Nutrition - Chapter 5 - Carbohydrates: Sugars, Starches, and Fiber

five signs of metabolic syndrome

1. elevating fasting triglycerides 2. high fasting blood glucose 3. hypertension 4. low fasting HDL cholesterol 5. large waist circumference

according to 2020-2025 dietary guidelines for Americans, people should limit their added sugar intake to less then what percent of total calories

10%

RDA for carbohydrates

130 g/day

each gram of a sugar alcohol supplies how many kcal on average?

2 kcal

glycogen is found in (plant/animals)

animals

aspartame

artificial sweetener made from two amino acids (phenylalanine and aspartic acid) and methanol

what artificial sweetener must patients with PKU avoid?

aspartame

type 1 diabetes

autoimmune disease that results in destruction of the beta cells of the pancreas, so the individual must obtain an exogenous source of insulin regularly

how can people reduce their risk of type 2 diabetes?

avoiding excess body fat, exercising daily, improving their diets

why is bloating a common experience after eating foods containing oligosaccharides?

bacteria in the colon use them for fuel, in turn created waste products as gases

type 2 diabetes

beta cells of the pancreas produce insulin, but the hormone's target cells are insulin-resistant, leading to elevated blood glucose levels

benefits of soluble fiber

binds to bile in intestines, can aid in lowering blood cholesterol, may reduce risk of heart disease

hypoglycemia

blood glucose level is too low to provide enough energy for cells

hemoglobin A1c

blood test to measure the amount of glucose that remains attached to the hemoglobin for the life of the red blood cell or about 2-3 months

what does pancreatic amylase do?

break down starch into maltose in the small inestine

what does the body metabolize for energy when glucose levels are low?

fat

poorly controlled diabetes is a major cause of...

heart disease, kidney failure, blindness, and poor blood circulation

epinephrine

hormone produced by the adrenal glands, secreted in response to declining blood glucose levels

insulin

hormone secreted by pancreatic beta cells that contributes to a decrease in blood glucose levels

glucagon

hormone secreted from pancreatic alpha cells that contributes to an increase in blood glucose levels

how are oligosaccharides used in the body?

human enzymes cannot readily break down oligosaccharides, so they are used as fuel by bacteria in the colon

what is the primary sign of diabetes?

hyperglycemia - hyper = excess - glycemia = blood glucose

what happens to glucose when it is ingested?

if cells need energy, the glucose goes to those cells where it is metabolized if cells don't necessarily need energy, the body stores the extra glucose as glycogen (liver can also convert excess glucose into fat)

what makes a carbohydrate simple?

if it contains either only one or two units of sugar (monosaccharide or disaccharide)

what makes a carbohydrate complex?

if it has many units of sugar linked together (polysaccharide)

how do diets rich in soluble fiber reduce risk of cardiovascular disease?

improving blood lipid levels, lowering blood pressure, and reducing markers of inflammation

lactose intolerance

inability to digest lactose properly because of a deficiency in the enzyme lactase

what do beta cells produce?

insulin

how does insulin work?

insulin lowers blood glucose by facilitating uptake and the use of glucose by muscle and fat cells

what can lead to hypoglycemia?

intake of complex and whole grains, healthy fats, protein, and fiber (yogurt, brown rice, whole grain bread)

what can lead to hyperglycemia?

intake of mostly carbohydrates, simple sugars, no fiber (gatorade, candy, pretzels, soda)

where are fibers used in the body?

intestinal bacteria in the large intestine break down and metabolize (ferment) soluble fiber for energy

why does physical activity improve diabetes control?

it increases glucose uptake by muscles, reducing blood glucose levels and improving the body's insulin response

why is glucose so important?

it is a primary fuel for muscle and other cells (like red blood cells and brain cells)

starch and glycogen

large storage forms of glucose found in plants and animals

hepatic portal vein transports substances directly to the...

liver

starch is digested into

maltose

in industrial nations, people tend to eat (more/less) highly refined starches and added sugars?

more

why are most animal foods not sources of glycogen?

muscle glycogen breaks down quickly

what are the major sites for glycogen formation and storage?

muscles and liver

can the body use fatty acids to make glucose?

no

is fiber an essential nutrient?

no

is fiber digested in the small intestine?

no

eating high-fiber diets may reduce a person's risk of...

obesity, type 2 diabetes, certain intestinal tract disorder, and cardiovascular disease

how do plants make carbohydrates?

photosynthesis, using the sun's energy to combine carbon, oxygen, and hydrogen atoms from carbon dioxide and water

only ______ provides dietary fiber

plant foods

starch is found in (plant/animals)

plants

fad

practice that gains widespread popularity rapidly then loses its appeal when people tire of the behavior and follow a newer trend

most common oligosaccharides in food

raffinose and stachyose

eating insoluble fiber can make people have more (regular/abnormal) bowel movements?

regular

fructose

same chemical formula as glucose, but a slightly different structure, often found in fruits

galactose

same chemical formula as glucose, but a slightly different structure, often found in lactose (milk)

what increases someone's risk for developing type 2 diabetes?

sedentary lifestyle, overweight, genetics, certain ethnic groups

in which organ of the GI tract are all disaccharides and complex carbohydrates broken down into monosaccharides?

small intestine

what is the main site for carbohydrate digestion and absorption?

small intestine

where does absorption of monosaccharides occur?

small intestine

benefits of insoluble fiber

soften stool and accelerate passage of contents though the GI tract, decrease transit time

why have nonnutritive sweeteners been a subject of controversy?

some have been found to be harmful

resistant starches

starches found in seeds, legumes, whole grains, and some fruits and vegetables that resist digestion and are not broken down in the human GI tract

nutritive sweeteners

substances that sweeten and contribute energy to foods

alternative sweeteners

substances that sweeten foods while providing few or no kilocalories

what artificial sweetener is considered useful in baking because it resists destruction by heat?

sucralose

examples of a nutritive sweetener

sucrose, fructose, honey, molasses, or high fructose corn syrup

examples of alternative sweeteners

sugar alcohols - sorbitol - xylitol - mannitol

why does sugar alcohol not supply more kcal/g?

sugar alcohols are not fully absorbed by the intestinal tract

nonnutritive sweeteners

sugar substitutes that provide negligible, if any, energy

what is much of the sucrose in the American diet refined from?

sugarcane and sugar beets

what contributes to a plant's fiber content?

supportive structures and protective seed coats

why do humans crave sweet foods?

sweet foods usually contain carbohydrates, which are a major source of energy for cells

lipolysis

the breakdown of fats and other lipids by hydrolysis to release fatty acids

ketone bodies

the by-products of the incomplete breakdown of fat

what is the difference between drinking orange juice and a soda if they both supply similar amounts of sugars?

the orange juice will contain micronutrients and antioxidant phytochemcials to the diet, which the soda will not

hemoglobin

the protein in red blood cells that carries oxygen

why is refined sugar not a good source of carbohydrates?

the refining process strips away the small amounts of vitamins and minerals in unrefined sugar (empty calories)

the FDA permits a grain to be labeled as "whole grain" if it contains...

the starchy endosperm, oily germ, and fiber-rich bran seed components in the same relative proportions as they exist in the intact grain

why is it important that intestinal bacteria can use fiber for energy?

their by-products can sometimes be used by the cells that line the large intestine for energy

does HFCS or sucrose have more fructose?

they have the same amount

how do cells get energy from glucose?

they metabolize glucose to release the energy stored in the chemical bonds

why are added sugars added to foods?

to contribute to flavor, browning and tenderness, and preservation of food

how can the liver use simple sugars?

to make glycogen or fat, can also release glucose into the bloodstream if the body needs energy

what do plants and animals use complex carbohydrates for?

to store energy or make certain structural components

glycemic index

tool to measure the body's insulin response to a carbohydrate-containing food

glycemic load

tool to measure the body's insulin response to a carbohydrate-containing food; similar to the glycemic index, but also factors in a typical serving size of the food

carbohydrates provide food for mouth bacteria that can cause...

tooth decay

T/F: fructose is sweeter than glucose

true

T/F: it is better to count carbohydrates thanes the glycemic index for choosing foods

true

T/F: refined starches often do not satisfy hunger

true

gestational diabetes

type of diabetes that can develop during pregnancy

under what conditions does the body form excessive keystone bodies?

when there is not enough glucose to metabolize for cellular energy

a meal plan for diabetes focuses on moderate intakes of...

whole grains, vegetables, fruits, legumes, poultry, fish, and low-fat dairy foods

do carbohydrates contribute to excess body fat?

- carbohydrate calories are easier to eat in excess than fat or protein - carbohydrate consumption reduces the body's ability to expend energy and burn calories

AI for fiber

38 g/day for men 25 g/day for women

each gram of mono- or disaccharide supplies how many kcal?

4 kcal

each gram of starch supplies how many kcal?

4 kcal

most healthcare professionals recommend an individual with diabetes having meals with how many grams of carbohydrates?

45-60g

what percent of calories in the diet should come from carbohydrates?

45-65%

AMDR for carbohydrates

45-65% of total calories

what percentage of kcal does a typical American get from carbohydrates?

47%

the standard to which the glycemic index compares all foods to is

50 g of digestible carbohydrates

according to the ADA, people with diabetes should try to maintain HbA1c levels below

7%

hypoglycemia may be diagnosed when the blood glucose level is

70 mg/dL

glucose

C6H12O6, most important monosaccharide in the body, often found in fruits and vegetables

T/F: since fiber is not digested, it also cannot be metabolized by gut microbiota

false

metabolic syndrome

a cluster of conditions that increase the risk of heart disease, stroke, and diabetes

high fructose corn syrup (HFCS)

a highly sweet syrup that is manufactured from corn

therapeutic lifestyle changes (TLC)

actions, such as avoiding excess body fat, exercising daily, and improving the diet, that promote health and reduce risk for chronic disease

ketosis

adaptive metabolic state in which the body primarily uses fat for energy

oligosaccharides

carbohydrate made up of 3 to 10 monosaccharide units

diets high in fiber, particularly soluble fiber, reduce the risk of _____ by improving blood lipid levels, lowering blood pressure, and reducing markers of inflammation

cardiovascular disease

how does glucagon work?

causes the liver to convert stored glycogen into glucose, which is released into the bloodstream

what additional role do carbohydrates play in the body (apart from being a source of energy)?

cellular membranes have carbohydrates, so they serve as the "glue" that holds cells together in tissues

examples of dietary fiber

cellulose, pectin, gums, lignins

pancreatic islet

cluster of endocrine cells in the pancreas that secretes hormones to regulate glucose metabolism

dietary fiber

complex carbohydrates that cannot be broken down by the digestive system

A1c

component of hemoglobin that attracts some glucose in the blood

what type of reactions form disaccharides?

condensation

hyperinsulinemia

condition in which the pancreas releases an excessive amount of insulin; over time, condition may contribute to the development of type 2 diabetes

ketoacidosis

condition that occurs in the absence of insulin when excess acetoacetate and betahydroxylbutane in the bloodstream lower the blood's pH

what does salivary amylase do?

converts starch into maltose in the mouth

T/F: sugary foods cause hyperactive behavior

false

potential outcome of consuming alternative sweeteners and why

diarrhea, because sugar alcohol are not fully absorbed by intestinal tract

lactase

enzyme that breaks down lactose molecule into glucose and galactose

maltase

enzyme that splits maltose molecule into two glucose molecules

sucrase

enzyme that splits sucrose molecule into glucose and fructose

primary risk factors of metabolic syndrome

excess abdominal fat and insulin resistance

major signs and symptoms of hyperglycemia

excessive thirst, frequent urination, blurred vision, poor wound healing

T/F: if a nutritive sweetener is the first or second ingredient on the product's ingredient label, the food probably does not contain a lot of added sugars

false

T/F: insulin is secreted more readily when fats and proteins are consumed, rather than carbohydrates

false

any fiber that is not used by microbiota comes out of the body as...

feces

how does gestational diabetes affect the baby?

fetus receives too much glucose from the hyperglycemic mother -- fetus gains weight rapidly and can be abnormally heavy at birth

a gram of fiber supplies how many kcal?

fewer than 3 kcal

soluble fiber

forms of dietary fiber that dissolve or swell in water

insoluble fiber

forms of dietary fiber that generally don't dissolve in water

what do alpha cells produce?

glucagon

galactose and fructose are converted to what in the liver?

glucose

sucrose

glucose + fructose

lactose

glucose + galactose

maltose

glucose + glucose

how are monosaccharides absorbed?

glucose and galactose are absorbed via active transport and fructose passes via facilitated diffusion

three most important dietary monosaccharides

glucose, fructose, galactose

diabetes mellitus

group of serious chronic diseases characterized by abnormal glucose, fat, and protein metabolism

women with poorly controlled diabetes or gestational diabetes are more likely to...

have miscarriages, stillbirths, and premature deliveries