Chapter 8 Flashcards
water-soluble vitamins
what are the water-soluble vitamins?
B-vitamins
Thiamin (B1)
Riboflavin (B2)
Niacin (B3)
Pantothenic acid (B5)
Pyridoxine (B6)
Biotin (B7)
Folate (B9)
Cobalamin (B12)
Other water-soluble vitamins
Ascorbic acid (Vitamin C)
Choline (maybe)
what is the function of co-enzymes?
-The B vitamins function as co-enzymes
(small molecules that enable enzymes
to function)
* Coenzymes attach at the active site of
the enzyme
* Co-enzymes participate in biochemical
reactions involving energy release or
catabolic/anabolic reactions
Roles of B vitamins
-The metabolism of energy-yielding
nutrients (CHO, fat, protein)
requires vitamin input
* Because B-vitamins are readily
excreted from the body and have
limited storage, they should be
consumed daily
* An occasional lapse causes no
harm
consequences of grain processing
-When germ, bran and husk layers
are discarded (only starchy
endosperm remains)
* Leads to loss of B-vitamins and other
vitamins and minerals
* Bread and cereal products are then
enriched with four B vitamins
(thiamin, riboflavin, niacin and folic
acid) – also iron
* Increased glycemic response
* Decreased fiber intake
major sources of thiamin
-Protein and grain groups
* Whole grains, pork,
read-to-eat breakfast
cereals, enriched
grains, peas, orange
juice, organ meats,
dried beans
Thiamin deficiency is disease
is called ‘beriberi’
thiamin (main functions)
helps the body release energy from carbs. Serves as part of the coenzyme thiamin pyrophosphate to participate in ATP-producing pathways. Contributes to chemical reactions that synthesize RNA, DNA, and neurotransmitters. Assists the body in the breakdown of carbohydrates and protein
Thiamin (recommendations)
RDA Men: 1.2 mg
RDA Women: 1.1 mg
D.V.: 1.2 mg
UL: none
Riboflavin (main functions)
-easily destroyed by sunlight
-forms coenzymes flavin dineucleotide and flavin mononucleotide to participate in metabolic pathways. Through these coenzymes, contribute to growth, development, and metabolism of drugs and nutrients. contributes to the metabolism of of vitamins and minerals
-is stored in the liver, heart, kidneys in small amounts
riboflavin (Recommendations)
RDA Men: 1.3 mg
RDA Women: 1.1 mg
DV: 1.3 mg
UL: none
Riboflavin in foods
sour cream, orange juice, asparagus, yogurt, cereal, beef liver
Riboflavin (deficiency)
known as ariboflavinosis- inflammation in the tongue and mouth, dermatitis, cracked skin around mouth
Niacin (main functions)
forms compunds nicotinamide and nicotinic acid, which contributes to cellular metabolic pathways. enzamatic forms of niacin contribute to the metabolic processes that form ATP. Plays a role in maintenance of some of the body’s antioxidant systems and maintenance of genome integrity and to regulation of gene expression
Niacin (Recommendations)
RDA Men: 16 mg
RDA Women: 14 mg
DV: 16 mg
UL: 35 mg (nicotinic acid forms)
Niacin (food groups)
sour cream, banana, baked potato, soy milk, foretified cereal, beef liver
Niacin B-3 (deficiency)
-pellegra means “rough and painful skin”
-symptoms: diarrhea, dermatitis, dementia, death
-common in places where corn was staple with low protein diet
-tryptophan can turn into niacin
-soaking corn in alkaline solution releases niacin
Niacin B-3 (toxicity)
-very high doses can lower blood triglyceride and cholesterol levels (from 500-2000 mg/day)
-side effects: niacin flush (rapid heartbeat, flushing)
-seen when intakes are at 300 mg
-UL is 35 mg
Pantothenic acid B-5 (main functions)
-contributes to the synthesis of coenzyme A (coA). Through CoA, enables chemical reaction that allow release of energy from macronutrients
-activates fatty acids for energy production
-contributes to fatty acid synthesis
Pantothenic Acid B-5 (recommendations)
AI: 5 mg
DV: 5 mg
UL: none
Pantothenic Acid B-5 (food sources)
mayo, orange juice, mushrooms, milk, whole wheat, sunflower seeds
Pantothenic Acid B-5 (deficiency)
- hard to detect bc similar to other B-vitamin deficiencies
Vitamin B-6 (pyridoxine) (main functions)
-contributes to several enzymes involved in carbohydrate, protein, and lipid metabolism
-serves as a building block for coenzyme for PLP, which is needed in synthesis nonessential amino acids.
-regulates homsysteine metabolsim
-contributes to the synthesis of neurotransmitters
-can be stored in liver (along with B-12)
-pyridoxine, pyridoxal, pyridoxamine
Vitamin B-6 (pyridoxine) (food sources
-in every food sources but mainly animal foods and fortified cereals
-heating freezing foods can easily destroy vitamin B-6
Vitamin B-6 (pyridoxine) (recommendations)
RDA: 1.3 mg
DV: 1.7 mg
UL: 100 mg
Vitamin B-6, B-12 (toxicity)
can lead to permanent nerve damage
Biotin (Vitamin B-7) (main functions)
-aids in chemical reactions
-contributes to developmetn of coenzymes that aid in the synthesis of of glucose and fatty acids
-related coenzymes also assists in the breakdown of of certain amino acids
-plays role in histone modification, thus contributing to gene regulation
-biotin deficiencies are rare bc as the gut microbiota synthesize some biotin that the body can absorb
-biotin bioavailability is altered significantly in different foods bc due to the nutritent being bound to proteins: ie eggs
Biotin B-7 (recommendations)
AI: 30 mcg
DV: 30 mcg
UL: none
Folate B-9 (main functions)
-DNA synthesis
-New cell synthesis
-cell division
-accepts single carbon compounds to help form DNA and metabolize amino acids
-contributes to the formation of neurotransmitters
- may help to improve depression
Folate B-9 (recommendations)
RDA: 400 mcg
DV: 400 mcg
UL: 1000 mcg (synthetic only)