Tag Archives: Obesity

Weight loss improves memory in type II diabetes

25 May

A thesis from Umeå University titled “Brain function and glucocorticoids in obesity and type 2 diabetes including effects of lifestyle interventions.”  From the conclusion:

” Cortisol levels are linked to prefrontal brain structure and, at least in type 2 diabetes, lower memory performance. Furthermore, the dysregulated GC metabolism in obesity can be reversed by long-term diet- induced weight loss. Finally, dietary interventions with associated metabolic improvements alter functional brain responses during memory testing, including increased activation of the hippocampus. Whether these changes are linked to alterations in GC exposure and mediate improved cognition requires further study. “

Junk food, cognition and the arrow of causation

10 Apr

A paper published in Physiology & Behavior suggests a junk food diet (defined as highly processed food)  cognitive impairment in rats. It is often argued that sedentary lifestyle and bad diet contribute to obesity. This paper presents evidence that sedentary lifestyle is an effect of bad diet. Here is a press release on the research:

“Overweight people often get stigmatized as lazy and lacking discipline,” Blaisdell said. “We interpret our results as suggesting that the idea commonly portrayed in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause, rather than an effect, of laziness. Either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue.”

 

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Obesity and executive dysfunction

9 Apr

I recently came across this 2007 paper titled: “Elevated body mass index is associated with executive dysfunction in otherwise healthy adults.” Here is the abstract:

“There is growing evidence that obesity is linked to adverse neurocognitive outcome, including reduced cognitive functioning and Alzheimer disease. However, no study to date has determined whether the relationship between body mass index (BMI) and cognitive performance varies as a function of age. We examined attention and executive function in a cross-section of 408 healthy persons across the adult life span (20-82 years). Bivariate correlation showed that BMI was inversely related to performance on all cognitive tests. After controlling for possible confounding factors, overweight and obese adults (BMI > 25) exhibited poorer executive function test performance than normal weight adults (BMI, 18.5-24.9). No differences emerged in attention test performance, and there was no evidence of a BMI × age interaction for either cognitive domain. These results provide further evidence for the relationship between elevated BMI and reduced cognitive performance and suggest that this relationship does not vary with age. Further research is needed to identify the etiology of these deficits and whether they resolve after weight loss.”

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Maternal obesity linked to infant brain inflammation

6 Sep

At least in rats.

In this experiment, female rats were put on a diet high in saturated fat and trans-fats for 4 weeks prior to mating and maintained on that diet through pregnancy and lactation.

When compared to controls both the mothers and pups had significantly higher body weights and the pups exhibited brain inflammation and the problems with spatial learning.

Here is the complete abstract:

“Obesity is well characterized as a systemic inflammatory condition, and is also associated with cognitive disruption, suggesting a link between the two. We assessed whether peripheral inflammation in maternal obesity may be transferred to the offspring brain, in particular, the hippocampus, and thereby result in cognitive dysfunction. Rat dams were fed a high-saturated-fat diet (SFD), a high-trans-fat diet (TFD), or a low-fat diet (LFD) for 4 wk prior to mating, and remained on the diet throughout pregnancy and lactation. SFD/TFD exposure significantly increased body weight in both dams and pups compared to controls. Microglial activation markers were increased in the hippocampus of SFD/TFD pups at birth. At weaning and in adulthood, proinflammatory cytokine expression was strikingly increased in the periphery and hippocampus following a bacterial challenge [lipopolysaccharide (LPS)] in the SFD/TFD groups compared to controls. Microglial activation within the hippocampus was also increased basally in SFD rats, suggesting a chronic priming of the cells. Finally, there were marked changes in anxiety and spatial learning in SFD/TFD groups. These effects were all observed in adulthood, even after the pups were placed on standard chow at weaning, suggesting these outcomes were programmed early in life.”

More on the obesity dementia link

25 Jun

Why is obesity linked to dementia? One possibility is that obesity causes type II diabetes, which, in turn is a risk factor for dementia. Dr. Mirkrin does a good job of explaining this hypothesis.

This suggests that the things, like exercise and a plant based diet, that reduce the risk of  type II diabetes also reduces the risk of dementia.

Obesity and dementia

20 Jun

A study published in the March issue of the journal Obesity suggests that current projections may underestimate the prevalence of dementia in the future.

It is well know that the number of cases of dementia will increase as result of the aging of the baby boom generation. However,  these forecasts have not factored in the fact that many people now in middle age are obese and, thus, are at a higher risk for dementia.

The authors of the study project that in the United States the rate of dementia will be 9% higher than current estimates In China they project the rate will be 19% higher. They call for policies that will help reduce midlife obesity.

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