America is often stereotyped as a country defined by overindulgence and slothfulness. We eat copious amounts of food that are full of cholesterol, high in saturated fat content, and loaded with sugars, yet often treat exercise as an unnecessary chore. Obviously, this unhealthy combination leads to many issues like obesity, diabetes, and heart disease, but does this lifestyle compromise the wellbeing of the mind too?
What’s the issue?
When the health of the mind decreases, the resulting issue can be defined as dementia. Dementia is a broad term used to classify symptoms of various diseases and conditions that are a result of decreased brain function that develops due to genetic, environmental, and lifestyle factors. Alzheimer’s disease (AD) is the most common form of severe dementia that impairs cognitive ability including memory and thinking and decreases one’s ability to complete typical daily tasks unaided.
As the 6th leading cause of death in the US, AD is so prevalent that it affects 1 in 9 people aged 65 and older (Alzassociation 2016). This disease is extremely debilitating, so scientists have been actively researching to determine if any other factors besides one’s genetic predisposition increase the risk of developing Alzheimer’s or other forms of dementia.
Does what you eat affect your risk?
One study conducted by Leah C. Graham explored the relationship between the chronic consumption of a “western diet” and developing AD in a mouse model. This western diet (WD) mimicked the diet of the majority of people in the western world by including “high levels of animal fat and protein, lower levels of essential nutrients, and higher levels of simple carbohydrates including high fructose corn syrup” (Graham et.al. 2016).
Experimenters separated mice that were genetically modified to be predisposed to developing late-onset AD into two groups and provided them with identical living conditions excluding their diets. After the eight-month study, the brains of the mice that were fed the WD were compared to the brains of the mice that were fed the control diet. It was found that the consumption of a western diet leads to the damage of neurons, the cells of the brain, and increases the risk of developing AD.
Another study researched the effects of various diets on dementia such as diets high in saturated fatty acids, dairy products, alcohol, and the Mediterranean-type diet in humans. It was found that diets with elevated levels of saturated fatty acids and lower levels of dairy products have negative effects on age-related cognitive decline and cognitive function. Increased consumption of fish and other unsaturated fatty acids and light to moderate consumption of alcohol have been associated with a decreased risk of developing AD. The Mediterranean diet combines multiple micro- and macro- nutrients that, individually, serve as potential protective factors against dementia and pre-dementia syndromes (Solfrizzi et.al. 2011).
So, we now know that certain diets affect the way that the brain develops and maintains its function, increasing or decreasing one’s risk for developing AD or other forms of dementia. Are there any other factors?
Does an active lifestyle affect your risk?
A study conducted by Rina Patel utilized an observational, non-experimental design to determine if an active lifestyle decreases the likelihood of developing Alzheimer’s disease. In this study, families of participants with and without AD were asked to complete a questionnaire regarding the subjects’ level of physical activity during middle adulthood. Through various statistical tests, it was found that the non-Alzheimer’s participants were more active in their middle adulthood than the Alzheimer’s participants. Although the final sample size of this study (determined by the number of returned surveys) was too small to generate any conclusive generalizations for a much larger population, these results support Patel’s hypothesis that an active lifestyle in middle adulthood decreases one’s risk for developing AD in late adulthood (Patel 2002)
Now we know that leading an active or lethargic lifestyle also affects one’s risk of developing AD. Do diet and lifestyle affect one’s risk separately or is it a combination of the two that determine the likelihood of developing dementia?
Is obesity directly correlated to developing dementia?
Obesity is a health condition characterized by extremely high levels of body fat. Obesity often develops from the combination of overeating unhealthy foods and not leading an active lifestyle. Can obesity itself lead to dementia?
In one study, the relationship between “midlife body mass index (BMI) and clustering of vascular risk factors and subsequent dementia and AD” (Kivipelto et. al. 2005) was investigated. Vascular risk factors are things that influence the wellbeing of the heart and often lead to obesity such as high blood pressure, cholesterol, and tobacco use. The study’s participants’ vascular risk factors and BMI were measured twice, once when they were considered middle aged (mean age of 50.6) and then again (on average) 21 years later. During the follow-up appointments, diagnosis of dementia was also measured. It was concluded that obesity in middle adulthood is associated with an increased risk of dementia and AD later in life (Kiyipelto et. al. 2005).
So it seems that obesity, not diet or exercise alone, may be the culprit of the rise in AD and dementia cases in America.
Although studies show that there is a causal relationship between obesity and dementia, some may argue that obesity decreases one’s risk for developing dementia. They claim that overeating provides your body with additional nutrients that protect the brain from deteriorating, however, there have been no studies that can definitively conclude this (Ossola 2015).
So should we all lose weight? Not necessarily. To maintain the body’s homeostasis, one should never lean to extremes, whether it be obesity or emaciation, as both with can lead to serious health concerns. The risk of dementia is lowered when one combines healthy food choices with healthy lifestyle choices.
Maybe we should try to break the American stereotypes and choose a salad and a jog over a Big Mac and a video game. Not only will our bodies be healthier, our minds will be healthier.
Alzassociation. Latest Alzheimer’s Facts and Figures. Latest Facts & Figures Report. 2016 [accessed 2016 Sep 29]. http://alz.org/facts/
Graham LC. 2016. Chronic consumption of a western diet induces robust glial activation in aging mice and in a mouse model of Alzheimer’s disease. Scientific Reports [accessed 2016 Sep 11]; 6. http://www.nature.com/articles/srep21568
Kivipelto M. 2005. Obesity and Vascular Risk Factors at Midlife and the Risk of Dementia and Alzheimer Disease.JAMA Neurology [accessed 2016 Sep 29]; Vol. 62, No. 10.
Ossola A. 2015 Apr. People Who Are Obese Are Much Less Likely to Get Dementia with Age. Popular Science (April).
Patel R. 2002. The Effect of Active Lifestyle in Middle Adulthood Alzheimer’s Disease Prevention: A Non-Experimental Design. [accessed 2016 Sep 4];
Solfrizzi V. 2011. Diet and Alzheimer’s Disease Risk Factors Or Prevention: The Current Evidence.Expert Review of Neurotherapeutics [accessed 2016 Sep 4]; 11.5:677–708.