Can lifestyle changes reduce the risk of Alzheimer's?

Research published in the journal Alzheimer's Research and Treatment Intensive lifestyle modifications have been shown to significantly improve cognition and functioning in patients with mild cognitive impairment or early dementia due to Alzheimer's disease.

study: The effect of intensive lifestyle changes on the progression of mild cognitive impairment or early dementia due to Alzheimer's disease: a randomized controlled clinical trialImage credit: Prostock-studio / Shutterstock

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Several lifestyle factors, including unhealthy diet, lack of exercise, smoking, obesity, diabetes, social isolation, and mental stress, are known to contribute to the onset and progression of dementia, including Alzheimer's disease.

A total of 12 potentially modifiable risk factors have been identified by the Lancet Commission on Dementia Prevention, Intervention and Care, which together account for approximately 40% of the global dementia burden.

Existing evidence suggests that a high intake of vegetables and omega-3 fatty acids reduces the risk of Alzheimer's disease by 38% and 60%, respectively. In contrast, consuming saturated and trans fats has been shown to more than double the risk of Alzheimer's disease.

Studies investigating lifestyle risk factors have found that multidomain lifestyle interventions are more effective than single-domain interventions in reducing the risk of dementia and Alzheimer's disease. Multifaceted interventions of diet, exercise, cognitive training, and vascular risk monitoring have been shown to preserve cognitive function in older adults at high risk of developing dementia.

In this multi-centre randomised controlled clinical trial, scientists investigated the effect of an intensive 20-week multi-domain lifestyle intervention on the progression of mild cognitive impairment or early dementia in people with Alzheimer's disease.

Study design

The trial was conducted on 51 adults aged 45 to 90 years who had been diagnosed with mild cognitive impairment due to early Alzheimer's disease dementia. Of all participants, 26 were randomly assigned to the intervention group and 25 to the usual habits and care control group.

Participants in the intervention group followed an intensive multi-domain lifestyle program for 20 weeks. The lifestyle intervention included diet (a minimally processed, plant-based diet low in harmful fats, refined carbohydrates and sweeteners and selected supplements), moderate exercise, stress management approaches and support groups. Participants in the control group were asked to make no lifestyle changes for the 20 weeks.

At the 20-week follow-up, all participants underwent clinical and cognitive assessments. Four tests were administered to assess participants' cognitive and functional changes: Clinical Global Impression of Cognitive Impairment (CGIC), Alzheimer's Disease Assessment Scale-Cog (ADAS-Cog), Clinical Dementia Rating-Sum of Boxes (CDR-SB), and Clinical Dementia Rating-Global (CDR-G).

As secondary outcome measures, blood-based biomarkers such as plasma Aβ42/40 ratio and microbiome taxa were also analyzed. Plasma Aβ42/40 ratio is used to assess the pathological risk of Alzheimer's disease in patients with mild cognitive impairment or dementia.

Important Observations

Analysis of the primary outcome at week 20 revealed that cognition and functioning improved significantly in the multidomain lifestyle intervention group and worsened in the control group.

The lifestyle intervention group had significantly less progression to clinical dementia compared with the control group.

Analysis of blood-based biomarkers revealed a 6.4% increase in plasma Aβ42/40 ratio in the intervention group and an 8.3% decrease in the control group. A higher plasma Aβ42/40 ratio is known to be associated with less beta-amyloid deposits in the brain (a key hallmark of Alzheimer's disease).

Other biomarkers, glycated hemoglobin, insulin, Glycoproteins Acetyl, low-density lipoprotein cholesterol, and beta-hydroxybutyrate (ketone bodies) also showed improvements in the intervention group compared with the control group.

Overall, this study found that the degree of lifestyle change (between baseline and 20-week follow-up) and adherence to desired lifestyle changes were significantly associated with changes in cognitive function.

In other words, greater adherence to the prescribed lifestyle intervention was associated with more significant improvements in cognition and functioning.

Microbiome analysis showed significant improvements in the intervention group but not in the control group, specifically, induction of microbial species known to be associated with a reduced risk of Alzheimer's disease and reduction of microbial species known to be associated with an increased risk of the disease.

Significance of the study

The study found that 20 weeks of intensive lifestyle modification had beneficial effects on cognition and functioning in patients with mild cognitive impairment or early dementia due to Alzheimer's disease.

These lifestyle changes could be considered valuable interventions to prevent Alzheimer's disease, as they are available at a much lower cost than treating the disease.

As the scientists suggest, future clinical trials should consider larger sample sizes and longer follow-up periods to determine the long-term outcomes of intensive lifestyle changes in a more diverse population of Alzheimer's patients.