Health & Medicine - Posted by Sarah Yang-Berkeley on Friday, December 7, 2012 17:31 - 10 Comments 
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(No Ratings Yet) Loading ...How carbs from food end up as fat
The researchers point out that fatty liver disease can result from overindulging in carbohydrates. They suggest avoiding refined sugars that increase blood insulin levels quickly, but note that there are complex carbohydrates—such as those in legumes, fruits, and vegetables—that should be part of a healthy diet. "Limiting consumption of sodas, cakes, and cookies is a good idea for many reasons, even during the holidays," says Hei Sook Sul of UC Berkeley. (Credit: v1ctory_1s_m1ne/Flickr)
UC BERKELEY (US) — The same gene that helps convert a big plate of holiday cookies into fat could also provide a new target for potential treatments for fatty liver disease, diabetes, and obesity.
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The text of this article by Futurity is licensed under a Creative Commons Attribution-No Derivatives License.
Researchers are unlocking the molecular mechanisms of how our body converts dietary carbohydrates into fat, and as part of that research, they found that a gene called BAF60c contributes to fatty liver, or steatosis.
In the study, to be published online December 6 in the journal Molecular Cell, the researchers found that mice that have had the BAF60c gene disabled did not convert carbohydrates to fat, despite eating a high-carb diet.
“This work brings us one step forward in understanding fatty liver disease resulting from an excessive consumption of carbohydrates,” says the study’s senior author, Hei Sook Sul, professor at University of California, Berkeley’s Department of Nutritional Science and Toxicology.
“The discovery of this role of BAF60c may eventually lead to the development of treatment for millions of Americans with fatty liver and other related diseases.”
What’s fatty liver?
More than three-quarters of obese people and one-third of Americans have fatty liver, or steatosis, according to epidemiological studies. A diet excessively high in bread, pasta, rice, soda, and other carbohydrates is a major risk factor for fatty liver, which is marked by the abnormal accumulation of fat within a liver cell.
After a meal, carbohydrates are broken down into glucose, an immediate source of energy. Excess glucose gets stored in the liver as glycogen or, with the help of insulin, converted into fatty acids, circulated to other parts of the body and stored as fat in adipose tissue. When there is an overabundance of fatty acids, fat also builds up in the liver.
“Fatty liver caused by the high intake of carbohydrates can be as bad as that due to excessive alcohol intake, and it contributes to various diseases including type 2 diabetes,” says Sul. “The conversion of excess glucose into fatty acids occurs in the liver, but there are many steps in this process that have not been fully understood.”
Sul’s lab previously reported the role of a gene called DNA-PK in this process. The researchers found that DNA-PK, known to help repair breaks in DNA, acts as a signaling molecule for insulin that enhances the formation of fat from carbohydrates in the liver.
The newest discovery puts the spotlight on BAF60c, a molecule known for its role in remodeling the structure of chromatin, a mass of DNA and proteins found in the cell’s nucleus.
In the cells
The lead authors of the study, postdoctoral researcher Yuhui Wang and former graduate student Roger Wong, both at Sul’s laboratory, discovered BAF60c’s role in the conversion of dietary carbohydrates to fat.
They found that BAF60c resides in the cytoplasm, outside the cell’s nucleus. Once insulin binds to a receptor on the cell surface, it sends a signal to modify BAF60c so that it enters the nucleus. There, BAF60c binds to regions of chromatin that contain genes coding for various enzymes involved in the conversion of carbohydrates to fat. This action sends the signal to churn out more of the enzymes, enhancing the conversion of carbohydrates to fat.
The researchers tested the role of BAF60c by both increasing and decreasing its function in various experiments in live mice. Mice that had triple the normal levels of BAF60c in their livers produced significantly higher levels of fat-producing genes, even when they were fasting. In contrast, disabling BAF60c disrupted the formation of fatty acids, even when the mice feasted on a carb-heavy diet.
The researchers point out that fatty liver disease can result from overindulging in carbohydrates. They suggest avoiding refined sugars that increase blood insulin levels quickly, but note that there are complex carbohydrates—such as those in legumes, fruits, and vegetables—that should be part of a healthy diet.
“Limiting consumption of sodas, cakes, and cookies is a good idea for many reasons, even during the holidays,” says Sul.
The National Institutes of Health supported this study.
Source: UC Berkeley
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10 Comments
kimbee
It shouldn’t be necessary to ‘take them off the shelves’. People really should be able to take responsibility for what they put into their own bodies. Plus it’s not fair on those of us who can control our weight.
In today’s responsibility free society (spot the grumpy old fart) it’s only natural that we should look to science to bail us out instead of taking matters into our own hands…
Personally, being a bit of a consequence-dodger myself, I’m overjoyed that the carbs that once front-loaded my pants with my belly can now be shat out along with the rest of the rubbish I can’t digest and I can get off this boring paleo diet and start eating all those terrifically moreish treats,loaded with HFCS and white flour, just in time for the festive season too!
Where the hell did I put that advent calendar!?
kimbee
Andy – am I the grumpy old fart? Nooooooooo! I suppose the grumpy bit’s right though. I’m just bitter because I’m naturally skinny, if everyone else gets skinny too then no-one will coo over me and say ‘Oooo aren’t you lucky, you can eat anything!’
Janknitz
How are people to take personal responsibility for what they put in their own bodies when they are constantly bombarded with the wrong information? They are told that all fat is bad, and that carbs are good so they should eat six servings a day. They are told grains are essential to the diet, with loads of accompanying sugar (natural and added). That’s our obesity epidemic, right there.
There must first be education about what REALLY causes obesity before personal responsibility can be effective. Too many people who are very responsible eat lots of carbs because they erroneously believe them to be healthful. Those of us who “get it” don’t need to have crackers and cookies banned from grocery shelves. We just don’t buy them. And if everyone else followed suit, they’d soon disappear from the shelves without any government push.
kimbee
Janknitz – well it becomes an argument about consumerism then doesn’t it? Advertising and marketing of any product can lead to grey areas of morality. I grew up a rural area and in an age before the internet. I received a good food education, at home, well before I ever left school. I can understand how this must be difficult for people who grow up in cities and are constantly bombarded with advertising. I think people need to be taught to question their sources in general because I think that this problem is bigger than just food.
Thanks for giving this article.i have enjoyed this article very much.I have read good
Mark
So does this fat also end up in arteries too, causing heart disease? What kind of fat profile does the processing of carbs have? Does it raise triglycerides, ldl and hdl? Lots of questions, but I’ve been following this for awhile, and have cut back on my grain and sugar intake opting instead for ‘slow’ vegetable-basec carbs.
MIke
@Mark
The science seems to be pointing to that it is inflammation that causes heart disease. Root cause of the inflammation is junk food, refined carbs and industrial seed oils. Good fats, including saturated fats, seem to be either neutral or beneficial.
Great article. That cookie is cute, but I wouldn’t eat it, too many carbs!
It’s time to take those delicious crackers and cookies off the grocery shelves. Ban the sodas too. – Or should we just let fatty liver disease and preventable diabetes belong to the Darwin Awards?