Fundamentals of Nutrition: Chapter 7 The Vitamins

What are vitamins defined as?

an essential, noncaloric, organic nutrient needed in tiny amounts in the diet

What are the 2 categories of vitamins?

fat-solube and water soluble

What are the fat-soluble vitamins?

vitamins, D, A, K, and E

what are the water soluble vitamins?

eight B vitamins and vitamin C

what are vitamin precursors?

compounds that can be converted into active vitamins

Precursors are also called…..

provitamins

What is vitamin A’s precursor?

beta-carotene

Beta-carotene is converted into which form of vitamin A

retinol

Where are vitamins A, D, K, and E found?

fats and oils of foods

What do the fat soluble vitamins require for absorption?

bile

Once absorbed, where are fat-soluble vitamins stored?

liver and fatty tissues until the body needs them

True or False: its not necessary to eat foods containing each fat-soluble vitamins everyday because they are stored.

true

When do deficiencies of the fat-soluble vitamins occur?

when the diet is consistently low in them

When are deficiencies of the fat-soluble vitamins likely to happen?

When the diet is low in fat because fat is necessary for absorption of these vitamins

What are the three forms of vitamin A that are active in the body

retinol, retinal, and retinoic acid

Where is retinal stored?

in the liver

What is the most common precursor of vitamin A?

beta-carotene

What are some roles of vitamin A?

eyesight (night blindness)

gene regulation

cell differentiation

immune function

reproduction

fetal development

what is cell differentiation?

the process by which immature cells become mature, functioning cells

Why is vitamin A’s role in cell differenctiation, especially epithelial tissue important?

it is critical for maintaining enterocytes and healthy skin

How common is vitamin A toxicity?

not common, very rare

Where is vitamin A toxicity most commonly found?

from vitamin A supplementation of retinol (not beta-carotene supplement)

What can increase the risk of vitamin A toxicity?

taking certain medications

What is an example of medications increasing the risk of vitamin A toxicity?

when taking accutane, used to treat acne, vitamin A supplements should be avoided.

what is the most serious symptom caused by Vitamin A toxicity?

liver failure

true or false: vitamin A deficiency (VAD) has a high rate in developed countries?

false, low rate

What percent of children 5 and under in developing countries are affected by vitamin A deficiency?

20%

VAD is the world’s leading preventable cause of childhood _____

blindness

What are the 2 ways to meet your vitamin A needs?

1. consuming the active form, retinol, in animal food sources

2. consuming beta-carotene in plants

What is the RDA for Vitamin A?

adult female: 700 ug/day

adult male: 900 ug/day

What is the upper level intake for vitamin A?

3000 ug/day

What are the best sources of active vitamin A, retinol?

liver and fish oil

dairy products

eggs

What are the best sources of beta-carotene?

orange and yellow fruits and veggies

What is vitamin D known as?

the “Sunshine vitamin”

How is vitamin D synthesized?

endogenously (within the body) from UVB sunray exposure

true or false: vitamin D is found naturally in a lot of foods.

false, only a few foods

What foods are vitamin D found in naturally?

egg yolk, butter, fatty fish, and mushrooms

Vitamin D is considered a nutrient and a ______

hormone

What is a main role of vitamin D?

blood calcium regulation

Vitamin D stimulates the _______ tract to increase absorption of _________

intestinal, calcium

blood calcium (increases or decreases) calcium excretion in the urine.

decreases

vitamin D facilitates the release of ______ from bones

calcium

What are some additional role of vitamin D?

cell differentiation and bone health

how does vitamin D affect cell differentiation

stimulus formation of mature bone cells, critical for bone health

how does vitamin D affect bone health?

vitamin D is necessary for calcium absorption

a lack of Vitamin D leads to calcium deficiency and inadequate ________ ___________

bone mineralization

What percent of the US population have low blood concentrations of vitamin D?

18%

What is rickets?

vitamin D deficiency disease in children; characterized by abdominal growth of bone and manifested in bowed legs or knock-knees, outward bowed chest deformity, and knobs in the ribs

What is osteomalacia?

adult expression of vitamin D deficiency disease, characterized by an overabundance of unmineralized bone protein

what is osteoporosis

weakening of bone mineral structures caused by calcium loss that occurs commonly with advancing

what is vitamin D toxicity usually caused by?

large doses of vitamin D supplements- not by diet or sun exposure

What negative effects can happen when there is elevated calcium in the blood

elevated calcium in the blood can begin to accumulate in the kidney, heart, blood vessels, damaging these organs

what is the RDA for vitamin D?

adult males and females: 15ug/day

what is the tolerable upper level intake for vitamin D?

100ug/day

What are the vitamin D food sources

egg yolks, butter, fatty fish, and mushrooms

milk is often fortified with vitamin D

other foods:

orange juice, margarine, breakfast cereals

What is the active form of vitamin E is alpha-tocopherol?

alpha-tocopherol

What are the 4 tocopherol compounds?

alpha tocopherol

beta tocopherol

gamma tocopherol

delta tocopherol

What is the primary function of vitamin?

an antioxidant

What do antioxidants protect against?

radical damage (oxidative stress)

What are free radicals?

atoms or molecules with one or more unpaired electrons that make the atom or molecule unstable and highly reaction.

what is oxidative stress?

a theory of disease causation involving cell and tissue damage that arises when free radicals reactions exceed the capacity of antioxidants to quench them

When can free radicals be absorbed in the body?

during normal cellular metabolic processes or taken into the body from the environment

What and the sources of free radicals?

cellular reactions

air pollution

radiation exposure

cigarette smoke

ozone exposure

What does oxidative stress lead to?

inflammation and cell damage associated with aging processes, cancer development, heart disease, diabetes, and other diseases

antioxidants ______ free radicals

neutralize

What is the primary source of antioxidants?

our diet

What are the key antioxidant vitamins?

beta carotene

vitamin E

Vitamin C

What is a key antioxidant mineral?

selenium

True or False: severe vitamin E deficiency is common

false, its rare

What is the average daily intake of alpha-tocopherol from food (including enriched and fortified sources)

8.5 mg for adult men

6.5 mg for adult females

What is the RDA for Vitamin E?

15mg/day

Vitamin E deficiency arises in some conditions that impair fat absorption, such as _______

cystic fibrosis

How can vitamin E deficiency affect infants?

infant formula could be lacking in vitamin E

What is a consequence of severe vitamin E deficiency?

erythrocyte hemolysis and resulting hemolytic anemia

What is erythrocyte hemolysis?

rupture of red blood cells

What is hemolytic anemia?

decreased ability of the blood to carry oxygen carbon dioxide due to rupturing of red blood cells

What can make vitamin A Toxicity more likely

due to supplementation not dietary intake

What is the primary concern of excessive vitamin E intake?

is impaired blood clotting, which can increase risk of hemorrhage

Vitamin E supplementation is ___________ if taking anticoagulant medications (blood thinner)

contraindicated (not recommended)

What is the RDA for Vitamin E?

15 mg/day

what is the tolerable upper level intake for vitamin E

1000 mg/day

What are the major sources of alpha-tocopherol

veggie oils

nuts and seeds

green leafy veggies

What are some examples of oils that are a source of vitamin E?

wheat germ oil and safflower oil

what are some examples of nuts and seeds that are a source from vitamin E?

sunflower seeds, almonds, and peanut butter

True or false: vitamin K can be obtained only through a food source

false, it can be obtained from food and non food sources

intestinal bacteria ________ vitamin K

produce

what are the primary functions of vitamin K?

blood clot and bone healing

What are the roles of vitamin K?

it’s necessary for blood clot formation

its is necessary for the synthesis of key bone proteins

Why do new borns receive a dose vitamin K?

to prevent hemorrhage

true or false: vitamin K deficiency is rare

true

Why are individuals who are required to take chronic antibiotic medications are at greater risk for vitamin k deficiency?

the medication kills bacteria in gastrointestinal tract that normally produce vitamin K.

What does vitamin K deficiency increase the risk of?

osteoporosis and hermorrage

excess vitamin K intake, most likely from supplementation, increases the risk of….

blood clot formation (thrombosis)

people who have been diagnosed with what disease may need to avoid excessive vitamin K intake

cardiovascular disease

People diagnosed with cardiovascular disease are often on anticoloagulant (blood thinners) medications. why?

to prevent blood clot formation

What is the adequate intake of vitamin K?

adult female: 90ug/day

adult male: 120 ug/day

What is the tolerable upper level intake of vitamin K?

not determined

What are the best food sources for vitamin K?

green leafy veggies

broccoli

What are types of leafy green veggies that are a source of vitamin K

turnip or collard greens

spinach

kale

What is vitamin C also known as?

ascorbic acid and ascorbate