Chapter 7 – The Vitamins
Definitions and Classifications of Vitamins
Vitamins
-Organic Compounds
-Vital to life
-Indispensable to body functions
-Needed in minute amounts
-Noncaloric essential nutrients
Fat-Soluble Vitamins
-In general, absorbed into the lymph
-Travel in blood in association with protein carriers
-Stored in the liver or with other lipids in fatty tissues; some can build up to toxic concentratrions
            -Vitamin A
            -Vitamin D
            -Vitamin E
            -Vitamin K

Water-Soluble Vitamins
-Absorbed directly into the blood stream
-Travel freely in blood stream
-Most are not stored to any great extent
-Excess excreted in urine
-Lower risk of toxicity than fat-soluble vitamins
-B vitamins
Thiamin (B1)
Riboflavin (B2)
Niacin (B3)
Folate
Vitamin B12
Vitamin B6
Biotin
Pantothenic acid
-Vitamin C
Precursors = provitamins
-Transform to one or more active vitamin forms

The Fat-Soluble Vitamins
ADEK
-Found in fats and oils of foods
-Require bile for absorption
-Stored in liver and fatty tissues until the body needs them
Body can survive weeks of consuming foods that lack these vitamins
-As long as a diet as a whole provides average amounts that approximate recommended intakes
-Excess vitamins A and D from supplements can easily reach toxic levels
Deficiency is likely when diet is consistently low in fat-soluble vitamins
Fat malabsorption diseases can cause loss in dissolved undigested fat
-Likewise, mineral oil laxatives
Extraordinarily-low-fat diets
-Such diets interfere with absorption of these vitamins
Three forms active in the body
-Retinol
-Stored in the liver
-Converted to other forms as needed
-Retinal
-Retinoic acid
Plant-derived precursor: beta-carotene

Vitamin A
A Jack of All Trades
-Vision                        -Maintenance of body linings and skin
-Immune Defense       -Growth of bones and the body
-Reproduction            -Normal cell development
Control of Gene Expression
-Retinoic acid activates or deactivates certain genes
-Affecting protein production
Eyesight
-Light passes through the cornea before striking the retina
-Keratin accumulation (keratinization) of the cornea can occur with vitamin A deficiency
-Can lead to xerosis (drying) and to thickening and permanent blindness (xerophthalmia)
-If discovered early, can be reversed with vitamin A supplementation
-Can be prevented if a child regularly consumes fruits and vegetables
-The retina contains light-sensitive nerve cells
-Light bleaches the vitamin A-containing pigment rhodopsin
-This breaks off the vitamin, initiating an impulse to the optic center in the brain
-The vitamin reunites with the pigment, and there is a little vitamin A destruction
-Vitamin A must regenerate the supply
-If vitamin A supply runs low, a lag occurs before the eye can see again after a flash of bright light (night blindness)
-May indicate vitamin A deficiency
Skin and Body Linings
-Vitamin A is needed by all epithelial tissues
-These tissues serve as protection from invasion by pathogens as well as to other             damage
-Vitamin A promotes cell differentiation
-When deficient, cell differentiation and maturation are implied
-Leading to, for example, a failure of mucus-producing cells to produce mucus    and a subsequent increase in keratin-producing cells
-Making tissue more vulnerable to infection
-Retinoic acid is being studied as a possible cancer treatment
When deficient:
-Keratinization of the cornea leads to xeropthalmia
-In the lungs, displacement of mucus-producing cells increase the risk of repiratory infection
-In the vagina, this process leads to vaginal infections
Immunity
-Plays a role in the regulation of genes that produce immune system proteins
-Vitamin A deficient child, for example:
-Weak immune system à severe measles à vitamin A stores used by immune   system and disease infection causes vitamin A to be lost from body à less      vitamin A, the worse the disease à even if disease is survived, there is likely to be corneal damage
Vitamin A Deficiency around the World
-Worldwide about 3-10 million of children suffer from signs of severe Vitamin A deficiency
-Xeropthalmia, blindness, diarrhea
-Reduced food intake worsens condition
-About 275 million more children suffer milder deficiency
-Impaired immune system and increased infection risk
In some areas, Vitamin A and other deficiencies are the norm
Supplemental vitamin A cuts childhood death rates by about 50%          
-In U.S. vitamin A supplements are recommended for certain groups of infants and children with measles
Vitamin A supplementation is of benefit to those suffering complications from diseases such as malaria, lung diseases, and HIV
Vitamin A Toxicity
-From supplements or fortified foods
-Abdominal pain, hair loss, joint pain, stunted growth, bone and muscle soreness, cessation of menstruation, nausea, diarrhea, rashes, liver damage, enlarged spleen, may weaken the bones
-Early symptoms: loss of appetite, blurred vision, growth failure in children,        headache, skin itching, irritability
-Pregnant women
-Chronic use of supplements about 3x-4x amount recommended for pregnancy    may cause fetal malformation
-Single large dose (100x need) may cause fetal malformation
Children who mistake chewable vitamin pills for candy are at risk
Adolescents who take large doses thinking it will correct acne
-Accutane is derived from vitamin A
-Vitamin A itself has no effect on acne
With the possible exception of liver, healthy people amounts of vitamin A-rich foods without risking toxicity
Vitamin A Recommendations
-Since the vitamin is stored, even though recommendations are given as a daily amount, the vitamin need not be consumed every day
-DRI
Male: about 900 micrograms / day
Female: about 700 micrograms / day
-Higher when lactating
Children: less
Diet that includes 5+ servings of vegetables and fruit per day is sufficient to meet needs
Some food tables and supplements express vitamin A content in international units (IU)
-1 IU = 0.3 micrograms retinol
Avoid taking supplements that exceed the UL of 3,000 micrograms
Sources of Vitamin A
-Vitamin A is found in foods of animal origin
-Richest sources are liver and oil
-Also milk, milk products, and fortified foods
-Plants contain beta-carotene, a vitamin A precursor
Beta-Carotene
-Most abundant of the caratenoid precursors
-Vitamin A activity for vitamin A precursors is measured in retinol activity equivalents (RAE)
-about 12 micrograms of beta-carotene = about 1 RAE
Excessive beta-carotene will not cause vitamin A toxicity
-However, it can cause people to turn a bright yellow due to deposition in subcutaneous fat
Does Eating Carrots really promote good vision?
-Yes, as do all bright (deep) orange fruits and vegetables
-Along with dark green vegetables
Carotenoids and Diseases
-Lack of dietary beta-carotene increases the increase of the most common form of untreatable age-related blindness, macular degeneration
-Progressive loss of function of the part of the retina most crucial to vision
Beta-carotene from foods and elevated beta-carotene in the blood are associated with reduced cancer risk
-Beta-carotene supplements do not show the association
-Smokers who take beta-carotene supplements are at an increased risk of cancer
Beta-carotene is one of the major dietary antioxidants
-Along with: vitamin E, vitamin C, selenium, and many other phytochemicals
-Dietary antioxidants are just one class of a large number of substances in whole foods that seem to benefit health synergistically

Vitamin D
Not essential in the sense that the body can make all it needs with the help of sunlight
-However, many people, especially African and Mexican Americans, may border on vitamin D insufficiency
Roles of vitamin D
-Regulation of blood calcium and phosphorus levels
-Often at a generous level
-When more calcium is needed vitamin D acts to raise blood calcium levels
-Draws calcium from bone
-Promotes calcium absorption
-Promotes calcium retention by the kidneys
Functions as a hormone
Plays a role in the brain, heart, stomach, pancreas, skin, reproductive organs, some cancer cells, stimulates cell maturation (including immune system cells)
Deficit promotes:
-high blood pressure, some cancers, type 1 diabetes, heart disease, rheumatoid arthritis, multiple sclerosis
Too Little Vitamin D – A Danger to Bones
-Rickets
-Vitamin D deficiency disease in children
-Characterized by abnormal bone growth
-Bowed, or knock-knees, outward-bowed chest, knobs on ribs
Adolescents who consume soft drinks rather than fortified milk and who prefer indoor to outdoor activities often lack the vitamin D that is needed to prevent bone loss later in life
Older individuals may have painful joints and muscles due to low vitamin D levels
Osteomalacia, the adult form of rickets
-Characterized by an overabundance of unmineralized bone protein
-Most often occurs in women with low calcium intake and little exposure to the sun and who go through repeated pregnancies and periods of lactation
Too much Vitamin D – A Danger to Soft Tissue
-Most potentially toxic of all vitamins
-May be directly toxic to the bones, kidneys, brain, nerves, heart, arteries
-Toxicity symptoms include: appetite loss, nausea, vomiting, increased urination, increased thirst, severe form of psychological depression due to effects on the central nervous system
If overdoses continue: dangerously high blood calcium levels arise, forcing calcium to be deposited in soft tissues
-Such as the heart, blood vessels, lungs, kidneys, pulp cavity of teeth (while enamel thins)
At risk:
-Infants whose parents think that if some is good more is better
-Older people who over-supplement
Intakes of 5x recommendations have been associated with signs of vitamin D toxicity
UL: 50 micrograms per day (2,000 IU on supplement labels)
How Can People Make a Vitamin from Sunlight?
-Most people rely on exposure to sunlight to maintain adequate vitamin D nutrition
-UV exposure to a cholesterol compound in the skin transforms it into a vitamin D precursor which is absorbed into the blood
-The liver and kidneys finish converting the precursor to the active form of          vitamin D
Skin synthesis of vitamin D poses no risk of toxicity
-The sun itself begins breaking down excess vitamin D made in the skin
-Sunbathers are at risk of skin damage and skin cancer
-Sunscreens with SPFs of 8 or above can reduce these risks, but they also prevent           vitamin D synthesis
In most places, during warmer months, just being outdoors when the sun is overhead, even in lightweight clothing, promotes skin synthesis of vitamin D
Factors affecting sun exposure and vitamin D synthesis
-Skin color, air pollution, city living, clothing, geography, indoor lifestyle, season, sunscreen, time of day
Recommendations for vitamin D intake increases with age
-19 to 50 years: 5 micrograms / day
-51 to 70 years: 10 micrograms / day
-70+ years: 15 micrograms / day
Sources:
-Small amounts from butter, cream, fortified margarine
-Fortified milk, sunlight
-Only two fortified plant sources exist:
margarines and certain cereals

Vitamin E
Consists of four tocopherol comounds
-Alpha, beta, gama, delta
-Alpha-tocopherol is the standard for vitamin E activity
The Extraordinary Bodyguard
-Antioxidant defending the body against oxidative damage
-Damage that results when free radicals formed during normal metabolism disrupt the structure of cellular lipids, DNA, proteins
Free radical activity may lead to cancer, heart disease or other diseases
Vitamin E is preferentially oxidized, thus protecting cells
Vitamin E’s antioxidant effect is especially crucial in the lunds
-Where cells are exposed to high oxygen concentrations
Also protects red blood cells, white blood cells, may play other roles in immunity, plays a role in nerve development
Supplements do not provide health benefits
-However, supplements may improve the immune response in healthy elderly      people
Vitamin E Deficiency
-Wide variety of symptoms in laboratory animals, most symptoms not reproduced in humans
-Vitamin E is widespread in food, making it difficult to create a vitamin E-deficient diet
-Body stores large amounts in fatty tissues
-Cells recycle vitamin E
Infants born before the transfer of vitamin E from the mother to the infant
-Erythrocyte hemolysis, resulting in anemia
Adults: loss of muscle coordination and reflexes with impaired movement, vision, and speech
Associated with fat malabsorption diseases
-disease or injury to the liver, gallbladder, pancreas
Low intakes likely when extremely-low-fat diets are consumed for years
-People who rely solely on fat replacers to the exclusion of real fat
Vitamin E is destroyed by food processing and heating
Chronically low intake may play a role in other diseases
-Low body stores of vitamin E and selenium promote viral virulence
Research has discredited claims that supplemental vitamin E:
-Improves athletic endurance and skill
-Enhances sexual performance
-Cures male sexual dysfunction
Vitamin E Requirements, Toxicity, and Sources
-DRI: 15 milligrams / day
-Average U.S. intake falls below this
Need increases with increased polyunsaturated fatty acid (PUFA) intake
Destroyed by heat processing and oxidation
No toxicity from food sources
Ordinary supplemental doses over a period of months do not seem to induce toxicity
In humans, occasional reports of breast soreness in women, fatigue, emotional distress, and other vague complaints
Large doses may increase the effects of anticoagulant medications
Brain hemorrhages may occur in smokers taking 50 milligrams / day for over 6 years
UL for alpha-tocopheral: 1,000 milligrams (450 IU)
Widespread in foods
-Most raw oils
-20% of dietary vitamin E comes from vegetable oils
-20% from fruits and vegetables
-none of which qualify as a good source
-15% from fortified cereals and other grain products
Smaller amounts from meat, poultry, fish, eggs, milk products, nuts, seeds
Wheat germ is a good source
Animal fats have almost no vitamin E

Vitamin K
Functions:
-Synthesis of blood clotting proteins
-Does not improve clotting in those with diseases such as hemophilia
-Interferes with function of blood thinners
-Synthesis of normal form of bone proteins that bind minerals to bone
-Adequate intake may reduce risk of hip fracture
Sources:
-Leafy green vegetables
-Cooked spinach and collard greens average 300 micrograms / 3 ounces
-Lettuce, broccoli, other members of the cabbage family average 100 micrograms           / 3 ounces
-Intestinal bacteria, canola and soybean oils, fortified cereals
-1 egg and 1 cup of milk: 25 micrograms each
At birth newborns are given a dose of vitamin K to hold them until vitamin K-producing bacteria establish themselves in their intestinal tract
Deficiency
-Unlikely in adults
-Even if the seldom eat vitamin K-rich foods
-At risk:
-Newborns
-Those who have taken antibiotics that kill the beneficial, along with the harmful,           bacteria in their intestinal tract
-Low bile production
Toxicity
-Rare among healthy adults
-No UL
-Infants and pregnant women:
-Toxicity can result from oversupplementation with synthetic vitamin K
Symptoms of Toxicity
-Red blood cell breakage
-Colors skin yellow
-Liver release of bilirubin into blood
-leads to jaundice
-Bilirubin in the brain of an infant can cause brain damage or death

The Water-Soluble Vitamins
Viamin C and the B Vitamins
-Cooking and washing with water leaches them out of food
-Easily absorbed
-Excess easily excreted in urine
-Some can remain in lean tissues for 1+ months
Advice for meeting needs
-Choose foods that are rich in water-soluble vitamins to achieve the recommended intakes over 3 days’ time
Toxicity
-Never from food
-Can occur from the large doses concentrated in some vitamin supplements
-Those the usual result will be to have expensive urine
Vitamins for Athletes
-Competitive athletes with an appropriate diet almost never need supplements
-The increased energy needed to fuel exercise requires increased energy   consumption
-With an appropriate diet, the needed vitamins automatically follow

Vitamin C
Scurvy
-Vitamin C (ascorbic acid) deficiency
-Hazard of long distance seagoing journeys of 200+ years ago
-To avoid scurvy, British sailors were given lime juice
The Work of Vitamin C
-Mainenance of connective tissues
-Formation and maintenance of collagen
-Component of bones, teeth, skin, tendons, scar tissue, capillaries
-Cofactor in the production of carnitine
-Plays a role in transporting fatty acids within cells
Antioxidant
-Protects substances found in foods and the body by being oxidized itself
-Some oxidized vitamin C is lost and must be replaced by the diet
-Much is not lost and is recycled back to the active form
-In the intestines, protects iron from oxidation
-Thus promoting its absorption
In the blood
-Protects blood constituents from oxidation
-Protects and recycles Vitamin E
Supplements seem useless against heart disease, cancer, other diseases
-Unless they are prescribed to treat a deficiency
In test tubes, high concentrations of vitamin C act as a prooxidant
-Activating oxidizing elements, such as iron and copper
-One study of men given 500 milligrams / day showed an increase in markers of oxidation
Deficiency Symptoms
-Most scurvy symptoms are due to the breakdown of collagen
-Loss of appetite, growth cessation, loose teeth, swollen ankles and wrists tiny red          spots in the skin where blood has leaked out of capillaries, anemia
Risk of scurvy in the U.S. is low, with the exception of
-Some elderly people
-Low intakes of fruits and vegetables combined with a poor appetite lead to low vitamin C intakes
-People addicted to alcohol or other drugs
-Infants fed cow’s milk who do not receive vitamin C in formula, fruit juice, or other sources
-Breast milk and infant formula supply enough vitamin C
Vitamin C supports immune system function and so protects against infection
Vitamin C and the Common Cold
Studies are yet to conclusively show that vitamin C can prevent or reduce the severity of colds
One group of researchers have found the following
-Daily dosages of vitamin C, taken regularly, do not prevent colds
The same group of researchers have also found
-Some small benefit from vitamin C in high doses (1 gram) taken at the onset of a cold
-This may shorten the duration of colds by about 1.5 days and reduce the severity of symptoms by about 40%
-The effect may be greater in children then adults
-In adults, doses near the UL (2 grams/day) may be required to produce any effect
Two grams per day for 2 weeks seems to reduce blood histamine
-The substance responsible for sneezing, runny or stuffy nose, swollen sinuses
-At these doses, Vitamin C may work like a weak antihistamine
-Or its antioxidant or other activities may improve the body’s immunity
The placebo effect
-In one study, half the experimental subjects received a placebo but thought they were receiving vitamin C
-This group reported having fewer colds than the group that had received vitamin C but thought they were receiving the placebo
Is too much Vitamin C Hazardous to Health?
-One effect observed with a 2-gram dose is alteration of insulin response to carbohydrate in people with otherwise normal glucose tolerances
-Other adverse effects include digestive upsets, such as nauseas, abdominal cramps, excessive gas, diarrhea
Massive doses may interfere with medications to prevent blood clotting
And may be dangerous for people with an overload of iron in the body
-Vitamin C increases iron absorption and releases iron from storage
Rarely is consuming more than 100-300 milligrams / day beneficial
-Absolute minimum is 10 milligrams / day
-UL: 2 grams
Those with kidney disorder and those with too much iron in their blood may be more susceptible to adverse effects
-Should avoid taking vitamin C supplements
Vitamin C from food is always safe
The Need for Vitamin C:
-Adult DRI
-Males: 9 milligrams
-Females: 75 milligrams
-These amounts are close to the point at which the body’s pool of vitamin C is     full: about 100 milligrams / day
Food Sources of Vitamin C
-300 milligrams : 1 cup orange juice for breakfast, salad for lunch, stalk of broccoli, a potato for dinner
-Vitamin C in fruits and vegetables are prone to destruction by heat and oxygen
-Fresh, raw, and quickly cooked are best
-Store properly and consume promptly

The B Vitamins in Unison
B vitamins act as part of coenzymes
-A small molecule that combines with, and activates, an enzyme
B vitamins’ Role in Metabolism
-Metabolism of carbohydrates, lipids, and amino acids
-Thiamin, riboflavin, niacin, panthothenic acid, and biotin all help release the energy stored in the energy-yielding nutrients
Vitmain B6 helps the body make protein
Folate and vitamin B12 help cells to multiply
B Vitamin Deficiencies
-Every cell is affected
-Symptoms include: nausea, severe exhaustion, irritability, depression, forgetfulness, loss of appetite and weight, muscle pain, impaired immune response, loss of control of the limps, abnormal heart action, severe skin problems, swollen red tongue, teary or blood s
hot eyes
Cell renewal depends on energy and protein which depend on the B vitamins
-Digestive tract and blood are damaged
-In children, full recovery may be impossible
-A thiamin deficiency during growth can cause permanent brain damage
Deficiency of any one B vitamin rarely shows up alone
Thiamin (B1)
Role
-Energy metabolism
-Nerve processes and tissue reponse
Deficiency: beriberi
-Loss of sensation in the hands and feet, muscular weakness, advancing paralysis, abnormal heart action
-Wet beriberi
-Characterized by edema
-Dry Beriberi
-No edema
Deficiency: Wernicke-Korsakoff Syndrome
-Alcohol abuse with severe thiamin deficiency
-Alcohol displaces food in the diet, impairs thiamin absorption, promotes thiamin excretion in the urine
-Symptoms: Apathy, irritability, mental confusion, disorientation, loss of memory, jerky eye movements, staggering gait
-almost indistinguishable from alcohol abuse itself
-Treatment: thiamin injection
Sources
-Small amounts in many foods
-Pork products, leafy green vegetables, whole grain cereals, legumes
-DRI:
-Men: 1.2 mg/day
-Women: 1.1 mg/day
-higher if pregnant or lactating
Riboflavin
Role
-Energy metabolism of all cells
Deficiency
-Likely when thiamin is deficient
-May go undetected because thiamin deficiency symptoms are more severe
-At risk:
-Children who lack milk products and meat
-Perhaps some U.S. elderly
-Symptoms: cracks at the corner of the mouth (cheilosis), Hypersensitivity to light, reddening of the cornea, skin rash
-Treatment: A diet that remedies riboflavin deficiencies also remedies a thiamin deficiency
Sources
-Milk and milk products
-Leafy green vegetables
-Whole-grain breads
-Fortified cereals
-Some meats
Niacin
Role
-Energy metabolism
Deficiency
-Pellagra
-Diarrhea
-Dermatitis
-Dementia
-Death
At risk for pellagra:
-Poorly nourished people living in urban slums
-Particularly those with alcohol addiction
-Still common in parts of Africa and Asia
Sources
-Tryptophan, which is abundant in almost all proteins, can be converted to niacin
-Thus a person eating adequate protein will not be deficient in niacin
-Niacin in the diet is stated in terms of niacin equivalents (NE)
Toxicity
-Large doses of a form of niacin may be a part of a treatment to lower blood lipids associated with cardiovascular disease
-Do not try this at home
-Large doses of niacin can injure the liver, cause peptic ulcers, cause vision loss
Certain forms of niacin supplements in amounts 2x-3x the DRI can cause niacin flush:
-Dilation of the capillaries of the skin with perceptible tingling that, if intense, can be painful
Folate
Role
-DNA synthesis
-Metabolism of several amino acids
Deficiency
-Because immature red and white blood cells and cells of the GI tract divide rapidly, they are most vulnerable to a deficiency
-Anemia
-Related to anemia of vitamin B12 malabsorption
-Diminished immunity
-Abnormal digestive function
With deficiency, some evidence for increased
-Cardiovascular risk
-Colon cancer risk
-Cervical cancer risk
Deficiency may result from
-Inadequate intake
-Illnesses that impair folate absorption
-Increased excretion
-Medications that interact with folate, or otherwise increase the body’s need
Neural tube birth defects
-Range form slight problems in the spinal cord to mental retardation
-Severely diminished brain size
-Death shortly after birth
-Arise in the first few days or weeks of pregnancy
-Most women eat too few fruits and vegetables to supply even 50% of the folate needed to prevent such birth defects
All enriched grain products are fortified with folic acid
-An especially absorbable synthetic form of folate
-Since fortification began, folate intakes have increased and there has been an almost 25% drop in the national incidence of neural tube defects
-It is expected that there will also be declines in some other birth defects and       miscarriages
Toxicity
-UL for synthetic folate from supplements and enriched foods is 1,000 micrograms/day
-Folate can mask vitamin B12 deficiency
-Excess folate may be antagonistic to the actions of some anticancer drugs
Unit of measure
-Synthetic folate that enriches foods and is in supplements is absorbed more readily than naturally occurring food folate
-Dietary Folate Equivalent (DFE) converts all forms of folate into units that are equivalent to the folate in food
Sources
-Leafy green vegetables
-Fresh, uncooked vegetables and fruits
-The heat of cooking and oxidation that occurs during storage destroy much of the          folate in foods
-Eggs contain folate
-Orange juice and legumes contain folate
-Contain factors that may interfere with folate absorption
-Milk may enhance folate absorption
DRI
-Heathy adults: 400 micrograms / day
-Women of childbearing age: 400 micrograms / day of folic acids from supplements or enriched foods in addition to the folate that naturally occurs in their foods
Medications
-Of all the vitamins, folate is most likely to interact with medications
-Ten major groups of drugs, including antacids and aspirin and its relatives, oral contracetptives, anticonvulsants, smoke interfere with the body’s use of folate
-Occasional use of these drugs is ok
-Frequent users need to pay attention to their folate intake
Vitamin B12
Role
-Vitamin B12 is activated by folate
-Folate is activated by vitamin B12
-Maintenance of the sheaths that surround and protect nerve fibers
Deficiency
-Damaged nerve sheaths
-Creeping paralysis
-General malfunctioning of nerves and muscles
Deficiency results in failure of folate to make red blood cells
-Therefore, a vitamin B12 deficiency causes an anemia (pernicious anemia) identical to that of folate
-Large, immature red blood cells
-Treatment: administration of folate
-However, this allows the deficiency of B12 to continue undetected
At risk
-The possibility that folic acid enrichment of grains is masking B12 deficiencies
-Especially amoung vegetarians and the elderly
-Individuals who generally depend heavily on grains and consume little or no      meat or other animal products
-Malabsorption problems
The uniformed, strict vegetarian is especially at risk
-May not show signs of deficiency right away because the body stores up to six years’ worth of the vitamin
Pregnant or lactating vegetarian women may put their infant at risk of a vitamin B12 deficiency
-Resulting in irreversible nerve system damage
-Recognized when the infant displays nerve and cognitive problems that can last             into childhood
All strict vegetarians must be sure to use vitamin B12 –fortified products
-Vitamin B12-fortified soy drink, supplements
Diagnosis of deficiency is difficult
Often the damage will proceed unchecked
Absorption
-Requires intrinsic factor
-A compound made by the stomach
-The stomach’s acid liberates vitamin B12 from food; intrinsic factor then binds to the vitamin
-The complex is then absorbed from the small intestine into the blood
-In a few people an inherited defect in the gene for intrinsic factor makes vitamin B12 absorption abnormal, beginning in mid-adulthood
In later years, many people lose the ability to produce sufficient stomach acidity and intrinsic facto
-Leaving them vulnerable to chronic stomach infections and reduced ability to absorb vitamin B12
Treatment for defective absorption is B12 injections
Sources
-Foods of animal origin
-Not in foods from plants
Vitamin B6
Role
-100+ reactions in the tissues
-Needed to convert one kind of amino acid into other nonessential amino acids
-Aids in the conversion of tryptophan to niacin
-Hemoglobin synthesis
-Neurotransmitter synthesis
-For example, assists in the conversion of tryptophan to serotonin
-Assists in release of stored glucose from glycogen
-Contributing to the regulation of blood glucose
-Immune function
-Steroid hormonal activity
-Fetal brain and nervous system development
-Deficiency during this stage causes behavioral problems later
Deficiency
-Weakness                                         
-Psychological depression                
-Confusion
-Irritability
-Insomnia
-Greasy dermatitis
-Advanced cases of deficiency: convulsions
-May weaken the immune system
-Evidence that low intakes may be related to increased risk of heart disease
Toxicity
-UL: 0.1 gram
-Women who took 2+ grams /day in a mistaken attempt to cure PMS symptoms
-Numb feet
-Lost sensation in their hands
-eventually became unable to walk or work
-Recovered after they stopped taking the supplements
A single B6 supplement can deliver 2 grams of the vitamin, the equivalent of 3,000 bananas or 1,600+ servings of liver, or 3,800+ chicken breasts
Need
-Due to its roles in protein metabolism need is proportional to protein intake
Sources
-Protein-rich foods
-Meats, fish, poutry
-Potatoes, leafy green vegetables, some fruits
-Legumes and peanut butter
How Are B Vitamins Related to Heart Disease?
Homocysteine
-Inherited high levels correlate with a severe early form of cardiovascular disease (CVD)
-Some CVD sufferers without the inhereited disorder also accumulate homocysteine in the blood
-Elevated homocystein may be an indicator of CVD risk
A lack of some B vitamins in the diet contributes to elevated homocysteine levels
Deficiencies of folate or vitamin B12 or B6 causes excess homocysteine to build up in the blood
-Supplements of these vitamins lead to a significant drop in homocysteine level
-It is unknown how this affects a person’s CVD risk
High dietary intakes of folate and vitamin B6 correlate with lower blood values of other substances associated with CVD
-So far all evidence is circumstancial
Biotin
Role
-Energy metabolism
-Cofactor for several enzymes in the metabolism of carbohydrate, fat, protein
Deficiency
-Rare diseases
-Consumption of 24+ raw egg whites per day, which contain a protein that binds biotin, will result in a deficiency
-Cooking eggs denatures this protein
-Symptoms: abnormal heart action, loss of appetite, nausea, depression, muscle pain, weakness, fatigue, numbness of extremeties, dry around eyes, nose and mouth
Sources
-Wide spread in foods
Pantothenic Acid
Role
-Energy metabolism
-Coenzyme that plays a role in the release of energy from the energy nutrients
-Plays a role in 100+ steps concerned with the synthesis of lipids, neurotransmitters, and hemoglobin
Deficiency
-Rare diseases
-Symptoms: Vomiting, intestinal distress, insomnia, fatigue, hypoglycemia, increased sensitivity to insulin
Sources
-Widespread in foods
 Non-B Vitamins
Choline
-When there is none in the diet, the body cannot make enough to meet its needs
-Common in foods
-Deficiencies are practically unknown outside the laboratory
Carnitine = vitamin BT
-Non-vitamin: not an essential nutrient from humans
-An important component of cells
-Deficiencies can be experimentally induced
-Abundant in ordinary foods
-Supplements unnecessary for healthy people eating a balanced diet
Inositol
-Non-vitamin: not an essential nutrient for humans
Lipoic acid
-Non-vitamin: not an essential nutrient for humans

Controversy: Vitamin Supplements: Who Benefits?
Nearly 40% of the U.S. population take a vitamin supplement
What the Experts are saying
-Some conclude that healthy people might benefit from a multiple vitamin supplement taken every day or two
-Others conclude that the potential risks of supplementation outweigh the unproven benefits
-Supplements should only be taken when there is a risk of deficiency
-People who omit any major food group probably need certain supplements
-Beta-carotene supplements are probably hazardous
-Especially to those who smoke and consume alcoholic beverages
-Limit intake of preformed vitamin A
-Elevated vitamin A in the blood is a marker for increased risk of hip fractures
Some Valid Reasons for Taking supplements
-People with nutrient deficiencies
-Women in their childbearing years (supplemental or enrichment sources of folic acid are          recommended to reduce risk of neural tube defects in infants)
-Pregnant or lactating women (they made need iron and folate)
-Newborns (they are routinely given a vitamin K dose)
-Infants (they made need various supplements)
-Those who are lactose intolerant (they need calcium to forestall osteoporosis
-Habitual dieters (they may eat insufficient food)
-Elderly people often benefit from some of the vitamins and minerals in a balanced diet
-Victims of AIDS or other wasting illnesses (they lose nutrients faster than foods can     supply them)
-Those addicted to drugs or alcohol
-Those recovering from surgery, burns, injury, or illness (they need extra nutrients to help          regenerate tissues)
-Strict vegetarians (they may need vitamin B12, vitamin D, iron, and zinc)
-People taking medications that interfere with the body’s use of nutrients
Supplements Must Be Safe, or the Government Would Not Allow Their Sales, Right?
-The FDA does not test supplements to ensure their safety and effectiveness
The FDA is to ensure that supplements do not pose a “significant or unreasonable risk” or illness or injury to consumers
-Requires safety documentation and reports of adverse effects from manufacturers
-Who are not required to supply such information
-Consumers may report adverse effects directly to the FDA
Dietary Supplement Health and Education Act (DSHEA)
-Supplements
-Must provide a Supplement Facts panel of nutrient information
-Must not be adulterated
-Must not make label claims for the diagnosis, prevention, treatment, or cure of   illness
-May bear “structure/function” claims
Result has been the deregulation of the supplement industry
The FDA has identified hazardous supplements only after there has been actual harm to consumers
Problems Impending the FDA’s Oversight of Supplements: The FDA currently faces four major problems with regard to supplemental oversight strategies:
1) The volume of supplement sales and use is too high to ensure adequate post-marketing safety within the current legal structure
2) The FDA’s funding and staff are insufficient to allow identification of supplement hazards and implementation of appropriate actions against them
3) The broad array of ingredients in the products sold impedes identification of hazards
4) Failure to require manufacturers to report serious adverse effects associated with supplemental use undermines FDA efforts to ensure supplement safety
Structure/Function Claims
-Less regulated than health claims
-Must include a disclaimer absolving the FDA from responsibility
Marginal Deficiencies and Oxidative Stress
-For example, a diet lacking in vitamin C will have a subclinical increase in oxidative stress before symptoms of scury appear
-Oxidative stress is damage inflicted on living systems by free radicals
Suboptimal intakes of antioxidant nutrients may be linked to chronic disease
-As body cells use oxygen, they produce free radicals
-Radiation, pollution, tobacco smoke, etc. can also cause free-radical formation
-When free-radical activity in the body exceeds antioxidant defenses, a chain of oxidation increases oxidative stress, triggering the onset of diseases
The evidence linking antioxidant nutrients, oxidative stress, and chronic diseases is inconclusive
Diets rich in foods with abundant antioxidants correlate with low disease rates
People whose blood is below normal for antioxidant nutrients have elevated rates of chronic diseases
-Restoring these nutrients leads to a drop in chronic disease incidence
Marginal Deficiencies, Cancer, and Other Diseases
-DNA damage from marginal deficiencies may mimic the cancer-causing damage from radiation
-DNA is both damaged more readily when nutrients are lacking and more slowly repaired
-Resulting in a build up of damage that can cause disease
Many forms of cancer occur among poorly nourished, low-income populations
-Reversing subclinical deficiencies may reduce the incidence of cancer and other diseases among such people
Menstruating women, young children and the elderly may suffer from the effects of vitamin and mineral deficity
-Resolving these deficits may help reducte the incidence of a variety of illnesses
Arguments Against Supplements For Chronic Disease Prevention
-The general results of research have shown the otherwise well-nourished people benefit little, if at all, from taking supplements
-The healthy elderly may be an exception; they may benefit from taking supplements
Should we Take Supplements to Ensure Adequate Nutrients?
-Food, not supplements, is the best source of nutrients
Risks of supplementation
-High doses of vitamin A may delay blood clotting and may increase the risk of brain hemorrhage
-For some people, vitamin C supplements may increase the risk of iron overload
-In high doses, vitamin C supplements increase markers of oxidation
-Daily supplements of beta-carotene may increase the risk of lung cancer in smokers
-Supplements of vitamins A and D and many minerals can be toxic in large doses
-High doses of vitamin E interfere with the blood clotting abilities of vitamin K
Selection of a Multinutrient Supplement
-If you cannot meet your nutrient needs from food, a supplement containing nutrients only can be of benefit
-When taking a supplement look for a USP on the label
-This means that the product contains the ingredients listed and that it will           dissolve or disintegrate in the digestive tract
-It does not mean that this supplement has been tested for safety or effectiveness
-Consider these questions
-What form do you want – chewable, liquid, pills?
-What vitamins and minerals do you need?
-Avoid supplements that provide a daily dose exceeding the DRI or the                            UL for any nutrient
-Avoid
-“organic” or “natural” preparations with added substances are no better than      standard types, but cost much more
-“high potency” or “therapeutic dose”: more is NOT better
-items not needed in human nutrition
-“time release”: nutrients are incorporated into tissues where they are needed      whenever they arrive
-“stress formulas”: the DRI provides sufficient nutrients to meet your needs under           stress
-pills containing extracts of parsley, alfalfa, and other vegetable components
-Geriatric “tonics”: usually low in vitamins and minerals and high enough in       alcohol to inebriate
-any supplement sold with claims that today’s foods lack the nutrients they once contained
-Local or store brands may be both cheaper and as good or better than nationally advertised brands
-Take supplements with food