Erythritol is a relatively new addition to the list of sugar alcohols used in foods and other consumer products. It has about 70% of the sweetness of sucrose and, like other sugar alcohols, does not contribute to tooth decay. It is unique, as a sugar alcohol, in that it is rapidly absorbed in the small intestine and is eliminated from the body within 24 hours. Erythritol is present in such fruits as pears, melons, mushrooms, and grapes, as well as such fermented foods as wine, soy sauce, and cheese. Through a fermentation process, using a glucose-rich substrate, glucose is obtained by enzymatic hydrolysis. Glucose is then fermented by a yeast-like fungus to obtain Erythritol. As a note of caution for Stevia users, Erythritol, derived from fermented glucose, is also used as a blend with stevia. As with other sugar alcohols, there is concern over the laxative effects on young children who are easily dehydrated.
Hydrogenated starch hydrolysates (HSH) are a family of products found in a wide variety of foods and include such sugar alcohols as hydrogenated glucose syrups, maltitol syrups, and sorbitol syrups. They are produced by the partial hydrolysis of corn, wheat, or potato starch and the subsequent hydrogenation of the hydrolysate at high temperature under pressure. This procedure results in HSH that provide 40%-90% of the sweetness of sugar. The end product is also composed of sorbitol, maltitol and higher hydrogenated saccharides (maltitriitol and others). By varying the conditions and extent of hydrolysis, various mono-, di-, oligo-, and polymeric hydrogenated saccharides can be obtained.
HSH were developed by a Swedish company in the 1960s and have been used by the food industry for many years. Common names for major HSH subgroups are generally based on the most prevalent polyol comprising the HSH. For example, polyols containing 50% or more sorbitol are called sorbitol syrups; those with maltitol as the majority component are called maltitol syrups, maltitol solutions, or hydrogenated glucose syrups. Polyols that do not contain a specific polyol, as the majority component continue to be referred to by the general term “hydrogenated starch hydrolysate.” (see below Maltitol for more info on the term hydrogenated)
Isomalt is not a true sugar alcohol, but acts so much like it that it is placed in that category. While it causes diarrhea in some, it does not in others. It can be fully absorbed as a carbohydrate in some, but not at all in others, and only partially in most. Isomalt is made from beet sugar in a two-step process. The sugar components of glucose and fructose are used to make Isomalt, which has only half the calories of table sugar. The reason for the reduced calorie content is that human enzymes can digest Isomalt only in small amounts and more slowly than sugar. As a result, blood sugar and insulin levels do not change significantly following consumption. Because the human body uses about half of the Isomalt ingested, it can act like a fiber that stimulates the bowel to counteract constipation. Thus, ingesting too much can cause diarrhea.
Lactitol is a sugar alcohol that belongs to the osmotic family of drugs. This means that it is used as an over-the-counter remedy for constipation as well as a sweetener. It works by retaining water during the entire digestive process only to release its activity later in a rather dramatic episode of gastro-intestinal upset. The dosage recommended to fight constipation is 10 grams, but the amount found in one serving of Reese’s sugar-free candies, for example, is 19 grams. Who stops eating at just one of those!
Lactitol was discovered in 1920 but not used in foods until the 1980s. Made from lactose, a milk sugar, lactitol has about 40% of the sweetening power as table sugar. This mild sweetness makes it an ideal bulk sweetener for pairing with such high-intensity sweeteners as acesulfame-K, aspartame, and sucralose.
Maltitol is a larger sugar alcohol molecule than some of the others. It is made via the hydrogenation of maltose, which is obtained from starch. It is also unique in that it does not stimulate the cold sensors on the skin, so does not feel cool in the mouth as some of the others do. The synonyms for Maltitol are hydrogenated high maltose-glucose syrup, and hydrogenated glucose syrup. Since those knowledgeable in the health field are well aware of the meaning of hydrogenated (hydrogenation creates trans fats), Maltitol should also be excluded from a truly healthy diet. Like other sugar alcohols, Maltitol also has a laxative effect and consumption should be limited. Maltitol has 90% of the sweetness of table sugar and can be found in sugar free candies, cookies, and gum. Although Maltitol is often used to replace sugars in the manufacture of sugar-free foods, it may also be used to replace fat as it gives a creamy texture to food.
Mannitol is the alcohol form of mannose – a 6-carbon sugar found in such plants as the manna plant, seaweed, pineapples, olives, asparagus, sweet potatoes, and carrots. However, for commercial use, it is manufactured via a catalytic hydrogenation process from artificial sweeteners. Because Mannitol does not pick up moisture, it is often used in such products as gum, soft candy, breakfast cereals, frostings, diet foods, and vitamin supplements, as well as in those products that need their bitter taste disguised. Mannitol has only half the calories of glucose but has 70% of the sweetness of table sugar and it does not contribute to tooth decay. Because it is poorly absorbed, it can cause diarrhea and large doses can cause kidney damage.
Mannitol is not effective when taken orally because it cannot cross GI membranes. Therefore, injections are used as a diuretic to decrease intercranial pressure (ICP) and to force more fluids through the kidneys. However, according to one study, Patients with chronic renal insufficiency who are undergoing cardiac angiography, hydration with 0.45 percent saline provides better protection against acute decreases in renal function induced by radiocontrast agents than does hydration with 0.45 percent saline plus mannitol or furosemide.
The chemical structure of mannitol allows it to be absorbed more slowly by the body than regular sugars. Therefore, it has a smaller impact on blood insulin levels, making it and other sugar alcohols useful for diabetic foods. On the other hand, because it slowly absorbed, excessive consumption may have a laxative effect, typical of sugar alcohols. Because of this, products containing mannitol must include a laxative warning on the label if the mannitol content in a serving exceeds 20g. Mannitol has also been removed from the GRAS (generally recognized as safe) list and is regulated as an intrim food additive. Diabetics are cautioned that, by replacing carbohydrates with sugar alcohols in foods, their diet composition and adequacy may be altered since sugar alcohols are only partially digested and metabolized. Therefore, individuals relying on product label information to assist in carbohydrate counting could overestimate the amount of insulin required.
Sorbitol is a naturally occurring sugar alcohol but is not classified as a carbohydrate. Other names include cholaxine, clucitol, diakarmon, gulitol, karion, nivitin, sionit, sorbicolan, sorbite, d-sorbitol, sorbo, sorbol, sorbostyl, and sorvilande. Sorbitol is used mainly in meat and milk products, candies and other confections, and beverages. It occurs naturally in many fruits and seaweed. Commercial Sorbitol is synthesized by hydrogenation from glucose, but it does not form glucose in the body. Because it does not raise blood sugar levels, it is used in many dietetic foods, but it still has the same 4 calories per gram as carbohydrates. Sorbitol is not well absorbed in infants, small children, and many adults. It ferments in the large intestine, producing gas, bloating, cramps, and diarrhea. For these reasons, consumer groups in 1999 called on the US government for warning labels since the FDA had known for many years previously that there was a problem with this sugar substitute. Those with Crohns Disease or Irritable Bowel Syndrome are advised to avoid any products using Sorbitol (as well as Olestra, a fat substitute).
Xylitol is another sugar alcohol used as a sweetener. Often referred to as a wood sugar because it is extracted from birch bark, Xylitol can also be found in straw, corncobs, some cereals, and mushrooms. Small amounts also occur naturally in plums, raspberries, strawberries, cauliflower, and eggplant. It is a derivative of a common pentose, but is as sweet as sucrose. According to Simon Doughty, Global Business Development Manager for Johnson Matthey Catalysts, Xylitol is made on an industrial scale by a process called hydrogenation over a nickel catalyst. The catalyst used to make Xylitol is called Sponge Nickel and the cooling sensation stems from its negative heat of dissolution.
Although it has no effect on the teeth, it has been known to cause bladder and adrenal gland tumors when used over an extended period of time. There is a congenital enzyme defect (most common in those of Jewish descent) that causes a condition called pentosuria. These people are unable to digest Xylitol, but there does not seem to be any associated disabilities with the condition. The only real problem is that these people may be misdiagnosed as having diabetes.
References
Sugar Alcohols
Erythritol
Hydrogenated starch hydrolysates
Isomalt
Lactitol
Maltitol
Mannitol
Sorbitol
Xylitol
