Foodchem - vitamins

Organic substances required in the diet in small quantities for normal growth and development

B complex, C

A, D, E, K

• retinol
• axerophthol

pre-formed vitamin A found in animal sources

Carotenoids: beta-carotene, alpha-carotene, beta-cryptoxanthin

• vegetable oils (particularly palm oil)
• green leafy vegetables (like spinach)
• peppers
• tomatoes
• carrots
• fruits like melon, mango, cantaloupe, papaya, pumpkin

in the liver since it is fat soluble

enough to meet needs for up to a 2 years supply

• liver
• fish oil
• fatty fish (salmon, trout, mackerel, tuna, sardines)
• egg yolk
• cheese whole milk
• butter

• margarine
• fruit drinks
• salad dressing
• cake mixes
• ice cream

• for its vitamin A activity 
• as a food colorant

in the all-cis-retinal form

convert all-cis-retinal form to the all-trans-isomer

binds with opsin (protein in the eye) to form rhodopsin

• the rhodopsin is split to regenerate the opsin and the trans-form of retinal
• this splitting process results in impulses or signals being transmitted to the brain where it is interpreted into "light" and "dark"

the trans-retinal is converted back into the all-cis form to continue the cycle

antioxidant activity is due to the highly unsaturated nature of the vitamin which enables it to scavenge free radicals and prevents them from causing oxidative damage to biological molecules and tissues (like biological membranes)

vitamin A maintains appetite for food for normal growth

surface linings of the eyes, respiratory tract, urinal tract, intestinal tract

helps maintain the integrity of blood cells to make them able to defend the body against invasion by foreign bodies

retinol as retinoic acid binds to the receptors in the nucleus known as retinoic acid receptors (RARs) to regulate gene transcription

• lipid maladsorption conditions
• eating too little fat in the diet

• use of oral contraceptives
• diseases and infections
• chronic heavy intake of alcohol

impaired vision

air/oxygen, light, heat, acidic conditions

neutral to slightly alkaline conditions

high levels can lead to accumulation of H₂O in the brain, called HYDROCEPHALIA

headaches, confusion, blurred vision

• ergocalciferol (D₂)
• cholecalciferol (D₃)

a group of steroids with vitamin D activity

in plant materials, but only as D₂

• fish (sardines, tuna, salmon)
• fish liver oils
• eggs

margarine, milk, butter, cheese

• yeast
• mushrooms

• in the presence of sunlight
• in the liver and kidney

hydroxylated into the mono- and di- hydroxylated forms that have more potent biological activity

enables synthesis from precursor molecules: egostreol and 7-dehydrocholesterol

Calcium and phosphorous from the intestines into skeletal tissues for their building and maintenance

converted to the active hormonal forms in the liver (25-hydroxycholecalciferol) and in the kidney (1,25-dihydroxycholecalciferol)

• poor bone and teeth development
• in children, as bent or crooked limbs (RICKETS)
• in adults, as thinning of bones (OSTEOMALACIA)

Osteomalacia results from a defect in the bone-building process, while osteoporosis develops due to a weakening of previously constructed bone.

• genetic defects in the vitamin D receptors
• severe liver or kidney disease
• insufficient exposure to sunlight

• vitamin D
• it is not destroyed by processing/storage procedures like pasteurization, boiling, freezing, etc

• light
• air/oxygen

• weakness, tiredness, headaches
• nausea and vomiting
• loss of appetite
• slow growth
• excessive thirst and urination
• protein presence in the urine
• kidney failure

• 8 closely related compounds:
• 4 are tocopherols
• 4 are tocotrienols
• each category has an alpha, beta, gamma and delta name to distinguish it

from the Greek words related to fertility and childbirth

alpha-tocopherol

no, they must obtain it from external sources?

mainly in fatty tissues, as well as liver and muscle tissues

• yeasts
• mushrooms

• wheat germ
• vegetables (broccoli, kale, collard greens, leafy greens, cabbage)
• vegetable oils (sunflower seeds and oil)
• fruits (pumpkin, avocado, kiwi)

• fatty fish oils
• liver
• dairy products

yes, protects body tissues from oxidative damage from normal metabolism or toxic agents

vitamin C, beta-carotene, selenium

LDL

prevents platelet aggregation (anticoagulant)

the enzymes that participate in the hydroxylation of vitamin D

no, deficiency is rare because it is widespread in foods

• people who cannot absorb dietay fat due to inability to secrete bile salts
• people with genetic abnormalities in their alpha-tocopherol transfer protein
• premature, very low birth-weight infants

• impaired coagulation
• hemolysis
• anemia
• skin and nerve disorders
• impaired immune disorders

• generally non-toxic
• high levels may interfere with utilization of the other fat soluble vitamins (A, D, K)
• stomach upset, diarrhea, dizziness

One of the most unstable vitamins and activity is hindered by several processing conditions (exposure to oxygen and light, as well as from reactions with hydroperoxides) except under neutral and slightly acidic conditions

• phylloquinone
• metaquinone

menadione

• the natural ones:
• phylloquinone (K₁)
• menaquinone (K₂)

• plants
• intestinal bacteria in mammals

the natural forms

• menadione (synthetic)
• can cause toxicity in excess in infants via breakdown of bilirubin and red blood cells to cause jaundice and anemia 

• green leafy vegetables, oats, soy bean, potatoes, brussels sprouts, spinach, cabbage, cauliflower, coffee, green tea
• fruits like avocado, prunes, kiwi

• bacon
• organ meats (liver, kidney, brain)
• egg yolk
• butter
• cheese

cereals

synthesis of blood proteins (for coagulation) and bone proteins (for bone development)

glucose into glycogen for storage

carboxylation of protein molecules essential for blood-clotting (prothrombin, factors VII, IX & X), and bone proteins (osteocalcin) for calcification

rare, except in newborn infants or from excessive use of antibiotics

failure of blood clotting (hemorrhages)

• oxygen
• exposure to light
• extreme cold (freezing)
• alkaline conditions

• heat treatment
• soluble in acidic conditions
• exposure to air

B₁, B₂, B₆, B₁₂, niacin, folic acid, pantothenic acid, biotin

thiamine

a pyrimidine residue and a thiozole residue

TTP (thiamine pyrophosphate)

• cereals
• whole grains
• green leafy vegetables

meats (pork, beef, lamb, poultry)

Brewer's yeast

• also known as co-carboxylase
• a cofactor for several crucial enzymes in intermediary metabolism (ex pyruvatte dehydrogenase, pyruvate decarboxylase, alpha-ketoglutorate dehydrogenase, transketolase (in the pentose phosphate pathway))

aids in efficient metabolism of carbohydrates

• low energy, tiredness
• anorexia
• mental depression
• confusion
• impaired synthesis of the crucial biomolecules
• Beriberi

vitamin B1

• additives like sulfites destroy the vitamin
• lost to cooking water
• neutral and alkaline conditions
• exposure to oxygen

flour and other grain/cereal products to compensate for losses during processing

considered non toxic because it is excreted in urine and sweat

can affect insulin and thyroid production

riboflavin

• 3 ringed flavin
• 5C alcohol (ribitol)

• FMN (flavin mononucleotide) in which the riboflavin is phosphorylated at the 5-position of ribitol
• FAD (flavin adenosine) in which the ribitol group in riboflavin is esterified with adenosine diphosphate

by intestinal bacteria

• green leafy vegetables
• peas
• tomatoes
• whole grains
• cereals

• organ meats
• lean meats
• eggs
• fish
• milk and dairy products

electron carriers in the electron transport chain and oxidative phosphorylation (both can accept H to form the reduced forms)

major biological molecules (fats, carbs, proteins, nucleic acids) for energy production

proper circulation and proper skin formation

• protein use
• growth
• pregnancy
• lactation
• wound healing

• lost to cooking water
• light
• heat
• alkaline conditions

• acids
• oxygen
• dry heat

• skin disorders
• hardening of the cornea
• destruction of red blood cells, leading to anemia
• nervous disorders

• excess alcohol and antibiotic use can kill off the intestinal bacteria and cause deficiency
• but deficiency is rare, since it's produced by intestinal bacteria

• numbness in extremeties
• yellow pigmented skin and veins
• discolored urine (very yellow in color)

niacin

• nicotinic acid
• nicotinamide

• NAD and NADP
• these both act as hydrogen acceptors in metabolism to form the reduced equivalent
• NADH2 is used to generate energy via transfer to FMN of FAD and the ETC
• NADPH2 is used for the synthesis of biological molecules like nucleic acids, fats, hormones, amino acids/proteins

• cereals
• peas
• nuts
• green leafy vegetables
• whole grains

• fish
• poultry
• organ meats (liver, kidney)
• lean meats
• seafood (salmon, tuna)
• cheese
• eggs
• milk

yeast

• dehydrogenation reactions
• ETC and oxidative phosphorylation
• synthesis of biomolecules (like fatty acids)

• skin disorders (dermatitis)
• diarrhea
• dementia (pellagra)
• death

no, very rare

• vitamin B3
• only lost to cooking water because it is water soluble

pantothenic acid

• coenzyme A
• pantothenate

• pantothenic aid
• panthenol

• whole grains, cereals and seeds
• green leafy vegetables
• nuts

• shellfish
• eggs
• cheese
• meats
• milk
• liver
• kidney

• Brewer's yeast
• intestinal microflora

• CoASH (coenzyme A)
• Acyl carrier protein (ACP)

• participate in several steps in carb, lipid, and protein metabolism
• several enzymes (more than 70) require these cofactors for activity
• required for synthesis of nerve regulating substances, like acetylcholinesterase

• impaired growth
• anemia
• skin disorders

• rare since we consume it widely in foods and also synthesized by intestinal bacteria
• prolonged use of alcohol and antibiotics kills off intestinal bacteria which can cause deficiency

generally considered as non toxic

• air
• slightly acidic to neutral pH (5-7)

• extreme pH conditions
• dry heat

pyridoxol

• pyridoxol
• pyridoxine
• pyridoxamine

• PALP (pyridoxal phosphate)
• PALP is phosphorylated by pyridoxal kinase

no they are incapable

• carrots
• whole grains
• seeds, nuts
• peas
• bananas
• grapes
• potatoes

• fish (salmonids, tuna, halibut, herring, mackerel)
• liver
• lean meats (beef, pork, lamb, poultry)
• eggs
• cheese

brain, liver, muscle

Brewer's yeast

transaminases and deaminases that catalyze transamination and deamination reactions in amino acid metabolism

• purine nucleotides
• certain amino acids (glycine, serine, methionine, and choline)

it is widespread in the foods we consume

• when certain drugs bind PALP and prevent its availability for their normal functions
• examples of these drugs include:
• isoniazid (used for treatment of tuberculosis)
• hydrallazine (anti-hypertensive drug)
• cycloserine (antibiotic)

• skin disorders - lesions on skin and mucosa
• loss of appetite
• tiredness
• anemia
• convulsions

acidic and neutral pH

• light
• air
• heat
• alkaline pH

considered non-toxic

biotin

2 fused rings

• fruits
• vegetables
• seeds

• organ meats (liver, kidney, heart, brain)
• lean meats
• fish
• eggs
• milk

• Brewer's yeast
• synthesized by intestinal bacteria

• carboxylases and decarboxylases
• these are essential CO₂ carriers for carboxylation (like in fatty acid synthesis) and decarboxylation (like in catabolism of carbs and proteins) reactions

• Acetyl CoA carboxylase
• pyruvate carboxylase

biotin binds reversibly with CO₂ to form carboxybiotin (biotin +CO₂ --> carboxybiotin) 

rare

excessive consumption of raw eggs (avidin found in egg white is an antagonist of biotin) and prolonged use of antibiotics can cause deficiency of the vitamin

• dermatitis
• anorexia
• nausea
• muscular pain
• skin disorders
• loss of appetite
• anemia

lost to cooking water, otherwise one of the most stable vitamins

• air
• acid
• neutral pH

non-toxic

folic acid

• pyridine
• p-amino benzoic acid (PABA)
• glutamic acid

folacin, folate, vitamin B_e, vitamin B_M

• pulses
• grains
• green leafy vegetables
• fruits
• cabbage
• French beans

• liver
• eggs
• milk

• Brewer's yeast
• synthesized by intestinal bacteria

pteridine, PABA, and glutamate

tetrahydrofolate (THF)

• acts as a C-1 carrier
• unlike biotin that carries CO₂, THF carries C-1 groups in the form os -CH₃, -CH₂, H-C=O (i.e. methyl, methylene, and formyl groups)

• essential in the metabolism of biological molecules (like fats, nucleic acids, amino acids)
• breakdown of uneven numbered fatty acid chains, and a 3-C compound (propionyl CoA) is the end product
• THF enables the propionyl CoA to be elongated to the 4-C methylmalonyl CoA mutase
• ethylmalonyl CoA thus formed is isomerized to succinyl CoA by methylmalonyl CoA mutase, succinyl CoA then goes into the TCA cycle
• succinyl CoA then goes into the TCA cycle

required in the synthesis of homocysteine

generally regarded as non toxic

sufficient folate must be present in the diet to prevent deficiency because of the high demand for its use in the synthesis of biological molecules, for example by pregnant and lactating women

• impaired synthesis of nucleic acid and ultimately in anemia
• blood levels of homocysteine rise and may cause cardiovascular problems

acidic conditions

• heat
• air
• light
• neutral and alkaline conditions

cyanocobalamine

• porphyrin ring (or tetrapyrol ring) structure with cobalt as the central atom
• known as a corrin ring

microorganisms

obtain them from microbial sources and accumulate them in the liver, where it is in the bound form either as methyl cobalamin or 5'-adenosyl cobalamin

• fish and shellfish
• lean meat
• eggs
• dairy products
• liver
• kidney

no, must be released from its association with these groups to have activity

there are no plant sources

anemia

• heat
• acid
• neutral conditions

• destroyed when boiled under alkaline conditions
• unstable to air, oxygen, and light

• L-ascorbic acid (most acitivity)
• dehydro-L-ascorbic acid (reduced activity)
• ketogulonic acid (no activity)

• humans
• guinea pigs

• most fruits and vegetables
• citrus fruits, strawberries, peppers, cauliflower, tomatoes

• organ meats (like liver)
• milk and dairy products

scavenges free radicals from the body to protect against oxidation to biological molecules and tissues

plays an important role in the interconversions between the oxidized and reduced forms of cytochromes ('a' and 'e') in the electron transport chain

• hydroxylation of proline into hydroxyproline
• hydroxylation of lysine into hydroxylysine
• as a result these resulting molecules are able to undergo extensive hydrogen bonding to stabilize/strengthen biological molecules (ex hydroxyproline in collagen for muscles, vascular tissues, and cartilage)

• Cu and P (important in bone/teeth formation)
• Fe (important in formation and functioning of blood cells)

nitrosamines

• heavy smokers
• elderly people
• individuals on long-term drug therapy

• impaired formation and functions of collagen and RBCs
• oxidative damage to biological molecules

scurvy - symptoms of scurvy include bleeding gums, loose teeth, susceptibility to colds and infections, reddish eyes and skins (from the breakdown of blood cells)

ascorbic acid turns into uric acid

• crystallization of uric acid
• accumulation of uric acid crystals in the joints results in a painful condition known as GOUT

since vitamin C enhances uptake of Fe (especially from plant foods), individuals for whom high iron levels are a problem, high levels of vitamin C can be toxic and lead to dark/bloody stools, dizziness, loss of consciousness, and even coma

• very unstable, lost under most processing conditions
• heat
• neutral to alkaline conditions
• exposure to light and air
• lost to cooking water

pro-oxidants

• oxidization to the dehydro- form, which has reduced biological activity
• futher oxidation leads to the formation of the diketo-L-gulonic acid form, which means total loss of activity