CHAPTER 17- PART 3

Protein in the Body

PROTEIN DIGESTION

Digestion – proteins are denatured by hydrochloric acid in the stomach

Body creates all of its proteins from 20 different amino acids

PROTEIN DIGESTION: PART 1

Figure 6.6

PROTEIN DIGESTION: PART 2

Figure 6.6

PROTEIN DIGESTION: PART 3

Figure 6.6

PROTEIN DIGESTION: PART 4

Figure 6.6

AMINO ACID ABSORPTION Amino acids are absorbed in the small intestine Amino acids are transported to the liver from the

intestines via the portal vein In the liver, amino acids are

Used to synthesize new proteinsConverted to energy, glucose, or fatReleased to the bloodstream and transported to

cells throughout the body Occasionally proteins are absorbed intact

HOW DOES THE BODY USE PROTEIN? Functions of protein

Provide structural and mechanical supportMaintain body tissuesFunctions as enzymes and hormonesHelp maintain acid base balanceTransport nutrientsAssist the immune systemServe as a source of energy when necessary

Structural protein – collagen helps build bones

- ligaments that bind them

- tendons that connect them to the muscles

New growth and repair

They make up enzymes for helping chemical reactions

They make up antibodies in the immune system

Supply energy

MUSCLES, LIGAMENTS, TENDONS, AND BONES

Without these particular structural proteins, we would look more like this….

WELL, MAYBE NOT EXACTLY…

PROTEINS

Proteins are made of long chains (polymers) made of monomers.

All proteins are made of the monomer…

AMINO ACID

Body creates all of its proteins from 22 different amino acids

13 are manufactured 9 are essential amino acids – body

needs them but cannot make them

PROTEIN QUALITY Complete proteins

Contain all nine essential amino acidsUsually animal source are complete proteinsAre considered higher quality

Incomplete proteins Low in one or more essential amino acidUsually plant sources are incomplete

Complete proteins contain amounts of all nine essential amino acids.

SOURCES INCLUDE:*Fish, meat,

poultry, eggs, milk, cheese, yogurt, and many soybean products.

Incomplete proteins

lack one or more essential amino acids.SOURCES INCLUDE:

*Beans, peas, nuts, and whole grains.

Vegetarian Diets-Reasons

HealthReligionEthicalEnvironmentalTasteVegetarians must consume adequate amounts of a variety of food and should plan meals well

TYPES OF VEGETARIAN DIETS

Vegetarian diets can be a healthy eating style that may help reduce the risk of some chronic disease

Some vegetarians abstain from all animal products

Some vegetarians eat eggs and dairy in limited amounts

Vegetarians must plan their diets carefully to meet their nutrient needs, especially Protein Riboflavin Iron Vitamin B12

Zinc Vitamin A Calcium Omega-3 fatty acids Vitamin D

Potential risks of a vegetarian dietUnderconsumption of certain nutrientsProteinVitamin B12

VEGETARIAN VS MEAT EATERS Vegetarian reduced risk

obesitydiabeteshypertensionheart diseasedigestive disorderscancer

Meat eaters growth support during

critical times.

A teen female whose ideal body mass is 55 kg needs about 44 g of protein a day (55kg X 0.8 g/kg = 44 g)

Determine your RDA (0.8 gram/kg) 0.8 gram/kg

0.9 for males under age 18 wt in lb/2.2 lb per kg)x0.8=RDA