The Role of Supplemental Complex Dietary Carbohydrates and Gut Microbiota in Promoting Cardiometabolic and Immunological Health in Obesity: Lessons from Healthy Non-Obese Individuals
Dietary fibers promote beneficial physiologic effects including laxation, and/or blood cholesterol attenuation, and/or blood glucose attenuation. Carbohydrates are one of the most important sources of energy for our bodies. These nutrients come in a variety of forms with the most common being sugars, starches and fibres. Sugar is the simplest form of carbohydrates and includes fruit sugar (fructose), table sugar (sucrose) and milk sugar (lactose).
Fibrous foods have the ability to delay gastric emptying, slow small bowel transit time, bind toxins and irritating bile acids, and normalize gut motility. Note that some pet food companies take this approach to an extreme, formulating foods that contain more than 50 percent carbohydrates (and low-quality sources at that!).
They are formed of long chains of sugars, most commonly glucose. Like oligosaccharides, they may be linear or branched. Important polysaccharides are starch, glycogen (animal starch), cellulose , and chitin .
The animals’ bloodstream then carries the glucose to every cell in the body and cells turn the glucose into energy by a process known as oxidation, in which glucose combines with oxygen and releases energy. In a sort of reverse process, an animal turns a plant into the energy that the plant “captured” from the sun. Diabetes is a disease in which the body cannot metabolize carbohydrates, and either doesnâ€™t make or doesnâ€™t respond to insulin, a hormone secreted by the pancreas that is used to transport glucose to the bodyâ€™s cells. In individuals with type 1 diabetes, the pancreas fails to produce insulin, thus causing blood glucose levels to remain the same after meals. This condition is known as hyperglycemia.
When energy intake exceeds energy expenditure, excess calories from fat, protein, and carbohydrate can be used to form glycogen. It is made up of repeating glucose units and is highly branched. During times of fasting or in between meals, these chains can be broken down to single glucose units and used as an energy source for the body. Although found in animal tissue, animal products do not contain large amounts of glycogen because it is depleted at the time of slaughter due to stress hormones.
The glucose is then absorbed into your blood as blood sugar or blood glucose, and is delivered to your cells with the help of insulin. Cells then convert the glucose into ATP (or cell energy) which fuels your bodily functions like running, breathing and thinking. The process whereby cells turn glucose into energy is called glycolysis. The leftover glucose is stored in your liver, muscles and other cells for later use, however, if it is not used it turns into fat.
To circumvent this potential interpretational problem, we aimed at providing an overview about whether and how dietary supplementation of different complex carbohydrates changes the gut microbiome in healthy non-obese individuals. We then reviewed whether the reported changes in gut bacterial members found to be established by complex carbohydrates would benefit or harm the cardiometabolic and immunological health of the host taking into account the alterations in the microbiome composition and abundance known to be associated with obesity and its associated disorders.
Like starch, glycogen is made up of chains of glucose linked by alpha bonds; but glycogen chains are more highly branched than starch. It is this highly branched structure that allows the bonds to be more quickly broken down by enzymes in the body. The primary storage sites for glycogen in the human body are the liver and the muscles.
All carbohydrates are absorbed in the form of monosaccharides. The small intestine is highly efficient at this, absorbing monosaccharides at an estimated rate of 120 grams per hour.
These individuals must receive daily injections of insulin to control their blood glucose levels. In type 2 diabetes, there may be sufficient insulin, but the bodyâ€™s cells may be resistant to it. Once again, this causes blood glucose levels to rise. Type 2 diabetes can be treated through oral medication and proper diet, although the need for insulin injections may develop later on.
To avoid ketosis, daily carbohydrate intake should include a minimum of 50 to 100 grams. In terms of dietary fiber, a minimum intake of 20 to 35 grams per day is recommended. Low-carbohydrate diets, such as the Atkins and South Beach diets, are based on the proposition that it’s not fat that makes you fat. Allowing dieters to eat steak, butter, eggs, bacon, and other high-fat foods, these diets instead outlaw starches and refined carbohydrates on the theory that they are metabolized so quickly that they lead to hunger and overeating. This theory, which was first popularized in the nineteenth century, came under scathing criticism from the medical establishment during the early 1970s when Dr. Robert Atkins published the phenomenally popular low-carb diet bearing his name.
After the carbohydrates have passed through the stomach and into the small intestine, key digestive enzymes are secreted from the pancreas and the small intestine where most digestion and absorption occurs. Pancreatic amylase breaks starch into disaccharides and small polysaccharides, and enzymes from the cells of the small-intestinal wall break any remaining disaccharides into their monosaccharide components. Dietary fiber is not digested by the small intestine; instead, it passes to the colon unchanged. The glycemic index (GI) – the rate at which carbohydrates are absorbed into the bloodstream – is, in general, lower for foods containing complex carbohydrates than simple carbohydrates, but there are exceptions. A number of factors influence a foodâ€™s GI, including processing, type of starch, fiber content, ripeness (of fruit), fat or acid content, preparation, and how each individualâ€™s body processes food, including how much the food is chewed, and how quickly it is swallowed.
Carbohydrates come almost exclusively from plants, vegetables, and grains. Milk is the only animal-based product that contains a significant amount of carbohydrate. Carbohydrates are usually divided into three main categories. The first category, the monosaccharides, are simple sugars that consist of a single carbohydrate unit that cannot be broken down into any simpler substances.
All normally digested dietary carbohydrates are absorbed; indigestible fibers are eliminated in the feces. The monosaccharides glucose and galactose are transported into the epithelial cells by common protein carriers via secondary active transport (that is, co-transport with sodium ions). The monosaccharides leave these cells via facilitated diffusion and enter the capillaries through intercellular clefts.