Alzheimer’s Disease: Is it the Fate of Aging?
Updated: Aug 20
“Aging is not lost youth but a new stage of opportunity and strength.”
Dementia and Alzheimer’s Disease (AD) are two terms we commonly associate with aging. If you have experience with AD you know how devastating it is for the person afflicted as well as the caregivers who witness the inevitable decline. But, does memory loss and loss of cognitive function have to be what some of us might expect as we age?
What is Alzheimer’s Disease?
Alzheimer’s Disease (AD) is an irreversible neurodegenerative disease where there is progressive loss of both memory and cognitive function (Pizzorno, Murray, Joiner-Bey, 2016). It is a type of dementia where 80% of all cases are caused by AD (Weller & Budson, 2018).
AD is eventually diagnosed when everything else has been ruled out. True diagnosis can only be done postmortem when a biopsy of the brain can reveal the hallmarks of AD, both beta-amyloid plaque build-up AND neurofibrillary tangles (Pizzorno, Murray, Joiner-Bey, 2016). These tangles play a prominent role in the neuron (brain cell) losing its connection to other neurons and to eventually dying (NIH, n.d.). The beta-amyloid plaque accumulates between neurons, disrupting cell function (see image below). As brain cells die, connections between entire networks of neurons are lost and the brain begins to atrophy.
What are the symptoms?
As brain cells lose functionality and connections and they begin to die, different parts of the brain are affected causing symptoms, such as:
Executive function loss (judgment and decision-making)
Visuospatial function loss
Erratic behavior, mood changes
Eventual loss of the ability to perform basic activities of daily living
(Weller & Budson, 2018).
What are the risk factors for AD?
Risk factors for AD include a combination of:
Age (it is mostly a disease of the elderly)
Sex (women have a higher prevalence because they live longer)
Genetic factors - (APOE-4, PSEN1, PSEN2, etc.) (Huat, et al., 2019).
Heavy metals toxicity, especially aluminum, lead, cadmium (Huat, et al., 2019).
Lifestyle factors, such as diet, exercise (both physical and mental),
Alterations in the gut microbiota (Kowalski & Mulak, 2019).
Cardiac and metabolic disorders (Huat, et al., 2019).
Reduced social interaction (Huat, et al., 2019).
Head or brain injury (Huat, et al., 2019).
Not my gut microbiota again?
Your gut microbiota again.
In a nutshell, age-related changes in the gut microbiota of the elderly, resembling a less diverse and less stable environment, lead to a loss of gut barrier integrity (increased permeability). This leads to increased production of inflammatory cytokines and bacteria-derived components in circulation, a weakened blood-brain barrier and eventually the cascade from neuroinflammation to neural injury and finally neurodegeneration (Kowalski & Mulak, 2019). There is no doubt about it, gut dysbiosis and impaired gut/host interactions play a key role in neurodegeneration (Kowalski & Mulak, 2019).
Why is this important?
Well, the communication that exists between the central nervous system (CNS) and the enteric nervous system (ENS) - the one responsible for neural communication in the gut - along the brain-gut axis, is very active your entire life. (Kowalski & Mulak, 2019). The gut microbiota play a pivotal role in both early brain development and adult neurogenesis (the making of new neurons). In addition to the communication between the CNS and ENS on the neuronal level, there are mechanisms of communication that also exist in immune, hormonal, and metabolic signaling (Kowalski & Mulak, 2019). And, let’s not forget the neurotransmitters that are synthesized in the gut; namely serotonin and dopamine.
Lastly, you’ve heard that 70% of the immune system lives in the gut, right? Well, in addition to protecting us from infection, the main function of the immune system, it’s also responsible for neural function and development (Kowalski & Mulak, 2019).
It is indeed all interconnected.
What can I do?
PREVENTION! PREVENTION! PREVENTION!
It’s never too early to start taking care of your beautiful brain. There are MANY things you can do, however, we’re going back to the gut and probiotics.
Fermented foods are neuroprotective (Kim, et al., 2016). They have the power to improve the activity and bioavailability of food, to influence the HPA-axis, and to improve cognitive function through the modulation of neurotransmitters (Kim, et al., 2016).
So, eat fermented foods or take a probiotic supplement religiously!
Here are some delicious examples of fermented foods to add to your diet:
Sauerkraut and other lacto-fermented vegetables/pickles
Yogurt, kefir (non-dairy options, too)
Soy sauce, tamari
Alternatively, you could take a probiotic supplement. Reach for a couple of different brands with varying strains so you get some diversity as you would from food. Some reputable brands include Flora Udo’s Choice, BioKult, New Chapter, and Innate Response Formulas. Follow the dosing recommendations on each package.
Probiotics can decrease the effects of antibiotics and conversely, antibiotics can also kill off probiotics. These should be taken 2 hours apart.
Alzheimer's disease. (2018, December 08). Retrieved from https://www.mayoclinic.org/diseases-conditions/alzheimers-disease/symptoms-causes/syc-20350447
Huat, T. J., Camats-Perna, J., Newcombe, E. A., Valmas, N., Kitazawa, M., & Medeiros, R. (2019). Metal Toxicity Links to Alzheimer's Disease and Neuroinflammation. Journal of Molecular Biology, 431(9), 1843-1868. doi:10.1016/j.jmb.2019.01.018
Image. (n.d.). 5 probiotic-rich food drinks to heal your body. Retrieved from https://medium.com/naturehub/5-probiotics-rich-food-drinks-to-heal-your-body-acf5a02bbf24
Image. (n.d.). Cartoon. Bugs, brain, microbiota, gut-brain axis. Retrieved from
Image. (n.d.). Normal brain, Alzheimer’s brain. Retrieved from
Image. Verrecchia, F. (n.d.). Woman carrying bouquet of flower white walking on street.
Retrieved from https://unsplash.com/photos/VyarWMe4C2A
Kim, B., Hong, V. M., Yang, J., Hyun, H., Im, J. J., Hwang, J., . . . Kim, J. E. (2016). A Review of Fermented Foods with Beneficial Effects on Brain and Cognitive Function. Preventive Nutrition and Food Science, 21(4), 297-309. doi:10.3746/pnf.2016.21.4.297
Kowalski, K., & Mulak, A. (2019). Brain-Gut-Microbiota Axis in Alzheimer’s Disease. Journal of Neurogastroenterology and Motility, 25(1), 48-60. doi:10.5056/jnm18087
National Institute of Health. National Institute of Aging. (n.d.). What happens to the brain in alzheimer's disease? Retrieved from https://www.nia.nih.gov/health/what-happens-brain-alzheimers-disease
Pizzorno, J. E., Murray, M. T., & Joiner-Bey, H. (2016). The clinician's handbook of natural medicine. Elsevier.
Weller, J., & Budson, A. (2018). Current understanding of Alzheimer’s disease diagnosis and treatment. F1000Research, 7, 1161. doi:10.12688/f1000research.14506.1