately preserves reasoning, learning, and memory skills (known as cognition). Harvard Study: 6 Diets Improve Long-Term Brain Health.

Diets Improve Long-Term Brain Health

Study Limitations and Scientific Caution

While there is a strong association between diet and cognition, the researchers caution that current research does not provide sufficient evidence to conclude that one’s diet alone can completely prevent cognitive decline. Harvard Study: 6 Diets Improve Long-Term Brain Health.

However, researchers have found three similar studies with positive outcomes, which confirms that the diet can be a key variable associated with long-term cognitive health.
Experts also recommend that individuals seeking to promote cognitive health engage in other activities, such as physical activity, mental challenges, and adequate sleep.

Conclusion: A Lifelong Investment in Brain Health

The findings from the Harvard Study confirm an important point: there is no single “diet” to ensure healthy brain function. The truth is that there are many dietary habits you can adopt to support your cognitive function. Harvard Study: 6 Diets Improve Long-Term Brain Health.
What is most important to remember is to maintain the structure of a healthy diet throughout your midlife and throughout your lifetime to affect your cognitive function. Harvard Study: 6 Diets Improve Long-Term Brain Health.