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The human body converts ingested carbohydrates to GLUCOSE, which is a specific sugar molecule used as energy in the bloodstream.  There are there are two types of sugars: simple sugars (monosaccharides) and compound sugars (disaccharides). Oligosaccharides are short-chain carbohydrates containing 3-9 monosaccharide units. Polysaccharides are long chains of monosaccharides are often longer than 10 monosaccharide units and can either occur naturally or be manufactured for use as food additives.


  • Fructose: occurs naturally in fruits, some root vegetables, cane sugar and honey and is the sweetest of the sugars. It is known as fruit sugar and is one of the components of sucrose. It is used as a high-fructose syrup, which is manufactured from hydrolyzed corn starch that has been processed to yield corn syrup, with enzymes then added to convert part of the glucose into fructose.  Agave Syrup is another high-fructose sweetener commonly added to foods.
  • Galactose: is generally found as the other half of lactose (milk sugar) and is less sweet than glucose. Interestingly, galactose is a component of the antigens found on the surface of red blood cells that determine your blood type.
  • Glucose: occurs naturally in fruits and plant juices and is the primary product of photosynthesis but can also be manufactured from starch by enzymatic hydrolysis.  It was originally found in grapes and is similar in structure to dextrose (manufactured from corn starch).


  • Lactose: (galactose + glucose) occurs naturally milk. It is broken down into its constituent parts by the enzyme lactase during digestion. Children have this enzyme but some adults no longer form it and they are unable to digest lactose.  The ability of adults to produce lactase is known as lactase persistence and people who are lactose-intolerant can consume some dairy products (eg, some yogurts and cheeses) because the fermentation process converts lactose into lactic acid. Bacteria in the microbiome may also help to digest lactose.
  • Maltose: (glucose + glucose) is formed during the germination of certain grains (eg. barley), which is converted into malt, the source of the sugar's name. Maltose is less sweet than glucose, fructose or sucrose. It is formed in the body during the digestion of starch by the enzyme amylase and is itself broken down during digestion by the enzyme maltase
  • Sucrose: (fructose + glucose) is found in the stems of sugarcane and roots of sugar beet. It also occurs naturally in some fruits and roots (like carrots) alongside fructose and glucose. The range of sweetness depends upon the proportions of sugars found in these foods. Sucrase enzymes split sucrose into its constituent parts during digestion.


  • Maltodextrin is a food additive that can be 3 to 17 monosaccharide units derived from starch.  Its sweetness depends on the length of polymerization with shorter chains having higher sweetness and solubility.


Storage Polysaccharides

  • Starch
  • Glycogen (sometimes known as animal starch)

Structural Polysaccharides

  • Arabinoxylan
  • Cellulose
  • Chitin
  • Pectin

High Fructose Sweeteners

While fructose is commonly found in fruits, fruit contains small amounts and it is bound to dietary fibre.  Food manufacturers like to use sweeteners containing high quantities of fructose (like High Fructose Corn Syrup) because it is sweeter than other sugars and cheaper to produce, which makes it a great processed food additive for manufacturers.  Corn starch is readily converted to glucose with enzymes and this glucose is then processed into fructose.  The danger to human health is that, while glucose can be metabolized throughout the body, fructose can only be metabolized in the liver into glycogen and triglycerides.  The liver has a limited capacity to store glycogen and excess amounts result in fatty liver disease, which is commonly associated with metabolic syndrome (diabetes, hypertension, obesity, and dyslipidemia).

Excess levels of the following foodstuffs metabolized in the same way in the liver, overload mitochondria in tissues, and cause metabolic syndrome:

  • Transfats
  • Branched Chain Amino Acids (eg, protein powder, corn-feed beef, chicken, & fish)
  • Ethanol
  • Fructose