3.2 KiB
- Carbohydrates are a class of nutrients that is a major source of energy for the body
- Can also server as a glue that holds cells togehter
- Classified as simple or complex
- Plants are rich sources of carbohydrates There are 3 categories of carbs.
Sugars
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A monosaccharide is a simple sugar that is the basic molecule of carbohydrates:
- Glucose: Primary fuel for muscles, nerves, and other cells, the most common.
- Fructose: In fruits, honey, and certain vegetables
- Galactose: Component of lactose
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A disaccharide is a simple sugar comprised of two monosaccharides.
- Maltose: Disaccharide composed of two glucose molecules "malt sugar"
- Sucrose: Disaccharide composed of a glucose and fructose molecule "table sugar"
- Lactose: Disaccharide composed of a glucose and a galactose molecule "milk sugar"
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High fructose corn syrup is a syrup obtained from the processing of corn
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No conclusive evidence that the use of HFCS causes poor health and disease
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Excessive calories from beverages sweetened with HFCS contributes to increased risk for diabetes and heart disease
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Nutritive sweeteners are substances that sweeten and contribute energy to foods
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Each gram of mono or disaccharide supplies 4 kcal
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Added sugars are sugars added to foods during processing or prep
- The main source of added sugars in the American diet is sugar sweetened beverages.
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Alternative sweeteners are substances that sweeten foods while providing few or no calories
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Sugar alcohols are alternative sweeteners use to replace sucrose in some some sugar free foods:
- Sorbitol, xylitol, mannitol
- Not fully absorbed by the intestinal tract
- Supply 2kcal/g
- Can cause diarrhea when consumed
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Non-nutritive sweeteners are a group of synthetic compounds that are intensely sweet tasting compared to sugar
- Examples include Aspertame, Saccharin, Acesulfame-K, Neotame, and Sucralose
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Glycogen = storage form of glucose
- A highly branched storage polysaccharide in animals
- Muscles and liver are major storage sites
Starches
Complex carbs have 3 or more monosaccharides bonded together
- Starch is a storage polysaccharide in plants.
- Composed of amylose and amylopectin
- Rich sources include:
- Bread and cereal products made from wheat, rice, barley, and oats
Fiber
- Plants also use complex carbohydrates to make supportive and protective structures
- Dietary fiber is non-digestible plant material
- Most types are polysaccharides
- Soluble fiber
- Forms of dietary fiber that dissolve or swell in water. includes pectins, gums, mucilages, and some hemicelluloses
- Delays stomach emptying, slows glucose absorption and lowers blood cholesterol
- Insoluble fiber
- Forms of dietary fiber that generally do not dissolve in water: Includes cellulose, hemicelluloses, and lignin
- Helps with bowel movements and fecal bulk
Consumption
- In developing nations, diets supply 70% or more of energy from unprocessed carbs
- In industrialized nations, people tend to eat more highly refined starches and added sugars
- Americans consume about 30% of energy from added sugars (600 kcal/day)
- Regular soft drinks and energy drinks are major sources of added sugars in Americans' diets
- According to the dieterary guideline