Chapter 4 - Carbohydrates: Plant-Derived Energy Nutrients

Adequate Intake (AI) for Fiber

25 g/day for women 38 g/day for men 14 g fiber for every 1,000 kcal/day

How Much Carbohydrate? AMDR:

45% to 65% of daily calories

Fasting Hypoglycemia

Pancreas produces too much insulin, even when someone has not eaten

Reactive Hypoglycemia

Pancreas secretes too much insulin after a high-carbohydrate meal

How Much Carbohydrate? RDA:

130 grams/day To supply adequate glucose to the brain

Diabetes

Inability to regulate blood glucose levels

Lactose Intolerant

Insufficient enzyme lactase to digest the lactose-containing foods Symptoms: gas, cramping, diarrhea

Glycemic Index

A foods' potential to raise blood glucose

The Liver & Carbohydrate Digestion

All monosaccharides re converted to glucose by the liver. Glucose circulating in the blood is our primary energy source. Excess glucose is stored as glycogen in the liver and the muscles

Type 1 Diabetes

Body does not produce enough insulin. Causes hyperglycemia (high blood glucose). Requires insulin injections. May be autoimmune disease

Soluble Fibers

Complex carbohydrate. Dissolve in water, viscous, and gel-forming. Fermentable, digested by intestinal bacteria. Associated with risk reduction of cardiovascular disease and type 2 diabetes. Examples: pectin, gum, mucilage Found in: citrus fruits, berries, oats, and beans

Fiber

Complex carbohydrate. Long polysaccharide chains. Dietary Fibers - non digestible parts of plants Functional Fibers - non digestible forms of carbohydrates extracted from plants and have known health benefits Total Health Benefits = Dietary Fiber + Functional Fiber

Insoluble Fibers

Complex carbohydrate. Not water-soluble, non viscous. Cannot be fermented by bacteria in the colon. Promote regular bowel movements, alleviate constipation, and reduce diverticulosis Examples: lignins, cellulose, hemicellulose Good sources: whole grains, seeds, legumes, fruits, and vegetables

Starch

Complex carbohydrate. Plants store carbohydrates as this. Amylose - straight chain of glucose Amylopectin - branched chain of glucose Resistant Starch (fiber) - glucose molecules linked by beta bonds are largely indigestible Sources: graines, legumes, fruits, and vegetables

Glycogen

Complex carbohydrate. Storage of glucose for animals (humans). Not found in food and therefore not a source of a dietary carbohydrate. Stored in liver and muscles

Polysaccharides

Consists of HUNDREDS TO THOUSANDS of glucose molecules. Starch, glycogen, and fibers

Oligosaccharides

Contain 3 TO 10 monosaccharides

Monosaccharides

Contain ONE molecule. Glucose, fructose, and galactose

Disaccharides

Contain TWO molecules. Lactose, Maltose, and Sucrose

Simple Carbohydrates

Contain one or two molecules. Commonly referred to as sugars

Glycemic Load

Determines effect of a food on a person's glucose response. Grams of carbohydrates are multiplied by the glycemic index

Carbohydrate Digestion

Digestion that occurs in the small intestine, NOT the stomach

Digesting Fiber

Do not have enzymes to digest fiber. Bacteria in Large Intestine can break down some fiber. Most fiber remains undigested and is excreted

Monosaccharides in Digestion

Enzymes digest disaccharides to monosaccharides: Maltase, Sucrase, Lactase. These monosaccharides are absorbed into the cells lining the small intestine and enter bloodstream

Ketosis in the Role of Carbohydrates

Fats breakdown during fasting forms ketones. Excess ketones increase blood acidity and cause ketoacidosis. Sufficient energy from carbohydrates prevents ketone production as alternate energy source

What are Carbohydrates?

Important source of energy for all cells. Composed of Carbon, Hydrogen, and Oxygen. Good sources found in fruits, vegetables, and grains

Type 2 Diabetes

Insulin Sensitivity: cells become less responsive to insulin Metabolic Syndrome: a cluster of risk factors that increase risk for this type Once known as adult-onset diabetes Increasing in children and adolescents Causes: genetics, obesity, and physical inactivity Treatment: weight loss, healthy eating, regular exercise, medications

Simple Carbohydrates in Diets: Simple Sugars

Lead to tooth decay, may increase "bad cholesterol", decrease "good cholesterol", contribute to obesity

Hypoglycemia

Low blood glucose. Symptoms: shakiness, sweating, anxiety, weakness

Low Glycemic Index

Low to moderate fluctuations in blood glucose. Benefits: risk reduction for heart disease and colon cancer. Foods: beans, fresh vegetables, whole wheat

Blood Glucose

Must be closely regulated. Controlled by these hormones: Insulin Glucagon Epinephrine Norepinephrine Cortisol Growth Hormone

Fortified foods

Nutrients added that did not originally exist in the food (or existed in insignificant amounts)

Enrichment foods

Nutrients ar lost during processing and have been added back so the food meets a specified standard

Gluconeogenesis

Occurs when a diet is deficient in carbohydrate. The body will make its own glucose from protein. Amino acids from these proteins cannot be then used to perform any of their other functions

Non-Nutritve (alternative) Sweeteners

Provide little or no energy. Safe for adults, children, people with diabetes

Energy in the Role of Carbohydrates

Red blood cells use only glucose for energy. Both carbohydrates and fats supply energy for daily activities. Glucose is especially important for energy DURING exercise

Epinephrine and Norepinephrine

Secreted by adrenal glands and nerve endings when blood glucose is low. Increases glycogen breakdown in the liver releasing glucose into the blood. Responsible for "fight or fight" response

Glucagon

Secreted by alpha cells of the pancreas. Stimulates the liver to convert glycogen to glucose. Stimulates gluconeogenesis, the production of glucose from amino acids

Insulin

Secreted by beta cells of the pancreas. Stimulates glucose transporters (carrier proteins) to help take glucose from the blood across the cell membrane. Stimulates the liver to take up glucose and convert it to glycogen

Cortisol and Growth Hormone

Secreted by the adrenal glands to act on the liver, muscle, and adipose tissue. Cortisol: Increase gluconeogenesis, Decrease muscle Glucose use Growth Hormone: Decrease muscle glucose uptake, Increase fatty acid mobilization, Increase glucose output

Nutritive Sweeteners

Sucrose, fructose, honey, and brown sugar contain 4 kcal energy per gram Slow-absorbing sugar alcohols: 2-3 kcal/gram

High Glycemic Index

Sudden surge in blood glucose

Glucose

The most abundant carbohydrate. Produced by plants through Photosynthesis