Nutrition 201 Exam 2

CWRU NUTR 201 content for exam 2

vitamin

essential, organic dietary compounds needed in small amounts. Not directly yielding energy, but participate in energy yielding metabolic rxns

Fat soluble vitamins

Vitamins, A D, E, K

Water soluble vitamins

Vitamin B, folate, choline

Functions of vitamins

Coenzymes, antioxidants, cell growth, development, blood clotting, synthesis of body structures, neurotransmitters

Digestion of fat soluble vitamins

Bile is necessary for digestion, absorbed and travel on chylomicrons through the lymphatic system

Digestion of water soluble vitamins

Absorbed in the small intestine and released directly into the blood

Digestion of vitamin K

Small amount produced by intestinal bacteria, which is then absorbed in addition to dietary Vitamin K

Problem with low fat diets

No fat means no transporters for fat soluble vitamins

What leads to malabsorption of water soluble vitamins

Intestinal diseases (reduced area for absorption), alcohol abuse

Vitamin storage

Generally fat soluble vitamins are stored and water soluble vitamins are not stored

Where are vitamins stored

liver and adipose tissue

Which water soluble vitamins are stored

B6 and B12

Vitamin A function

eyesight (macula) , gene regulation, epithelial tissue, cell differentiation, reproduction, growth, immune

Disorders of vitamin A

macular degeneration, night blindness

Dietary vitamin A

preformed / retinoids (animal products) or provitamin a / caratanoids (plant foods—dark green, orange, yellow)

Beta carotene

pro vitamin A, antioxidant. present in dark green and yellow orange fruit/vegtables

Antioxidants

quench oxygen free radical species and protect cellular structures from destructive chain reactions

Vitamin A toxicity

possible, but only usually seen in people who are consuming retinoid supplements. pain, loss of appetite, liver damage, dry skin and mucous membranes, coma

teratogenic

Vitamin a toxicity levels so high that they can cause birth defects or spontaneous abortion

Vitamin D / calcitriol

currently classified as a vitamin, but is probably more accurately a pro hormone that can be made by exposing skin to UV light. Dietary intake helps prevent deficiency

Role of vitamin D

Maintain blood calcium and phosphorus, maintaining bone health by regulating absorption

Dietary sources of vitamin D

fatty fish, cod liver oil, fortified milk, fortified cereal, supplements with ergocalciferol

Vitamin D skin formation

can provide 80-100% of the vitamin D needed, but dependent on age, location, season, skin color

Rickets

Deficiency of vitamin D. In children, bones weak and bowed. Enlarged heads, deformed pelvis, bowed legs. More common with fat malabsorption diseases (cystic fibrosis or other) dark skin (low synthesis), low dietary intake

Osteomalacia

Rickets in adults. Poor calcification of new bones. typically seen with kidney or liver disease, dark skin, obesity, low activity, low intake, low sun exposure.

Vitamin D toxicity

excess calcium deposits in kidneys heart and lungs, anorexia, N/V, pain

Vitamin E

8 naturally occurring compounds. Mainly functions as an antioxidant.

Dietary sources of vitamin E

plant oils, avocado, almonds, peanuts, sunflower seeds Vitamin E can be destroyed by heat/light.

Vitamin E deficiency risk populations

Smokers, preterm infants, fat malabsorption

Vitamin E deficiency characteristics

hemorrhage, weakness, coordination and vision problems

Vitamin K

role is mainly for synthesis of blood clotting factors (koagulation) and Bone metabolism

Dietary vitamin K

phyloquinones - green vegetables menoquinones - from fish

Special source of vitamin K

about 10% of daily value comes from synthesized vitamin K from bacteria in the colon

Infant vitamin K

Infants are not born with any bacteria in the colon, and are not born with any stores of vitamin K. Without a vitamin K injection major brain hemorrhage and poor clot formation is possible.

Vitamin K toxicity

no upper limit set, storage is limited and so it is more readily excreted

Vitamin C/ Ascorbic acid

primary role as an antioxidant. Forms connective tissue like collagen, immune support by decreasing oxidation of abc, increase absorption of iron.

Dietary sources of vitamin C

citrus, peppers, green vegetables

Special populations for vitamin C

smokers, increased 35mg per day because of antioxidants

Vitamin C toxicity

no major long term effects. Bloating, inflammation, and diarrhea. People predisposed to kidney stone formation can have increase risk

Vitamin C deficiency

scurvy, poor collagen synthesis. Bleeding gums and joints, small hemorrhage, fx, pain, depression diarrhea, death.

Vitamin C and common cold

large dose vitamin C can be effective in early stages of cold.

B vitamin group main function

Generally used as metabolic coenzymes

Thiamin

B vitamin, coenzyme for metabolism of carbs and nervous system function

Dietary sources of thiamin

Not hard to find in most foods (especially enriched grain), but some foods have types that are not digestible

What happens to excess B vitamins

No harmful side effect, excreted in the urine

Riboflavin

B vitamin, component of coenzymes, activator of other B vitamins, and antioxidant functions

Sources of riboflavin

Milk products, grain, eggs, meat - breaks down in light (store in paper/plastic)

Niacin

B vitamin, used to synthesize niacin coenzymes (NAD+ / NADP+) important in metabolism

Niacin rich foods

Poultry, meat, fish, enriched grain, mushrooms, peanuts — can also be synthesized from tryptophan

Niacin toxicity

can only be achieved through enriched foods and supplements. Causes facial flushing, hives, rash, sweating

Niacin deficiency

Pellagra, causes dermatitis, diarrhea, depression, death

Folate

B vitamin used in DNA synthesis and methylation, amino acid metabolism, neurotransmitter synthesis

Folate rich foods

Liver, legumes, leafy greens, enriched grains

Folate upper level

if upper level is exceeded then it can mask B12 deficiency

Vitamin involved in neural tube formation

Folate

Vitamin B12

cell replication, nerve sheaths, only in animal foods

Vitamin B12 rich foods

compounds are synthesized by bacteria in soil, so it can only come from animal products

B12 deficiency

peripheral neuropathy, megaloblastic anemia, elevated plasma homocysteine ( marker for heart attack and stroke)

B6

B vitamin important in folate and amino acids, releases glucose from glycogen, required in heme, and neurotransmitter synthesis

B6 toxicity

excessive supplementation can cause permanent nerve damage

Regulation of dietary supplements

Widely unregulated, not required to say what is in it, if it is effective, etc

Cons of dietary supplements

lack fiber, phytochemical, limited in nutrients, potential for toxicity

USP and consumer lab

third party verification for supplementation