Obesity May Accelerate Brain Aging

natehoy writes "According to the US News and World Report, a recent study has shown a link between obesity and the loss of neurological tissue. The brains of elderly patients who were obese had on average 8% less tissue than their trimmer counterparts. Overweight patients had brains lighter by about 4%. This could have implications for the onset of dementia illnesses such as Alzheimer's. Just one more risk factor to add to the growing body (no pun intended) of reasons to try and stay trim."

Comments

I also noticed a link

[Monkeedude1212]

Between Obesity and the loss of food in my kitchen.

But seriously - this seems like its leading to a "Overweight people aren't smart enough to care about their health" kind of thing.

Re:I also noticed a link

[eln]

No, actually I think this study might have some merit. You see, fat people tend to have fat, stubby fingers. It is very difficult to play the Nintendo DS, with its small buttons and tiny touch screen, with fingers that resemble sausages. Even the Wii is difficult to play for morbidly obese people, since its buttons are also small, and the physical movement required is beyond the capability of those whose couches have become permanent parts of their anatomy.

What does this have to do with brain aging, you might ask. Elementary, my dear lardass. Without the Nintendo Brain Age series of games, how can we possibly keep our brains from aging? They're like steroids for your brain, except the link between the games and shrinking testicles has not yet been firmly established. So, unless we can come up with a good way for fat people to play these Brain Age games without causing them to sweat even more profusely than they already do, I'm afraid they're all doomed to early-onset Alzheimer's.

It's basic common sense, really.

Re:I also noticed a link

[Entropius]

You can do perfectly good statistics on 94 people.

Any good scientific study includes both the effect ("8% brain loss") alongside an estimation of the error ("8% +/- 4%"). Over in the life sciences, when comparing the results from two groups (fat/normal, say) they like to give the probability that any difference they saw was due to chance, with suitably small values of this probability meaning that the result is considered "statistically significant".

Having a limited sample size makes it less likely that a small effect will be above this threshhold for significance (since you can't distinguish it from the noise), but it does nothing to impair the validity of the statistics themselves, so long as all the errors are estimated correctly (which they should be, if you do your math honestly).

Now, of course, the article linked in the summary doesn't actually give the significance level or the error estimates or any of those other things that are crucial to a scientific result actually meaning anything. But this is a condemnation of the shitty state of science reporting, not of the study itself.

These morally chiding "correlation" studies

[elrous0]

Do they even TRY to adjust for the fact that fat people avoid getting health care most of their lives (because they're more likely to get tired of getting harassed by their doctor about their weight every time they go in for even a flu shot), drink more than thin people (getting shit on regularly can have that effect on people), and have crappier jobs than their normal-sized counterparts with the consequent lower incomes and inferior health care (because it's a lot harder to get hired)?

I'm not pretending that obesity has no effect on someone's health. But it just irks the hell out of me that these sensational studies always fail to adjust for these sorts of related factors in favor of the sensational (and grant whoring) headline of "Obesity correlates with such-and-such other calamity." I'm sure you could produce a study arguing that obesity makes you stupid too, by simply failing to adjust for the fact that the obese are often geographically concentrated in areas (like the American South) where public education is shit and poverty is high.

Why don't we just say that fat people are worse than Hitler and be done with it? You know, the way we've already done with anyone who dares smoke anything other than marijuana (which is somehow magically good for you), or who eats meat, or who drives an SUV (which some self-righteous asshole will probably link to sudden infant death syndrome in some future study), or any of the hundred other things that are going to kill us all any day now.

Is it any coincidence that the medical profession was once closely linked to the idea that all illness was caused by immoral behavior?

Re:These morally chiding "correlation" studies

[CannonballHead]

Is it any coincidence that the medical profession was once closely linked to the idea [thinkquest.org] that all illness was caused by immoral behavior?

Interestingly enough, in the Old Testament, Job's three friends made this mistake and were actually reprimanded for it. Calamity and "bad stuff" (including illness) does not, even in the Old Testament, mean judgment from God for immoral behavior.

Re:These morally chiding "correlation" studies

[b0ttle]

... the fact that the obese are often geographically concentrated in areas (like the American South) where public education is shit and poverty is high.

"American obesity rates are the highest in the world with 64% of adults being overweight or obese"
http://en.wikipedia.org/wiki/Obesity_in_the_United_States

Re:These morally chiding "correlation" studies

[mcgrew]

drink more than thin people (getting shit on regularly can have that effect on people)

I haven't seen that to be the case; I don't see more fat people in bars than I do on the street. In fact, there are a higher percentage of fat people where I work than in my favorite bar, although that's probably because most of the people at work sit at a desk, while my favorite bar's clientelle is mostly construction workers.

and have crappier jobs than their normal-sized counterparts

The ones with the crappiest jobs usually are doing physical labor, and as such are generally a lot more fit than the average slashdotter, whether he's a skinny nerd or a fat nerd.

Why don't we just say that fat people are worse than Hitler and be done with it?

Gee, this early in the thread and Godwin has been invoked? I wish overweight people would be less self conscious about themselves. Except women -- "you're getting too skinny" can get you laid! I'm all for fat women, they're easier to seduce than hotties.

You know, the way we've already done with anyone who dares smoke anything other than marijuana (which is somehow magically good for you)

Actually, there have been studies showing benefits to potsmoking, including a greatly reduced risk of cancer among those who also smoke tobacco.

or who eats meat

Come on now, it's only a tiny but vocal minority against carnivorousness. Join PETA (People Eating Tasty Animals)

or who drives an SUV

OK, you got me there. Driving an SUV is an almost sure sign of a reduced intellect. They cost more to drive than any other class of vehicle, and more people die in them per passsenger mile than any other type of vehicle due to their poor handling and braking and high center of gravity and lack of crumple zones. SUV drivers drive badly not from lack of driving skill but because their vehicles suck. Plus, ask an SUV driver why they have it and they'll say "it carries so many passengers", but notice SUVs on the road and you'll see very few with more than the driver. If you carry passengers, get a minivan -- more passengers, better mileage, and they're the safest vehicles on the road.

But in the end, you have to die from something. When my grandmother was 95 she said to me "I don't know why people want to live to be a hindred, it ain't no fun bein' old!"

She was overweight when I was a kid, but when she reached her mid seventies or early eighties she started losing weight. Her mind was sharp as a tack until the day she died (at age 99).

Re:These morally chiding "correlation" studies

[natehoy]

I think the study adjusts for those factors perfectly well, in fact you're introducing some interesting possibilities as to an explanation for the link. The study (which is small, so we should obviously be cautious about drawing too many conclusions from it) only states that people who are obese appear to have less brain function. A few theories were forwarded to explain the link, but your theory is just as sound, and doesn't disprove the possible link.

Let's follow your chain of events for a moment. John is obese. John avoids his doctor because he's tired of being hassled about his weight. Fair enough - that's pretty common.

John is now in a negative feedback loop. He's receiving almost no advice on his diet, no encouragement to exercise, and probably is understandably demoralized from being called "fatty" and getting unwelcome advice from health freakazoids that he's likely to give up on health maintenance entirely. Poorer nutrition and less exercise mean that John's entire body is going to suffer, including the brain.

It's actually as good a theory as any. Obesity would have a significant correlation with people who are not caring for their overall health properly, and obesity can be both cause and effect in this case. John isn't a bad guy, he's just stuck in a rut, and he's headed for possible trouble.

I know John's story.

I'm 6' 3" and used to weigh very close to 300 pounds. I avoided my doctor for over a decade for the same reason John might.

It's tough to get started losing weight, and having a bunch of skinnyminnies around you crybabying about how you should get off your very large posterior and do something is not, repeat not, helpful. It's demoralizing, and makes the task of getting started look all that much harder.

It took a health scare for me to start the very long, very hard trail, and I'm now down to 215 (still mildly overweight, but I can ride my bike 30 miles a day without any problems). I wish terribly that I had learned my lesson an easier way, but I didn't, and I'm sure being obese for as long as I was will have long-term consequences. But I was where I was, and I understand how very hard it is to get started, and how the general attitude of society toward the obese does not make them want to help themselves. I wanted to just curl up with my Ben and Jerry's and donuts and leave me the hell alone.

I've encouraged several friends over the years to get up and just take short walks with me, and started a couple of them on the road to weight loss, but you've got to approach that sort of overture carefully, and have a sense for when your friend is ready to start helping themselves, then offer them some encouragement.

Re:These morally chiding "correlation" studies

[LrdDimwit]

So you 1) point out that correlation does not equal causation, then proceed to 2) say that it's likely that the obesity causes the brain aging seen in this study?

Because that is essentially your argument: that obesity directly causes a host of other factors, which collectively explain the observed correlation (brain aging). Therefore, obesity causes the mental decline, only indirectly. I fail to see any significant difference between the implication that obesity directly harms the brain, and that obesity, while not in itself injurious, causes people to behave in ways that are.

Re:These morally chiding "correlation" studies

[natehoy]

I had the same shock when I went to France and spent a week in Orleans. At the time, I weighed 205 and I'm 6'3", so I didn't stand out amongst the French population. I walked around Paris for a day, then spent most of my time in Orleans (when I wasn't working) walking down the pedestrian district trying French food.

I saw three people who were heavy enough to stand out, and all three were Americans.

When I got back to JFK Airport in the US, it was almost shocking to see how many people were large.

The things we get used to and don't even realize it...

The funny part was that I ATE LIKE AN EFFING KING in France. I denied myself NOTHING, and ate cheese by the ton. And came back 2 pounds lighter. I'm sure it helped that I only used my car to go back and forth to work, and the rest of my time was spent walking (4-5 miles a day, minimum).

I'm sure it also helped that there was very little sugar in what I ate in France, and it was all food prepared by people who care about the quality of what they were serving. Even the cafeteria food at the company I was working for ran circles around the nicer restaurants here in the US, and the restaurants? Oh. My. God. I have never eaten anything like it.

Now I get it

[mcgrew]

Fat women have always hit on me. Now I know why -- they're stupid!

However, from TFA:

Dr. Jonathan Friedman, an associate professor of surgery and neuroscience and experimental therapeutics at the Texas A&M Health Science Center College of Medicine noted that the causal relationship here is not clear.

Another possibility is that The brains of overweight people have more receptors for the neurotransmitter serotonin than those of people of normal weight, suggesting that being overweight may be down to more than just eating habits and may have an origin in brain chemistry. Clearly, more study is warranted.

From the New Scientist article on the ssubject of big people with little brains:

In an as yet unpublished study, Thompson's team has shown that exercise, which improves cardiovascular health and blood flow, protects the very brain regions that had shrunk in the current study. "The most strenuous kind of exercise can save about the same amount of brain tissue that is lost in the obese," he says. This indicates that it is blood flow that drives brain health, not the other way round. As these areas undergo the most remodelling throughout adult life, they may be more sensitive to any changes in oxygen supply and nutrients, Thompson suggests.

But Deborah Gustafson at the University of Gothenburg in Sweden, who previously found that overweight women had less brain tissue than their leaner counterparts, questions whether obesity is driving brain atrophy or vice versa. She points out that brain atrophy in the frontal and temporal lobes, which also control eating behaviour and metabolism, could cause weight gain. "There are not enough longitudinal data available for us to know which is the chicken and which is the egg."

Possible Viral Link

[TheNarrator]

Perhaps this has something to do with the virus / obesity link: http://www.sciencedaily.com/releases/2006/01/060130031548.htm

There is accumulating evidence that certain viruses may cause obesity, in essence making obesity contagious, according to Leah D. Whigham, the lead researcher in a new study, "Adipogenic potential of multiple human adenoviruses in vivo and in vitro in animals," in the January issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology published by the American Physiological Society. The study, by Whigham, Barbara A. Israel and Richard L. Atkinson, of the University of Wisconsin, Madison, found that the human adenovirus Ad-37 causes obesity in chickens. This finding builds on studies that two related viruses, Ad-36 and Ad-5, also cause obesity in animals. Moreover, Ad-36 has been associated with human obesity, leading researchers to suspect that Ad-37 also may be implicated in human obesity. Whigham said more research is needed to find out if Ad-37 causes obesity in humans. One study was inconclusive, because only a handful of people showed evidence of infection with Ad-37 -- not enough people to draw any conclusions, she said. Ad-37, Ad-36 and Ad-5 are part of a family of approximately 50 viruses known as human adenoviruses.

The link between carbohydrate consumption and AGEs

[brian0918]

This should be obvious. There is already a clear understanding of the cause of obesity via carbohydrate consumption, combined with the effects of said consumption on the production of advanced glycation endproducts (AGEs) in the brain, and their effect on cognitive function.

Best Reason So Far

[Metal_Demon]

I have been overweight for over ten years now and this is the best reason to slim down I've heard yet. I take a great deal of pride in my intelligence, so anything that puts it at risk can not be tolerated.

actual paper

[flynt]

Here is a link to the actual publication.

http://www3.interscience.wiley.com/cgi-bin/fulltext/122539667/HTMLSTART

It always bothers me that these aren't provided, we can read the the actual results and not the news version!

WTF

[VisiX]

It is not obvious to fat people you insensitive clod!

Re:The link between carbohydrate consumption and A

[dogmatixpsych]

If I may offer my opinion as someone who researches cognitive aging and the brain, I think the link (without actually reading the article) is likely due to cerebrovascular factors. People who are overweight often have high or highly varying blood pressure. They also often have arterosclerosis and all sorts of plaque build-up in the blood vessels. Basically their cardiovascular systems in general do not work as efficiently.

The brain is very power hungry. It needs virtually uninterrupted blood flow to function well. People who have reduced blood flow (efficiency) could have lower blood perfusion in the brain. Their neurons may just be slowly starved of enough oxygen and nutrients. People who are overweight are at increased risk for developing strokes, particularly so-called "silent strokes" that might not have apparent effects at first but could over time.

I don't think it's the obesity as much as the cardiovascular issues that are associated with it. I've seen the brains of older adults who have (uncontrolled or long-term) high blood pressure and by and large, they are not pretty. Their white matter is often pretty messed up. They often have larger ventricles (more brain atrophy) and do worse on cognitive tests.

In any case, being overweight is one of the worst things you can do to your overall health. Maybe not now, but in old age overweight (particularly obese) people are going to have a lot of problems - physical and cognitive. Again, I deal not with individuals as much as with groups of people so everything I say should be taken as "on average."

Re:The link between carbohydrate consumption and A

[ShakaUVM]

There is already a clear understanding of the cause of obesity via carbohydrate consumption, combined with the effects of said consumption on the production of advanced glycation endproducts (AGEs) in the brain, and their effect on cognitive function.

I'd be very cautious when using the words "clear understanding" with nearly anything in cognitive science. Scientists didn't even pay attention to neurotropic factors in the brain until relatively recently, and if you ignore factors that can cause neural growth (like... excercise - scientists are guessing that excercise is neurotropic since we need to often map out new areas when walking a lot) it's hard to make a statement that obsesity caused by eating too much is the cause of cognitive decline, as opposed to obesity caused by not exercising enough. In fact, I think that if you exercise a lot, obesity almost vanishes as a cause of a lot of problems.

You also have related issues like eating too much / not exercising enough contributes to diabetes, and having high blood glucose levels causes a wide variety of problems, such as damage to small blood vessels and a (likely related) decline in neural function.

But we're still in the stone age when it comes to all this kind of stuff.

Avoiding Obesity is Difficult

[erroneus]

Once upon a time, obesity was a sign of wealth. Food was different in those days and only by consuming large quantities of it could you hope to gain the wealthy appearance of obesity.

These days, the opposite is true. Our food is different in its content and in its richness. Average portion offered for sale are larger. And while it's true that people do less physical work, doing some basic calculation associated with calorie intake versus calorie burn and the increase of calorie burn with added exercise will reveal that exercise is not as effective at controlling weight as is controlling intake.

It is my observation that reducing the intake of food is the most significant thing anyone can do when attempting weight control and what's more, there is no "I have no time for it" excuse when attempting to do so. It is also my observation that reducing the intake of food is extremely difficult for a variety of reasons. Our habits and expectations are hard to change when ordering or preparing food. (for example, don't we all feel like a cheap-ass for not ordering that double-quarter-pounder meal deal instead of ordering from the dollar menu to get smaller portions?) Further, the content of our most available foods are a lot higher in calories than they have been in the past and this is largely due to increases in highly processed ingredients and preservatives and the like. While other nations have outlawed many of the more offensive ingredients, the U.S. has failed to issue as many restrictions which I believe is one of the most significant reasons that the U.S. is one of the most obese nations in the world today.

So what can we do? The best thing is to buy less and eat less. It takes a lot of effort to eat less, but in time your stomach will shrink and it will actually become difficult to eat as much as you are now accustomed to eating. This helps a lot, but it's the best answer for everyone and often leads to feelings of hunger and tiredness even after the adjustment in intake is made. (Keep in mind that the purpose of expensive and elective gastric alteration surgical is to serve this exact cause but people prefer to make these changes in their bodies rather than to make changes in their self-discipline.) Another thing is to start sending comments to your government representatives about fixing healthcare by fixing the problems with our food! (Imagine national healthcare costs plummeting because we aren't getting diabetes or any of the other health problems associated with obesity with the same frequency. That's what we see in nations with better controls over food content and since we're all the same species, we can expect similar results by enforcing similar rules.)

And before anyone start the criticism or attacks, let me just say that I am obese. I am working on it, but it's damned hard. I'm 200lbs (+/- 5lbs) when I should be 180lbs or less. I own more clothes that I cannot wear than clothes that I can. (I don't want to buy more "fat clothes" because that merely feeds the problem. I want to wear my old clothes.) And to better tie my commentary in with the original story, I feel a LOT less smart than I was when I was operating at my prime weight. And since I have been losing weight, I am feeling a lot more alert and aware than I have in a while and I sleep better and need less sleep as well. The benefits are obvious. And when the main course of action is simply to do less of what is causing the problem, it's not unreasonable or even expensive to pull off. I sure as hell haven't stopped eating at McDonald's... I just eat slightly more than the contents of a kid's meal instead of super-sizing everything.

Bogus stats, however.

[mikehoskins]

I saw this quote: "the researchers studied brain images of 94 people in their 70s who had participated in an earlier study looking at cardiovascular health and cognition."

At that point, I said, "Stop. What a useless study." Look at the sample size again... 94?!?!? That has a roughly 10% margin of error built in to the sample size (at a 95% confidence interval). At least they included the sample size! ...and then there's the operative word "study...." That, word (in the singular, no less), gives me all sorts of warm fuzzies.

So, is that 8% (+/- 10%) less brain mass for obese elderly people or a range from 7.2% to 8.8% for obese elderly people, based on this sample and a 95% confidence interval? I'm thinking the former.

In statistics class, this was called by the name "statistical deception." Just because a single study of 94 people says so, don't believe it. It has a roughly 50% chance of being right -- or wrong (at a 100% confidence interval) but so do psychics, horoscopes, and fortune cookies.

Junk science prevails in the popular press. Anything sensational gets front-page headlines -- it gets grant money and sells news. It doesn't matter that the next study contradicts it, the next supports it, the next contradicts that one, and on and on the tennis match goes....

Once this has been peer reviewed numerous times with tens of thousands of people per study, call me. I'll be getting a snack, in the mean time.

Here's a couple of links to refresh people with the term "margin of error:"
    http://en.wikipedia.org/wiki/Margin_of_error
    http://www.isixsigma.com/library/content/c040607a.asp

Re:Bogus stats, however.

[GreenCow]

I sense that you may have some concern over the implications of this study. If you think these results troubling and wish to discredit them, consider asking for a wider study rather than calling it junk science. Their margin of error may be off, but I doubt it's by a significant enough amount to warrant being labeled 'Junk Science'