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Dr Christophe de Jaeger (Longevity and geriatrics)
A meta-analysis reviewed all that has been published on the links between different diets and their impact on Alzheimer’s disease. Result: Mediterranean or ketogenic diets seem to slow down, even protect people from cognitive degeneration.
Alzheimer’s disease remains partly mysterious and treatments today do not cure or block it. Can diet have an influence on the progression of the disease? To answer this question, a meta analysis on nutrition interventions has been conducted recently. The review aimed to highlight the role of certain diets in slowing the progression of Alzheimer’s disease and improving patients’ quality of life.
Western diet increases risk, Mediterranean diet protects us
The researchers selected the most relevant and best quality publications on this topic published between 2018 and 2022 in the scientific databases PubMed, Web of Science, Scopus and Cochrane Library. A total of 38 studies were retained, including 17 randomized clinical trials and 21 systematic reviews and/or meta-analyses.
Examination of its analyzes thus revealed 3 main pieces of information:
- The Western diet is a risk factor for developing Alzheimer’s disease;
- The Mediterranean diet, the ketogenic diet and supplementation with omega-3 fatty acids and probiotics are protective factors;
- The protective effect of these interventions is only significant in cases of mild to moderate Alzheimer’s.
Other links are also redundant: a poor quality diet is a risk factor for developing Alzheimer’s disease, which deteriorates cognitive performance and verbal fluency. Malnutrition and unintentional weight loss are associated with an increased risk of mortality in patients with Alzheimer’s disease.
Nutrients and the quality of the microbiota play a big role
In detail, the entire analysis points to several explanations for these favorable or unfavorable links. A diet with a high glycemic index or refined carbohydrates, such as the Western diet, is associated with increased accumulation of Aβ peptides in the brain. An even more deleterious effect which carriers of a genetic predisposition: APOE-ε4. (APOE-ε4 being a genetic risk factor associated with Alzheimer’s disease and dementia, as well as insulin resistance). The Western diet therefore increases levels of inflammation.
On the contrary, adherence to the Mediterranean diet improves cognitive outcomes, increases gray matter volume, improves memory, and decreases memory decline. The ketogenic diet has also been shown to be useful in the treatment of Alzheimer’s disease. This is due to an adequate intake of vitamin E, a powerful antioxidant and anti-inflammatory agent. Observational cohort studies have shown that people with Alzheimer’s disease have significantly lower levels of tocopherols, tocotrienols, and total vitamin E compared to the general population.
Adequate levels of omega-3 polyunsaturated fatty acids, particularly EPA and DHA, are also associated with slower rates of cognitive decline and reduced risk of dementia.
Microbiota dysbiosis is an obvious risk factor for the development of Alzheimer’s disease. High-fat diets, the use of antibiotics or the lack of probiotics and/or prebiotics can also modify the composition of the microbiota and therefore be a risk factor for Alzheimer’s disease.
Alzheimer’s: diet and exercise are helpful
For Dr. Christophe de Jaeger, physiologist and specialist in aging, this conclusion is not really surprising:
“Western diets are inflammatory and thus promote the emergence of neurodegenerative diseases. Conversely, Mediterranean diets and those that avoid refined sugars have a positive influence. The novelty here is that this state of affairs is apparently supplemented by probiotics present in these diets, which also prove to be protective. According to this work, it would be in our interest to benefit from this type of scheme!”.
With regard to the fact of acting on the quality of life, via the plate, here again, the expert approves the conclusions of this study:
“Nutritional interventions may be useful in Alzheimer’s disease and may even, a priori, slow progression and improve patients’ quality of life. As soon as a patient is taken care oflzheimerian, as soon as we take an interest in him, in his health, that we recommend a diet not loaded with refined sugars and fat, correctly balanced in vitamins, we can only help his brain to defend itself against diseases neurodegenerative. If in addition, we add physical exercise, we will put a whole set of elements that will be favorable to the individual and to his intellectual functioning.
Slide: How to react to a loved one with Alzheimer’s disease?