Chapter 7 Vitamins Flashcards
Essential nutrients to be provided by diet
Vitamin D synthesized by the body but still considered vitamin.
Vitamins
- -Organic molecules needed in very small amounts for cellular metabolism.
- -Perform specific metabolic functions
- -Vitamins except D are not synthesized; dietary intake. D created by body
Dietary reference intakes (DrIs)
- -recommended dietary allowance(RDA)
- -adequate intake (AI)
- -tolerable upper intake level (UL)
Vitamin categories
Water soluble
Fat soluble
Solubility affects
Water sol. absorbed small intestine and then pass into bloodstream
Fat sol. Bile
Water-soluble
- B complex vit. (Thiamine, riboflavin, niacin, pyridoxine, folate, vit. B12, biotin, pantothenic acid) choline, vit C
- minimal storage
- deficiencies develop more quickly
- usually low risk of toxicity
Fat-soluble
A,D,E,K
- excess stored in body
- deficiencies longer to develop
- greater risk of toxicity
Food sources
Vitamins in almost all foods Synthetic vitamins (same function)
Synthetic vitamin
Best to consume vitamins from food sources
May lack other benefits found in foods
Photochemicals
Phytochemicals
Nonnutritive substances in plant-based foods that appear to have disease-fighting properties.
Thiamine (B1)
Coenzyme in energy metabolism
*role in nerve functioning related to muscle actions
Recommended intake and sources
* sources- lean pork, whole/enriched grains and flours, legumes, seeds and nuts
Thiamine cont’d
Deficiency: beriberi: ataxia, tachycardia
- -marginal: psychologic disturbances, head ache, fatigue, irritability
- -wet vs dry beriberi
- -wernicke-korsakoff syndrome
- -risk: alcoholism, renal dialysis, anorexia, gastrectomy
- -toxicity: nontoxic
Ataxia
Muscle weakness and loss if coordination
Tachycardia
Rapid beating of heart
Wet beriberi
Manifests w/ edema, affecting cardiac functioning by weakening the heart muscle and vascular system.
Dry beriberi
Nervous system, producing paralysis and extreme muscle wasting.
Wernicke-Korsakoff syndrome
Cerebral form of beriberi
Most common disorder of CNS as a neuropsychiatric affect of chronic excessive alcohol intake on nutritional status.
Riboflavin (B2)
Coenzyme in energy release
Recommended intake/sources
*RDA 1.3 mg men; 1.1 women
*need related to total kcal intake, energy needs, body size, metabolic/growth rate
*sources: milk, enriched grains/cereals, whole grains, veggies, dairy, meats, fish, poultry, eggs
*very light-sensitive: kiss increases on exposure to artificial and natural light; list in cooking water.
Riboflavin cont’d
Deficiency: ariboflavinosis
* cheilosis, glossitis, seborrheic dermatitis
Toxicity: non toxic
Ariboflavinosis
Name for a group of symptoms associate w/ riboflavin deficiency.
Lips become swollen and cracks in corners (cheilosis)
Tongue becomes inflamed, swollen, and purplish red (glossitis)
Seborrheic dermatitis
Skin condition characterized by greasy scales, may occur in regions of ears, nose, and mouth.
Niacin(B3)
Nicotinic acid and niacinamide
*coenzyme for many enzymes, especially energy metabolism; critical for glycolysis and tricarboxylic acid (TCA) cycle
Niacin contd
RDA: 16 mg NE men 14 women
*RDA stated as niacin equivalent (NE)
*a.acid and tryptophan precursor of niacin
*60 mg tryptophan converts 1mg niacin
Diets adequate in protein=adequate in niacin
Sources: protein; meats, poultry, fish, legumes, enriched cereals, milk, coffee, tea.
Niacin contd
Pellagra
*3 D’s
1. Diarrhea: GI tract damage alters digestion, absorption, excretion, leading to glossitis, vomiting, and diarrhea.
2. Dermatitis: symmetric scaly rash occurs only on skin exposed to sun
3. Dementia: severe deficiencies, confusion, anxiety, insomnia, paranoia develop
At risk: excessive alcohol consumption; malabsorption
Niacin contd
Toxicity: causes vasodilation and flushing effect
- UL 35 mg NE per day
- pharmacological doses: 3-9g, may lower total cholesterol, decrease LDL and increase HDL
- -require monitoring to prevent liver damage, gout, and arthritis
Pyridoxine (B6)
Pyridoxine, pyridoxal and pyridoxamine
- -pyridoxal phosphate (PLP) acts as coenzyme in metab. Of aacids and proteins
- necessary to hemoglobin synth
- req. for conversion of tryptophan to niacin
- coenzyme for fatty acid and CHO metab
- supplements of B6, folate, and B12 may reduce risk of CAD
