Nutrition Series: Simple vs. Complex Carbohydrates

Nutrition Series: Simple vs. Complex Carbohydrates

There is a lot confusion regarding the term: simple and complex carbohydrates. How do you know which is which as the terms aren’t indicative how quickly they are digested, metabolized, and absorbed or even the nutritional value of carbohydrates.

The confusion lies in how the same number of carbon, hydrogen and oxygen atoms, connected differently, are arranged to create the three main players: monosaccharides, oligosaccharides, and polysaccharides.

This image, from Precision Nutrition, gives a simple outline of the connectivity of the different arrangements of carbon, hydrogen, and oxygen.

 

Monosaccharides which are single, or simple, sugars, have one sugar group.

Three main single monosaccharides, or single sugars, are:

• Galactose Source: Dairy
• Glucose Source: Fruits, vegetables, pasta, grains, flour, bread, rice, table sugar or anything starchy)
• Fructose Source: Fruit sugar, sugar additives; very sweet

Oligosaccharides are short chains of monosaccharides, linked together; some can be simple, while others complex.

Two linked monosaccharides are disaccharides, three linked monosaccharides are trisaccharides, and so on.

Common Oligosaccharides are two sugar combinations: also called disaccharides:

• Sucrose: (Glucose+Fructose) This is commonly referred to as table sugar, cane sugar, brown sugar, high fructose corn syrup, molasses, maple syrup and added to many foods.
• Lactose: (Glucose+Galactose) Milk and dairy have a carbohydrates called lactose, when people lack the enzyme to break these two sugars apart they are considered lactose intolerant.
• Maltose: (Glucose+Glucose) This isn’t a common sugar; can be found in malted beer, sprouted grains and also barley malt sweetener.

Polysaccharides are long (complex chains of 10+) linked monosaccharides; straight or branched; forming a polymer. These long chains of polysaccharides can be found in: breads, cereals pasta grains like rice and oats. Vegetables like: corn, peas and potatoes are starchy complex sugars.

Common polysaccharides:

• Starch Source: Plant Cells: Amylose (linear) and amylopectin (highly branched) are two main forms
• Glycogen Source: Animal Cells: made from glucose monosaccharides during glycogenesis
  
• Fiber Source: Plant Cells:
  • Soluble: Dissolves in water; forms a gel like substance in intestinal tract
  • Insoluble: Indigestable; Does not dissolve in water; resistant to human enzymatic activity; converted to short chain fatty acids.

*foods resistant to stomach acid and digestive enzymes, while remaining mostly intact, are also known to cause gas.  Foods like: beans, garlic, leeks, onions, rye, asparagus, barley and Jerusalem artichokes can make you uncomfortable and gassy.

It is reported that eating high fiber foods more often, helps your body to produce more enzymes, which in turn assist with digestion thereby causing less gas.

 

Digestion of foods can be seen in this excellent animation from WHfoods.com

Click to start the animation. Run your mouse over the parts of the digestive track to see what they do.