Vitamin

Shinta Rosalia Dewi

Introduction

• Vitamins are organic (carbon) compounds neededfor normal function, growth and maintenance.

• Vitamins are minor components of foods thatplay an essential role in human nutrition.

• Several of the vitamins influence the chemicalnature of food, by functioning as reducing agents,radical scavengers, reactants in browningreactions, and flavor precursors

• Some vitamins occur in foods as provitamins—compounds that are not vitamins but can bechanged by the body into vitamins.

The sources of vitamins

• Meats, poultry, fish, and beans provide thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, and vitamin B12.

• Milk and milk products provide vitamins A and D, riboflavin, pyridoxine, and vitamin B12.

• Bread and cereals provide thiamin, riboflavin, niacin, pyridoxine, folate, pantothenic acid, and biotin.

• Fruits and vegetables provide vitamins A and K, ascorbic acid, riboflavin, and folate.

• Fats and oils provide vitamins A and E.

Classification

• Water-soluble vitamins travel in the blood and are stored in limited amounts. These are readily excreted from the body through urine.

• Fat-soluble are stored in the liver and fatty tissues. These are not readily excreted from the body.

Vitamin Differences

Water Soluble

Vitamins

Fat Soluble Vitamins

Absorption Directly into blood Along with lipids through lymphatic system

Storage Circulate freely in water filled parts of body

Stored with fat

Excretion Excesses through urine

Not as easily excreted; stored in body

Toxicity Possible from supplements

More easily reaches toxic levels - from supplements

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The Nature of Vitamins

• Nutritional Value lost by:

– Light

– Heat

– Oxidation

– Bacteria

– Enzymes

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Water Soluble Vitamins

• Vitamin C

• B1, thiamine

• B2, riboflavin

• B6, pyridoxamine

• B12

• Biotin

• Panothenic acid

• Niacin

• Folacin

Vitamin C (L-ascorbic acid)

• This vitamin occurs in all living tissues, where it influences oxidation-reduction reactions.

• Vitamin C is widely distributed in nature, mostly in plant products such as fruits (especially citrus fruits), green vegetables, tomatoes, potatoes, and berries.

• The only animal sources of this vitamin are milk and liver.

Functions

– amino acid metabolism

– collagen synthesis

– helps absorb heme-iron

– immune system function

– antioxidant

• Vitamin C is the least stable of all vitamins and is easily destroyed during processing and storage.

• The rate of destruction is increased by the action of metals, especially copper and iron, and by the action of enzymes

• Exposure to oxygen, prolonged heating in the presence of oxygen, and exposure to light are all harmful to the vitamin C content of foods.

• Because oxygen is required for the breakdown, removal of oxygen should have a stabilizing effect. For the production of fruit drinks, the water should be deaerated to minimize vitamin C loss.

• Enzymes containing copper or iron are efficient catalysts of ascorbic acid decomposition.

• In fruit juices, the enzymes can be inhibited by pasteurization, deaeration, or holding at low temperature for a short period.

• Ascorbic acid is oxidized in the presence of air under neutral and alkaline conditions.

• At acid pH (for example, in citrus juice), the vitamin is more stable.

B-1 Thiamin

• Important in:

– Producing energy from carbohydrates

– proper nerve function

– stabilizing the appetite

– promoting growth and good muscle tone

– ATP production

Struktur thiamin

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pyrimidine thiazole

Sources of B-1

• Pork

• Fish

• Liver

• Nuts

• Whole grain or enriched breads and cereals

B-1 Deficiency

• Loss of appetite

• Weakness & Feeling tired

• Insomnia

• Loss of weight

• Depression

• Heart & Gastrointestinal problems

B-2 Riboflavin

• Important in:

– energy production

– carbohydrate, fat, and protein metabolism

– formation of antibodies and red blood cells

– cell respiration

–maintenance of good vision, skin, nails, and hair

– alleviating eye fatigue

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Sources of B-2

• Large amounts in

–dairy

– eggs

–meats

• Small amounts in

– leafy green vegetables

– enriched grains

B-2 Deficiency

• Itching and burning eyes

• Cracks and sores in mouth and lips

• Bloodshot eyes

• Dermatitis

• Oily skin

• Digestive disturbances

B-3 Niacinamide & Niacin

• Important in:

– energy production

–maintenance of skin and tongue

– improves circulation

–maintenance of nervous system

–health of the digestive track

B-3 Niacinamide & Niacin

• Two Types

–Niacinamide (Nicotinamide)

• does not regulate cholesterol

–Niacin (Nicotinic Acid)

• highly toxic in large doses

• Inosital Hexaniacinate is a supplement that gives the cholesterol regulation without high toxicity

Niacin

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B-3 Deficiency

• Pellegra– Dermatitis

– Diarrhea

– Dementia

– Death

• Gastrointestinal disturbance, loss of appetite• headache, insomnia, mental depression• fatigue, aches, and pains• nervousness, irritability

B-6 Pyridoxine

• Important in:– Production of red blood cells

– conversion of tryptophan to niacin (B-3)

– immunity

– nervous system functions

– reducing muscle spasms, cramps, and numbness

– maintaining proper balance of sodium and phosphorous in the body

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B-6 Deficiency

• nervousness, insomnia

• loss of muscle control, muscle weakness

• arm and leg cramps

• skin lesions

B-12 Cobalamin

• Important in:

– proper nerve function

– production of red blood cells

– metabolizing fats and proteins

– prevention of anemia

– DNA reproduction

– energy production

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B-12 Deficiency

• anemia

• nerve damage

• hypersensitive skin

FAT-SOLUBLE VITAMINS

• Vitamin A

• Vitamin D

• Vitamin E

• Vitamin K

Vitamin A (Retinol)

• Highest levels of vitamin A are found in certain fish liver oils, such as cod and tuna.

• Other important sources are mammalian liver, egg yolk, and milk and milk products.

• The synthetic vitamin A is made as acetate or palmitate and marketed commercially in the form of oil solutions, stabilized powders, or aqueous emulsions.

• The compounds are insoluble in water but soluble in fats, oils, and fat solvents.

• Vision – Generates pigments for the retina

– Maintains surface lining of eyes

• Bone growth

• Reproduction

• Cell division and differentiation

• Healthy Skin

• Regulate Immune System

Source

• Animal Sources – Eggs

– Meat

– Cheese

– Milk

– Liver

– Kidney

– Cod

– Halibut fish oil

Plant Sources

• Carrots

• Sweet Potatoes

• Cantaloupe

• Pink Grapefruit

• Apricots

• Broccoli

• Spinach

• Pumpkin

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Structure

Lots of double bonds, good anti-oxidant

• There are several provitamins A; these belong to the carotenoid pigments. The most important one is β-carotene, and some of the pigments that can be derived from it are of practical importance.

• Beta-carotene occurs widely in plant products and has a high vitamin A activity.

• Citrus fruits are a good source of provitamin A, which results m the presence of β-cryptoxanthin, β-carotene, and α-carotene.

• Gross (1987) reported a total of 16 carotenoids with provitamin A activity in citrus fruits.

• Because of the highly unsaturated character of the molecule, it is quite susceptible to oxidation— especially under the influence of light, whether sunlight or artificial light.

• Vitamin A is unstable in the presence of mineral acids but stable in alkali.

• Vitamin A and the carotenoids have good stability during various food processing operations

• Losses may occur at high temperatures in the presence of oxygen.

• The form in which vitamin A is added to food products may influence its stability.

• Vitamin A in beadlet form is more stable than that added as a solution in oil.

• The beadlets are stabilized by a protective coating. If this coating is damaged by water, the stability of the vitamin is greatly reduced

Deficiency

• Night blindness

• Decreased resistance to infections

• Extremely dry skin, hair or nails

Too Much Can Be Toxic!!

• Hypervitaminosis A leads to toxic symptoms:

– Dry, itchy skin

– Headaches and fatigue

– Hair loss

– Liver damage

– Blurred vision

– Loss of appetite

– Skin coloration

Vitamin D

• This vitamin occurs in several forms; the two most important are vitamin D2, or ergocalciferol, and vitamin D3, or cholecalciferol.

• Vitamin D2 occurs in small amounts in fish liver oils;

• vitamin D3 is widely distributed in animal products, but large amounts occur only in fish liver oils. Smaller quantities of vitamin D3 occur in eggs, milk, butter, and cheese

• The precursors of vitamins D2 and D3 are ergosterol and 7-dehydrocholesterol

• These precursors or provitamins can be converted into the respective D vitamins by irradiation with ultraviolet light.

• The provitamins can be converted to vitamin D in the human skin by exposure to sunlight.

• Margarine and milk are the foods commonly used as carrier for added vitamin D

• Vitamin D is extremely stable, and little or no loss is experienced in processing and storage.

• Vitamin D in milk is not affected by pasteurization, boiling, or sterilization

• Frozen storage of milk or butter also has little or no effect on vitamin D levels, and the same result is obtained during storage of dry milk.

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Vitamin D

• Can be stored in fat tissues (as can all fat soluble vitamins)

• We get vitamin D form fortified milk and cereal

• Toxicity is very dangerous

–Occurs only from excess supplementation

–Can lead to calcium deposits in kidneys, heart and blood vessels

Tocopherols (Vitamin E)

• The tocopherols are derivatives of tocol, and the occurrence of a number of related substances in animal and vegetable products has been demonstrated.

• Cotton seed oil was found to contain α -, β-, and γ-tocopherol, and a fourth, δ-tocopherol, was isolated from soybean oil.

• Baltes (1967) carried out tests in which two easily oxidizable fats, lard and partially hydrogenated whale oil, were stabilized with α-tocopherol and ascorbyl palmitate and citric acid as synergists.

• Without antioxidants, these fats cannot be used in the commercial food chain

• Processing and storage of foods can result in substantial tocopherol losses

• Loss of tocopherol during frying of potato chips

• Boiling of vegetables in water for up to 30 minutes results in only minor losses of tocopherol.

• Baking of white bread results in a loss of about 5 percent of the tocopherol in the crumb.

Vitamin K

• Can be divided into two groups : vitamin K1 and vitamins K2

• Vitamin K1 is slowly decomposed by atmospheric oxygen but is readily destroyed by light.

• It is stable against heat, but unstable against alkali.

Vitamin K1

• Good sources of vitamin K are dark green vegetables such as spinach and cabbage leaves, and also cauliflower, peas, and cereals.

• Animal products contain little vitamin K1, except for pork liver, which is a good source.