Essential Nutrients

Essential Nutrients – required for normal growth but not synthesized in the body and therefore necessary in the diet

1. Carbohydrates

2. Fats

3. Protein

4. Vitamins

5. Minerals

6. Water

CLASSIFICATION OF NUTRIENTS

A. According to their function in the body

1. Energy giving nutrients

Carbohydrates
Fats
Protein

2. Body building nutrients

Proteins make up the 20 % or 1/5 of the total body weight.
Fat nutrients make up another 20 % or 1/5 of the body weight.
Carbohydrates make up about 1%

3. Body regulating nutrients

Minerals make up the 4% of the body weight.
Vitamins make up about 28 grams of the body weight.
Water makes up approximately 60% of the body weight.

B. According to its chemical properties

1. Organic - nutrients that contain the element of carbon (C)

Carbohydrates
Fats
Protein
Vitamins

2. Inorganic - nutrients that do not contain carbon element

Minerals
Water

C. According to its mass

- the quantity necessary for cells and organisms to thrive

1. Macronutrients - are required in large quantities; involved as substrates in metabolic processes for energy

Proteins
Carbohydrates
Fats
Water (but not a substrate for energy)

2. Micronutrients - are needed in small quantities; involved in regulating metabolism and energy processes, but not as substrates.

Vitamins
Minerals.

CARBOHYDRATES

- composed of carbon, hydrogen, and oxygen (CHO)

FUNCTIONS

Providing energy - provides 4 kcal / gram
Protein-sparing action - they spare proteins for their primary function of building and repairing body tissues
Normal fat metabolism (antiketogenic) - prevent need for fat oxidation in the cells that can produce substances called ketones.
Providing fiber - fiber creates a soft, bulky stool that moves quickly through the large intestine

B. FOOD SOURCES
1. The principal sources are plant foods:

cereal grains
vegetables
fruits
sugars

2. The only substantial animal source is milk

Classification of Carbohydrates
A. Monosaccharides - are the simplest form of carbohydrates.

1. Glucose

- also called dextrose found naturally in corn syrup, some fruits and vegetables.

- is the form of carbohydrate to which all other forms are converted for eventual metabolism the central nervous system, the red blood cells, and the brain use only glucose as fuel; therefore, a continuous source is needed.

2. Fructose

- also called levulose or fruit sugar,

- is found with glucose in many fruits and in honey.

- is the sweetest of all the monosaccharides.
3. Galactose

- is a product of the digestion of milk.

- is not found naturally.

B. Disaccharides - are pairs of two monosaccharides - are sweet and must be changed to simple sugars by hydrolysis before they can be absorbed.

1. Sucrose - glucose + fructose; one of the sweetest and least expensive sugars

present in granulated, powdered, and brown sugar and in molasses

2. Maltose – glucose + glucose

an intermediary product in the hydrolysis of starch
produced by enzyme action during the digestion of starch in the body
also is created during the fermentation process that produces alcohol

3. Lactose – galactose + glucose

the sugar found in milk,
helps the body absorb calcium.
less sweet than monosaccharides or other disaccharides

C. Polysaccharides - commonly called complex carbohydrates because they are compounds of many monosaccharides (simple sugars)
1. Starch - storage form of glucose in plants

• it takes the body longer to digest them, thus, they supply energy over a longer period of time.

2. Glycogen - it is the storage form of glucose in the body (liver and muscles)

• sometimes called animal starch

• the hormone glucagon helps the liver convert glycogen to glucose as needed for energy.
3. Dietary fiber - also called roughage, is indigestible because it cannot be broken down by digestive enzymes.

Classification of Dietary Fiber
1. Insoluble fibers - it does not readily dissolve in water

Cellulose - is a primary source of dietary fiber

• no nutritional value but provides bulk for the stool.

Hemicellulose - is found mainly in whole-grain cereal.

• some is soluble; some is not.

Lignin - are the woody part of vegetables such as carrots and asparagus or the small seeds of strawberries

2. Soluble fibers - partially dissolves in water and form a gel that helps provide bulk for

the intestines

• they are useful also because they bind cholesterol, thus reducing the amount the blood can absorb.

pectin - edible thickening agent

mucilage - gel-forming dietary fiber

DIGESTION AND ABSORPTION AND METABOLISM of CARBOHYDRATES

monosaccharides - are absorbed from the intestine directly into the bloodstream, carried to the liver, where fructose and galactose are changed to glucose.
disaccharides - must be converted to the simple sugar glucose before they can be absorbed into the bloodstream
polysaccharides - are more complex, and their digestibility varies, after the cellulose wall is broken down,
starch is changed to the intermediate product dextrin; it is then changed to maltose and finally to glucose.
blood then carries glucose to the cells for oxidation to yield energy.
glucose metabolism is controlled mainly by the hormone insulin.
excess glucose is converted to glycogen and is stored in the liver and muscles.
when more glucose is ingested than the body can either use immediately or store in the form of glycogen, it is converted to fat and stored as adipose (fatty) tissue.
The only waste products of carbohydrate metabolism are carbon dioxide and water (except with cellulose)

CARBOHYDRATES DEFICIENCY
Marasmus - a condition resulting from severe malnutrition, afflicts very young children who lack both energy and protein foods as well as vitamins and minerals.

Ketosis - abnormal increase of ketone bodies in the body due to reduced or disturbed carbohydrate metabolism because of burning fat for daily fuel rather than glucose sourced from carbohydrates

CARBOHYDRATES EXCESSIVE CONSUMPTION
Obesity - excessive accumulation of body fat, usually caused by the consumption of more calories than the body can use.
Diabetes Type 2 - a disease in which the body’s ability to produce or respond to the hormone insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood and urine.
Cardiovascular Diseases - disease is the broad term for problems with the heart and blood vessels. These problems are often due to atherosclerosis.

PROTEINS

• comes from the Greek word “protos”, which means primary.

• approximately 18% to 20% of the human body is protein

• composed of carbon, hydrogen, oxygen and nitrogen

• made up of about 16% nitrogen, in both body tissue and food

• Nitrogen or protein balance of the body is an important factor in determining the body’s health

• Nitrogen is an essential element for all forms of life and is the structural component of amino acids from which animal and human tissues, enzymes, and many hormones are made.

Amino acids - compounds containing nitrogen and the building blocks of the protein molecule.
Polypeptides - a linear organic polymer consisting of a large number of amino-acid bonded together in a chain.

Antibody - a protein substance produced within the body that destroys or weakens harmful viruses and bacteria
Biologic value of protein (BV) - the ability of a protein to support the formation of body tissue.
Complete protein - a protein containing all the essential amino acids and are of high biologic value.
Incomplete protein - a protein lacking one or more of the essential amino acids or containing some of the amino acids in only very small amounts
Essential amino acids - amino acids that cannot be synthesized by the body and must be provided by food.
Nonessential amino acids: amino acids that can be synthesized by the body to meet its needs.
Kwashiorkor - a severe protein deficiency disease that occurs in infancy or early childhood and in high-risk hospitalized patients.
primary function is to build and repair body tissues.
important components of hormones and enzymes that are essential for the regulation of metabolism and digestion.
help maintain fluid and electrolyte balances in the body and thus prevent edema (abnormal retention of body fluids) - ONCOTIC PRESSURE
are essential for the development of antibodies and, consequently, for a healthy immune system
provide energy if and when the supply of carbohydrates and fats. in the diet is insufficient
each gram provides 4 kilocalories.
Proteins in the form of amino acids are not stored therefore, a daily intake is required.
Animal sources of protein (high biologic value) include milk and milk products, meat, fish, poultry, and eggs.
Plant sources (low biologic value) include breads and cereal products, legumes, nuts, and seeds, and textured vegetable protein

DIGESTION, ABSORPTION AND METABOLISM OF PROTEIN

mechanical digestion begins in the mouth and continue in the stomach chemical digestion occurs in the stomach and small intestine.
hydrochloric acid converts pepsinogen to enzyme pepsin - reduce protein to polypeptides pancreatic enzymes in the small intestine (trypsin, chymotrypsin, and carboxypeptidase) continue the chemical digestion of the polypeptides.
Intestinal peptidases finally reduce polypeptides to amino acids- amino acids are absorbed by the villi into the bloodstream transported via the portal vein to the liver and are carried by the blood to all body tissues to build new ones.

some amino acids stay in the liver to form liver tissue itself or to produce a wide variety of blood proteins
some (excess) amino acids are broken down, the nitrogen containing part is split off from the carbon chain. (deamination)
remaining parts are used for energy or are converted to carbohydrate or fat and stored as glycogen or adipose tissue

Essential Amino Acids —that which cannot be produce by the body and must be obtained from food.

Arginine (essential during childhood)
Methionine
Histidine (essential during infancy)
Leucine
Phenylalanine
Valine
Threonine
Lysine
Isoleucine
Tryptophan
(8 essential amino acids are required by adults and 9 are required by infants)

Nonessential Amino Acids — that which can be produced by the body

Alanine
Proline
Glutamine
Aspartic acid
Arginine (essential during childhood)
Cysteine
Histidine (essential during infancy)
Serine
Glycine
Glutamic acid
Asparagine
Tyrosine

NITROGEN BALANCE

nitrogen balance - when nitrogen intake equals nitrogen excreted.

positive nitrogen balance - exists when nitrogen intake exceeds the amount excreted.

this indicates that new tissue is being formed, and it occurs during pregnancy, during children’s growing years, when athletes develop additional muscle tissue, and when tissues are rebuilt after physical trauma such as illness or injury.

negative nitrogen balance - indicates that protein is being lost.

it may be caused by fevers, injury, surgery, burns, starvation, or immobilization

PROTEIN DEFICIENCY

muscle wasting will occur, and arms and legs become very thin
albumin deficiency will cause edema, resulting in an extremely swollen appearance.
children who lack sufficient protein do not grow to their potential size.
Infants born to mothers eating insufficient protein during pregnancy can have permanently impaired mental capacities.
Protein Energy Malnutrition (PEM) - lack both protein and energy-rich foods.
Kwashiorkor appears when there is a sudden or recent lack of protein containing food; edema; reddish pigmentation of hair and skin; fatty liver; retardation of growth in children; diarrhea; dermatosis; decreased T-cell lymphocytes with increased secondary infections

PROTEIN Excess Consumption

Azotemia - is an elevation of blood urea nitrogen (BUN) and serum creatinine levels.
Hyperammonemia - is a metabolic condition characterized by the raised levels of ammonia, a nitrogen-containing compound.

Lipids (Fats)

the word lipid is derived from “lipos” a Greek word for fat.
are greasy substances that are not soluble in water
are composed of carbon, hydrogen, and oxygen but with a substantially lower proportion of oxygen
triglycerides, phospholipids and sterols are all lipids found in food and human
fatty acids - are organic compounds of carbon atoms to which hydrogen atoms are attached, building blocks of fats.

FUNCTIONS

fats are a necessary part of cell membranes (cell walls)
act as carriers for fat-soluble vitamins A, D, E, and K
fat stored in body tissues provides energy when one cannot eat, each gram of fat contains 9 kilocalories.
Adipose (fatty) tissue protects organs and bones from injury by serving as protective padding and support
Body fat also serves as insulation from cold
fats provide a feeling of satiety (satisfaction) after meals

FOOD SOURCES

fats are present in both animal and plant foods.
animal foods that provide the richest sources of fats are fatty meats, cream whole milk lard, butter, egg yolk cheese
plant foods containing the richest sources of fats are vegetable oils avocados, nuts, olives, chocolate margarine
visible fats in food - fats that at are purchased and used as fats such as butter, margarine, lard and cooking oils.
hidden or invisible fats - found in other foods such as meat, cream, whole milk, cheese, egg yolk, fried foods, pastries, avocados, and nuts

Classification of Fatty Acids
A. According to Essentiality

Essential fatty acids (EFAs) - are necessary fats that humans cannot synthesize; must be obtained through diet.

are long-chain polyunsaturated fatty acids derived from linoleic, linolenic and oleic acids
two families of EFAs: omega-3 and omega-6

Necessary but nonessential fatty acids - the body can manufacture a modest amount, provided EFAs are present.

they are the omega-9 fatty acids

B. According to Degree of Saturation

1. Saturated Fatty Acids

its carbon atoms carry all the hydrogen atoms possible.
animal foods contain more saturated fatty acids.
plant foods that contain substantial amounts of saturated fatty acids are chocolate, coconut, palm oil, palm kernel oils.
foods containing a high proportion of saturated fats are usually solid at room temperature.
it is recommended that one consume no more than 7% of total daily calories as saturated fats.

2. Monounsaturated Fats

there is one place among the carbon atoms of its fatty acids where there are fewer hydrogen atoms attached than in saturated fats.
examples of foods are olive oil, peanut oil, canola oil, avocados, and cashew nuts
research indicates that monounsaturated fats lower the amount of low-density lipoprotein (LDL) (“bad cholesterol”) in the blood, but only when they replace saturated fats in one’s diet
it is recommended that one consume 15% of total daily calories as monounsaturated fats

C. Polyunsaturated Fats

▪ there are two or more places among the carbon atoms of its fatty acids where there are fewer hydrogen atoms attached than in saturated fats

The two major fatty acids denoted by the placement of their double bonds are:

Omega-3 fatty acids have been reported to help lower the risk of heart disease

ALA (alpha-linolenic acid) – omega 3 fatty acids found in plants
EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – found in fish and seafoods

Omega-6 has a cholesterol-lowering effect.

LA (Linoleic Acid)
ARA (Arachidonic Acid)
GLA (Gamma Linoleic Acid)
CLA (Conjugated Linoleic acid)

▪ foods containing polyunsaturated fats include cooking oils made from sunflower, safflower, or sesame seeds or from corn or soybeans; soft margarines whose major ingredient is liquid vegetable oil;

▪ fatty fish is rich source of omega 3

▪ foods containing high proportions of polyunsaturated fats are usually soft or oily

▪ Polyunsaturated fats should not exceed 8% of total daily calories.

D. Trans-Fatty Acid

Trans-fatty acids (TFAs) are produced when hydrogen atoms (hydrogenation) are added to monounsaturated or polyunsaturated fats to produce a semisolid product like margarine and shortening.
major source of TFAs in the diet is from baked goods and foods eaten in restaurants.
TFAs raise LDLs and total cholesterol.
Hydrogenation - turns polyunsaturated vegetable oils into saturated fats.
Margarine is made in this way

Common Lipid Compounds

TRIGLYCERIDES

are composed of three (tri) fatty acids attached to a framework of glycerol.
Glycerol is derived from a water-soluble carbohydrate.
constitute (95%) of lipids in the body, they are in body cells, and they circulate in the blood

CHOLESTEROL

Cholesterol is a sterol
It is not a true fat but a fatlike substance that exists in animal foods and body cells, does not exist in plant foods.
essential for the synthesis of bile, sex hormones, cortisone, and vitamin D and is needed by every cell in the body
the body manufactures 800 to 1,000 mg of cholesterol a day in the liver
is a common constituent (part) of one’s daily diet because it is found so abundantly in egg yolk, fatty meats, shellfish, butter, cream, cheese, whole milk, and organ meats (liver, kidneys, brains, sweetbreads)
Cholesterol is thought to be a contributing factor in heart disease because high serum cholesterol, also called hypercholesterolemia, is common in clients with atherosclerosis

LECITHIN

Lecithin is a fatty substance classified as a phospholipid.
It is found in both plant and animal foods and is synthesized in the liver.
It is a natural emulsifier that helps transport fat in the bloodstream.
It is used commercially to make food products smooth

VITAMINS

are organic (carbon-containing) compounds that are essential in small amounts for body processes
do not provide energy but enable the body to use the energy provided by carbohydrates, fats, and proteins
the name vitamin implies their importance “Vita” in Latin, means life.
are found in minute amounts in foods

Classification of Vitamins

1. Fat-Soluble Vitamins

Vitamins A, D, E, and K
they are not lost easily in cooking but are lost when mineral oil is ingested.
fat-soluble vitamins are transported through the blood by lipoproteins because they are not soluble in water.
excess amounts can be stored in the liver.
megadoses should be avoided to prevent toxicity.

2. Water-Soluble Vitamins

include Vitamin B Complex and Vitamin C
these vitamins dissolve in water and are easily destroyed by air, light, and cooking.
they are not stored in the body to the extent that fat-soluble vitamins are stored

Fat Soluble Vitamins

VITAMIN A

Retinol - active form of vitamin A, can be converted to retinal and retinoic acid (other active forms)

found in fat-containing animal foods such as liver, butter, cream, whole milk, whole-milk cheeses, and egg yolk,
also found in low-fat milk products and in cereals fortified with vitamin A

Carotenoids - inactive form of vitamin A, which are found in plants.

common carotenoids are beta-carotene, lutein, lycopene, and zeaxanthin.
beta-carotene is most efficiently converted to retinol.
important role in vision, bone growth, reproduction, and cell division, regulate the immune
system
carotenoids are labeled as an antioxidant.
beta-carotene - best sources are carrots, sweet potatoes, spinach, broccoli, pumpkin, squash (butternut), mango, and cantaloupe

A retinol equivalent (RE) is 1 μg retinol or 6 μg beta carotene or 3.33 IU (international units)

hypervitaminosis A (excessive intake of vitamin A) – signs include birth defects, hair loss, dry skin, headaches, nausea, dryness of mucous membranes, liver damage, and bone and joint pain

deficiency signs include night blindness; dry, rough skin; and increased susceptibility to infections.

avitaminosis A (serious lack of vitamins A) - can result in blindness or xerophthalmia, a condition characterized by dry, lusterless, mucous membranes of the eye.

lack of vitamin A is the leading cause of blindness in the world.

VITAMIN D

D2 (ergocalciferol) is formed in plants.
D3 (cholecalciferol) that is formed in humans from cholesterol in the skin.
- each is formed from a provitamin when irradiated with (exposed to) ultraviolet light
- both are equally effective in human nutrition.
Vitamin D is heat-stable and not easily oxidized.
Vitamin D is converted to a hormone.
promotes calcium and phosphorus absorption in the body for normal bone and tooth mineralization to occur and prevents tetany (involuntary muscle movement)
best source is sunlight, which changes a provitamin to vitamin D3 in humans.
best food sources of vitamin D are milk, fish liver oils, egg yolk, butter, and fortified argarin
Vitamin D levels are given as Adequate Intake (AI)
Hypervitaminosis D must be avoided because it can cause deposits of calcium and phosphorus in soft tissues, kidney and heart damage, and bone fragility
vitamin D deficiency inhibits the absorption of calcium and phosphorus in the small intestine and results in poor bone and tooth formation.
children may develop rickets, adults may develop osteomalacia - softening of bones.
A deficiency contributes to osteoporosis (brittle, porous bones).

VITAMIN E

Tocopherols and Tocotrienols
- an antioxidant, aided by vitamin C and the mineral selenium.
- found helpful in the prevention of hemolytic anemia among premature infants.
- enhance the immune system.
- used in commercial food products to retard spoilage.
Vegetable oils made from corn, soybean, safflower, and cottonseed and products made from them, such as margarine, are the best sources of vitamin E
wheat germ, nuts, and green leafy vegetables also are good sources.
the vitamin E requirement increases if the amount of polyunsaturated fatty acids in the diet increases appears to be relatively nontoxic, excess is stored in adipose tissue.
Deficiency is detected in premature, low-birthweight infants and in patients who are unable to absorb fat normally.
malabsorption can cause serious neurological defects in children, but in adults, it takes 5 to 10 years before deficiency symptoms occur.

VITAMIN K

is absorbed from the small intestine and slightly from the colon.
Vitamin K1 - phylloquinone, is found in green leafy vegetables such as spinach and in animal tissue.
Vitamin K2 - menaquinone, is synthesized in the intestine by bacteria and is also found in animal tissue.
vitamin K - menadione – synthetic vitamin K
essential for the formation of prothrombin
may be given to newborns immediately after birth because human milk contains little vitamin K
may be given to patients who suffer from faulty fat absorption.
may be given to patients after extensive antibiotic therapy.
as an antidote for an overdose of anticoagulant (blood thinner such as warfarin) or to treat cases of hemorrhage
cow’s milk is a much better source of vitamin K than human milk.
is provided in AIs and measured in micrograms (μg)
must be ingested daily, what is absorbed today will be utilized immediately with very little storage in the liver
ingestion of excessive amounts of synthetic vitamin K can be toxic and can cause a form of Anemia.
the only major sign of a deficiency of vitamin K is defective blood coagulation.
human deficiency may be caused by faulty fat metabolism, antacids, antibiotic therapy, inadequate diet, or anticoagulants

Water Soluble Vitamins

VITAMIN C

also known as Ascorbic Acid
is absorbed in the small intestine.
prevents scurvy.
has an important role in the formation of collagen -proteins that are the primary structural component of connective tissues.
an iron enhancer
has antioxidant properties and protects foods from oxidation, and it is required for all cell metabolisms.
it may be involved with the formation or functioning of norepinephrine, some amino acids, folate, leukocytes (white blood cells), the immune system, and allergic reactions.
believed to reduce the severity of colds.
it can reduce cancer risk in some cases by reducing nitrites in foods.
best sources are citrus fruits, melon, strawberries, tomatoes, potatoes, red and green peppers, cabbage, and broccoli.
is measured in milligrams (mg)
an average female adult requires 75 mg a day and an average male 90 mg. In times of stress, the need is increased.
cigarette smokers are advised to ingest 125 mg or more a day.
generally considered nontoxic.
an excess can cause diarrhea, nausea, cramps, an excessive absorption of food iron, rebound scurvy (when megadoses are stopped abruptly), and possibly oxalate kidney stones.
Deficiency are indicated by bleeding gums, loose teeth, tendency to bruise easily, poor wound healing, and, ultimately scurvy.

Vitamin B1 – Thiamine

a coenzyme
is absorbed in the small intestine.
is essential for the metabolism of carbohydrates and some amino acids.
also essential to nerve and muscle action
is found in many foods, but generally in small quantities.
measured in milligrams (mg)
daily thiamine requirement for the average adult female is 1.1 mg a day, and for the average adult male it is 1.2 mg a day.
an increase in calories increases the need for thiamine.
deficiency symptoms include loss of appetite, fatigue, nervous irritability, and constipation
an extreme deficiency causes beriberi - its deficiency is rare, however, occurring mainly among alcoholics.
others at risk include renal clients undergoing long-term dialysis, clients undergoing gastric bypass surgery for weight loss, and those who eat primarily rice
frequent consumption of large amounts of raw fish could cause thiamine deficiency.
there are no known ill effects from excessive oral intake of thiamine, but toxic if excessive amounts are given intravenously.

Vitamin B2 – Riboflavin

is absorbed in the small intestine.
is essential for carbohydrate, fat, and protein metabolism.
is also necessary for tissue maintenance, especially the skin around the mouth, and for healthy eyes
is widely distributed in animal and plant foods but in small amounts.
Milk, meats, poultry, fish, and enriched breads and cereals are some of its richest sources.
it is important, however, that milk be stored in opaque containers because riboflavin can be destroyed by light.
Some green vegetables such as broccoli, spinach, and asparagus are also good sources.
is measured in milligrams (mg)
average adult female daily requirement is thought to be 1.1 mg, and the adult male requirement is 1.3 mg.
requirement appears to increase with increased energy expenditure
requirement does not diminish with age.
because of the small quantities of riboflavin in foods and its limited storage in the body, deficiencies of riboflavin can develop.
deficiency can result in cheilosis.
its toxicity is unknown.

Vitamin B3 – Niacin

Niacin is the generic name for nicotinic acid and nicotinamide.
serves as a coenzyme in energy metabolism.
is essential for the prevention of pellagra.
used as a cholesterol-lowering agent.
the best sources of niacin are meats, poultry, and fish.
peanuts and other legumes are also good sources, enriched breads and cereals also contain some.
Milk and eggs do not provide niacin per se, but they are good sources of its precursor, tryptophan (an amino acid)
Vegetables and fruits contain little niacin.
is measured in as a niacin equivalent (NE)
One NE equals 1 mg of niacin or 60 mg of tryptophan.
the general recommendation is a daily intake of 14 mg/NE for adult women and 16 mg/NE for adult men
excessive amounts of niacin have caused flushing due to vascular dilation.
other symptoms include gastrointestinal problems and itching.
if excessive amounts of niacin are ingested, liver damage may result.
a deficiency of niacin is apt to appear if there is a deficiency of riboflavin.
deficiency symptoms include weakness, anorexia, indigestion, anxiety, and irritability.
in extreme cases, pellagra may occur – a disease characterized by sores on the skin and by diarrhea, anxiety, confusion, irritability, poor memory, dizziness, and untimely death if left untreated.

Vitamin B5 - Pantothenic Acid

from the Greek word pantothen that means “from many places”
is involved in metabolism of carbohydrates, fats, and proteins.
also essential for the synthesis of the neurotransmitter acetylcholine and of steroid hormones
is found extensively in foods, especially animal foods such as meats, poultry, fish, and eggs.
is also found in whole-grain cereals and legumes.
an estimated intake of 4 to 7 mg a day for normal adults
natural deficiencies are unknown.
toxicity from excessive intake has not been confirmed

Vitamin B6 – Pyridoxine

Pyridoxine, Pyridoxal, pyridoxamine
is essential for protein metabolism and absorption.
it aids in the release of glucose from glycogen.
with the help of vitamin B6, converts amino acids present in excessive amounts to those in which the body is temporarily deficient.
it also serves as a catalyst in the conversion of tryptophan to niacin.
it is helpful in the formation of other substances from amino acids.
example is the synthesis of neurotransmitters such as serotonin and dopamine.
some of the nutrient-dense sources of vitamin B6 are poultry, fish, liver, kidney, potatoes, bananas, and spinach.
is also found in whole-grain cereals especially oats and wheat.
refined grains are not a good source because this vitamin is lost during milling.
measured in milligrams (mg)
they need increases as the protein intake increases.
for adult females, the daily requirement is 1.3 to 1.5 mg and for males, 1.3 to 1.7 mg.
oral contraceptives interfere with the metabolism of vitamin B6 and can result in a deficiency.
deficiency is usually found in combination with deficiencies of other B vitamins.
symptoms include irritability, depression, and dermatitis.
in infants, its deficiency can cause various neurological symptoms and abdominal problem.
although its toxicity is rare, it can cause temporary neurological problems.

Vitamin B7 – Biotin

participates as a coenzyme in the synthesis of fatty acids and amino acids.
some of its best dietary sources are egg yolks, milk, poultry, fish, broccoli, spinach, and cauliflower.
also synthesized in the intestine by microorganisms, but the amount that is available for absorption is unknown.
measured in micrograms (μg)
an AI of 30 μg for adults
Deficiency symptoms include nausea, anorexia, depression, pallor (paleness of complexion), dermatitis (inflammation of skin), and an increase in serum cholesterol.
toxicity from excessive intake is unknown.

Vitamin B12 – Cobalamin

it is a compound that contains the mineral cobalt.
it can be stored in the human body for 3 to 5 years.
is involved in folate metabolism.
maintenance of the myelin sheath, and healthy red blood cells
in order to be absorbed, it must bind with a glycoprotein (intrinsic factor)
the best food sources of B12 are animal foods, especially organ meats, lean meat, seafood, eggs, and dairy products.
is measured in micrograms (μg)
the DRI for adults is 2 μg to 4 μg a day, but it increases during pregnancy and lactation.
deficiency is rare - caused by congenital problems of absorption.
may also be due to years of a strict vegetarian diet that contains no animal foods.
when the amount of B12 is insufficient, megaloblastic anemia may result.
if the intrinsic factor is missing, pernicious anemia develops.
deficiency may also result in inadequate myelin synthesis.
signs of vitamin B12 deficiency include anorexia, glossitis, sore mouth and tongue, pallor, neurological upsets such as depression and dizziness, and weight loss Folate
Folate, folacin, and folic acid are chemically similar compounds.
is needed for DNA synthesis, protein metabolism, and the formation of hemoglobin.