MIND diet cannot improve cognition in older persons

News

MIND diet cannot improve cognition in older persons

MIND diet cannot improve cognition in older persons.

NEJM: Defeated! The latest clinical trials show that the MIND diet cannot improve cognition and prevent the decline in hippocampal volume compared with a common diet that also controls calories.

A recent clinical trial result published by a research team at Rush University in the United States delivered a heavy blow.

They found that in cognitively unimpaired adults aged 65 and above with a family history of dementia and being overweight, the MIND diet, which controlled calorie intake for three years, showed a slight improvement in overall cognition. However, when compared to a regular diet with the same calorie control, there was no significant difference between the two groups.

Additionally, neither group showed any improvement in brain white matter hyperintensity volume, hippocampus volume, or total volume of gray and white matter [1].

The findings were presented at this week’s 2023 Alzheimer’s Association International Conference (AAIC) and simultaneously published in the New England Journal of Medicine.

MIND diet cannot improve cognition in older persons.

The MIND diet is a “Mediterranean-DASH diet that delays neurodegeneration” optimized on the basis of the Mediterranean diet and the DASH diet, emphasizing the intake of more plant foods, such as green leafy vegetables, nuts and berries, as well as fish and olive oil, and limiting the intake of foods high in saturated fat and sugar, such as red meat and processed meat, butter and margarine, full-fat cheese, pastries and candies, and fried foods.

Previous research has shown that the MIND diet is associated with higher levels of cognition and slower cognitive decline, as well as a lower burden of Alzheimer’s disease pathological markers.

To validate the findings of the correlation study, the researchers conducted this study. This is a 3-year double-center randomized controlled study. Participants were randomly assigned in a 1:1 ratio to a mildly calorie-restricted MIND diet group (the goal was to reduce intake of 250kcal per day) and a daily diet group with the same mild calorie restriction goal.

Participants were 65 years of age and older, with a 30-item Montreal Cognitive Assessment score ≥ 22 (range 0-30, the lower the score, the more severe the cognitive impairment), overweight (BMI ≥ 25), a family history of Alzheimer’s disease dementia, and poor eating habits (MIND diet score ≤ 8).

Among the 1,929 participants initially recruited, 1,325 were excluded due to reasons such as MIND diet score > 8, disease history or medication, and voluntary withdrawal.

Finally, 301 and 303 participants were enrolled in the MIND diet group and control group, respectively. Within 3 years, 26 and 14 participants in the two groups were lost to follow-up.

MIND diet cannot improve cognition in older persons.

Baseline profile of the MIND diet and control groups

At the baseline, the average MIND diet scores of the two groups were 7.7 and 7.8, respectively. After 6 months, the scores of the MIND diet group increased to 11.0 points and were maintained throughout the trial period.

The scores of the control group improved to 8.5 points. The weight loss of the two groups was 5.0kg and 4.8kg respectively.

The increase in the levels of antioxidant substances such as lutein, zeaxanthin and α/β carotene in the blood supports the continuation of the MIND diet intervention .

In terms of the primary endpoint, from baseline to 3 years after intervention, the overall cognitive score increased by an average of 0.205 standard units in the MIND diet group and by 0.170 standard units in the control group, and the increase in scores followed a similar non-linear pattern in both groups.

According to the intention-to-treat (ITT) analysis, the mean score change was not significantly different between the two groups (p=0.23). Other primary endpoints, such as changes in scores on four different cognitive dimensions, were similar to overall cognitive outcomes.

MIND diet cannot improve cognition in older persons.

Patterns of change in global cognitive scores between the MIND diet group (yellow) and the control group (blue)

A total of 267 participants agreed to undergo brain imaging at baseline, 201 of whom also underwent imaging at year 3.

After excluding one participant whose MRI quality was not acceptable, a total of 200 participants’ MRI data were available for analysis.

Overall, the volume of white matter hyperintensities (mainly related to aging and cerebrovascular disease) increased, and hippocampal volume and total brain volume decreased in both groups.

Changes in white matter hyperintensity volume, hippocampal volume, and total gray and white matter volumes were not significantly different in the MIND diet group compared with the control group.

MIND diet cannot improve cognition in older persons.

Changes from baseline in white matter hyperintensity, hippocampal volume, and gray and white matter volumes at 3 years in the MIND diet and control groups

At 3 years, the incidence of adverse events was similar in the two groups, with 127 adverse events occurring in 89 participants in the MIND diet group and 153 adverse events occurring in 91 participants in the control group.

The most common adverse events were cardiovascular and musculoskeletal events. A total of 10 deaths occurred during the trial, all unrelated to diet.

Therefore, in general, this clinical trial shows that in overweight elderly people aged 65 and over with a family history of dementia, the MIND diet has a small improvement in overall cognition for 3 years, but there is no significant difference compared with a normal diet that controls the same calorie intake.

Perhaps the dietary intervention did not improve cognitive function, or it may have taken longer to see different results, the researchers suggest.

What is MIND diet?

The MIND diet is a dietary pattern designed to promote brain health and reduce the risk of cognitive decline and neurodegenerative diseases, such as Alzheimer’s disease.

MIND stands for “Mediterranean-DASH Intervention for Neurodegenerative Delay.” It is a hybrid diet that combines elements of the Mediterranean Diet and the DASH (Dietary Approaches to Stop Hypertension) Diet.

The MIND diet emphasizes the consumption of specific foods that research suggests may be beneficial for brain health. These foods include:

1. Vegetables: Especially leafy greens and other non-starchy vegetables.
2. Berries: Such as blueberries and strawberries, known for their high antioxidant content.
3. Nuts: Walnuts are particularly highlighted due to their potential neuroprotective properties.
4. Whole grains: Foods like brown rice, quinoa, and oats.
5. Fish: Particularly fatty fish like salmon, which are rich in omega-3 fatty acids.
6. Poultry: Chicken and turkey are preferred over red meat.
7. Beans and legumes: Such as lentils and chickpeas.
8. Olive oil: A primary source of healthy fats in the Mediterranean diet.
9. Wine: In moderation, as studies have suggested that moderate alcohol intake may have some cognitive benefits.

On the other hand, the MIND diet recommends limiting the intake of certain less brain-healthy foods, including:

1. Red meat
2. Butter and margarine
3. Cheese
4. Pastries and sweets
5. Fried or fast food

The MIND diet has gained attention due to its potential association with a reduced risk of cognitive decline and Alzheimer’s disease.

However, as with any diet or lifestyle approach, it is essential to consult with a healthcare professional before making significant changes to your eating habits, especially if you have any underlying health conditions.

references:

[1] Barnes LL, et al. Trial of the MIND diet for prevention of cognitive decline in older persons. New England Journal of Medicine. 2023. DOI: 10.1056/NEJMoa2302368.