Chapter 8 Flashcards
Vitamins
Organic compounds needed in the diet in small amounts to promote and regulate the chemical reactions and processes needed for growth, reproduction, and the maintenance of health.
- organic
- micronutrient
- essential
- not energy yielding
- classified as water or fat soluble
- cofactors in cell functions
Water soluble vitamins
Vitamins that dissolve in water
- B, C
- are easily absorbed
- not stores in tissues excessively
- seldom reach toxic levels
- Thiamin B1
- Riboflavin B2
- Niacin B3
- Pantothenic acid
- Pyridoxine B6
- Biotin
- Folate
- Cobalamin B12
-Vitamin C
Fat soluble vitamins
Vitamins that dissolve in fat
- require bile and dietary fat for absorption
- transported in lymphatic system in chylomicrons before blood
- stored in body fat meaning that intakes can vary without a risk of deficiency
- may be toxic in excess : not easily excreted
- A, D, E, K
Vitamin examples in
- whole grains
- veggies and fruit
- protein foods
- Healthy fat
- B Vitamins
- B, C, A, E, K vitamins
- protein: B, Milk: B, A, D, K
- Vitamin E
Fortification
A term used generally to describe the process of adding nutrients to foods that are not normally there; such as the addition of vitamin D to milk
-some mandatory fortification by government
Ex:Table salt with Iodine, Vitamin D in milk, grains with B vitamins, iron
-prevents deficiencies leading to diseases but may also cause toxicity
Enrichment
Refers to a food that has had nutrients added to restore those lost in processing to a level equal to or higher than originally present
Bioavailability
A get real term that refers to how well a nutrient can be absorbed and used by the body
- 40-90% of vitamins absorbed
- fat soluble vitamins require fat in diet to be absorbed
- water soluble vitamins may require transport molecules
- some vitamins are absorbed in inactive provitamin people vitamin precursor forms that must be converted into active forms by the body.
Digestion of vitamins steps
- Chewing releases vitamins in food
- stomach digestion release vitamins and some niacin is absorbed here
- gallbladder releases bile which emulsifies fat and helps absorb fat-soluble vitamins
- Pancreas secreted digestive enzymes that aid in release of vitamins from food
- in small intestine, fat-soluble vitamins are incorporated into micelles, and then absorbed by simple diffusion. Once inside mucosal cells, fat-soluble vitamins are packaged into chylomicrons to enter lymph before passing into blood.
- water-soluble vitamins are absorbed from small intestine directly into blood
- in large intestine, bacteria synthesize small amounts of vitamins and some are absorbed
Provitamin or vitamin precursor
A compound that can be converted into an active form of a vitamin in the body
Ex: provitamin A is a name for beta-carotene, which has only about 1/6 the biological activity of retinol (vitamin A); the body uses an enzyme to convert beta-carotene to retinol
Does it take longer to develop a deficiency for water soluble or fat soluble vitamins
Water soluble-not stored and can easily be excreted in urine.
Fat-soluble are stored in liver and fatty tissues and cannot be excreted in urine
Coenzymes
Small non-protein organic molecules that act as carriers of electrons or atoms in metabolic reactions and are necessary for the proper functioning of many enzymes
-ex: B vitamins like thiamin, riboflavin, niacin, panthothenic acid and biotin serve as coenzymes for reactions that release energy from carbs, fat and protein
Beriberi
The disease resulting from a deficiency of thiamin (vitamin B1). Causes lethargy, fatigue, neurological symptoms like depression, and cardiovascular issues (heart issues)
-need bran or you get beriberi
Thiamin pyrophosphate
The active coenzyme form of thiamin. It is the predominant form found inside cells, where it aids reactions in which a carbon-containing group is lost as CO2.
-essential for production of ATP
Who is most at risk of beriberi
Alcoholics!
-alcohol disrupts absorption of thiamin
Wernicke-korsakoff syndrome
A form of thiamin deficiency associated with alcohol abuse that is characterized by mental confusion, disorientation, loss of memory, and a staggering gut
Best source of riboflavin in Canadian diet?
What protects riboflavin?
Milk, red meat, fish, asparagus, mushrooms, leafy greens
Light exposure
Flavin adenine dinucleotide (FAD)
Flavin mononucleotide (FMN)
The active coenzyme forms of riboflavin. The structure of these molecules allows them to pick up and donate hydrogens and electrons in chemical reactions
Can riboflavin be tired in body?
No-water soluble- is excreted in urine
Ariboflavinosis
The condition resulting from a deficiency of riboflavin
-inflammation of eyes, lips, mouth and tongue, scaly greasy skin eruptions, confusion
Pellagra
The disease resulting from a deficiency of niacin
- progressive physical and mental deterioration and death
- extreme fatigue
- indigestion
- dermatitis, diarrhea, dementia, death
Good sources of niacin
Meat (chicken) fish, peanuts, grains, legumes, wheat bran, tryptophan
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP)
The active coenzyme forms of niacin that are able to pick up and donate hydrogens and electrons. They are important in the transfer of electrons to oxygen in cellular respiration and in many synthetic reactions
Niacin equivalents (NE)
The measure used to express the amount of niacin present in food, including that which can be made from its precursor, tryptophan. One NE is equal to 1mg of niacin or 60mg of tryptophan
Sources of Biotin
Liver, egg yolks, yogurt and nuts
-avoid uncooked egg whites, protein avidin binds biotin making it unavailable
Panthothenic acid food sources
B vitamin
-meat, eggs, whole grains and legumes
Vitamin B6 sources
Found in both plant and animal foods
Pyridoxine
Pyridoxal phosphate
The chemical term for vitamin B6
The major coenzyme form of vitamin B6 that functions in more than 100 enzymatic reactions, many of which involve amino acid metabolism. Needed for formation of hemoglobin, and myelin on nerves
Single carbon metabolism
The transfer of single carbon groups, such as methyl groups between compounds.
-metabolizes homocysteine
Folate and Folacin
Folic acid
General term for the many forms of this vitamin
The monoglutamate form of folate, which is present in the diet in fortified foods and vitamin supplements
Sources of folate
Liver, yeast, asparagus, oranges, legumes, lentils
Foliage
Neural tube defects
Abnormalities in the brain or spinal cord that result from errors that occur during prenatal development. Defects in the brain are fatal, while those in the spinal cord often result in paralysis.
- folate deficiency can increase risk
- decreased by 50% since fortification in foods but increase in colon cancer
Epigenetics
The study of genetics unrelated to changes in the sequence of DNA, but related to its chemical modification due to reactions such as methylation
-folate has epigenetic role in NTD