Chapter 6 Protein

Dietary guidelines for Protein

Get less of red meat, poultry, or eggs. Better to get more from plant sources (legumes, nuts, etc) or seafood are recommended. Peanut Butter, Legumes Nuts seeds Not recommended food high in fats like sausage or bacon, processed meats, deli meats.

Proteins

Have nitrogen atoms in addition to the carbon, hydrogen, and oxygen and are a string of amino acids linked together. The amine group is attached to the acid group creating a linked chain until a protein is built.

Consequences of excess protein

Heart disease Increase the kidney's work load, may contribute to kidney disease. Diets high in red meats and processed meats associated with cancer risk. Not recommended to consume high protein diets.

Stomach Protein Chemical Digestion

Hydrochloric acid denatures protein in food -uncoils protein's strands: disrupts the 3D shape; -allows enzymes to have easier access - strands of polypeptides and a few free amino acids

DRI's (protein)

0.8 gram per kilogram of body weight No more of 35% of total calories

Gluten-Free diet

treatment for celiac disease (gluten causes the villi to flatten cause less absorption in the intestine); abnormal immune responses. Body attacked by its own immune system, triggered by protein in wheat. Not recommended for people that do not have celiac disease.

Protein Quality

The relative proportions of different amino acids in a protein food. -different amino acids are needed in different proportions in the human body.

Positive Nitrogen Balance

nitrogen intake exceeds excretion

Secondary Structure of Protein

protein structure is formed by folding and twisting of amino acid chain

Primary Structure of Protein

the amino acid sequence of the polypeptide chain

Negative Nitrogen Balance

Condition occurring when the body excretes more nitrogen than it takes in.

Residue

What is remaining of the amino acid after the anime group is removed.

Denaturation of Proteins

When a protein molecules loses its shape, it can no longer function as it was designed to do.

Gluten Free products

-Alternatives used for GF products include starches from buckwheat, corn, rice, and sorghum -Adding egg/milk/soy proteins and hydrocolloids can improve flavor and mouthfeel of GF foods

Small intestine Protein Chemical Digestion

-Pancreas secretes enzymes into small intestines; enzymes on surface and inside the small intestine -Proteins enter as polypeptides (string of amino acids) -Further break down to dipeptides (2 amino acids linked) and tripeptides (3 amino acids linked) -amino acids absorbed into blood; transported to the liver.

Denaturing Agents

- Heat (cooking), alcohol, acids (like stomach acid) - Digestion denatures proteins - Inactive proteins in food

Protein Synthesis

1. A gene (portion of DNA) serves as a template for messenger RNA (mRNA) -a gene contains the instructions for a specific protein: specific amino acids in a specific order 2. mRNA containing instructions for the protein goes to a ribosome: part of the cell responsible for making proteins 3. Transfer RNA (tRNA) molecules bring the correct amino acids in the correct order to a ribosome 4. The ribosome connects these amino acids together

AMDR (proteins)

10-35% of total kcals

Tertiary Structure of Protein

3D Shape; protein structure is formed when the twists and folds of the secondary structure fold again to from a larger 3D structure

Polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

A Legume

Able to fix/capture nitrogen and add it back to the soil Enhance soil fertility, used often in crop rotation with corn.

Extra Protein

All has to get converted into something else; no storage for this macronutrient. -body removes and excretes the amine group (nitrogen part) the rest is considered residue Uses the residue in three ways: -to meet energy needs To make glucose for storage as glycogen -to make fat or energy storage

Transporters (proteins)

Allow certain things into and out of the cells (specifically shaped for certain substance) Hemoglobin (oxygen) Lipoproteins (lipids)

Essential amino acids

Amino acids that are needed, but cannot be made by the body; they must be eatin in foods

High Quality Protein Quality foods

Ample amount of all 9 essential amino acids "complete or high quality protein" Meat, poultry, fish, dairy, eggs, quinoa, oats, and soy

Top contributor of Protein

Beef Poultry Milk Yeast bread Cheese Fish/Shellfish Pork Eggs Pasta Ham Cakes/cookies/quick breads/doughnuts Dried beans/lentils

Peptide Bonds

Bonds between amino acids

The Fate of Amino acid

Build proteins; any type of proteins. Make a needed compund other than proteins such as neurotransmitters, vitamins Converted to fat or Glucose Converting to a non essential amino acid

The Roles of Body Proteins

Building antibodies; part of immune system Maintaining fluid and electrolyte balance; proteins attract water Regulating pH of Body; acid/base balance. Serve as buffers; stabilize pH Providing structure and movement -muscle tissue: about 40% of body's proteins -skinned, bones, teeth, cartilage, etc Neurotransmitters; messenger molecules in the nervous system Blood clotting; prevent excess blood loss Providing energy and glucose; under conditions of inadequate carbohydrates - if we eat more proteins than we need.

Amino acids

Building blocks of proteins; carbon with a amine group (contains nitrogen), acid group, and side chain.

Glucogenic

Can generate glucose

Three different sources of energy

Carbohydrate, fat, protein.

Hormones (proteins)

Chemical messengers that are secreted by body organs Réponds to body conditions Example: insulin and glucagon are hormones that respond to high and low blood glucose

Non-essential Amino acids

Do NOT need to consume them from food Your body can make them out of other amino acids, carbohydrates, and/or fat.

Vegetarians

Do not eat animal-flesh foods (beef, food, poultry, fish, etc) Little concern about inadequate protein or getting enough of essential amino acids IF consuming balanced diet and enough calories

Vegans

Do not eat any animal-sourced foods (animal-flesh foods, eggs, and dairy) Little concern about inadequate protein or inadequate essential amino acids as long as incorporating both grains and legumes in diet IF consuming balanced diet and enough calories.

Protein supplements

Do not improve muscle mass more than eating food that has protein Not effective for weight loss Can be more expensive than getting protein from food

Extra protein make muscles grow strong?

Extra will not make bigger muscles Protein intake cannot replace exercise -exercise triggers the genes to build more muscle tissue proteins. Well-timed protein intakes can often further stimulate muscle group -eating protein after muscle workouts

protein synthesis

Forming proteins based on information in DNA and carried out by RNA

Deficient Amino Acids

Last resort is start using organs for proteins

Low Quality Protein Quality foods

Many foods that are low in at least 1 essential amino acids "incomplete or lower quality proteins" Plant Proteins; also less digestible

Function of Tertiary structure of Protein

May function as is or may need to join with other proteins, or to add a carbohydrate molecule, vitamin or mineral.

Protein Subgroups

Meat Poultry Eggs (not recommended) Seafood (recommended) Nuts, Seeds and Soy products (recommended)

Nitrogen Balance

Nitrogen excreted compared to nitrogen eaten; in healthy adults nitrogen in equals nitrogen out.

Mouth Protein Chemical Digestion

None

Amino acid Supplements

Not effective for weight loss Expensive May cause problems with absorbing other amino acids No better than amino acids from food May cause health risk

Advantages of Legumes

Protein Vitamin and mineral source Fiber

Complementary Proteins

Proteins that together make up a complete proteins Examples: legumes and grains, rice and beans, peanut butter and bread (peanuts are actually a legume, not a nut) Don't have to be eaten at the same time

Positive Health aspects of Vegetarian and Vegan diets

Provides defense against: -Heart and artery disease -high blood pressure -cancer Other health benefits -may help prevent cataracts, diabetes, diverticular disease, gallstones, and osteoporosis Some nutrients it be concerned about not getting

Side chain

Side chain is another name for an R group, also each amino acids have a different side chain. This is a group of atoms attached to the main part of a molecule and having a ring or chain structure.

Consequences of Protein Deficiencies

Slow growth in children Impaired brain and kidney function Weakened immune systems Impaired nutrition absorption

Enzymes (protein)

Speed up chemical reactions Each enzyme helps a particular chemical reaction Responsible for creating new molecules in the body

Deficiant Protein

Starts pulling from muscles and then tissues from organs, maintaining organs is more important than maintaining muscle. Not eating enough calories -starvation -dieting: intentionally decreasing calories -extremely active people; marathoners, other endurance athletes Not eating enough protein -eating enough calories, but low protein Muscle mass will decrease -lifting weights or strength training during weight loss can help preserve muscle.

Amino acids to Glucose

The R group gets cut off and turned into glucose; increases blood glucose when no carbohydrate is available. Amine is not converted. - waste product, incorporated by liver into urea. - or converted to other compounds that need nitrogen

Limiting Amino acid

They amino acid that prevents the protein from being formed; one amino acid cannot be substituted for another. If you dont have enough of an amino acid needed for a protein, you cannot finish making that protein.

Amino Acid absorption

Usually only single amino acids and dipeptides; some larger than dipeptides can be absorbed. -some may act as a hormone and regulate body functions (bio active) -may play a role in food allergies Different amino acids are absorbed at different sites on small intestines Some amino acids compete for the same sites -taking single amino acid supplements may reduce the absorption of other amino acids -generally not advised to take single amino acid supplements

Sickle Cell Anemia

a genetic disorder that causes abnormal hemoglobin, resulting in some red blood cells assuming an abnormal sickle shape

Non-celiac gluten sensitivity

a poorly defined collection of digestive symptoms that improves with elimination of gluten from the diet; test negative for celiac disease

Gluten

a protein found in wheat, rye, oats, and barley

Conditionally essential amino acids

amino acids that are normally considered nonessential but become essential under certain circumstances when the body's need for them exceeds the ability to produce them -errors of metabolism; missing enzymes to convert one amino acid to another -if you do not consume enough of the precursor for a non-essential amino acid -premature infants -burn victims; have a high need for amino acids