The Water Soluble Vitamins: B and C

 Water soluble vitamin  Part of the coenzyme, Thiamin Pyro Phosphate TPP  Assists in energy metabolism  Men 1.2 mg/d; women 1.1 mg/d  Prolonged deficiency leads to beriberi...  Occ

The Water Soluble Vitamins: B and C

Chapter 10

Nalini Narahari

Overview of Vitamins

 Vitamins are organic substances required in minute quantities (micrograms to milligrams)

 Vita means life; amine: nitrogen containing

 The first vitamins discovered has nitrogen

 Specific functions include:

 Nurture growth; reproduction; maintain life

 Prevent deficiency diseases

 Do not provide energy;

 Help the enzymes that release energy from the

• Vitamins present in foods are ingested

• Required in small quantities; measured in micro grams and milligrams

• Know the terms:

• Bioavailability; precursors; coenzymes

 Water soluble vitamin

 Part of the coenzyme, Thiamin Pyro Phosphate (TPP)

 Assists in energy metabolism

 Men 1.2 mg/d; women 1.1 mg/d

 Prolonged deficiency leads to beriberi

 Severe thiamin deficiency in alcohol abusers: Wernicke- Korsakoff syndrome

 Disorientation

 Loss of short term memory

 Jerky eye movements

 Staggering gait

 Food sources:

 Whole grain, fortified and enriched products

 Pork; ham

 Acts as coenzyme in many metabolic reactions

 Flavin Mono Nucleotide (FMN)

 Stable when heated

 Breaks down in light and radiation

 Milk sold in opaque/translucent containers

 Men 1.3 mg/d women 1.1 mg/d

 Occurs as nicotinic acid and nicotinamide

 Body transforms nicotinic acid to nicotinamide, a major form of niacin in the blood

 Body can make niacin from its precursor,

tryptophane

 Stable in heat

 Recommendations: 1998 RDA

 Men 16 mg/d Women 14 mg/d

 Milk; eggs, meat, poultry, fish,

 Whole grains and enriched products

 All protein containing foods

 About 2-dozen raw eggs!

 Symptoms include skin rash, hair loss, and

neurological impairments

 Food sources:

 Organ meats, egg yolks, soybeans, fish, whole

grains

Vitamin B6

 Occurs in three forms

 These forms can be converted to the coenzyme, pyridoxal phosphate (PLP)

 PLP can transfer amino acids, and thus body can make nonessential amino acids

 Alcohol interacts with Vitamin B6

 Destroys and makes it unavailable to the body

 The drug INH prescribed to treat tuberculosis acts

as an antagonist to the vitamin

 B6 supplements are given to patients

 B6 & carpal tunnel syndrome/oral contraceptives

 Recommendations:

 Adults (19-50 years) 1.3 mg/d

 Deficiency rarely occurs

 Symptoms include depression, confusion

 Toxicity first reported in 1983

 Women taking more than 2 mg of B6/day (PMS)

 Correlation between B6 and carpal tunnel syndrome not conclusive

 Food sources:

Folate (Folic Acid)

 Involved in protein metabolism

 Critical role in the synthesis of DNA

 Involved in new cell development

 Requires the help of the vitamin B12

 Folate is secreted into the GI tract with bile

 If the cells of the GI tract are injured/destroyed as

in the case of alcohol abuse, then folate can not

be absorbed, and leads to deficiency

 Unstable; destroyed by heat and oxygen

 Caution with food processing, preparation and storage

 Recommendations: 1998 RDA

 Adults 400 micrograms

 The difference in bioavailability of folate

from food versus supplements considered before setting the RDA for folate

 Deficiency leads to macrocytic or

megaloblastic anemia, and GI tract

deterioration

 Diarrhea, fatigue, depression and confusion

 Impairs cell division and protein synthesis

 Alters DNA metabolism

 Reported in babies fed on goat’s milk

 Folate perhaps most affected by drug interaction which has similar chemical structure

 Can lead to secondary deficiency

 Cancer cells need folate to multiply;

 Anti cancer drugs can create deficiency of folate

to other normal cells

 Antacids and aspirins interfere with folate

 Smoking and oral contraceptives affect

 FDA has mandated that grains should be fortified with folate ( on the food label)

 Folate and heart disease:

 Research studies have identified the role of folate

in defending against heart disease

 Folate deficiency may mask the vitamin B12 deficiency

 Food Sources:

 Fortified grains, green leafy vegetables(foliage), legumes, seeds, and liver

Vitamin B12 Cobalamin

 Close relationship between vitamin B12 and folate

 Depend on each other for activation

 Microwave cooking destroys B12

 Intrinsic factor:

 The HCL and pepsin in the stomach

release B12 from the protein foods to which

 The next step the intrinsic factor attaches

to B12

 Then the whole complex passes to the

small intestine where the gradual

absorption of B12 occurs

 Reabsorption of B12 happens continuously

 Adults 2.4micrograms

 Deficiency caused by inadequate absorption rather than poor intake

 Lack of HCL or lack of intrinsic factor

 Without HCL, the vitamin cannot be released from protein, and cannot attach to intrinsic factor

 Result is pernicious anemia due to a combination

of atrophic gastritis and lack of intrinsic factor

 Other factors are defective gene for intrinsic factor,

or if the stomach is injured or damaged

 In that case B12 must be injected

 Nasal spray of B12; absorption is rapid

 High dose of folate masks B12 deficiency

 In both deficiency states, the first symptom is that the blood cells grow rapidly

 Either of the vitamins-supplement will be effective

 However if folate is administered when B12 is

needed, the situation will be disastrous

 Results in devastating neurological symptoms

 B12 deficiency leads to nerve damage caused by destruction of myelin sheaths that protect the nerves

 Note: folate can clear the blood symptoms but cannot stop the nerve damage

 Food sources:

 Animal sources: meat, fish, poultry, eggs, shellfish, milk/products, fortified cereals; soy milk with B 12

Non- B Vitamins

 Choline:

 Body can synthesize; needed for the

synthesis of acetyl choline, a

neurotransmitter, and Phospholipid lecithin

 Deficiency may cause liver damage

 1998 AI men 550 mg/d; women 425 mg/d

 Food sources;

 Milk, liver,eggs and peanuts

 Inositol and carnitine:

 Nonessential nutrients synthesized in the

body from glucose and amino acids

respectively

 Inositol used in cell membranes

 No recommendations for either

 Vitamin imposters: caution!

 PABA; bioflavinoids, quinone, coenzyme Q10, B5,

Vitamin C: Ascorbic Acid

Vitamin C was isolated in 1930s

James Lind, a British physician did the first nutrition experiment on 12 sailors

 The pair who received the citrus fruits

recovered from scurvy

Functions include:

 Acts as an antioxidant

 Protects lipids in the blood and cell membranes from oxidative damage

 Assists in collagen formation as a cofactor

 Collagen is the main structural protein in bones, teeth and connective tissues

 Helps in the hydroxylation of carnitine

 Conversion of tryptophane to neurotransmitters serotonin and norepinephrine

 Cure for common cold and stress relief:

 Research is still inconclusive

 Vitamin C enhances iron absorption and regulates the absorption of copper

 Men 90 mg/d women 75 mg/d

 Smokers =35 mg/d

 Deficiency leads to scurvy

 Bleeding gums; pinpoint hemorrhage

 Fatigue; microcytic anemia

 Loss of appetite

 Slow wound healing; frequent infections

 Scaly and dry skin; neurological symptoms

 Toxicity:

 Nausea, abdominal cramps and diarrhea

 Interference with medical diagnostic tests

 False positive or false negative to detect diabetes

 Individuals taking anticlotting medication may counteract the effect if they take high doses of Vitamin C

 Also people with kidney disease

 Rebound scurvy:

 When mega doses of Vitamin C are taken, body excretes it rapidly

 When abruptly stopped, the body is unable

to stop excreting immediately

 Result is a state of Vitamin C deficiency

 Even though few studies to support the

theory, the Supplements need to be

tapered off

 Food sources:

 Citrus fruits, cabbage type of vegetables, green

leafy vegetables, cantaloupe, strawberries, lettuce, tomatoes, potatoes, papaya and mango

 Protect foods rich in vitamin C

 Store in airtight wrappers

 Close the lids tight

 Do not over cook the vegetables and do not

waste water after cooking

The Water Soluble Vitamins

Highlight Section

 Vitamin and mineral supplements

 Correct overt deficiencies

 Improve nutrition status

 Reduce disease risks

 Support increased needs

 Improve body’s defenses

 Toxicity issues; misleading claims; cost

 Regulation of supplements