Lecture 4 - Fundamentals of Nutrition

How many Kcals of energy do carbohydrates have?

4 kcals/g

Define carbohydrates that underwent processing

Refined

Define carbohydrates that remain in its natural state

Unrefined

What are empty calories?

Food or beverages that provide minimal vitamins and minerals (low nutrient density)

What % of calories does the 2020-2025 Dietary Guidelines for Americans recommend should come from added sugars?

Less than 10%

How many grams are in 1 teaspoon?

4 grams

What daily % value is consider high?

Any value >20%

How many parts of grain kernel do whole grain food have present?

Three

What are the parts of the grain kernel in whole grain foods called?

• Endosperm

• Bran

• Germ

Endosperm

• Largest portion of a grain kernel

• Contains starch & protein

• Some vitamins and minerals

Bran

• Outermost layer

• Concentrated source of dietary fiber, vitamins, and minerals

Germ

• Kernal base

• Embryo where sprouting takes place

• Source of vegetable oils and vitamin E

Define “Enriched”

Adding nutrients to a product after it was lost during processing

Simple carbohydrates

• Monosaccharides

• Disaccharides

Complex carbohydrates

• Glycogen

• Starch & fiber

• Oligosaccharides

Simple Carbohydrates: Monosaccharides

• Glucose (provides energy for the body)

• Galactose (component of actose)

• Fructose (fruit sugar/taste sweeter compared to glucose)

Simple carbohydrates: Disaccharides

• Maltose (Glucose + Glucose)

• Sucrose (table sugar; Glucose + Fructose)

• Lactose (milk sugar; Glucose + Galactose)

Complex Carbohydrates

• Oligosaccharides (3-10 monosaccharides), not digested by enzymes in the digestive tract.

• Nutrient source for bacteria in the gut
  

What are starches?

The storage form of carbohydrates in plants

Amylopectin

• Highly branched

• Readily broken down by enzymes

What is the storage form of carbohydrate in animals comprised of highly branched chains of glucose molecules

Glycogen

Where is glycogen stored?

The muscle and liver

Impact of carb loading

• Increases endurance

• Delays fatigue

• Enhances recovery

Where is Dietary fiber found?

Intact in plants

Functional fiber

Beneficial physiological effects

Examples of soluble fiber

• Pectins

• Gums

• Some hemicelluoses

Characteristics of soluble fiber

• Dissolve in water or absorb water to form viscous solutions

• Broken down by the intestinal microflora

• May lower blood cholesterol

Examples of insoluble fiber

• Cellulose

• Some hemicellulose

• Lignin

Insoluble fiber characteristics

• Opposite of soluble fiber

• Cell wall in plants

• Wheat and Rye bran

Application of Pectin in food

Thickening agent

Application of Xanthan & Locust Bean Gum in food

• Prevents solutions from separating (Gravies, pudding, reduced-far salad dressing)

Application of wheat bran in food

Reduce caloric content of foods

What breaks apart starch into smaller carbohydrates?

Pancreatic Amylase

Step 1 of carb breakdown in small intestine:

Pancreatic amylase breaks apart starch into smaller carbohydrates

Step 2 of Carbo breakdown in small intestine

Enzyme action to break apart double sugars and short glucose chains

Step 3 of carb breakdown in the small intestine

End products of carbohydrate digestion are simple sugars

They travel through the blood vessel to enter the body

• Starch is broken down into shorter polysaccharides

• No starch digestion occurs

• Breaks down starch to disaccharides and oligosaccharides

• Disaccharides and oligosaccharides are broken down into monosaccharides by enzymes

• Remaining is excreted in the feces

Steps of carbohydrate digestion

Galactose and Glucose

Lactase

Lactose intolerance

• Affects between 30-50 million adults

• Undigested lactose —> Large intestine

• Lactase is available in minimal amounts

What do foods with added calcium help?

They help meet dietary needs for lactose intolerance individuals

Indigestible carbohydrates

• Fiber

• Oligosaccharides

• Resistant Starch

Health benefits of indigestible carbohydrates

• Increase the amount of water or bulk in intestine

• Stimulate GI motility

• Promotes growth of healthy microflora

• Slows nutrient absorption

Dilutes the gastrointestinal tract contents resulting in delayed digestion and absorption

Fiber

Storage form of carbohydrates in animals and humans

Glycogen

Glycogen is broken down to generate…

Glucose

Advantage of more branching in glycogen

More areas for enzymes to bind to

Glucose, fructose, and galactose travel to the liver through…

Hepatic portal vein

Galactose and fructose are metabolized for…

energy

Glucose is stored as…

glycogen

Glycemic response

rate, magnitude, and duration of the rise in blood glucose that occurs after a particular food or meal is consumed

High glycemic index food

> 70

Low Glycemic index food

< 55

Index of glycemic response that occurs after consuming certain foods

Glycemic Load

Glycemic Load

Glycemic index x grams carbohydrate per serving

High Glycemic load score

20 or more

Low Glycemic load score

11 or less

Facilitates the uptake and storage of glucose into the muscle, liver, and fat-storing cells

Insulin

Released in response to low blood glucose levels

Glucagon

C₆H₁₂O₆ + 6O₂ —> 6CO₂ + 6H₂O + ATP

Cellular respiration

The breakdown of glucose in half into two pyruvate molecules

Glycolysis (step 1 of cellular respiration)

Low potential energy

Carbon dioxide

High potential energy

A carbohydrate

The only place that anerobic metabolism takes place

Cytoplasm

occurs in the Mitochondria of the cell

Acetyl CoA formation (second step of cellular respiration)

How many CO2 are produced at the end of the citric acid cycle

4 CO2

How many Electrons are produced at the end of the citric acid cycle

2 ATP

The last stage of cellular respiration

The electron transport chain

Aerobic metabolism

Occurs in the mitochondria

End of electron transport chain ATP

~30 glucose

• Muscle contraction during running

• Repair body tissues

Adenosine triphosphate

Every 1 glucose produces how many ATP?

30

ATP contains how many phosphate groups?

3

Forms when a phosphate group and its high energy bond is released during muscle contractions

ADP & AMP

Confusion, Seizures, and ultimately coma

low levels of glucose

Glycogen is broken down into…

Glucose

Production of new glucose from

Amino acids

Bodys protein is broken down to form

Glucose

Glucogenic amino acids can be used to make glucose when…

Carbohydrate is limited

Where does Gluconeogenesis occur?

In the liver or kidney cells

The body lacks carbohydrate to make oxaloacetate in the citric acid cycle

Ketone body formation

Autoimmune: Immune system destroys the cells that make insulin

Type I diabetes

Insulin resistance (cells do not respond to insulin) —> limited glucose enters cells

Type II diabetes

Pregnancy, hormonal changes

Gestational diabetes

Diabetes: Fasting blood glucose

> 126 mg/ml

Prediabetes: Fasting blood glucose

100-125 mg/100 ml

Normal: fasting blood glucose

< 100 mg/100ml

Exercising

> 30 minutes per day beneficial for the action of insulin

Occurs when diabetics over medicate, imbalance between insulin level and carbohydrate intake

Hypoglycemia

• Occurs in response to high carbohydrate foods

• Rise in blood glucose stimulates overproduction and release of insulin

• Glucose drops rapidly to abnormally low levels

Reactive Hypoglycemia

• Abnormal insulin secretion not related to food intake

• Related to hormonal deficiencies, tumors, and excess alcohol intake

Fasting Hypoglycemia

Produces acids readily

Sucrose

• Pouches develop on the wall of the intestines due to excessive pressure

• Accumulation of fecal matter in the pouches

Diverticulosis

Inflammation occurring in the pouches of the small intestine

Diverticulitis

Diets high in sugar may raise blood lipid levels and…

Increase heart disease risk

Diets high in whole grains have been found to…

reduce risk of heart disease

FODMAPS

Group of carbohydrates that may cause gastrointestinal symptoms such as gas, bloating, and diarrhea

• Lactose

• Oligosaccharides

• Polyols (sugar alcohols)

• Fructose

FODMAPs

Bloating and gas caused by FODMAPs because…

They reach the large intestine undigested and draw in more water which is utilized by the bacteria that reside in the large intestine

Minimum amount required to provide adequate glucose for the brain

RDA: 130 grams/day for adults & children

No more than 25% of energy should come from added reined sugars

AMDR: 45-65