Nutrition Exam 3 - Dr. Greene, Auburn University

What makes proteins different from carbohydrates and lipids?

All have carbon, hydrogen and oxygen, but only protein has nitrogen from the amino acids.

What do proteins do?

They regulate and maintain body function

Provide an essential form of nitrogen in the form of amino acids

How much of the body do proteins take up?

17% roughly

What are the building blocks of proteins?

Amino acids

What are amino acids composed of?

Central carbon, acid group, side chain/R group, and hydrogen

How many amino acids are in the different types of peptide bonds?

2 - Dipeptide, 3 - Tripeptide, many - Polypeptide

what is the sequence of amino acids called?

Protein Primary Structure

What does protein primary structure lead to?

protein higher order structure

How can you denature a protein?

Heat, strong acids and bases, and heavy metals. It causes the protein to unfold and it can't work properly.

What is the protein primary structure determined by?

DNA (kept in the cell's nucleus)

How are proteins made?

DNA gets transcribed to mRNA. mRNA leaves the nucleus and goes to the ribosomes and there the protein gets translated into tRNA

Describe protein synthesis (the formation of proteins)

DNA contains code structures, the copies of those codes are transferred to the cytoplasm via mRNA. The amino acids are taken in one at a time and coded with the aid of transfer RNA

What is the central dogma of Biology?

DNA

How can you change protein structures?

Genetic alterations can change the primary structure, it can be no big deal (silent mutation), but in other cases it can lead to genetic diseases like sickle cell anemia which is a single base substitution that changes the amino acid in the polypeptide of the hemoglobin protein

What is the process of the digestion of proteins?

Digestion of proteins begins in the STOMACH. The HCl denatures protein, pepsin (an enzyme) is released by cells in the stomach to break the peptide bond. Gastrin released in response to thinking about food, and it controls pepsin (breaks peptide bond of proteins resulting in protein fragments) and stomach acid release. Moves to small intestines: release of CCK which chyme stimulates. CCK causes pancreas to release proteolytic enzymes

Describe amino acid absorption

They are taken up by capillaries and used as building blocks for liver proteins, broken down for energy, released into blood, and converted to nonessential amino acids, glucose, or fat.

Amino acids are taken up by capillaries and transported to which organ?

Liver

How do proteins contribute to the immune function?

Antibodies are proteins, proteins are involved in all processes in the immune system

What is gluten sensitivity?

When there is an incomplete gluten breakdown in small intestine, leaving small peptides and amino acids that causes an inflammatory response.

What is different about protein absorption in infants?

Antibodies, mother passes on immunity to their child

True or False? Proteins are the most efficient source of food.

False. Glucose is the first, then fat.

How does the body get rid of nitrogen waste?

Urea

What are some issues with a high and low protein diet?

High: consuming a lot of fat with protein

Low: can cause muscle breakdown

What are functions of protein?

Producing vital body structures, maintaining fluid balance, contributing to acid-base balance, forming hormones and enzymes, transport and signaling receptors, and contributing to the immune function

What happens in protein inadequacy?

Decrease in immune function

What is a Vitamin?

A vitamin is an organic substance needed in only small amounts for the proper functioning of our body. They are essential to maintaining life.

In what food is protein found?

Meats. However for vegetarians and vegans, protein can be found in grains, beans, legumes, nuts, and seeds

Methionine is limiting in which foods? Lysine is limiting in what foods?

Methionine - Vegetables and legumes. Lysine - Grains and nuts

What are differences between animal proteins and plant proteins?

Animal proteins tend to be complete proteins (high-quality) - containing all the essential amino acids in abundance

Plant proteins tend to be incomplete proteins (low quality) - low in one or more essential amino acid

Why is protein not a primary energy source?

It wastes calories to metabolize amino acids for energy

What is the criteria to be classified as a vitamin?

The body is unable to synthesize enough of the compound to maintain health.

Absence of the compound from the diet for a defined period produces deficiency symptoms

Can be reversed when the compound is resupplied

A compound does not classify as a vitamin merely because the body cannot make it

What is a megadose?

Consuming beyond estimates of needs of not in a balanced diet

What are the fat soluble vitamins?

A, D, E, and K. they are absorbed in chylomicrons, stored in liver and fatty tissue, and not readily excreted.

What are the water soluble vitamins?

B and C. They are absorbed in the capillaries, in general are not stored to a great degree, and excess is excreted in urine.

Describe Vitamin A

Almost all is stored in the liver, too little or too much can cause severe problems.

There are three active forms of Vitamin A (Retinal, Retinol, and Retinoic Acid (they only exist in animal products. A=animal))

What are Carotenoids?

Carotenoids are contained in plant pigments that have phytochemicals called polyphenols. They are a provitamin form of Vitamin A. Some are precursors for Vitamin A/can be turned into Vitamin A

Beta-Carotene: carotenoid that can be sufficiently absorbed and converted into RETINOL

What are functions of Vitamin A?

They deal with health of epithelial cells and immune function. Help with cells that line the inside and outside of the lungs, intestines, stomach, vagina, urinary tract, bladder, eyes, and skin.

Eyesight: Vitamin A helps with vision. (Memory tip: Carotenoids - carrots. Carrots help you see.)

Possible cancer prevention

What foods contain good amounts of Vitamin A?

Fish, liver, butter, eggs, yogurt

What foods contain good amounts of Carotenoids?

Dark green and yellow-orange veggies

Describe Vitamin D

Fat soluble vitamin. Not just a vitamin but is also a hormone. The body can make vitamin D when exposed to UVB light.

What are functions of Vitamin D?

Requires skin, liver, and kidney to be functional.

Helps regulate blood calcium levels and bone metabolism (works with parathyroid hormone)

Helps regulate calcium and phosphorus absorption from intestine

Regulates the deposition of calcium in bone

Regulates calcium excretion from kidney

Helps in the development and can decrease risk of cancer in skin, colon, prostate, ovaries, and breasts.

What happens as a result of Vitamin D deficiency?

In children cause rickets, In adults causes osteomalacia

What happens with too much Vitamin D?

Too much can cause calcium deposits in soft tissues.. You can't develop vitamin D toxicity because of too much sunlight.

What foods contain good amounts of Vitamin D?

Fatty fish, fortified milk and yogurt, some breakfast cereals

Describe Vitamin E

Fat soluble vitamin. A family of compounds called Tocopherols

Alpha Tocopherol - Main form in the body

Gamma Tocopherol - foods

Acts as a fat soluble antioxidant

Resides mostly in cell membranes

What is the relationship between Vitamin E and antioxidants?

Oxidizing agents are seeking electrons

Example: the double bonds of unsaturated fatty acids in phospholipids

Oxidizing agents can create free radicals

As an antioxidant, vitamin E has electrons it can give up to the oxidizing agent

Result: protects components of the cell (phospholipids)

What does a deficiency of Vitamin E result in?

Can cause cell membrane to break down

This is particularly true in RBC, breaking of RBC is called hemolysis

This leads to hemolytic Anemia

Premature infants are particularly at risk

What does too much Vitamin E result in?

High doses interfere with clotting mechanism in body, leading to a hemorrhage (Think Grey's Anatomy: "He's Hemorrhaging! We have to evacuate that clot or he's gonna die!")

Thus, people at risk are individuals taking anticoagulants, high doses of aspirin or are deficient in Vitamin K

What foods contain good amounts of Vitamin E?

Plant oils (salad dressings, mayonnaise), ready-to-eat cereals, dry roasted sunflower seeds and almonds, some fruits and vegetables

Describe Vitamin K

Vitamin K is vital for blood clotting

The "K" of Vitamin K comes from the Danish spelling of coagulation

Vitamin K also activates proteins present in bone, muscle, and kidneys to give calcium binding ability to these organs

What does a deficiency of Vitamin K result in?

Poor Vitamin K intake is associated with hip fractures in women.

What does too much Vitamin K result in?

Nothing really. There is no risk of toxicity, so no Upper Limit has been set. However, megadoses may reduce the effectiveness of anticoagulation medications.

Describe Vitamin C

Water Soluble Vitamin. Compounds with antiscorbutic activity. Dietary form is ascorbic acid. Similar in structure to glucose. Essential for humans and some other species

What are functions of Vitamin C?

Formulation of Collagen: Strengthens structural tissues by increasing cross-connections between amino acids

Formulation of Other Compounds: Synthesis of carnitine; formation serotonin and norepinephrine, Antioxidant - Can readily accept and donate electrons

What does a deficiency in Vitamin C result in?

Can cause scurvy.

What does too much Vitamin C result in?

Nothing. Any excess is excreted through urine.

What foods contain a good amount of Vitamin C?

Citrus fruit, green peppers, Brussel sprouts, strawberries, tomatoes, fortified drinks

When is Vitamin C unstable?

Vitamin C is rapidly lost by processing and cooking food.

It is unstable in the presence of heat, iron, copper, or oxygen

This is why nutritionists say it is better to eat raw veggies than cooked veggies, because raw veggies have more nutrients.

Describe Vitamin B

Mostly coenzymes

Occur in many of the same foods as Vitamin C, so a lack of one B vitamin may mean others are also low in the diet

Functions as a precursor to Enzymes

B Vitamin deficiency symptoms typically occur in the brain, nervous system, skin, and GI tract (B=Brain!)

Several B vitamins are in while grains, but are removed during the milling process

-To counter these losses, flour in the US is enriched with four B vitamins (thiamin, riboflavin, niacin, and folate)

Describe Vitamin B6

Pyridoxine, Need for the activity of many enzymes (Carbohydrate, fat, and protein metabolism)

Particularly important in amino acid metabolism

Necessary for the synthesis of neurotransmitters

Important in the synthesis of hemoglobin

Important in the synthesis of white blood cells

Necessary for conversion of tryptophan to niacin

Describe Vitamin B12

Must bind to intrinsic factor, made by the stomach, in order to be absorbed.

Defective B12 absorption is common in older people

Animal products - meat, milk, poultry, seafood, eggs, ready-to-eat cereals

Is required to convert folate into its active form

Maintain the myelin sheaths that insulates neurons

What does a deficiency of Vitamin B12 result in?

Pernicious Anemia - Pernicious means "leading to death"

Symptoms - weakness, sore tongue, apathy, tingling in the extremities

Infants of vegans are at risk

Describe Folate

The term folate encompasses a variety of forms of the vitamin

Folic acid is the synthetic form

Functions: Single carbon supplier or donor, Coenzyme helps, Form DNA, Metabolize various amino acids and their derivatives

What does a deficiency in Folate result in?

Bone marrow produces immature red blood cells (megaloblasts) - Megaloblastic Anemia

10% of population has genetic defect in the metabolism of folate and as a result must consume 2x the RDA

What foods contain good amounts of folate?

Green leafy vegetables, organ meats, sprouts, other vegetables, dried beans, and orange juice

What is Thiamin (B1)?

Helps release energy from carbohydrates and certain amino acids

What are Riboflavin (B2) and Niacin (B3)?

Both aid in metabolism and are coenzymes

Riboflavin - Flavin adenine Dinucleotide (FAD)

Niacin - Nicotinamide adenine dinucleotide (NAD)

What is Pantothenic Acid?

Coenzyme A, aids in energy metabolism

Whats so important about water?

Basically everything needs water to survive. Losing water results in certain levels of dehydration that can result in death.

What is Intracellular Fluid?

water inside of cell

What is Extracellular Fluid?

water outside of cell

What is Diffusion?

Water moving from a high to low concentration

What do Ions do?

Ions control the movement of water between the intracellular and extracellular compartments

Ions are minerals with an electrical charge. They are also called electrolytes

What is osmosis?

The movement of water across a semipermeable membrane

What are the two types of minerals?

Major Minerals - > 100 mg/day

Trace Minerals -

What is the bioavailability of minerals?

How much we take in

- how much is in the food and our ability to absorb it

Describe minerals from plants

Depends on the soil its grown in

May be bound by dietary fibers and other molecules

Describe minerals in animals

Are not dependent on soil conditions

Absorbed better than plant source because fewer binders and dietary fibers

What are some examples of mineral binders?

Oxalates (spinach) - binds calcium

Phytates (grains) - binds calcium, iron, zinc, and others

What are examples of Mineral-Mineral Interactions?

Calcium-Iron: Zinc-Copper

What are examples of Vitamin-Mineral interactions?

Vitamin C - Improves iron absorption

Vitamin D - improves calcium absorption

What is mineral toxicity?

Minerals can be toxic in high levels, especially trace mineral

Not a problem when food is the source, but can be from mineral supplements

What are the major minerals?

Calcium, Phosphorus, Potassium, Sulfur, Sodium, Chloride, and Magnesium

Describe Calcium

Most abundant mineral in the body

99% of body calcium is in bone

Adults absorb 25% of the calcium in foods eaten

Increase in infants during pregnancy (up to 60%)

What foods contain good amounts of calcium?

Dairy products (Milk, cheese, yogurt), Breads/Rolls, Leafy vegetables (kale, collards, turnips, mustard greens)

Describe Sodium?

We absorb 100% of sodium consumed

30%-40% found in bone

The major positive ion found in extracellular fluid

Functions - fluid balance between compartments, nerve impulse conduction, absorption of glucose

What does sodium sensitivity entail?

For most people, the body will adjust to higher sodium intake by increasing urine output

10%-15% of adults are sodium sensitive

High sodium leads to increased blood pressure

Describe Chloride

An ion of Chlorine

Major negative ion for extracellular fluid

Used in producing stomach acid (HCl) and during immune response of white blood cells

Describe Potassium

Major positive ion in intracellular fluid compartment, 95% of body's potassium

Like sodium, potassium is important in fluid balance and nerve impulse transmission

Unlike sodium, increasing potassium intake is associated with lower blood pressure

Increased risk of deficiency - people on diuretics to treated high blood pressure, alcoholics, certain eating disorders

What foods contain good amounts of potassium?

Unprocessed foods are a good source of potassium

Rich source - Potatoes, plums, avocados, bananas, cantaloupe, melon, raisins. Leafy greens

What are the trace minerals?

Iron, Zinc, Selenium, Iodine, Copper, Chromium, Fluoride. ALL are toxic in excess.

Describe Iron

Present in every cell of the body

Absorb about 18% of iron that is present in food

Most iron associated with hemoglobin (RBC) and myoglobin (muscle) - heme iron

Other types are called non-heme iron.

When RBS die, iron is recycled. So we lose very little, except during bleeding

Which is more readily absorbed: Heme Iron or Non-Heme Iron?

Heme Iron is more readily absorbed than Non Heme Iron.

What does a deficiency in Iron result in?

Anemia - decreased oxygen-carrying capacity of the blood. Lower number of RBC and less oxygen to cells.

What does too much Iron result in?

Hemochromatosis - Genetic disease associated with increase in iron absorption. Iron builds up in liver and blood. If not treated, will lead to organ damage, especially liver and heart

Describe Zinc

About 40% of dietary zinc is absorbed

Zinc is a cofactor for up to 200 different enzymes

Functions: Growth, wound healing, Sexual maturity, Taste perception, Immune system, indirect antioxidant

What does a deficiency in Zinc result in?

First recognized in the 1960s from the middle east

Diet low in animal protein, exclusive use of unleavened bread (no yeast)

Symptoms: Acne-like rash, diarrhea, lack of appetite, Delayed wound healing, impaired immunity, Reduced sense of taste and smell, hair loss

What does too much Zinc result in?

It interferes with copper metabolism

What foods contain good amounts of Zinc?

High protein diets that are rich in animal sources

Describe Selenium

Indirect antioxidant, works with vitamin E to help protect cell membranes from oxidizing agents

Binds to enzymes - protects against oxidation

May have anticancer properties