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Neurodegenerative Disorders

The Mediterranean Diet and Age-related Neurodegenerative Disease

The Mediterranean diet is often credited as the ideal model of healthy eating. Multiple studies have proven its effectiveness in preventing a wide array of maladies, including diabetes mellitus, obesity, hypertension, cardiovascular disease, and cognitive disease (Aridi, 2020). Until recently, there was little evidence suggesting that this diet  protects against neurodegenerative disease, but with advances in technology, preliminary research has indicated this may be the case (ScienceDaily, 2021). As we age, we become more susceptible to developing neurodegenerative disorders, which are progressive diseases that impede the functioning of the central nervous system. While they do have a strong genetic component, they are also known to be triggered by environmental factors, such as exposure to certain toxins or viruses (NCI Dictionary). Although many of these factors are out of our control, we are able to decide what we are consuming.

The Mediterranean diet first got attention in the mid-twentieth century when studies confirmed  a significantly decreased amount of cardiovascular disease among Greek and Italian populations as compared to the rest of the world. It is believed that this can be attributed to the variety of fresh plant-based foods they consume, with most meals consisting primarily of vegetables, legumes, and whole grains. Processed foods with synthetic trans fats are substituted for lean meat and olive oil, which contains healthier unsaturated fats. Fish is often consumed as a good source of omega-3-fatty acids and is eaten in place of red meat.  Fresh fruit is also eaten as a substitute for desserts that are high in sugar and fat (Mayo Foundation, 2021).

Inhabitants of the small Greek island of Ikaria adhere the most strictly to this diet, except they eat significantly less meat and fish, replacing them with more vegetables which contain many more antioxidants. Such areas of the world where life expectancy is strikingly higher than in others are referred to as “blue zones,” and Ikaria certainly meets the qualifications, with people living eight to ten years longer than the average American. While the strong social culture of the island and the general active lifestyle there contributes to the overall health of the inhabitants, there is reason to believe their diets also play a key role. In addition to eating healthy, Ikarians drink herbal tea daily, which they make using freshly grown herbs. While they are also excellent sources of antioxidants, they are mild diuretics as well, working to lower blood pressure. This is actually directly related to neurodegenerative disease. According to Johns Hopkins research published in the Journal Neurology, the regular use of diuretics decreased the risk of Alzheimer’s by seventy-five percent, partially accounting for the fact that Ikarians over 85 have less than 10 percent chance of developing Alzheimer’s (Kotifani, 2020).

In Alzheimers and dementia, there is an accumulation of beta amyloid protein in the brain, forming clumps and causing neuronal cell death. The brain will also shrink in volume in a process called atrophy, thus manifesting as symptoms of memory loss, confusion, and disorientation. The German Center for Neurodegenerative Diseases has conducted studies following individuals’ diets over time and investigating the link between Mediterranean-like diets and protection against these physical changes in the brain in some healthy individuals and others that were identified as having a higher risk for these diseases. Magnetic resonance imaging was used to assess differences in brain volume and neuropsychological tests assessed the subjects’ memory and general cognitive abilities. Biomarker levels for beta-amyloid proteins in the cerebrospinal fluid of subjects were also measured. Subjects that more strictly adhered to the Mediterranean diet had consistently less beta-amyloid plaque deposits and performed better on memory tests. Their brains also showed less signs of atrophy and greater brain volume in the hippocampus, a brain structure essential to learning and memory. However, the underlying biological mechanisms at play are still poorly understood and are the focus of new research and longitudinal studies (ScienceDaily, 2021).

One factor contributing to the exceptionally low incidence of neurodegenerative disease in Ikaria and the results observed in atrophy studies is that consuming fresh foods means there are no neurotoxins. The US Food and Drug Administration permits the use of around 3,000 food additives, including some known neurotoxins like aspartame, diacetyl, monosodium glutamate (MSG), and aluminum. These target the central nervous system to reduce neuron functioning and elicit premature cell death. They are associated with a plethora of conditions, ranging from dementia and Alzheimers to anxiety, depression, headaches, and brain fog. Opting for fresh vegetables as opposed to processed food provides natural protection against these issues. However, mercury is a naturally-occurring neurotoxin that’s found in fish, which may contribute to why Ikarians, who avoid consuming too much of it, live even longer and have an even lower incidence of dementia and alzheimers than their other mediterranean counterparts (Alban).

Today, it is important to be aware of the dangers of consuming diets rich in processed foods, especially in the United States where this practice has grown to be so commonplace.  Unfortunately, the health and safety of consumers often takes a backseat to the monetary gain of large companies that have put a price-tag on the public’s health.  As more studies are conducted on the link between the Mediterranean diet and protection against neurodegenerative disease, it is advisable to steer clear of packaged foods with flashy labels, as they are designed by marketers to distract from the preservatives and high fat and sugar content. While it may seem difficult to live like Ikarians and consume what we perceive to be strict diets, they think their habits are just the norm. Thus, Americans should aim to emulate this lifestyle to thereby limit our risk of neurodegenerative disease to the extent that we can.  

 

References

Alban, P. (n.d.). 5 neurotoxins found in popular foods. Be Brain Fit. https://bebrainfit.com/neurotoxins-foods/. 

Aridi, Y. S., Walker, J. L., Roura, E., & Wright, O. R. L. (2020, April 28). Adherence to the Mediterranean diet and chronic disease in Australia: National Nutrition and    physical activity survey analysis. Nutrients. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7281974/. 

Kotifani, A. (2020, June 3). A Greek island’s ancient secret to avoiding Alzheimer’s. Blue Zones. https://www.bluezones.com/2018/11/a-greek-islands-ancient-secret-to-avoiding-alzheimers/. 

Mayo Foundation for Medical Education and Research. (2021, July 23). Mediterranean diet for heart health. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/mediterranean-diet/art-20047801. 

NCI Dictionary of Cancer terms. National Cancer Institute. (n.d.)., https://www.cancer.gov/publications/dictionaries/cancer-terms/def/neurodegenerative-disorder. 

ScienceDaily. (2021, May 6). Alzheimer’s study: A Mediterranean diet might protect against memory loss and dementia. ScienceDaily. from https://www.sciencedaily.com/releases/2021/05/210506105355.htm.

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