Called HPMC (hydroxypropylmethylcellulose), the cellulose-derivative has been used for decades as an additive in many foods and drugs, mainly to provide texture; this is the first study to demonstrate its potential as a functional food ingredient. HPMC, which is tasteless and odorless, could one day be added to hamburgers, pizza, hot dogs and other high-fat foods as a novel line of defense against diabetes, which is on the rise in the U.S.
If the results are seen in human trials, young people, often frequent consumers of high-fat fast-foods could benefit. HPMC will not prevent obesity, but may reduce the risk that obese people will develop diabetes.
Wallace H. Yokoyama, Ph.D., a research chemist with the small intestine says the less fat you eat, the better off you are but if you do eat high fat foods, then adding HPMC to it might help limit the damage. In their studies with hamsters, adding HPMC to the animals ™ high-fat diet prevented the development of insulin resistance; he estimates HPMC could make its way into food products as a functional food additive within one to two years. Human studies are anticipated.
Yokoyama ™s research team fed a group of hamsters a high-fat [J1]diet - about 38 percent of calories derived from fat - similar to the fat content of typical American fast-food diets over a four-week period, then compared them to a group of animals that were fed a low-fat (11 percent fat-derived calories) diet. As expected, the animals fed the high-fat diets developed insulin resistance, but the animals fed the low-fat diet did not. But when soluble cellulose in the form of HPMC was substituted for the insoluble fibre normally found in the high-fat diets and then fed to another group of test animals over the same period, it prevented insulin resistance, according to the researchers.
The investigative team also studied metabolic changes in the test animals at the genetic level by using special analytical techniques. They found significant differences in gene expression, as measured by messenger RNA changes, between animals that became insulin resistant and those that did not.
Yokoyama believes that although the exact mechanism by which HPMC works is unclear, it acts as a fat regulator. It appears to slow down the absorption of fats - either in the stomach, small intestine, or both - preventing high fat levels from overwhelming the digestive system, and seems to facilitate the normal transport of fat into the adipose tissue, where it is normally stored.
In contrast, fats that are taken into the body too quickly, as during a fast-food binge, tend to be rapidly shunted to non-adipose tissues such as the liver, heart and pancreas, where they can do extensive damage to cells. Pancreatic damage can lead to diabetes.
HPMC, which is manufactured by Dow Chemical Company, is used in many common food products such as fillings, sauces and glazes, where it usually functions as a texture modifier. Although it constitutes from 0.5 to 1.5 percent of the total ingredients found in individual servings of most of these food products, the researchers say that it is likely be added in higher proportions if used in food as a diabetes-fighter.
Already proven to be safe at lower amounts, the researchers do not anticipate that HPMC will cause any adverse effects at higher amounts. Based on animal studies, the researcher estimates that only a few grams (approximately 5 grams) would be needed to have a positive impact on health. But further studies are needed to determine effective doses, Yokoyama says.
Other researchers in this study include Qiming Shao and Gerard R. Lazo, also of the Agricultural Research Service; Wei-Shou Hu and Katie Wlaschin, of the University of Minnesota; and Peter M. Nissom and Miranda G.S. Yap, of the Bioprocessing Technology Institute in Singapore.
Syrian hamsters which were also fed a high fat (HF) diet similar in fat content to the American diet became insulin resistant. Earlier tests have shown that replacing cellulose in a HF diet with HPMC significantly decreases the incidence of insulin resistance. HPMC significantly reduced the glucose infusion rate, fasting plasma insulin, plasma lipids, overall fat distribution in non-adipose tissues, and the cell size of adipose tissues. A cDNA microarray, constructed from Chinese hamster ovary cells, was used to analyze gene expression in liver tissues from hamsters fed the HF or the HF with HPMC diets. Genes related to fat metabolism, glucose metabolism, insulin metabolism, inflammation, and glucose transport, were differentially expressed between the two groups. These results indicate that HPMC may prevent the cellular oxidative damage leading to diabetes by normalizing fat metabolism.