NUTRITION

CHPTR 6PROTEINS

What are proteins?

• They are the basic material of every body cell

• Greek meaning “of first importance”

Function of protein

• Builds and repairs tissue

• Protein can provide energy if there aren’t enough carbs and fats

More functions of proteins…

• Protein helps maintain fluid and electrolyte balances in the body preventing edema. Where there is protein, there is water…water dilutes the big protein molecules to separate them. Protein takes up a lot of space in the blood, it needs water to push molecules apart

• Proteins are essential for the development of antibodies which = a healthy immune system

• In order for proteins to build and repair tissue and cells, the correct number of amino acids must be present

How many calories are in 1 gram of protein?

• 4 calories

Sources of protein

• Animal food provides the highest quality they include:

• Meats fish • eggs • Poultry Milk and cheese• (These also contain saturated fats and

cholesterol) people must be careful

Catabolism & Anabolism

• Are important in the cells breaking down during metabolism (catabolism)

• AND

• From that breakdown, some amino acids are released into the blood and are recycled to build new and repair other tissue (anabolism)

Amino acids

• Are the building blocks of proteins and are the end products of protein digestion or hydrolysis

• Proteins themselves are too big to fit through digestion, they must be broken down to fit

Complete protein

• When we talk about amino acids, we talk about complete proteins…

• Complete proteins are proteins that contain all the essential amino acids

Essential amino acids

• Are necessary for normal growth and development and MUST BE PROVDIDED IN THE DIET

• The nonessential amino acids are produced in the body from essential amino acids, vits and minerals

Incomplete proteins

• These proteins don’t have all of the essential amino acids therefore, they cannot do the job of building and repairing

• The value of the incomplete protein becomes increased when you combine other incomplete proteins together (like vegetarians) they must combine foods to get all the amino acids

• Remember that protein-rich foods usually contain lots of saturated fat which is not good for you

• There are 20 amino acids but only 10 are essential to humans

Proteins contain…

• Carbon

• Hydrogen

• Oxygen AND….

• Nitrogen

Digestion

• Food enters the mouth and is chewed up

• Ptylin (amylase) mixes with the food in saliva

• The bolus is swallowed and travels down the esophagus

• It enters the cardiac sphincter and to the stomach

• It gets kneaded and torn

• And mixed with gastric lipase to act on any fat and HCL which prepares the stomach for pepsin which is an enzyme that reduces the proteins to polypeptides (a chain of 10 or more amino acids)

Polypeptide chain – this is still too big to fit as a whole string

• The polypeptides(chain of 10 or more amino acids) and chyme, travel to the duodenum where the final and last breaking down of anything you ate occurs

• The pancreas squirts out 3 enzymes, one is called protease which breaks down this polypeptide/amino acid chain into little pearl-like balls and removes it from its chain

After Digestion…

• The amino acids are now ready to be absorbed and travel to the jejunum and ileum to be pushed out of the intestinal wall, into the villi and out to capillaries

• At this point…

• What’s being pushed out of the intestines are amino acids from the original protein you ate

• The amino acids continues on into the bloodstream and travels to the cells to be used and metabolization occurs = energy, heat water and CO2.

• It is at this point that something new happens to the amino acid after the cell uses it…it turns to ammonia….yuck

To the liver

• The cell spits out the ammonia molecule and sends it back to the bloodstream.

• The liver picks up the ammonia molecule and strips, filters, deaminates the ammonia molecule in order to make it small enough to be excreted out of the kidney.

• Now it turns into a small uric acid or urea molecule

UREA

• UREA is a nitrogenous waste which mean it’s going to be part of the urine and this is normally found in urine

Urea

• Urea contains nitrogen…

• Urea is the chief nitrogenous waste product of protein metabolism and must get excreted out of the kidney

• The urea then leaves the liver and travels through the bloodstream that’s also filled with nutrients such as glucose, fatty acids (fat), and electrolyte salts

• This nutrient filled blood goes into the heart and out to the rest of the body including the kidneys where the urea is excreted out in urine from the kidneys

What makes urine yellow?

• The ammonia that was converted to urea which is a nitrogenous waste

• Your bloodstream carries the nutrients, amino acids and electrolytes out to the cells and all of the body organs. Your kidneys know that urea is present and the kidneys don’t like urea so they rid the body of the urea

• ***The amino acids can repair and rebuild as needed in the cells*** NCLEX

Broken Liver

Ammonia Can’t Be Broken Down

• When the amino acids can’t be broken down d/t liver failure, huge ammonia molecules float around the blood stream

• These ammonia molecules can’t go out of the kidney cause their too big

• They end up floating around the blood stream and go to the brain…

• Oh no

Encephalopathy

• The medication: Lactulose P.O. is used

• This med is usually a laxative but the ammonia molecules will bind to it and leave the body in the stool

Encephalopathy

• Encephalopathy (in-sef-a-lop-ithy) is mental confusion caused by the failure of the liver to remove ammonia and other toxins from the blood.

• Signs & Symptoms (S&S)

Encephalopathy symptoms

• Impaired consciousness• Sluggish or impaired speech• Drowsiness• Confusion• Coma• Mousy odor to breath• Pt can’t explain the meaning of simple sayings• Attempts to draw simple figures is impossible

Other treatments

• Exchange transfusions of (blood) may occur

Dietary Requirements

• Protein requirement is determined by • Age• sex• Size

• Recommendation is 15-20% of ones daily caloric intake

•

Protein supplements

• Are not good, our body is designed to take in protein by EATING it not supplementing it

Protein Deficiency

• If you don’t eat enough protein, muscle wasting occurs over a long time

• This is known as Marasmus

• ALSO CALLED PROTEIN ENERGY MALNUTRITION (PEM)

• And…

• Now you have water in your vessels and the water has no where to go (remember, water follows protein in the body because protein molecules are bigger than water molecules and water tries to spread the protein molecules apart)

• If there’s no protein to spread apart, water shifts from the vessels to find protein

• Then shifts out into other spaces (third spacing) which usually goes out into the abdominal cells and edema occurs in abdomen = Kwashiorkor

Vegetarians

• Must calculate protein intake regularly as to not become protein deficient

• Vegans must eat several incomplete proteins in order to get enough in

2 Deficiency Diseases from lack of protein

• 1) Marasmus – severe muscle wasting caused by lack of protein and all nutrients, happens over a long period of time

• 2) Kwashiorkor – deficiency disease caused by lack of protein, and fat deposits in the liver

• spindle-like arms and legs with bloated belly d/t fluid shift because there are no proteins. Skin lesions and changes in pigmentation are seen

Besides the protein deficiencies…

• Other symptoms of no protein include:

• Decreased appetite

• Decreased strength and healing

• Lethargy

• depression

Who needs the most protein?

• Children

• Pregnant moms

• Breast-feeding moms

• Elderly

• Burn pts

• Surgical pts

Protein Excess

• This is bad, kidneys and liver don’t like it

• Foods that have complete proteins usually contain saturated fat and cholesterol

• This leads to heart disease

• People who eat excessive amts of protein-rich foods, ignore the essential fruits and veggies

• Excess protein means more filtration through the liver and kidneys to filter out the urea = liver and kidney damage over time

People with liver damage…

• Cannot filter the ammonia and amino acids

• Therefore, the urea travels around the circulation and ends up traveling into the bloodstream and eventually to the brain

• Increased ammonia to the brain = encephalopathy of the brain and possible death

• Pts become very disoriented

Vegetarian diet

• Usually these people don’t eat enough proteins to get the complete protein requirement

• Therefore…

• They must eat various incomplete proteins in order to complete the requirement of a complete protein

The End