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Carbohydrates (CHO) are sugar-based molecules. Complex carbohydrates are chains of sugar molecules and are found in plant foods everywhere. Starch is a polymer or long string of glucose molecules, just as a protein is a long string of amino acids. Starch-containing plants are the universal staple foods. Carbohydrates include low caloric, low glycemic vegetables such as salad greens and plant fibers that have many health benefits.
Sugar has been blamed for all manner of health problems, often without justification. Many people who contact us with sugar concerns are misinformed and confused about the role of sugar in the body. They cannot differentiate among different kinds of sugar. They have not learned that glucose runs every cell alive on planet earth. Glucose, like oxygen and water is essential to life, but too much in the wrong place, at the wrong time can be harmful. The basic principle of life is that the right molecules have to be delivered to the right place at the right time. This principle is used to formulate elemental nutrient formulas such as Alpha ENF.
The idea is that glucose and fructose supply the energy that the body needs; the sugars are combined with all other nutrients following an ideal proportioning plan. If glucose utilization is impaired as in diabetes, then the rate of glucose absorption becomes critical. Small frequent doses will often be better utilized and high blood sugar peaks are avoided.
Human action is an expression of biological energy derived from food. Living cells are glucose-burning machines. Animals take advantage of the ability of plants to manufacture sugar and other nutrients. The energy, which supports us, is locked into the molecular bonds of a few basic fuel molecules: glucose, fructose, fatty acids, and amino acids. The energy is released as the energy-supplying molecules are dismantled by oxidation. Food-derived energy allows us to move, to do work by muscle contraction, and to keep warm. Body heat is generated by the metabolic activity of every cell. Carbohydrates and fats are the principle sources of energy; amino acids may be utilized as energy when glucose intake is limited or glucose utilization is impaired as in diabetes.
Some tissues such as muscle require insulin to absorb sugar. Other organs, such as the brain, do not require insulin and are prime glucose consumers. The liver tries to maintain blood sugar levels within a narrow normal range by either absorbing or releasing sugar. The liver stores sugar as glycogen and is also capable of producing sugar from amino acids if food does not supply adequate sugar. Slow absorption of sugars is better tolerated than the rapid absorption of larger amount. Complex carbohydrates in vegetables are ideal sustained-release sources of sugar.
Carbohydrates are energy and structural molecules produced by plants. Glucose is the key molecule in living systems and life is built around glucose and its related sugars. Plant foods are essential to animal life and form the bulk of most human diets. Rice, wheat, potatoes, yams, cassava, and corn are the world's most important staple foods. In the US, about 15% of agricultural production is devoted to vegetable cultivation. High-starch vegetables tend to be roots or tubers like potatoes, yams, turnips, winter squash, carrots, and beets. Yams and sweet potatoes are high-caloric root vegetables. Fruits tend to have a high sugar content, mostly glucose, fructose and sucrose. Fruit juices have the highest free sugar content of all plant foods except for sugar cane which stores sugar in its stalk. The green leafy vegetables are more chemically diverse and interesting foods that supply less digestible carbohydrate but more vitamins, minerals, and non-digestible fiber. The seeds of 30 or so common legume species are important vegetables, since they are cheap, available and are high in protein and fatty acids.
Sugars The principal sugars are glucose and fructose. These are the simplest CHO molecules, known by their single ring structure as monosaccharides. Glucose is the fuel of all living things, supplying energy to all living cells, both plant and animal. The creation of glucose begins in plants with the magic of photosynthesis. The sun's photons are the original energy source used by the chloroplasts of leaves to drive carbon, hydrogen, and oxygen atoms together to form glucose. Plants then use the newly synthesized glucose to fuel all their other synthetic processes, constructing tissues so that animals have food to eat. Fructose is the first cousin of glucose and occurs in fruit and corn syrup .
Sucrose is the sugar that is commonly called "sugar", often with negative connotations. Sucrose is the dominant sugar in most of our sweeteners, and it appears in refined form as white table sugar. Brown sugars and molasses are cruder sugar products which contain the same sucrose in the presence of many other substances not yet removed. The preference for brown sugars, syrups, molasses, and honey, in place of refined white sugar is not based on any important biological information. White table sugar, sucrose, has the advantage of containing less extraneous molecules and contaminants. Honey is preferable only by taste and implication (visions of bees, flowers, and summer days); it contains the same sugars, glucose, sucrose and fructose. Honey also contains bees' wings, legs, poop, pollens, and other assorted hive contaminants, and may offer some allergic reactions to sensitive individuals. Honey also carries the spores of the botulinus bacteria and should not be fed to infants since the spores can germinate in their intestine producing the deadly botulinus toxin. I personally prefer honey by taste, implication, and a lingering identification with Winnie the Pooh.
Fructose The intake of fructose has increased with the increased consumption of processed foods that are sweetened with sucrose, fructose itself and high-fructose corn syrup. In the US, fructose intake increased by 61% in adults from 1977 to 1997; sugar sweetened soft drinks became the largest single food source of calories in the US diet. High fructose corn syrup intake increased from 0 kg to 29 kg per person per year. Naturally occurring fructose intake from fruits remained unchanged. A US study involving 21,483 US adults and children found that a typical diet contains high fructose concentrations providing more than 10% of energy intake. Most of the fructose is added to soft drinks and processed foods and acts as an appetite stimulant. Adolescents (12 - 18 years of age) had the highest intake (72.8 g/day, or 12.1% of total energy intake). For 25% of adolescents, at least 15% of energy consumed came from fructose. Sugar-sweetened beverages were the largest source of fructose (30%) followed by grains (22%) and fruit or fruit juice (19%). Dansinger stated: "The addition of sucrose and high-fructose corn syrup (which are both 50% fructose) to processed foods and beverages is a major cause of the increased caloric intake from the calories in the sugars added to foods that already have high calorie counts, such as doughnuts and ice cream. This drives much of the obesity epidemic."
Fructose does not require insulin to enter cells. The idea that fructose is a good sugar for diabetics has several flaws, however. In mice and rats both high sucrose and fructose intakes create insulin resistance. Thresher et al concluded that fructose is the primary nutrient mediator of sucrose-induced insulin resistance and glucose intolerance.Increased fructose intake appears to increase atherosclerosis and the risk of heart attacks. Bantle, for example, placed 18 Type I (insulin-dependent) and Type II (noninsulin-dependent) diabetics on two diets: one contained carbohydrate as starch (glucose), and the other contained carbohydrate as fructose. When they consumed the fructose, the diabetics had fewer spikes in blood sugar levels. However, the diabetics' total cholesterol rose an average 7 percent, and their low-density lipoprotein (LDL) cholesterol rose almost 11 percent.
Sakai et al identified several mechanisms by which fructose could accelerate the complications of diabetes. They concluded: “…fructose accelerated the production of advanced glycation end-products more than glucose. In addition, fructose enhanced the reactive oxygen or oxygen radical generation and the associated degeneration of proteins and lipids. These actions of fructose appeared to be due to the formation of dicarbonyl compounds such as 3-deoxyglucosone, a highly reactive intermediate product formed in the advanced glycation stage. These results suggest that fructose is closely involved not only in glycation but also in the polyol pathway and peroxidation reactions through free radical formation. Thus, fructose is considered to be a more critical reducing sugar associated with the progression of diabetic complications than it has been thought until now.”
Carbohydrate Polymers: Polysaccharides
Large carbohydrate molecules form the structure of plants, and to a lesser extent, animals. A carbohydrate polymer, or polysaccharide, is a string of sugar molecules linked together. The cell walls of plants are constructed of elaborate polysaccharides made from 12 basic sugars. Cellulose is the main structural carbohydrate; it is a polymer of glucose units linked together to form a tough fiber. Vegetarian ruminants utilize special stomachs which host bacterial populations that break down cellulose.
Starch is the most valuable polysaccharide. The starch molecule is tree-like, with branches of varying length. Starch digestion begins in the mouth with salivary amylase, continuing in the small intestine with pancreatic amylase. Short chains of glucoses are referred to as alpha-dextrin, maltotriose (3GL), and maltose (2GL). Glucoamylase breaks these short chains down to individual glucose molecules which are absorbed. Starch is the best fuel, supplying sustained-release glucose.
Fiber There are several different types of carbohydrate polymers in fruit and vegetables that we are unable to digest. This material passes through the GIT as bulk fiber, undergoing modification and digestion by colon microorganisms. Several fibers have benevolent roles. The benefit seems to be the absorption or neutralization of the toxicity of other foods. Carbohydrate fiber contributes to the well-hydrated bulk of soft, easily-passed stools. Increased dietary fiber over a lifetime is associated with decreased incidence of bowel cancer and cardiovascular disease.
The colon's dense population of microorganisms are important in health and disease. The bacteria feed mostly on undigested carbohydrate, and 99% of them survive best in the absence of oxygen (anaerobic bacteria). It is estimated that 10-15% of starch from cereal grains, potatoes, and up to 50% of milk sugar in most adults enters the colon undigested where all the carbohydrates are fermented by colon bacteria. Many vegetables contain indigestible carbohydrate, welcomed by the colon flora. The gas associated with beans is mostly methane produced by the fermentation of carbohydrates. Colon fermentation also produces hydrogen gas, which may distend the colon and produce pain. Hydrogen, methane and carbon dioxide are odorless gases. The foul smells of colon gas are mostly volatile substances produced by the putrefaction of undigested protein. One can use the sniff-test to assess the colon's protein-carbohydrate balance: smelly gas reveals increased protein putrefaction and increased body ammonia, whereas non-odorous gas indicates healthier carbohydrate fermentation.
Many chemical substances are produced by colon bacteria and may be absorbed into the body. Some products are desirable, like the vitamins K, and Biotin. Other products are, nutrients like fatty acids which supply a small percentage of the calories extracted from food. Yet other substances produced in the colon may be undesirable and these include alcohols, lactic acid, and formate. The unpleasant smelling colonic gases are also absorbed and excreted by the lungs, giving the exhaled breath an unpleasant smell (halitosis). No amount of mouthwash, gum, or widely advertised candies will alter malodorous breath from colon gases, but diet revision can correct the problem.
The role of the colon as a metabolic organ is not well understood. One important metabolic role is the regulation of the body ammonia burden. Ammonia (NH3) is derived from dietary protein, the principle source of nitrogen in the body. Nitrogen freed from protein breakdown is toxic and must be excreted. Ammonia poisoning may occur in a variety of circumstances, especially liver disease. Subtle degrees of ammonia intoxication may be a cause of brain dysfunction in otherwise normal people. A generous intake of dietary fiber, as indigestible carbohydrate, aids colon bacteria in incorporating ammonia in their own structure and metabolism and results in a lower body ammonia burden.
Diets, deficient in fiber, and high in protein, produce the opposite effect - increased body burden of ammonia. Patients suffering liver disease with elevated blood ammonia are improved by the oral intake of lactulose, an indigestible carbohydrate which increases bacterial protein synthesis.
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