Chapter 4 Carbs

Under what dietary conditions do we increase our glycogen stores?

Amount of glycogen can be temporarily increased by carbohydrate-loading. This is used by endurance athletes to build up glycogen stores before an event.

Who is affected by lactose intolerance?

Between 30 and 50 million people in the United States are lactose intolerant. Up to 80% of African Americans are lactose intolerant compared to only about 15% of Caucasians.

What is lactose intolerance?

Condition where there is not enough of the enzyme lactase in the small intestine to digest milk sugar lactose. Infants tend to be able to break down lactose, but the ability decreases with age.

What is diabetes and what are the long-term complications of this disease?

Diabetes is categorized by high blood glucose levels due to a lack of insulin or unresponsiveness or resistance to insulin (constant high blood pressure). The elevated glucose causes damage to the large blood vessels, leading to an increased risk of heart disease and stroke. Affects 25.8 million Americans and accounts for $174 billion dollars in Healthcare for direct and indirect reasons.

How does fiber affect our gastrointestinal health?

Fiber causes distention (feeling enlarged) and slows emptying which is beneficial to people trying to lose weight because they feel fuller eating fewer calories.

How are bonds between monosaccharides formed? Broken?

Formed: Dehydration Reaction (Condensation)- These reactions release a molecule of water by taking a hydroxyl group from one sugar and a hydrogen atom from another. Broken: Hydrolysis Reaction- These reactions use water to add a hydroxyl group to one sugar and a hydrogen atom to another.

Describe gluconeogenesis and glycogenolysis (glycogen breakdown)

Gluconeogenesis-liver makes glucose from amino acids Glycogenolysis- creation of glucose

Where are 3 common simple carbohydrates found in the diet/body?

Glucose-produced in plants through the process of photosynthesis. Most often found as part of a disaccharide or starch Fructose-Found in fruits and vegetables Galactose- Part of lactose, the disaccharide in milk

What nutrition information is used to compare different carbohydrates?

Glycemic Index-a ranking of how a food affects blood glucose compared to the response of an equivalent amount of carbohydrate from a reference food.

List the different types of complex carbohydrates and where they are found in food

Glycogen-storage form of carbohydrates in animals. We don't consume glycogen in food because it is lost in animals shortly after slaughter. Starches-storage form of carbohydrates in plants. Made up of amylose and amylopectin. Consume starch in roots and tubers, (ex: potatoes) grains and seeds, and legumes. Also found in refined starches such as cornstarch. Fiber-cannot be digested by human enzymes and thus, cannot be absorbed into the body. But it still provides value to diet. Can reduce constipation and lower blood cholesterol. Found in intact plants and can be added to foods (ex:oat bran added to bread).

Describe what happens during the process of glycolysis.

Glycolysis- glucose breakdown. Metabolic reactions in the cytosol of the cell that split glucose into 2 three-carbon pyruvate molecules, yielding 2 ATP molecules.

What is the glycemic response?

How quickly and how high blood glucose rises after carbohydrate is consumed. Affected by the amount and type of carbohydrate eaten and the amount of fat and protein in that meal.

What is glycogen and where is it stored?

In humans, glycogen is stored in the liver and the muscles. We don't consume glycogen in food because it is lost in animals shortly after slaughter.

What causes lactose intolerance

Lactose is not digested in small intestine and passes into large intestine where it increases number of small molecules, eventually leading to acid and gas.

Under what dietary conditions are our glycogen stores depleted/used?

Low blood sugar

What are complex carbohydrates?

Many monosaccharides linked together in chains

Where does energy production from nutrients occur in our cells?

Mitochondria

How does fiber affect our cardiovascular health?

Moderates nutrient absorption. Increase the volume of intestinal contents and absorb water. Slowing the absorption of glucose reduces fluctuations in blood glucose levels.

What is the basic unit of a carbohydrate?

Monosaccaride

What is the main function of glucose in the body?

Most important carbohydrate fuel. It provides energy to body cells, the brain uses the most glucose.

What pathway produces the most ATP?

Oxidative Phosphorylation

How do different complex carbohydrates affect our glycemic response?

Refined sugars and starches generally cause a greater glycemic response than unrefined carbohydrates that contain fiber.

What are the differences between refined flour and unrefined flour?

Refined: Food that has gone through processes which that change or remove various components (vitamins, minerals, and fibers) of the original food Unrefined: Food that has not been altered from its original state

What foods are good sources of unrefined simple carbohydrates?

Sugar (anything ending with -ose)

Explain why drinking a sugar-sweetened beverage causes a person's blood glucose to rise faster than it does after eating a bowl of bran flakes.

Sugars and starches consumed alone leave the stomach quickly and are rapidly digested and absorbed, causing a sharp rise in blood glucose. Eating a high fiber food causes a slower, lower increase in blood sugar.

Why is added sugar considered a source of empty kcalories?

They provide few nutrients for the number of calories they contain

How do type 1, type 2, and gestational diabetes differ?

Type 1: Body's own immune system attacks the insulin-secreting cells of the pancreas. Accounts for 5% of diabetes cases in the United States. (Birth) Type 2: Body does not produce enough insulin to keep blood glucose in the normal range. Caused by both genetic and lifestyle choices. Increased chances if family has diabetes history, excess weight, and sedentary lifestyle. Accounts for 90-95% of all diabetes cases in the United States. Gestational: Diabetes that occurs during pregnancy. Usually disappears after pregnancy is complete and hormones return to their previous levels.

When blood sugar drops, how do we increase it to maintain normal levels?

Type 1: Insulin injection. (Cannot be taken orally) Type 2: Treated with medications that increase pancreatic insulin production, decrease glucose production by the liver, enhance insulin action, or slow carbohydrate digestion to keep blood glucose in the normal range.

What foods are good sources of unrefined complex carbohydrates?

Whole grain bread, legumes, fruits, vegetables, and milk

Muscle glycogen

provides glucose to the muscle as a source of energy during activity

Liver glycogen

releases glucose into the bloodstream for delivery to cells