In common usage, the term fat covers what actually are different types of adipose tissue accumulations in various places in the human body. Subcutaneous fat, not directly linked to obesity related pathologies, is located in the hypodermis region, while the visceral fat or intra -abdominal fat is located within the abdominal cavity and around internal organs like the stomach, intestines, kidneys or liver.
A high level of this type of fat is known as central obesity, which is considered highly dangerous and has been linked to cardiovascular diseases, type 2 diabetes, inflammatory diseases and other obesity related dysfunctions, as well as alterations of cognitive processes.
During their experiments, the scientists evaluated the impact that lifestyle factors like dietary habits and exercise have on the levels of abdominal fat. The study was aimed at African American and Hispanic American populations, as statistically these populations showed elevated risk levels for the development of visceral fat and some associated conditions, such as diabetes and high blood pressure.
A number of 1114 subjects were given extensive physical exams, combined with CT scans, in order to accurately determine the initial levels of intra-abdominal fat, and they were required to provide relevant data regarding their lifestyle through a questionnaire. After 5 years, the subjects undertook the same tests once again.
"Our study found that making a few simple changes can have a big health impact," stated Kristen Hairston, M.D, and one of the researchers involved in the study. The data gathered based on the results of the study proved that an increased level of soluble fiber consumption can be linked to a significant reduction of visceral fat.
The scientist also added that the research "is valuable because it provides specific information on how dietary fiber, especially soluble fiber, may affect weight accumulation through abdominal fat deposits" (as it observes the impact they have on specific adipose tissues and not the general fiber - fat relationship).
Dietary fibers are made up of the indigestible portions of plant foods. There are two types of fibers: soluble and insoluble. The latter ones are metabolically inert, and by absorbing water, they will help regulate and ease intestinal transit and defecation. Soluble fibers are fermented by bacteria inside the digestive tract to produce highly beneficial gases; they are physiologically helpful byproducts like short chain fatty acids (SCFA).
SCFA are linked to numerous useful effects on physiological processes, including stabilizing blood glucose levels, boosting immune protection by stimulating production of T helper cells, antibodies and leukocytes, preventing the development of colonic polyps, suppressing cholesterol synthesis and regulating glucose absorption.
Dietary fibers can be found in all plants in various amounts, with some of them being more rich in soluble or insoluble fibers. "Ten grams of soluble fiber can be achieved by eating two small apples, one cup of green peas and one-half cup of pinto beans," the researchers explain. Peas, lupines and other beans, oats, rye and barley, as well as fruits like plums, bananas, apples and pears or as vegetables like broccoli, carrots or onions all contain high levels of soluble fiber that can easily make for the necessary daily amount.
Sources for this article include: