NUTR 202--Chapter 9: Vitamins

When we make Vitamin D, where does it become activated?

After synthesizing vitamin D, it becomes activated in the kidneys.

Vitamin C

Also known as ascorbic acid. Considered an antioxidant. Since it's water-soluble, it protects parts of cells in the watery parts.

Vitamin D

Also known as cholecalciferol. It's also classified as a hormone and a steroid. Its precursor is cholesterol.

What population is at greatest risk for vitamin E deficiency?

Although vitamin E deficiency is rare, it is most likely to occur in premature infants.

Pyridoxine deficiency

Anemia, depression, dermatitis, convulsions, weakened immune response

Food sources of B12

Animal based foods: milk, cheese, meat (organ meats), poultry, and seafood --fortified ready-to-eat cereals, supplements

B Vitamins

B Vitamins function in energy metabolism as coenzymes, or cofactors. Coenzymes combine with an enzyme to increase its activity. As coenzymes and cofactors, the B vitamins help release energy from foods although they don't provide energy directly.

Thiamin

B1 --Part of the coenzyme thiamin pyrophosphate (TPP). This plays a role in releasing energy stores in carbs and some amino acids. --Also assists in function of nerve and muscle cell activity

Riboflavin

B2 --Riboflavin is a part of the coenzymes Flavin mononucleotide (FMN) as well as Flavin adenine dinucleotide (FAD). --Like thiamin, riboflavin is involved in the releasing of energy from foods. FAD is an "electron shuttle"

Niacin

B3 Niacin is found in two chemical forms: --Nicotinamide --Nicotinic acid Used to release energy from macronutrients, every metabolic pathway in the body uses one of the two niacin-containing coenzymes --Nicotinamide adenine dinucleotide (NAD) --Nicotinamide adenine dinucleotide phosphate (NADP) --Also used in the synthesis of fatty acids

Pyridoxine

B6 B6 actually has seven forms but pyridoxine is the most active. --Most important function is the conversion of one type of amino acid into another, known as transamination. --Also involved in the synthesis of glucose and some types of liquids. --Production of the neurotransmitter serotonin from tryptophan --Hemoglobin synthesis

Nonfood sources of Vitamin K include...

Bacteria in the large intestine which is the most significant source for humans

Why are water-soluble vitamins less toxic than fat-soluble vitamins?

Because water-soluble vitamins are rapidly excreted with the urine

Food sources of pyridoxine

Beef liver, meats, poultry, salmon, baked potatoes.

Thiamin deficiency

Beriberi is a disease caused by thiamin deficiency

Define beriberi

Beriberi occurs when the heart becomes enlarged, fluid accumulates under the skin, and the muscles weaken and atrophy.

Function of folate

Cell division, DNA requires folate during cell division. Also it is crucial in the maintenance of numerous tissues in the body like hair, skin, linings of digestive and urinary tract, etc.

Wernicke-Korsakoff syndrome

Characterized by severe thiamin deficiency in alcoholics. Symptoms include disorientation, loss of short-term memory, jerky eye movement.

Naturally concentrated food sources of Vitamin D include...

Cod liver oil, salmon, sardines, shrimp

How do we make our own Vitamin D?

Diet/liver cholesterol in the skin combines with UV rays to form the precursor form of vitamin D. Then, a vitamin D binding protein comes in and it all heads to the blood, then it's sent to the liver to form the non-active form of vitamin D. Then this is sent to the kidneys to be converted into the active form of vitamin D. Now it enhances calcium absorption in small intestine.

Factors that influence vitamin D synthesis include...

Distance from the equator, amount of clothing coverage on the body, sunscreen usage, cloud cover or smog, skin color, and age.

What are free radicals?

Free radicals are unstable compounded with an unpaired electron. They attack other molecules which initiates a chain reaction. They damage cell membranes, proteins, enzymes, and DNA. Vitamin E donates an electron to neutralize free radicals (stability).

Food sources of Vitamin K include...

Green vegetables such as spinach, kale, and cruciferous vegetables. Green fruits including avocado and kiwi. As well as some vegetable oils.

How does cooking affect the level of vitamin C in foods?

Heat and exposure to air can destroy and diminish these foods

Niacin toxicity

"Niacin flush", redness in the face, arms, and chest due to dilation of capillaries. Happens when niacin consumption is 3 to 4 times the RDA. Also liver injury can occur.

Vitamin D Toxicity

Toxicity is not common, but can occur from overuse of supplements Symptoms include nausea, vomiting, and diarrhea.

Fat Soluble Vitamins

Vitamin A (beta-carotene precursor) Vitamin D Vitamin K Vitamin E

Vitamin A Toxicity

Vitamin A can be toxic because it is stored in the liver and fat tissue. Therefore, a lot can accumulate since it's stored for a long time.

Bone metabolism

Vitamin A stimulates the bone cells that break down the inner part of the bone -Deficiency can lead to poor growth in children

What are three dietary sources of Vitamin C?

Kiwis, strawberries, orange juice

Vitamin A Toxicity Symptoms

Liver damage, birth defects in babies. Pregnant women are advised to consume beta-carotene for vitamin A

Food sources of Niacin

Milk, eggs, meat, poultry, fish, whole grain and enriched breads and cereals. Can be synthesized from tryptophan in the body.

Food sources of riboflavin

Milk, enriched breads, cereals, and pasta

Fortified foods rich in Vitamin D include...

Milk, margarine, cereals, and juices.

What population is at greatest risk for Vitamin K deficiency and why?

Newborns are at a greater risk for Vitamin K deficiency due to several factor. For one, breast milk is a poor source of Vitamin K, it doesn't contain adequate amounts for the child. Second, the GI tract of infants is relatively sterile when they are first born. This is an issue because Vitamin K is synthesized by bacteria in the large intestine. Since they don't have the bacteria yet to make vitamin K, their risk for deficiency increases. Vitamin K deficiency is rare in adults, but can happen when antibiotics are taken because it kills bacteria

Early stages of vitamin A deficiency for normal vision

Night blindness Reversible

Pyridoxine toxicity

Numb feet, loss of sensation in hands, depression, headaches, fatigue, etc.

Vitamin A

Occurs in nature in 3 different chemical forms: -Retinol (most active form, stored in liver) -Retinal -Retinoic acid Specific cells covert retinol to one of the other two forms Measured in Retinol Activity Equivalents (RAE)

What are potential reasons for increased vitamin D needs in older adults?

Older adults might need an increase in vitamin D because of their decreased ability to convert vitamin D into its active form, as well as the fact that they might not get as much sunlight.

Vitamins

Only required in milligram and microgram amounts. Involved in biochemical reactions. Not a fuel source, they don't provide energy. Organic (carbon), some contain nitrogen.

Food sources of folate

Orange juice, green, leafy vegetables, legumes.

Niacin deficiency

Pellagra, the "four Ds": dementia, death, diarrhea, dermatitis

What population(s) is/are at risk of developing vitamin D deficiency?

People at risk for vitamin D deficiency are children to do not get enough sunlight, increased use of sunscreen, etc. which leads to developing Rickets. Adults, especially older women, are at risk of vitamin D deficiency.

Food sources of thiamin

Pork, whole grains, fortified breakfast cereals, enriched grains, peanuts

Why is this population at risk?

Premature infants are at risk because they have not had sufficient time to build up vitamin E stores, which normally begin in the last weeks of pregnancy. This can also lead to anemia for them, because RBCs rupture with vitamin E deficiency.

Wet beriberi

Primarily affects the cardiovascular system

Dry beriberi

Primarily affects the nervous system

Provitamins

Substances that need to be converted in order to have vitamin-like activity in the body Example: beta-carotene is a provitamin that gets converted into vitamin A.

Vitamin C Toxicity

Supplementing more than the 2,000 mg daily UL will result in diarrhea and bloating

Cell differentiation

The process by which specialized cells develop that are capable of performing specific functions

Retinol Activity Equivalents (RAE)

The units in which carotenoids are measured

Water Soluble Vitamins

Vitamin C (ascorbic acid) Thiamin (B1) Riboflavin (B2) Niacin (B3) Pantothenic acid (B5) Pyridoxine (B6) Biotin (B7) Folate (B9) Cobalamin (B12)

Water-soluble vitamins include...

Vitamin C and B vitamins

Vitamin E Toxicity

Vitamin E can be toxic. Signs of toxicity include headache, nausea, blurred vision, reduced sexual function in men, chapped lips, inflammation of the mouth, etc.

Riboflavin deficiency

Deficiency of riboflavin occurs in conjunction with deficiencies of other water-soluble vitamins. Results in sore throat, cracks at the corner of the mouth, a swollen, glossy tongue, skin rashes, and hypersensitivity to light

Folate (naturally occurring) toxicity

Folic acid has a greater chance of being toxic because although it is synthetic, it has an easier time being absorbed in the small intestine.

Food Sources of Vitamin E

Food sources of vitamin E include vegetable oils, margarine, and salad dressings.

Food sources of vitamin A (preformed--ready to use)

Found in animal-based or fortified foods as well as plant based foods -Fortified milk, cheese, cream, butter, eggs, liver -leafy, green vegetables, orange and red produce (will have to be converted form)

Functions of Vitamin E

--Acts as an antioxidant --Enhances immune function --Required for nerve cell development

Vitamin D deficiency

--Children who are vitamin D deficient can develop Rickets, where bones are softened and deformed cause of the inability to deposit calcium in newly formed bone. Rickets cases in children are increasing. --Adults can develop osteomalacia, a softening of the bones that results from vitamin D deficiency.

Unique things about B12

--Contains the mineral Cobalt as a part of its structure --It's synthesized by bacteria and other microorganisms --Found naturally only in foods of animal origin --Stored in body in significant amounts --Requires intrinsic factor for absorption

Functions of Vitamin D

--Controls metabolism of calcium and phosphorous. Vitamin D stimulates the small intestine to secrete calbindin which is used to increase calcium absorption, so more calcium is absorbed from food --Vitamin D also stimulates the kidneys to conserve calcium by decreasing urinary excretion --Vitamin D stimulates bones to release calcium to help maintain blood calcium levels --Cell differentiation

Folate deficiencies

--Macrocytic anemia occurs when folate isn't present, so DNA replication cannot occur. This makes immature large RBCs. --Spina bifida occurs when the spine fails to close properly. This results from folate deficiency during pregnancy. --Ancephaly can also occur from a lack of folate during pregnancy. This is a fatal congenital malformation of the development of the brain and skull.

Functions of Vitamin C...

--Serves as an antioxidant against free radicals. It protects cell constituents in the watery areas of the cell. --Production of collagen. Collagen forms connective tissues. --Plays a role in healing wounds and maintaining structure of blood vessels. --Facilitates iron absorption in GI tract

Sources of Vitamin D

--Sunlight --Very few foods are naturally concentrated in Vitamin D. These foods include cod liver oil, salmon, sardines, shrimp, mushrooms exposed to UV light, etc. --Fortified foods provide majority of dietary vitamin D which include, milk or margarine, cereals, and juices.

Primary function of Vitamin K...

--The primary function of Vitamin K is its role in blood clotting. Vitamin K is indirectly involved with the production of the protein fibrin, which forms blood clots. --Vitamin K also is needed for the synthesis of the bone protein osteocalcin

Functions of B12

--Vitamin B12 is essential in converting folate into its active form --It maintains the insulating lining that covers myelin sheath

Functions of vitamin A

-Crucial to normal vision -Maintenance of healthy cornea tissue -Immune function -Cell differentiation -Gene regulation -Bone metabolism

Immune function of vitamin A

-Disease resistance, particularly for children -Production of white blood cells -Vitamin A required for epithelial cells

Gene regulation

-Role in turning genes on and off -Indirect role in the regulation of metabolism Retinoic acid has the greatest influence on gene regulation

Deficiency regarding cornea tissue

-Short term--cornea becomes dry and hardened -Long term--Xeropthalmia, permanent loss of vision

Vitamin E

A fat soluble vitamin primarily found in cell membranes. Not just one compound, but a group of compounds called tocopherols (alpha, beta, gamma, & delta). The strongest is alpha-tocopherols.

Provitamin A (needs to be converted form)

Converted to active form as needed. -beta-carotene is an example that is found in plant-based foods like green, leafy vegetables, orange and red produce (apricots, cantaloupe, carrots, sweet potatoes, pumpkins).

Primary forms of Vitamin D

D2 and D3

B9

Folate is consumed in two forms: --folate (naturally occurring) --folic acid (synthetic form, easier to absorb in GI, more absorbed in the small intestine).

In infants, a sign of vitamin C deficiency includes...

Scorbutic Rosary, an abnormal formation on the ribcage where the ribs appear beaded

Vitamin C deficiency...

Scurvy and anemia

What condition is caused by vitamin C deficiency?

Scurvy, a disease noted for bleeding gums that eventually leads to death

What population has an increased requirement for Vitamin C and why?

Smokers need an increased amount for Vitamin C because Vitamin C protects the body against damaging compounds in tobacco smoke

Vitamin E as an antioxidant...

Vitamin E is an antioxidant nutrient that fights against free radicals.

How does Vitamin K work in blood clotting?

Vitamin K is required to convert prothrombin to thrombin. Then thrombin can form the clot by converting fibrinogen to fibrin. Therefore, Vitamin K helps activate fibrin.