A Twisted Tale of Genes, Microbes, and Alzheimer's, Part 2
Modifiable risk factors, including diet, may contribute to 40 percent of dementia risk.
“To mourn someone who is still alive brings a particular, complicated pain. And often it brings guilt; to mourn someone who has not yet died is to consign them to a kind of death.” ― Nicci Gerrard
Last week, we looked at some new research about how genetics and gut microbes may affect the onset and outcome of Alzheimer's. But there are still some open questions. For one, the study could only show associations between dementia and microbes, so it is possible that the causality goes the other way: Instead of imbalanced microbes leading to Alzheimer’s, perhaps Alzheimer’s causes certain gut bacteria to dominate.
It's complicated
Due to the incredible complexity of biological systems, it is often difficult to establish causality. However, we know from several mouse studies that microbes can affect brain health. If microbes are causal, that is hugely important, because the makeup of your gut microbes—your microbiota—is under your control. The researchers on this study speculate that some of the bacteria they found may be promising therapeutic targets against Alzheimer's and aging in general.
Every meal you consume changes your microbiota, with some species boosted and others diminished to accommodate the nutrients in your diet. By eating the right foods, you can simultaneously improve diversity and diminish pathogens. That means it is possible that we can control the onset and progression of Alzheimer's with diet and supplements.
What to Do
What kind of diet do you need to lower your odds of getting Alzheimer's? Many studies show that a diversity of species is the best indicator of gut and brain health. To improve your gut diversity, you should eat a highly varied diet. One such diet is the Mediterranean diet, which is known for its variety and emphasis on vegetables and fish.
Some dietitians recommend eating 30 different veggies each week. Many of us aren’t even aware that 30 different veggies exist, but they can be delicious if prepared properly. In the Internet age, we have no excuse for not giving them a try. Concentrate on those that are high in fiber, including artichokes, onions, lentils, asparagus, and mushrooms. The fiber feeds the microbes that produce butyrate, keeping your gut and mind in the pink.
If you don’t have the time to cook, you might try a prebiotic supplement that offers a blend of natural fiber and polyphenols that can fill in the gaps. Also, fermented foods are amazing sources of probiotics, prebiotics, and postbiotics (the substances produced by beneficial microbes). These include yogurt (without added sugar), kimchi, kefir, sauerkraut, and natural pickles. The stuff in the center of the store generally does not contain live cultures. The ferments you want are in the refrigerator aisle.
Although the mechanisms are not thoroughly worked out, eating right and maintaining a diverse microbiota can’t hurt, and may prevent or postpone Alzheimer’s. A Lancet Commission on dementia considers that modifiable risk factors contribute to 40 percent of dementia risk. That’s just one more reason to take care of your oral and gut microbes.
References
Cammann, D., Lu, Y., Cummings, M.J. et al. Genetic correlations between Alzheimer’s disease and gut microbiome genera. Sci Rep 13, 5258 (2023).