Midlife Obesity Linked to Earlier Alzheimer's

Jigsaw puzzlie, of senior man, falling apart
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Obesity has been linked to a whole host of diseases, including cancer, cardiovascular disease, and diabetes, among others. Now researchers have linked it to Alzheimer disease as well.

When and How

Researchers have specifically found that obesity in middle age, or midlife, predicts an earlier onset of Alzheimer disease—and a higher burden of disease (meaning that the disease will be more severe when it hits).

In an analysis of the Baltimore Longitudinal Study of Aging, researchers looked at the relationship between midlife body mass index (BMI) and the time of onset of Alzheimer disease as well as the severity of the disease. The study authors found that higher BMI in middle age (50 years of age) was associated with an earlier onset of Alzheimer disease as well as higher measures of disease severity.

The researchers found that there was more amyloid deposition (a defining factor of Alzheimer disease) in the brain of patients with a higher midlife BMI, as compared with those who had a healthy BMI at age 50. This indicates a more severe form of the disease.

The researchers concluded that a healthy BMI at midlife may thus delay the onset of Alzheimer disease. This is encouraging, because it means that getting your BMI to a healthy level during midlife can stave off the onset of Alzheimer's. And many of the healthy activities that go into losing excess weight and maintaining a healthy weight, like a balanced diet and regular exercise, are also factors that maintain a healthy brain and help prevent dementia in and of themselves.

Obesity and Dementia

Earlier studies have consistently shown that obesity is associated with dementia, and as BMI gets higher, so does the degree of risk. In another study similar to the one above, but conducted in eastern Finland, researchers followed patients for a total of 26 years, measuring their BMI at an average age of 50 as well as later, at an average age of 71.

The researchers observed which patients developed dementia later in life, and found that, again, higher midlife BMI was associated with a higher risk of dementia and Alzheimer disease.

An analysis of the Swedish Twin Registry by researchers concluded that “both overweight and obesity at midlife independently increase the risk of dementia [and Alzheimer disease].”

Others have found that diabetes, which is an obesity-related disorder, may lead to an earlier onset of dementia. So there are multiple reasons to focus on losing excess weight in a healthy way.

Stave Off Weight Gain in Middle Age

The evidence seems clear at this point: overweight and obesity at midlife puts one at a higher risk of developing dementia as well as an earlier onset of Alzheimer disease. Unfortunately, midlife is also a time at which many individuals tend to gain weight, as metabolism slows down a bit and many become more sedentary.

Knowing this, however, should lead to greater vigilance in middle age to keep up an active lifestyle and eat healthfully.

There are, fortunately, many ways to do this.

One innovative diet that is aimed at promoting brain health is known as the MIND diet. This diet was created by a group of researchers who gave it the lengthier name of the "Mediterranean-Dietary Approach to Systolic Hypertension (DASH) diet intervention for neurodegenerative delay (MIND) diet score." A mouthful, to be sure! So it is known simply as the MIND diet.

This score captures components of both the Mediterranean diet and the DASH diet that have been shown to be protective against cognitive decline and Alzheimer disease. And, like those diets, the MIND diet has been found in research studies to slow mental decline; it may also reduce the risk of Alzheimer disease.

This shows that what you eat really does matter. To follow the MIND diet, you need to be aware of 15 food groups, ten of which are considered to be "brain-healthy food groups," and five of which are the food groups to avoid. Read the full article on the MIND diet to understand more about it and to learn more about these food groups.

Sources

Chuang YF, An Y, Bilgel M, et al. Midlife adiposity predicts earlier onset of Alzheimer’s dementia, neuropathology and presymptomatic cerebral amyloid accumulation. Mol Psychiatry 2015 Sep 1. [Epub ahead of print]

Diabetes in midlife may hasten dementia in later life. Harv Health Lett 2015;40:8.

Morris MC, Tangney CC, Wang Y, Sacks FM, et al. MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimers Dement 2015;11:1007-14.

Tolpannen AM, Ngandu T, Kareholt I, et al. Midlife and late-life body mass index and late-life dementia: results from a prospective population-based cohort.

Whitmer RA, Gunderson EP, Quesenberry CP Jr, et al. Body mass index in midlife and risk of Alzheimer disease and vascular dementia. Curr Alzheimer Res 2007;4:103-9.

Xu WL, Atti AR, Gatz M, Pedersen NL, et al. Midlife overweight and obesity increase late-life dementia risk: a population-based twin study. Neurology 2011;76:1568-74.

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