Nutrition Class: Carbohydrates Lecture

Overview

• Focus on digestion and metabolism of carbohydrates.

Digestion Process

Mouth

• Enzymes: Amylase begins breakdown of starches.
• Importance of chewing to increase surface area for digestion.

Stomach

• No amylase present.
• Food softening and kneading occurs.
• High fiber foods fill you up, encouraging healthier eating.

Small Intestine

• Pancreas releases amylase to further digest starch into maltose, sucrose, and lactose.
• Enzymes on Villi: Lactase, maltase, sucrase break down disaccharides.
• Sugars absorbed: glucose, fructose, galactose.

Large Intestine

• Soluble fibers can ferment, causing gas.
• Insoluble fibers pass through the body.

Sugar Metabolism

• Glucose: remains glucose in the body.
• Fructose: converted to glucose in liver; excess can become fat.
• Galactose: converted to glucose.

Storage of Glucose

• Glycogen: stored in muscles and liver.
• Regulation by insulin and glucagon.
• Blood sugar regulated by pancreas.

Insulin Function

• Produced when blood sugar rises.
• Promotes glucose uptake and storage in liver and muscles as glycogen.
• Excess glucose converted to fat if glycogen stores are full.

Glucagon Function

• Released when blood sugar drops.
• Liver converts glycogen back to glucose to stabilize blood sugar.

Energy Use and Regulation

During Exercise

• Epinephrine: increases glucose and fat release for energy.
• Occurs 10-20 minutes into exercise.
• Promotes breakdown of glycogen in muscles.

Hormones Involved

• Insulin: after meals, for storage.
• Glucagon: between meals, for release.
• Epinephrine: during stress/exercise, for increased energy release.

Additional Resources

• Recommended animation on Canvas for a visual explanation of insulin and glucagon.

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These notes cover the key points of the lecture on carbohydrates, their digestion, metabolism, and the hormonal regulation involved. They provide an overview of how the body processes carbohydrates from consumption to energy utilization.