New research published in Nutritional Neuroscience provides evidence linking a specific dietary pattern to healthier levels of Alzheimer’s disease biomarkers. The study suggests that middle-aged adults who closely follow the MIND diet are less likely to exhibit the pathological protein buildup associated with the condition. These findings imply that dietary habits may influence brain health years before any symptoms of memory loss appear.
Scientific understanding of how nutrition impacts the brain has evolved significantly in recent years. Medical professionals recognize that dietary patterns like the Mediterranean diet and the DASH diet support cardiovascular health. The MIND diet combines elements from both of these approaches to specifically target neuroprotection. While prior observational studies indicated that the MIND diet correlates with slower cognitive decline, the biological reasons for this remain under investigation.
“There is a gap in our understanding of the biological mechanisms that may explain how the MIND diet is associated with cognitive health,” said study author Mary Yannakoulia, a professor of nutrition and eating behavior at Harokopio University.
“Although observational evidence has consistently shown that greater adherence to the MIND diet is associated with a reduced risk of Alzheimer’s disease and slower cognitive decline, the underlying biological mechanisms remain unclear. One potential pathway involves amyloid beta deposition, a hallmark of Alzheimer’s pathology, that is known to begin accumulating many years before clinical manifestations.”
“So far, no studies have examined whether adherence to the MIND diet is associated with amyloid beta concentrations in cerebrospinal fluid samples among middle-aged individuals without dementia. Addressing this issue could shed light on whether dietary habits influence Alzheimer’s-related brain changes during the crucial preclinical phase, helping to inform strategies for early prevention.”
The research team analyzed data from the ALBION study, which is a project based in Greece. The final sample consisted of 250 participants. The median age of these individuals was sixty-five years. None of the participants had a diagnosis of dementia at the beginning of the study.
To assess dietary habits, the investigators used a rigorous interview process. Trained dietitians conducted four separate twenty-four-hour dietary recalls with each participant. One interview occurred in person, while the other three took place over the phone. These interviews covered three weekdays and one weekend day to capture a complete picture of typical eating habits.
Based on the food reported in these interviews, the researchers calculated a MIND diet score for every participant. This scoring system evaluates adherence to fifteen specific dietary components. There are ten brain-healthy food groups included in the score. These are green leafy vegetables, other vegetables, berries, nuts, beans, whole grains, fish, poultry, olive oil, and wine.
The scoring system also accounts for five food groups considered unhealthy for the brain. These include red meats, butter and stick margarine, cheese, pastries and sweets, and fried or fast food. Participants received points for eating healthy foods frequently and for limiting unhealthy foods. The total score could range from zero to fifteen, with higher scores indicating better adherence to the diet.
The researchers also needed to measure the biological markers of Alzheimer’s disease. They performed lumbar punctures to collect cerebrospinal fluid from the participants. In this fluid, they measured the concentration of a protein called amyloid beta 42. In a healthy brain, this protein is cleared away effectively.
In people developing Alzheimer’s disease, this protein clumps together to form plaques in the brain tissue. When these plaques form in the brain, the levels of the protein in the spinal fluid drop. Therefore, low levels of amyloid beta 42 in the fluid are considered a pathological sign. The researchers defined a specific cutoff point to identify participants with abnormal protein levels.
The statistical analysis compared the diet scores against the results of the spinal fluid tests. The researchers divided the participants into four groups based on their diet scores. These groups ranged from the lowest adherence quartile to the highest adherence quartile. They then used logistic regression models to calculate the odds of having pathological protein levels.
The study identified an association between the MIND diet and amyloid beta levels. Participants in the highest adherence group were significantly less likely to have abnormal amyloid beta concentrations compared to those in the lowest group. The analysis showed that those who followed the diet most closely had roughly fifty-seven percent lower odds of showing this specific sign of Alzheimer’s pathology.
The researchers adjusted their calculations to account for various factors that could influence the results. They controlled for age, sex, and years of education. They also adjusted for total calorie intake to ensure that overeating or undereating did not skew the findings. The association remained significant even after accounting for medical conditions like diabetes, hypertension, and high cholesterol.
In addition to the overall diet score, the researchers examined the fifteen individual components of the diet. They wanted to see if any single food group drove the results. Their initial analysis suggested that green leafy vegetables had the strongest link to better outcomes. Participants who ate more leafy greens appeared to have a lower risk of amyloid pathology.
However, the strength of this specific finding regarding leafy greens diminished when the researchers applied further statistical corrections. Because they tested many different food groups, they had to adjust their math to prevent false positives. After this correction, the link between leafy greens alone and amyloid levels was no longer statistically significant. This suggests that the benefit likely comes from the overall dietary pattern rather than one single food.
The researchers also looked at a subgroup of participants who had genetic data available. They specifically checked for the APOE4 gene variant, which is a known risk factor for Alzheimer’s disease. Even when accounting for this genetic risk, the relationship between the MIND diet and healthier biomarker levels remained consistent.
There are some limitations to this research. The study utilized a cross-sectional design. This means it looked at diet and biomarkers at a single point in time. It provides a snapshot of the participants’ health but cannot prove that the diet caused the changes in protein levels. It is possible that people with better brain health simply choose to eat better.
The use of dietary recalls relies on memory, which can introduce errors. Participants might not remember exactly what they ate or might alter their reports to appear healthier. However, using four separate recalls helps to minimize this potential error. The researchers also noted that the study was relatively small, with only 250 people.
Future research needs to address these limitations to validate the findings. Long-term studies that follow participants over many years would help clarify the direction of the relationship. Randomized clinical trials are necessary to determine if adopting the MIND diet can actively lower amyloid levels. Scientists also need to investigate other biomarkers to get a more comprehensive view of brain health.
“Our findings suggest that adopting a brain-healthy dietary pattern, such as the MIND diet, may be associated with lower levels of Alzheimer’s-related biomarkers in the brain, even in individuals that do not experience dementia symptoms,” Yannakoulia told PsyPost. “In practical terms, the MIND diet emphasizes the consumption of plant-based foods, i.e.green leafy vegetables, berries, legumes, whole grains and nuts, and the use of olive oil as the primary cooking and salad oil.”
“Adopting such eating habits might help reduce processes linked to neurodegeneration, including inflammation and oxidative stress, thereby supporting long-term brain health. The present findings are preliminary and are derived from a cross-sectional design; they support though the growing evidence that everyday diet plays a significant role in preserving cognitive function and promoting brain health across the lifespan.”
The study, “Association between adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet and cerebrospinal fluid Alzheimer’s disease biomarkers in middle-life individuals without dementia: the ALBION study,” was authored by Archontoula Drouka, Stelios Chatzispyrellis, Dora Brikou, Eva Ntanasi, Eirini Mamalaki, Stylianos Chatzipanagiotou, Christopher Papandreou, Konstantinos Rouskas, Yian Gu, Nikolaos Scarmeas, and Mary Yannakoulia.
