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Study: High-fat foods cause brain scarring
January 6th, 2012
01:31 PM ET

Study: High-fat foods cause brain scarring

Keeping pounds off long-term is difficult for even the most successful dieter, and scientists may now be on the path to determining why.

A study published recently in The Journal of Clinical Investigation shows that high-fat foods cause damage to the hypothalamus - an area in the brain responsible for hunger, thirst and the body's natural rhythms and cycles - in rodents.

“These are really important papers that begin to push the idea out that we’re not in control as much as we think we are,” says Dr. Steven R. Smith, co-director for the Sanford-Burnham Diabetes and Obesity Research Center, who wasn’t involved with the study.

However, Smith says researchers must first determine if the scarring happening in the rodent models will translate to the human condition. Not everything that scientists observe in rodents also applies to humans, of course, but it is a starting point.

“This is the tip of the spear. We’ve been talking a lot about diet and willpower and exercise and this sort of thing.  This is radically different [thinking] - that diets can actually re-program the structure of the brain.”

The human body is designed to regulate how much fuel is stored as fat through a process called energy homeostasis, the study's lead author Dr. Michael Schwartz says. For a normal-weight person, that's good.  But once a person becomes obese, his or her body seems to want to stay at that new weight permanently.

"That's the biggest problem with obesity treatment," says Schwartz, director of the Diabetes and Obesity Center of Excellence at the University of Washington. "Obese people can lose weight, but they have trouble keeping it off."

Schwartz and his team found evidence of inflammation, or neuron injury, in rats and mice only three days after the rodents consumed foods high in fat.  Although the effect subsided temporarily, a long-term diet of unhealthy fare left permanent damage. Schwartz believes the brain's attempt to heal the injured neurons results in gliosis, a process that leads to scarring in the central nervous system.

The researchers also found a 25% reduction in the number of POMC cells in the rodents on a high-fat diet. POMC cells play a critical role in the body's fat control system, helping regulate appetite and prevent excess weight gain.

"Losing those cells would help explain why a new elevated level of body weight would occur," Schwartz says.

Smith says that the study is the result of more than a decade of hard work from neuro-scientists around the world who are trying to understand the body’s weight loss system.

“It may be a little bit more complicated than how hard we try and what we food we eat,” Smith says. “I don’t know if that makes people feel better or worse, but it gets us out of the blame game.”

He believes this study represents a step in the right direction for obesity treatment.

“Let’s say we could get the wiring straight again and we could reverse some of this gliosis [scarring],” Smith says. “What if we could get the wires to work right again, and make it easier to lose weight? I think that’s really an exciting idea.”

Schwartz’s team analyzed human MRIs during their study, discovering higher levels of gliosis in obese patients. The findings suggest the structural damage occurring in the rodents' brains may be duplicated in humans.

"Most wonder, 'Why can't I keep the weight off?'" Schwartz says. "Trying to come up with an explanation for it has been a challenge. This may be putting us on the path to understanding better why it's so hard."


soundoff (195 Responses)
  1. Funny pictures x rays

    Marking friends on facebook and myspace, as well, isn't brand-new. It's been used by people for quite a while... Possesses been recently plenty of exciting. Specifically, for individuals who don't ...its funny

    January 19, 2012 at 00:10 | Report abuse | Reply
  2. joana

    In no point in the paper is a it mentioned WHAT TYPE OF FAT they fed the rodents. For all I know it could have been TRANSFAT, which has already been proven to have significant damaging effects on health. WHAT KIND OF SCIENCE IS THAT????? It's obvious that the type of fat is the most important thing to mention.
    Plus ... how many rodents naturally live on a high fat diet unlike humans. We know of several ethnicities who traditionally lived from a high fat diet.

    February 9, 2012 at 20:06 | Report abuse | Reply
  3. joana

    this kind of stuff is fed to rats in labs to fatten them up:

    they call that a high fat diet. I'd call it absolutely unnatural including TRASFAT (hydrogenated fat), CASEIN, and SUCROSE.

    February 9, 2012 at 20:25 | Report abuse | Reply
  4. Jerrilynn Woodson, RN

    It's IRRESPONSIBLE MISLEADING studies like this one that keep Americans confused about what to eat. Many of these studies compare "high-fat" diets that ALSO contain a lot of carbohydrates. Consider the picture at the top of the study depicting a juicy fatty hamburger patty ALONG WITH FRENCH FRIES AND WHITE BUN!! This is typically what they are calling a "high-fat" diet, but it's the CARBS from the FRIES and WHITE BREAD that cause the damage. No doubt, the good doctor endorsing this study is trying to sell some books and refuses to admit he was wrong on prior writings that supposedly fat is bad, now that new science is proving otherwise, these dinosaurs don't want to admit they were wrong, so they keep pushing the same old garbage that fat is bad. Here are some BETTER, NON-BIASED studies. The first is from Johns Hopkins School of Medicine: http://www.liheart.org/latest-news/high-fat-heart-health/ and here's another: http://medicalxpress.com/news/2012-05-high-fat-diet-lowered-blood-sugar.html As an RN, I educate diabetics and the general public on healthy eating, but junk articles endorsing low fat diets make it difficult. Don't be fooled! Want a healthy diet? Choose a PALEO diet that avoids all processed foods and simple carbohydrates and incorporates plenty of healthy fats and proteins, whole eggs, beef, nuts, cheese, etc.

    May 27, 2012 at 12:40 | Report abuse | Reply
    • LAGraham

      And let's not forget: Fat cannot convert INTO FAT! The brain REQUIRES a certain amount of fat to MAINTAIN its cell neurons. It's the TYPE of fat that should be examined – not fat itself. Go back about 30-40 years ago to when Nestles decided it would be healthier for babies if it removed fat and salt from its baby foods; we had a resounding increase in mental retardation and other brain-development-related conditions.

      May 27, 2012 at 16:14 | Report abuse |
    • daniel

      your ignorant ass didn't even read the study. there were no carbs used on the test subjects.

      October 27, 2012 at 19:27 | Report abuse |
    • daniel

      your ignorant ass didn't even read the study you linked to.

      October 27, 2012 at 19:31 | Report abuse |
  5. Dariusz

    Although the effect subsided temporarily, a long-term diet of unhealthy fare left permanent damage. THis she forgot about neurogenesis in this region? http://www.sciencedirect.com/science/article/pii/S009130221300023X

    http://www.sciencemag.org/content/310/5748/679

    http://www.cell.com/trends/endocrinology-metabolism/abstract/S1043-2760(13)00174-4

    November 18, 2014 at 18:03 | Report abuse | Reply
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Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.