Carbohydrates
Table of Contents
Carbohydrates may be classified as monosaccharides, disaccharides or polysaccharides depending on the number of monomer (sugar) units they contain. They are a diverse group of substances, with a range of chemical, physical and physiological properties.[11] They make up a large part of foods such as rice, noodles, bread, and other grain-based products,[12][13] but they are not an essential nutrient, meaning a human does not need to eat carbohydrates.[14] The brain is the largest consumer of sugars in the human body, and uses particularly large amounts of glucose, accounting for 20% of total body glucose consumption.[15] The brain uses mostly glucose for energy; if glucose is insufficient however, it switches to using fats.[16]
Monosaccharides contain one sugar unit, disaccharides two, and polysaccharides three or more. Monosaccharides include glucose, fructose and galactose.[17] Disaccharides include sucrose, lactose, and maltose; purified sucrose, for instance, is used as table sugar.[18] Polysaccharides, which include starch and glycogen, are often referred to as ‘complex’ carbohydrates because they are typically long multiple-branched chains of sugar units.
Traditionally, simple carbohydrates were believed to be absorbed quickly, and therefore to raise blood-glucose levels more rapidly than complex carbohydrates. This, however, is not accurate.[19][20][21][22] Some simple carbohydrates (e.g., fructose) follow different metabolic pathways (e.g., fructolysis) that result in only a partial catabolism to glucose, while, in essence, many complex carbohydrates may be digested at the same rate as simple carbohydrates.[23] The World Health Organization (WHO) recommends that added sugars should represent no more than 10% of total energy intake.[24]
The most common plant carbohydrate nutrient, starch, varies in its absorption. Gelatinized starch (starch heated for a few minutes in the presence of water) is far more digestible than plain starch, and starch which has been divided into fine particles is also more absorbable during digestion. The increased effort and decreased availability reduces the available energy from starchy foods substantially and can be seen experimentally in rats and anecdotally in humans. Additionally, up to a third of dietary starch may be unavailable due to mechanical or chemical difficulty.
Source: https://en.wikipedia.org/wiki/Human_nutrition
Mono-, Di,- Poly-, Saccharides
Monosaccharides
single molecule sugar chains
- Glucose = Honey / Fruit
- Fructose = Corn Syrup / Tomatoes
- Galactose = Dairy Products & Meat / Legumes
Disaccharides
double molecule sugar chains
- Sucrose = Table Sugar / Peanut Butter
- Lactose = Dairy / Cheese
- Maltose = Grains / Beer
Polysaccharides
multi bonded molecule sugars
- Starches = Potatoes / Grains
- Glycogen = Fresh Fruits / Whole Grains
Dietary Fiber / an Inert carbohydrate
Dietary fiber is a carbohydrate, specifically a polysaccharide, which is incompletely absorbed in humans and in some animals. Like all carbohydrates, when it is metabolized, it can produce four Calories (kilocalories) of energy per gram, but in most circumstances, it accounts for less than that because of its limited absorption and digestibility.
The two subcategories are insoluble and soluble fiber. Insoluble dietary fiber Consists mainly of cellulose, a large carbohydrate polymer that is indigestible by humans, because humans do not have the required enzymes to break it down, and the human digestive system does not harbor enough of the types of microbes that can do so. Soluble dietary fiber Comprises a variety of oligosaccharides, waxes, esters, resistant starches, and other carbohydrates that dissolve or gelatinize in water. Many of these soluble fibers can be fermented or partially fermented by microbes in the human digestive system to produce short-chain fatty acids which are absorbed.
Whole grains, beans, and other legumes, fruits (especially plums, prunes, and figs), and vegetables are good sources of dietary fiber. Fiber is important to digestive health. Fiber can help in alleviating both constipation and diarrhea by increasing the weight and size of stool and softening it. Fiber provides bulk to the intestinal contents, and insoluble fiber especially stimulates peristalsis – the rhythmic muscular contractions of the intestines which move digesta along the digestive tract. Some soluble fibers produce a solution of high viscosity; this is essentially a gel, which slows the movement of food through the intestines. By slowing the absorption of sugar, fiber may help lower blood glucose levels, lessening insulin spikes and reducing the risk of type 2 diabetes.