Vitamins

Chapters

9/10

Understanding Vitamins• A few myths…

– If a little is good, then a lot is better.– Vitamins are energy boosters.– Vitamins work exclusively of one another.

• Vitamins in foods– Natural sources: all food groups– Enriched and fortified foods

Vitamins: An Overview

• All types of foods contain vitamins. Provitamins are vitamin precursors that the body can convert to the active vitamin form. Growing conditions, storage, processing, and cooking all affect the amounts of vitamins in foods.

• For at the last 3,000 years, there has been an empirical understanding that some diseases (which we now call vitamin deficiency diseases) could be cured by eating certain foods.

Vitamins and Energy

• The body does not metabolize vitamins to yield ATP.

• They are not a source of energy.• Many of the B-vitamins (water-soluble)

facilitate the metabolic reactions that release energy from carbohydrate, fat, and protein.

Fat-Soluble Vitamins

• Vitamins A, D, E, and K.• These vitamins are like lipids and soluble in

fat.• These vitamins are absorbed along with fat

into the lymphatic circulation.• These vitamins often have precursors.

Fat-Soluble Vitamins

• Lipoproteins carry triglycerides and fat soluble vitamins through the lymph and bloodstream.

• The liver stores most of the fat soluble vitamins and packages them for delivery via the bloodstream to other tissues.

• Fat soluble vitamins are less vulnerable to cooking losses.

Water Soluble Vitamins

• The 8 B vitamins and vitamin C are soluble in water.

• These vitamins are absorbed directly into the bloodstream.

• Water soluble vitamins do NOT need lipoprotein carriers.

Water Soluble Vitamins

• The kidneys filter out excesses of water soluble vitamins and excrete them in the urine.

• Most water soluble vitamins are not stored in significant amounts.

• Water soluble vitamins are vulnerable to cooking losses.

Storage and Toxicity (Fat Soluble)

• Fat soluble vitamins accumulate in the liver and adipose tissues.

• Once the vitamin stores have been established, we can go for days, weeks, or even months without these vitamins.

• Excessive intake can exceed the body’s storage capacity and have toxic effects.

Storage and Toxicity (Water Soluble)

• Water soluble vitamins are not stored in appreciable amounts.

• Therefore, they should be part of your daily diet.

Storage and Toxicity (Water Soluble)

• Consuming excesses of water soluble vitamins usually is harmless. The body secretes the excess.

• Megadoses of the following water soluble vitamins can be toxic: vitamin B6, folate, niacin, and vitamin C.

Exceptions to the Storage Rule

• Water soluble vitamin B12 is stored more readily than the other water soluble vitamins.

• Fat soluble vitamin K is excreted more readily than the other fat soluble vitamins.

Vitamin Toxicity

• Vitamin toxicity is rarely linked to high vitamin intakes from food or to the use of supplements that contain 100 to 150 percent of the recommended amounts.

• People who take megadoses of one or more of the vitamins run a high risk of toxicity.

Vitamin Absorption

Definitions

• Vitamins: Organic compounds necessary for reproduction, growth, and maintenance of the body.

• Provitamins: Inactive forms of vitamins that the body can convert into active useable forms.

• Vitamin precursers: Same as provitamins.

Fat Soluble Vitamins

• A• D• E• K

Vitamin A Functions

• Vision.• Cell differentiation.• Immune function.• Reproduction.• Bone health.

Vitamin A Food Sources

• Preformed Vitamin A– Liver– Milk– Eggs

• Beta-carotene– Yellow-orange fruits and vegetables

Forms of Vitamin A

• The body uses three active forms of vitamin A, collectively known as the retinoids.– Retinol – alcohol form of vitamin A.– Retinal – aldehyde form of vitamin A.– Retinoic acid – acid form of vitamin A.

Forms of Vitamin A

• Retinol is the key player.• Your body can easily convert retinol to retinal.• Retinal can reform retinol or irreversibly form

retinoic acid.• Carotenoids (provitamin A) are precursors of

vitamin A.

Causes of Vitamin A Deficiency

• Newborns (esp. premature) are at risk. Their liver stores are low.

• Impoverished people may suffer marginal vitamin A deficiency due to poor diets.

• Liver damage due to alcoholism and liver disease can prevent the liver from storing much vitamin A.

• Some medicines alter lipid absorption.

Causes of Vitamin A Deficiency

• Fat absorptions conditions: chronic diarrhea, celiac disease, Crohn’s disease, cystic fibrosis, pancreatic insufficiency.

• Restrictive diets such as in anorexia nervosa.• Zinc deficiency will causes symptoms of

vitamin A deficiency because it is required for A to function properly.

Vitamin A Deficiency

• Vitamin A deficiency is rare in the United States and Western Europe.

• Leading causes of childhood blindness worldwide. (Est. 500,000 per year)

Symptoms of Vitamin A Deficiency

• Night blindness.• Xerophthalmia – dryness of the eyeball• Hyperkeratosis – skin thickening• Infection• Retards growth and development• Leads to bone deformities• Death

Causes of Vitamin A Toxicity

• The Tolerable Upper Intake Level (UL) for vitamin A is 3,000 micrograms RAE as retinol.

• Occurs with supplementation, but is rare from diet.

• A sustained diet of liver or fish oils could cause it.

Symptoms of Vitamin A Toxicity

• Fatigue• Vomiting• Abdominal pain• Bone and joint pain• Loss of appetite

Symptoms of Vitamin A Toxicity

• Skin disorders• Headache• Blurred or double vision• Liver damage which leads to jaundice• Can be fatal

Excess Vitamin A and Birth Defects

• Preformed vitamin A, taken in excess, is a known teratogen.

• Birth defects associated with excess vitamin A:– Cleft palate– Heart abnormalities– Brain malfunction.

Excess Vitamin A and Birth Defects

• Excess vitamin A is most hazardous when taken two weeks prior to conception and the first two months of pregnancy.

• Can also cause spontaneous abortions.• Prenatal supplements should not have retinol.• Beta-carotene is safe.

Carotenoids

• Carotenoids are naturally occuring compounds that give the deep yellow, orange, and red colors to fruits and vegetables.

• They are also abundant in dark green vegetables, but the carotenoid colors are hidden by chlorophyll.

Carotenoids

• Some carotenoids can be converted to vitamin A and are called provitamin A carotenoids. Some cannot be converted.

Carotenoids

Carotenoid Functions

• Many function as vitamin A precursors.• Antioxidants• Boost the immune system.• Filter harmful blue light in the macula.

Carotenoid Functions

• Decrease risk of certain types of cancer.– Lycopene (prostate cancer)– Lutein, zeaxanthin, alpha-carotene, and lycopene

(lung cancer)– Alpha-carotene, beta-carotene, lutein, and

zeaxanthin (breast cancer)

Carotenoid Toxicity

• Large intakes of carotenoid rich foods have not been associated with toxicity.

• Carotenodermia – a harmless yellow-orange cast to the skin due to high levels of carotenoids in the bloodstream resulting from consumption of extremely large amounts of carotenoid rich foods, such as carrot juice.

Carotenodermia

Carotenoid Food Sources

• Food sources– Yellow-orange vegetables– Orange fruits– Dark-green leafy vegetables

Cooking Carotenoids

• In foods, fibrous proteins tightly bind carotenoids, so your body absorbs only 20 to 40 percent of what you consume.

• A few minutes of cooking breaks some of the chemical bonds in food.

• This helps release carotenoids making them easier to absorb.

Mucous Membrane Integrity

• Mucous membranes contain a higher percentage of goblet cells.

• Without retinoic acid, fewer stem cells become goblet cells and these surfaces become hard and scaly.

Vitamin A and Vision

• Deficiency of vitamin A results in progressive vision loss from temporary night blindness, then reversible blindness, and finally permanent blindness.

• In addition, the lack of mucous secretions and reduced immune function make the person with vitamin A deficiency vulnerable to infections. Vitamin A toxicity can result from the use of supplements, even with dosages just a few times higher than the RDA.

Vitamin A: Not Just For Eyes

• A recent study conducted in Nepal showed that women who took vitamin A supplements during pregnancy had a much lower risk of maternal mortality than those who took a placebo.

• The researchers concluded that regular and adequate intake of vitamin A or beta-carotene can reduce the risk of pregnancy-related death in areas where vitamin A deficiency is common.

Vitamin D

• Synthesis– Made in the skin from cholesterol– Activated in liver and kidney

Vitamin D Functions

• Regulate blood calcium levels.• Regulates cell differentiation and growth.• Protective against colorectal cancer.• Essential for bone health.

Vitamin D Adequate Intake (AI)

• The AI levels for infants and children from birth to 18 years is 5 micrograms per day.

• Vitamin D synthesis decreases with age, so the vitamin D recommendations increase.– 19 to 50 years – 5 micrograms– 51 to 70 years – 10 micrograms– 71 and up – 15 micrograms– 1 microgram = 40 international units (IU)

Vitamin D Sources

• Given sufficient sunlight, your body can synthesize all of the vitamin D it needs.

• Vitamin D is found in oily fish (e.g. herring, salmon, and sardines) as well as cod liver oil and other fish oils.

• Few foods naturally contain vitamin D, so milk and other foods such as cereal are fortified with it.

Causes of Vitamin D Deficiency

• Inadequate sun exposure.• Sunscreens with an sun protective factor (SPF)

of 8 or more block vitamin D synthesis.• Living in a northern region.

– Sunlight is too weak to synthesize vitamin D during the winter months.

Symptoms of Vitamin D Deficiency

• Without vitamin D, the intestines absorb only 10 – 15% of dietary calcium.

• Rickets in children.• Osteomalacia (“soft bones”) in adults.• Osteoporosis – increased bone turnover, with

an increased risk of fractures.

Causes of Vitamin D Toxicity

• Sun exposure does NOT cause vitamin D toxicity.

• High supplement doses can be toxic.

Symptoms of Vitamin D Toxicity

• Hypercalcemia – a high concentration of calcium in the blood.– Inhibits the kidney’s ability to concentrate urine.– Can cause excess calcium in the bloodstream to

leave deposits in the soft tissues of the body, including the kidneys, blood vessels, heart, and lungs.

• Promotes bone loss as increased blood levels of vitamin D pull calcium from the bones.

Vitamin D

• Deficiency– Rickets in children– Osteomalacia and

osteoporosis in adults

• Toxicity– Hypercalcemia

Osteoporosis

• A lack of vitamin D can lead to osteoporosis. • Vitamin D supplements in elderly women slows

bone turnover, increases bone density, and decreases non-vertebral fractures.

Vitamin D and Colon Cancer• A recent study examined whether

people who have high vitamin D intakes have a lower risk of colon cancer than people with low vitamin D intakes.

• Researchers collected data from subjects from 13 VA medical centers aged 50–75. These participants were followed, and data collected for three years.

• The hypothesis was confirmed, with results indicating that consuming vitamin D plus calcium may be a low-risk preventive strategy for colon cancer.

• This study also showed that smoking and moderate to heavy alcohol use increased the risk of colon cancer.

Vitamin E Functions

• Antioxidant properties.• Stops peroxidation – a form of free radical

damage that promotes atherosclerosis.• May lower the risk of some chronic diseases

such as heart disease.• May slow the progression of Alzheimer’s

disease.

Vitamin E

• Functions– Antioxidant

• Protects cell membranes from free radicals

Vitamin E Food Sources

• Wheat germ oil contains the highest concentration of useable vitamin E.

• Vegetable and seed oils, such as safflower, cottonseed, and sunflower seed oils are also rich sources.

• Nuts and seeds.• Strawberries and some leafy green

vegetables.

Loss of Vitamin E from Food Sources

• Cooking, processing, and storage of food reduce vitamin E content.

• Milling of wheat to make white flour removes most of the vitamin E rich wheat-germ. Chloride oxide for bleaching removes any remaining.

Loss of Vitamin E from Food Sources

• Oxidation destroys vitamin E. Heat and light accelerate oxidation.

• Roasting destroys 80% of the vitamin E in almonds.

Causes of Vitamin E Deficiency

• Fat mal-absorption syndromes (such as cystic fibrosis).

Symptoms of Vitamin E Deficiency

• Premature hemolysis – Red blood cells breakdown due to oxidation.

• Hemolytic anemia occurs in premature infants who are born before the mother tyramsfers vitamin E to the baby during the last few weeks of pregnancy.

Symptoms of Vitamin E Deficiency

• Neurological problems that affect the spinal cord and peripheral nerves occurs with prolonged vitamin E deficiency.

Causes of Vitamin E Toxicity

• Over-supplementation.

Symptoms of Vitamin E Toxicity

• It counters vitamin K’s blood clotting mechanism.

• People on anticoagulant medications such as warfarin (Coumadin) or aspirin should be cautious with vitamin E supplementation.

Vitamin E

• Food sources– Nuts and seeds– Wheat germ– Oils, margarine,

salad dressing• Deficiency

– Hemolysis• Toxicity is rare.

Photo © Photodisc

Free Radical Damage

• Vitamin E helps prevent free radical damage to polyunsaturated fatty acids in cell membranes.

Vitamin K Functions

• Necessary for blood clotting.• Assists in bone formation.

Vitamin K Sources

• Food sources. (absorbed in the SI).– Green leafy vegetables (especially spinach, turnip

greens, broccoli, and Brussels sprouts.– Vegetable oils (soybean, cottonsead, canola, and

olive)– Egg yolks, butter, and some cheeses have small

amounts. Liver.

• Bacteria in our Large Intestine (colon). (Absorbed in the LI).

Causes of Vitamin K Deficiency

• Inadequate dietary intake.• Fat-malabsorption syndromes.• Prolonged use of antibiotics destroy the

intestinal bacteria that produce vitamin K in the colon.

Symptoms of Vitamin K Deficiency

• Bleeding.

Causes of Vitamin K Toxicity

• The body excretes vitamin K much more rapidly than the other fat-soluble vitamins.

• Toxicity from food is rare and no upper limit has been established.

• Excessive supplementation could cause toxicity.

Symptoms of Vitamin K Toxicity

• A vitamin K overdose can cause hemolytic anemia.

Vitamin K

• Functions– Blood clotting– Formation of bone

• Food sources– Green vegetables,

liver, egg yolks

Vitamin K and Bone Health

• Osteocalcin is an abundant bone protein that is required for bone mineralization and maturation.

• Vitamin K helps in the carboxylation of osteocalcin, greatly enhancing its calcium-binding properties.

Water Soluble Vitamins

• Eight B vitamins– Thiamin (B1), roboflavin (B2), niacin (B3),

pantothenic acid, biotin, folate, B6, and B12

• Vitamin C

Water Soluble Vitamins

• The kidneys readily remove and excrete excess water-soluble vitamins, with the exception of B12.

• Water-soluble vitamins are particularly susceptible to destruction by heat or alkalinity, which can break the chemical bonds between atoms.

• Prolonged heat such as baking destroys chemical bonds.

Water Soluble Vitamins

• Baking soda is used to reduce cooking time and intensify the vegetable’s color. It is alkaline and degrades vitamins. Vitamin C, thiamin, and riboflavin are especially vulnerable to heat and alkalinity.

Water Soluble Vitamins

• Water soluble vitamins are hydrophillic and leach into water during cooking.

• Steaming and stir-frying use less water and are therefore better cooking methods.

B Vitamins

• B vitamins act primarily as coenzymes, or as parts of coenzymes.

• All B vitamins function in energy producing metabolic pathways.

• Some also function in other metabolic pathways not related to energy.

B Vitamins as coenzymes

Refined Grains and Nutrients

• During the milling process, much of the B content is removed along with the germ, bran, and husk.

Refined Grains and Nutrients

• The FDA requires enrichment with the B vitamins thiamin, riboflavin, niacin, and folic acid. The process of refining also removes vitamin B6, magnesium, and zinc which are NOT replaced.

• Consume whole-grains instead.

Thiamin (B1) Functions

• Thiamin is the vitamin portion of the coenzyme thiamin pyrophosphate (TPP).

• TPP participates in decarboxylation during glucose metabolism. (Coenzyme in energy metabolism)

• TPP helps in synthesizing and regulating neurotransmitters.

Thiamin Food Sources

• Pork• Legumes• Some nuts and seeds• Whole grains

Causes of Thiamin Deficiency

• Heavy alcohol consumption contributes calories without nutrients and interferes with Thiamin absorption.

• Highly processed foods that are not enriched.

Symptoms of Thiamin Deficiency

• Beriberi• Wernicke-Korsakoff Syndrome• Muscle weakness• Loss of appetite• Nerve degeneration

Beriberi

• This deficiency disease occurs in people whose main source of energy is polished rice, which is common in Southeast Asia.

• Beriberi is from the Singhalese language (spoken in Sri Lanka) that means “I can’t, I can’t”.

• Initial symptoms include weakness, irritability, headache, fatigue, and depression (appear withing 10 days without Thiamin).

Beriberi

• 2nd stage “dry” beriberi (without edema): nerve degeneration, muscle wasting, poor arm and leg coordination, deep pain in the calf muscles.

• 3rd stage “wet” beriberi: enlarged heart, heart failure, severe edema.

Beriberi

Wernicke-Korsakoff Syndrome

• Alcohol induced malnutrition is the most common cause.

• Symptoms include mental confusion, staggering, and constant rapid eye movements or paralysis of the eye muscles.

Thiamin Toxicity

• There are no known reports of Thiamin toxicity.

• The kidneys rapidly excrete excess Thiamin via the urine.

Riboflavin (B2 or vitamin G) Functions

• Part of two coenzymes: flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD).

• Participate in oxydation-reduction reactions.• Participate in the citrus acid cycle.• Supports antioxidants.

Riboflavin Food Sources

• Milk, yogurt, cottage cheese.• Organ meats such as liver and kidney.• Mushrooms.• Added to enriched grain products.

Causes of Riboflavin Deficiency (ariboflavinosis)

• Rare.• Alcoholism.• Barbiturate drug use (e.g phenobarbital).• Cancer, heart disease, and diabetes may also

cause or worsen a riboflavin deficiency.

Symptoms of Riboflavin Deficiency

• Glossitis – tongue gets shiny, smooth, and inflamed.

Symptoms of Riboflavin Deficiency

• Angular Stomatitis – the skin at the corners of the mouth becomes cracked.

• Cheilosis – the lips become inflamed and split.

Symptoms of Riboflavin Deficiency

• Seborrheic dermatitis – the oil producing glands of the skin become clogged.

Symptoms of Riboflavin Deficiency

• If the deficiency becomes severe, anemia develops.

Causes of Riboflavin Toxicity

• There are no known reports of riboflavin toxicity.

• The kidneys rapidly excrete excess riboflavin via the urine.

Niacin Functions

• Niacin is a name for both nicotinic acid and niacinamide.

• Conenzymes nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NAPD+).

• Coenzymes in energy metabolism.

Niacin Functions

• Participate in oxidation-reduction reactions.• Supports fatty acid synthesis. • Participates in at least 200 metabolic

pathways.

Niacin Food Sources

• Meat, poultry, fish.• Whole grains.• Enriched grain products.• Mushrooms, peanuts, liver, and seafood.• Stable when heated.

Causes of Niacin Deficiency

• A diet high in corn and little other variety. A protein in corn tightly bounds niacin. Soaking corn in a solution of lime releases niacin.

• Your body can make Niacin from the amino acid tryptophan.

• Tryptophan is found in protein rich animal foods.

Symptoms of Niacin Deficiency

• Pellagra– Dementia– Diarrhea– Dermatitis– Death (severe cases)

• Originally name aml de la rosa “red sickness”• Redness around the neck• Roughened skin

Pellagra

Causes of Niacin Toxicity

• Niacin in the form of nicotinic acid is known to lower blood levels of LDL cholesterol while raising HDL cholesterol when taken in doses of 1,300 to 3,000 milligrams.

• Adverse effects can be seen with doses as low as 250 milligrams (15 to 17 times the RDA for adults.

Symptoms of Niacin Toxicity

• Flushing of the face, arms, and chest• Itching• Headaches• Rash• Nausea

Symptoms of Niacin Toxicity

• Glucose intolerance• Blurred vision• Liver abnormalities can show up within a

week of supplementation.

Pantothenic Acid Functions

• A component of coenzyme A (CoA), which is in turn a component of acetyl CoA.

• Acetyle CoA– Starts the citric acid cycle.– Building block for fatty acids.– Precursor to ketone bodies

Pantothenic Food Sources

• Pantothenic acid id widespread in the food supply.

• Chicken, beef, potatoes, oats, tomato, liver, kidney, yeast, egg yolk, broccoli, whole grains.

• Damaged easily with freezing and canning.

Causes of Pantothenic Deficiency

• Virtually non-existent in the general population.

• Diets that lack the nutrient.

Symptoms of Pantothenic Deficiency

• Irritability• Restlessness• Fatigue• Apathy• Malaise• Sleep disturbances

Symptoms of Pantothenic Deficiency

• Nausea• Numbness• Tingling• Muscle cramps• Staggering gait• hypoglycemia

Causes of Pantothenic Acid Toxicity

• Pantothenic acid does not appear to be toxic at high doses.

Biotin Functions

• Amino acid metabolism• Fatty acid synthesis• Synthesizing DNA• Assists in energy production

Biotin Food Sources

• Cauliflower• Liver• Peanuts• Cheese• A biotin-lysine complex called biocytin is

found in some proteins.

Causes of Biotin Deficiency

• Biotin deficiency is rare.• Raw eggs whites contain a protein called

avidin that binds to biotin and prevents absoprtion.

• Some anticonvulsant drugs break down biotin.• Some infants are born with a deficiency of the

enzyme biotinidase, which releases biotin from biocytin.

Symptoms of Biotin Deficiency

• Initial hair loss.• Rash.• Convulsions and other neurological disorders.• Eventually, untreated deficiency causes

changes in blood pH that can lead to coma and death.

Causes of Biotin Toxicity

• Biotin does not appear to be toxic at high doses.

Vitamin B6 Functions

• Coenzyme in protein and amino acid metabolism.

• Coenzyme in carbohydrate metabolism• Supports the immune system by assisting in

while blood cell synthesis.• Assists in red blood cell synthesis.• Assists in the synthesis of neurotransmitters.• Helps convert tryptophan to niacin.

Vitamin B6 Food Sources

• Meat, poultry, fish• White potatoes and other starchy vegetables• Non-citrus fruits• Bananas• Sunflower seeds

Causes of Vitamin B6 Deficiency

• Deficiencies are rare• Alcohol decreases the absorption of B6

• Cirrhosis and hepatitis prevent the liver from metabolizing B6 to its coenzyme form.

• Refined grains lose B6 and it is not replaced during enrichment.

Symptoms of Vitamin B6 Deficiency

• Microcytic hypochromic anemia• Seborrheic dermatitis• Neurological symptoms

– Depression– Confusion– convulsions

Causes of Vitamin B6 Toxicity

• Megadoses of supplemental vitamin B6– Often self-prescribed for PMS– Often recommended for carpal tunnel syndrome

Symptoms of Vitamin B6 Toxicity

• Irreversible nerve damage– Affects the ability to walk– Causes numbness and tingling in the extremities

Protein & Carbohydrate Metabolism

• One of the primary tasks of PLP (pyridoxal phosphate) is to help metabolize amino acids and other nitrogen-containing compounds.

• PLP plays a key role in transamination reactions, helping transfer an amino group from an amino acid to a keto acid and produce a new amino acid.

• Transamination, catalyzed by PLP, enables the body to make the 11 nonessential amino acids. Without adequate supplies of vitamin B6, all amino acids become “essential,” meaning the body cannot synthesize them and must obtain them from the diet.

• Through its role in transamination reactions, PLP participates in gluconeogenesis —producing glucose from amino acids. In addition, PLP facilitates glycogen breakdown.

Vitamin B6, Folate, and Heart Disease

• Moderately high blood levels of the amino acid homocysteine are associated with fatal cardiovascular events.

• Homocysteine blood levels are influenced by dietary intake of B6, folate, and vitamin B12. Low intake of B6 or folate can result in high homocysteine levels.

• Because the body accumulates large vitamin B12 stores to draw on when needed, variations in B12 intake seldom affect homocysteine levels.

• The body lowers homocysteine levels in one of two ways: (1) two PLP-dependent enzymes help convert homocysteine to cysteine, or (2) folate and vitamin B12-dependent enzymes help convert homocysteine to methionine.

• An increase in fruit and vegetable intake also can affect homocysteine levels.

Folate Functions

• Coenzyme that assists in DNA synthesis• Assists in amino acid metabolism• Assists in cell division• Needed for red blood cell synthesis and

maturation

Folate Food Sources

• Spinach and other dark-green leafy vegetables• Asparagus• Broccoli• Orange juice

Folate Food Sources

• Wheat germ• Liver• Sunflower seeds• Legumes

Folate Deficiency

• May be the most prevalent deficiency• Up to 10% of the U.S. population may have

inadequate folate stores.• Folate is extremely vulnerable to heat,

ultraviolet light, and exposure to oxygen.• Cooking and other food processing techniques

destroy folate.

Causes of Folate Deficiency

• Inadequate folate consumption– Malnutrition due to famine or poverty– Cultural cooking methods– Eating habits that avoid raw folate sources– Alcoholism– Excessive dieting, anorexia nervosa, and bulimia

• Inadequate folate absorption– Abnormal mucosal cells in GI tract

Causes of Folate Deficiency

• Increased folate requirements– Pregnancy and lactation– Blood disorders, leukemia, lymphoma, psoriasis

• Impaired folate utilization– Associated with vitamin B6 deficiency

Causes of Folate Deficiency

• Altered folate metabolism– Alcohol– Barbiturates– Sulfa drugs and anticonvulsants impair folate

absorption

• Excessive folate excretion– Prolonged diarrhea

Symptoms of Folate Deficiency

• Megaloblastic anemia• Low birth weight babies and premature

deliveries• Neural tube defects

– Spina bifida– anencephaly

• Women of childbearing age need 400 micrograms / day of folic acid

Megaloblastic Anemia• When red blood cell precursors in

the bone marrow cannot form new DNA, they cannot divide normally.

• These precursor cells continue to grow and become large, fragile cells called megaloblasts.

• Megaloblasts displace red blood cells, resulting in megaloblastic anemia.

Spina Bifida

Causes of Folate Toxicity

• Over supplementation

Symptoms of Folate Toxicity

• Excessive folate intake can mask a B12 deficiency

• Hypersensitive people can suffer from hives or respiratory distress (rare)

Can Folate Prevent Cancer?

• When women took multivitamins containing folate for at least 15 years, they had a 75 percent reduction in colon cancer risk, according to the Harvard Nurses’ Health Study.

• Folate intakes of more than 600 milligrams per day reduced breast cancer risk by 50 percent.

Vitamin B12 (Cobalamin) Functions

• Needed for normal folate metabolism– Necessary for DNA and red blood cell synthesis

• Maintains the myelin sheath around nerves

Vitamin B12 Food Sources

• Animal foods– Meats– Fish– Poultry– Eggs– Milk

• Fortified foods such as cereal• Synthesized by bacteria in animal stomachs

Causes of Vitamin B12 Deficiency

• Inadequate intake• Impaired absorption

– Pernicious anemia – autoimmune disorder in which the body destroys the parietal cells in the stomach

– A loss of parietal cells means a loss of intrinsic factor, which is necessary for B12 absorption

Symptoms of Vitamin B12 Deficiency

• Deficiency anemia• Nerve damage

– Myelin sheath swells and breaks down– Brain abnormalities and spinal cord degeneration– Neurological symptoms

• Tingling and numbness in extremities• Abnormal gait• Cognitive changes (loss of concentration, memory loss,

disorientation, dementia)

Causes of Vitamin B12 Toxicity

• Vitamin B12 does not appear to be toxic at high doses.

Vitamin C Functions

• Antioxidant – reducing agent• Assists in collagen synthesis• Enhances iron absorption• Helps synthesize carnitine (fatty acid shuttle),

norepinephrine, epinephrine, serotonin, thyoxine (thyroid hormone), bile salts, steroid hormones and purine bases (DNA synthesis)

• Enables lymphocytes to function properly

Vitamin C Food Sources

• Citrus fruits• Tomatoes• Broccoli• Strawberries• Kiwi fruit

Vitamin C Food Sources

• Cabbage• Spinach and leafy greens• Green peppers• Potatoes

Causes of Vitamin C Deficiency

• Vitamin C is highly vulnerable to heat and oxidation; therefore, fresh fruits and vegetables are the best source.

• Inadequate dietary intake• Restrictive diets• Alcoholism

Symptoms of Vitamin C Deficiency

• Scurvy– Inability to synthesize collagen, connective tissues

breakdown– Gums and joints begin to bleed– Weakness develops– Small hemorrhages around the hair follicles on

arms and legs– Healed wounds reopen– Bone pain, fractures, diarrhea, depression

Scurvy

Causes of Vitamin C Toxicity

• Supplementation with megadoses.

Symptoms of Vitamin C Toxicity

• Megadoses of vitamin C do not appear to be acutely toxic; however, some people can develop nausea, abdominal cramps, diarrhea, and nosebleeds when taking more than 2,000 milligrams daily for a prolonged period.

Vitamin-like Compounds

• The body synthesizes many vitamin-like compounds that assist in metabolism.– Choline– Carnitine– Inositol– Taurine– Lipoic acid

Watermelon Works Overtime

• Compared to freshly picked fruit, watermelon stored for 14 days at 70°F gained up to 40 percent more lycopene and 50 percent to 139 percent extra beta-carotene.

• Study findings showed watermelons continue to produce these nutrients after they are picked and that chilling slows this process.