Friday, December 07, 2007

With Gene, Carbohydrates Stored as Fat

I actually had a laugh-out-loud moment this morning as I read the first paragraph in the article - Scientists discover genetic basis for why high-carb diets make us fatter - which read:

A high-carb diet has always been considered as a factor behind piling on the pounds. Now, a study in mice conducted by researchers at the University of Wisconsin-Madison has found that the genetic basis as to why this happens. [emphasis mine]

Always? Okay, whatever...

Blogging on Peer-Reviewed ResearchThe study, published in the December 5 issue of Cell Metabolism, found that mice with and without a particular gene - SCD-1 - processed carbohydrate in their liver differently. Those with the gene converted the glucose from carbohydrate to fat to be stored and grew fat; those without the gene utilized the carbohydrate for energy and remained a normal body weight.

The media is focusing heavily on the supposed "refined" aspect of the carbohydrates consumed by the mice, but abstract itself makes no mention of "refined carbohydrate;" noting the dietary comparison included a high-sucrose, very low-fat diet compared with a high-fat diet to investigate differences in the metabolism of mice with and without the SCD-1 gene.

The lead researcher, James Ntambi, noted, "It looks like the SCD gene in the liver is responsible for causing weight gain in response to a high-carbohydrate diet, because when we take away the gene's activity the animals no longer gain the weight. These findings are telling us that the liver is a key tissue in mediating weight gain induced by excess carbohydrates."

Since this was a study in mice, it was refreshing to see that one article, in the Star, noted that "Human studies have shown that people on high carbohydrate diets have "dramatic" increases in their levels of the SCD enzyme."

While many articles are implying that a drug may be developed to inhibit the gene in humans, Scientific American got to the point quickly, "This finding reveals that the liver determines whether or not eating refined carbohydrates will lead to fat gain. The researchers say this system is a good example of a direct diet-gene interaction. But they also say that a drug to turn off that fat-making liver gene wouldn’t be a good idea. Without that gene, the mice could no longer make glucose. They ended up hypoglycemic—suffering from low blood sugar. So the solution is, sadly, what you already knew: eat fewer processed carbohydrates."

I'd take a step further and say eat fewer carbohydrates, period.


  1. Anonymous11:36 AM

    This is truly enlightening. It would be wonderful if I knew more about the interdependencies between the pancreas, liver, and other digestive organs. I wonder if there is a correlation between having this gene, overconsuming carbohydrates, gaining weight, and Type 2 diabetes. Not all overweight or obese people have diabetes, but I take it from this article, that evidently this gene would make you more suspectible to the disease.

  2. Anonymous12:15 PM

    In a way, this is another example of science proving common sense: some people, like me and all but two of my first- and second-degree relatives, gain weight on a high-carb diet, and some people, like my husband and all his first- and second-degree relatives, don't. This would suggest there's a genetic basis for the carb-weight gain effect.

    The weird thing about looking at this from the genetic level is that we already knew, not just from common sense but from scientific evidence, that the liver processes extra carbohydrate into triglycerides. What does knowing the exact gene that causes this buy for us, other than, as the researchers stated, the possibility of drug therapy?

    Aside from the possibility of side effects like hypoglycemia, the other problem with gene therapy is that it will be expensive, whereas changes to diet are relatively inexpensive. Sure, meat costs more than pasta, but drugs cost wayyyy more than both meat and pasta.

    I don't get why so many researchers, especially those dealing with biochemistry, continue to make the refined vs. unrefined carb distinction. It may take a little longer for whole wheat bread to be broken into glucose, but that's still its ultmate fate.

    Dianne, aka Migraineur