Human Nutrition Vitamins and Minerals

Toxcicity of B6

It attaches to enzymes in the muscle and other tissues and will remain in the body. It can reach toxic levels, usually due to excess intake of supplements. Nerve damage Difficulty walking Tingling in legs and feet Large doses do not cure carpal tunnel syndrome.

How do you get Vitamin D through the diet?

Only a few animal foods—notably, eggs, liver, butter, some fatty fish, and fortified milk—supply significant amounts of vitamin D. Infant formulas are fortified with vitamin D in amounts adequate for daily intake as long as infants consume at least one liter (1000 milliliters) or one quart (32 ounces) of formula. Breast milk is low in vitamin D, so vitamin D supplements are recommended for infants who are breastfed exclusively and for those who do not receive vitamin D-fortified formula per day.

How do you intake vitamin D?

Sun exposure cannot meet everyone's vitamin D needs. The skin pigment melanin and use of suncreens reduce vitamin D production. Sunlight intensity during winter in some locations is not sufficient to make enough vitamin D. Vitamin D needs based on dietary sources Adults 15 to 20 μgr(600 to 800 I U) per day, depending on age U L: 100 μg (4,000 I U) Children 15 μgrper day U L: 50 μg (2,000 I U)

Storage of Vitamins

The liver is the main storage site for vitamin A; to a lesser extent for vitamins K and E. Vitamin D is mainly stored in the fat and muscle tissue. Can build up in the body to the point of toxicity

Food Sources of Thiamin

Thiamin occurs in small quantities in virtually all nutritious foods, but it is concentrated in only a few foods. Legumes, sunflower seeds, and enriched and whole-grain breads are valuable sources of thiamin.

Overall Structure of Vitamins

All vitamins contain carbon, hydrogen, and oxygen. Some vitamins contain nitrogen and sulfur. The chemical structure of each vitamin is unique. Each vitamin is a singular unit. Vitamins are absorbed intact. Vitamins perform numerous essential functions. Some vitamins have more than one role in metabolism.

Absorption of Vitamins

Attached to proteins in foods, released in the stomach Are absorbed in the duodenum Packaged in chylomicrons → lymph → bloodstream Lack of fat can lead to deficiency.

What is the source of Vitamin D?

Called the "sunshine vitamin" even though its a Hormone Derived from a reaction between ultraviolet rays and a form of cholesterol in the skin Exposure to sunlight can synthesize all of the body's vitamin D needs. Considered a conditionally essential nutrient Also known as calciferol, vitamin D comes in two major forms. Vitamin D2 derives primarily from plant foods in the diet. Vitamin D3 derives from animal foods in the diet and from synthesis in the skin. These two forms of vitamin D are similar and both must be activated before they become fully functional.

What are two phytochemicals?

Carotenoids Flavonoids

Recommended Amounts and Food Sources of Folate

Dietary Folate Equivalents (D F E) Unit used to define the R D A for folate Accounts for differences in absorption between synthetic folate and folate in food Synthetic folic acid is absorbed 1.7 times more efficiently than natural folate. Major food sources Dark green leafy vegetables, legumes, and seeds Enriched pasta, rice, breads, and cereals Liver

What are free radicals?

Free radicals are molecules with an unpaired electron. By-products of the body's metabolic reactions Molecules with an unpaired electron, which makes them unstable Factors that increase free radical production include: U V light Exposure to toxins from smoking Exposure to environmental pollutants Oxidative stress occurs when free radicals accumulate faster than the body can metabolize them. Damages D N A and body proteins, and alters cell structure Excess free radicals contribute to chronic diseases.

Functions of Vitamin C

Helps to maintain the immune system Promotes white blood cell synthesis May reduce the body's response to stress Aids in the conversion of tryptophan and tyrosine to serotonin and norepinephrine Aids in the synthesis of thyroxine Converts cholesterol to bile Eating foods containing vitamin C at the same meal with foods containing iron can double or triple the absorption of iron from those foods.

Deficiency of Vitamin K

Infants are born with too little vitamin K. Deficiency severe enough to affect blood clotting is extremely rare. May cause hip fracture in older men and women

Toxicity of Vitamin K

No known adverse effects Individuals taking anticoagulant medications should keep vitamin K intake consistent. Changes in intake can increase or decrease drug effectiveness.

Vitamin E Toxcity

No known risk of consuming too much vitamin E from natural food sources Overconsumption of synthetic form in dietary supplements and fortified foods can increase risk of a hemorrhage

Daily Needs for Vitamin C

R D A for adults Males: 90 milligram/day Females: 75 milligram/day Smokers: An additional 35 milligram/day Upper limit: 2,000 milligram/day

Daily Allowance of Thiamin

R D A for adults Males: 1.2 milligram/day Females: 1.1 milligram/day Major food sources Enriched and fortified foods Whole-grain foods Lean pork

Daily Allowance and Food Sources of Riboflavin?

R D A for adults Males: 1.3 milligram/day Females: 1.1 milligram/day Major food sources Milk (fortified) Yogurt Enriched and fortified cereals and grains Riboflavin is light sensitive; the ultraviolet rays of the sun or of fluorescent lamps can destroy it, as can irradiation. For this reason, milk is often sold in cardboard or opaque plastic containers to protect the riboflavin in the milk from light.

How is Vitamin D metabolized?

The liver manufactures a vitamin D precursor. Next, the liver and then the kidneys alter the second precursor to produce the active vitamin. Whether made from sunlight or obtained from food, vitamin D requires the same two conversions by the liver and kidneys to become active.

What vitamins can reduce risk of vision loss?

Vitamin C, vitamin E, beta-carotene Zinc and copper

What vitamins help neutralize free radicals, helping to counteract oxidation in cells?

Vitamin E Vitamin C Selenium Flavonoids Carotenoids

What is vitamin toxicity?

(hypervitaminosis): Rare Results from ingesting excess vitamins, which leads to tissue saturation Can damage cells, sometimes permanently Results from supplementing with megadoses of vitamins; does not occur from eating foods The Dietary Reference Intakes include a tolerable upper intake level (U L) for most vitamins, to prevent excess.

What are the daily needs and food sources of Pantothenic Acid?

A I for male and female adults: 5 milligram/day Based on the amount needed to replace excretion through urine Major food sources Widespread in a large variety of foods Largest amounts in: Whole-grain cereals Nuts and legumes, peanut butter Meat, milk, and eggs Can be destroyed by heat, so processed foods (canned vegetables, fish, meat) are lower than fresh foods

Needs for B12 supplementation

A few people have an inherited defect in the gene for intrinsic factor, which makes vitamin absorption abnormal beginning in midadulthood. Many others lose the ability to produce enough stomach acid and intrinsic factor to allow efficient absorption of vitamin in later life due to atrophic gastritis. In these cases, vitamin must be supplied by injection to bypass the defective absorptive system. The anemia of the vitamin deficiency caused by lack of intrinsic factor is known as pernicious anemia.

Vitamin B12 Deficiency

Causes Low intake, as with vegan diets Malabsorption without adequate H C l Insufficient pancreatic enzymes Gastric bypass Vegans are at special risk for undetected vitamin deficiency for two reasons: first, they receive none in their diets, and second, they consume large amounts of folate in the vegetables they eat. Macrocytic anemia Due to folate deficiency Pernicious anemia Fatigue Shortness of breath Long-term consequence Nerve damage (tingling and numbness in arms and legs) Breastfed infants born to vegan mothers with low concentrations of vitamin in their breast milk can develop severe neurological symptoms such as seizures and cognitive problems

What are the two forms of Vitamin D?

Cholecalciferol (vitamin D3): Produced in the skin and found in animal foods Ergocalciferol (vitamin D2): Found in plants and dietary supplements

Metabolic Function of B6

Coenzyme for more than 100 enzymes Most involved in protein metabolism Amino acid metabolism P L P needed in transamination to form nonessential amino acids Absorption Seventy-five percent bioavailable All forms absorbed in small intestine by passive diffusion Bound to albumin and transported to the liver Active form Pyridoxal phosphate (P L P) Stored mostly in the muscle, some in the liver

Metabolic Functions of Vitamin C

Collagen synthesis Occurs by hydroxylation reactions where collagen serves as the matrix on which bone is formed, the material of scars, and an important part of the "glue" that attaches one cell to another. Antioxidant Reduces risk for heart disease and cancer Accepts or donates electrons to balance free radicals Iron absorption is enhanced. Plant sources of nonheme iron

Vitamin B6

Collective name for several related compounds. The vitamin has long been known to play roles in carbohydrate, fatty acid, and protein and amino acid metabolism. In the cells, vitamin helps convert one kind of amino acid, which the cells have in abundance, to other nonessential amino acids that the cells lack. It also aids in the conversion of the amino acid tryptophan to niacin and plays important roles in the synthesis of hemoglobin and neurotransmitters, the communication molecules of the brain. Vitamin also assists in releasing stored glucose from glycogen and thus contributes to the regulation of blood glucose. Absorption Seventy-five percent bioavailable All forms absorbed in small intestine by passive diffusion Bound to albumin and transported to the liver Active form Pyridoxal phosphate (P L P) Stored mostly in the muscle, some in the liver

Ribofalvin (B2)

Composed of a side chain and ring structure Two coenzyme forms Flavin mononucleotide (F M N) Flavin adenine dinucleotide (F A D) Stable during cooking except in the presence of ultraviolet light Absorption Attached to proteins in food Released in the presence of hydrochloric acid in the stomach Absorbed by active transport in the small intestine

What does deficiency of thiamin cause?

Deficiency Beriberi Symptoms include loss of appetite, weight loss, confusion, muscle weakness, peripheral neuropathy Classifications Wet: Edema and congestive heart failure Dry: Muscle wasting without edema or nerve degeneration Wernicke-Korsakoff syndrome Caused by chronic alcohol abuse Causes of deficiency Inadequate dietary intake Malabsorption Alcoholism Prolonged diarrhea Times of increased need with too little intake Pregnancy and lactation Inadequate thiamin intakes have been reported among the nation's malnourished and homeless people. Similarly, people risk thiamin deficiency when they derive most of their energy from empty-kcalorie foods and beverages. Alcohol is a good example.

Vitamin C DEficiency

Deficiency Scurvy Bleeding gums Coiled or curly arm hairs Wounds won't heal Rough rash Prevented with 10 milligram of vitamin C per day

Deficiency of B6

Deficiency symptoms Sore tongue Inflammation of the skin Depression Confusion Vitamin deficiency is expressed in general symptoms, such as weakness, confusion, and dermatitis. Microcytic hypochromic anemia Red blood cells are small and pale. Often caused by excessive alcohol consumption

Deficiency of Pantothenic Acid

Deficiency: Rare May experience: Fatigue Nausea Vomiting Numbness Muscle cramps Difficulty walking

Vitamin A toxicity

Excessive amounts of preformed vitamin A can accumulate to toxic levels. Toxic levels occur by taking supplements, not with food intake. >15,000 μ grams can cause symptoms of toxicity. Hypervitaminosis A can lead to liver damage and even death. Overconsumption: During pregnancy can cause birth defects in the face, skull, and C N S of the child Can potentially result in osteoporosis and bone fractures in adults Carotenoids in foods are not toxic. Do not pose serious health problems Excess carotenoids can cause carotenodermia. Overconsuming beta-carotene supplements May increase a smoker's lung cancer risk. The availability of breakfast cereals, instant meals, fortified milk, and chewable candy-like vitamins, each containing 100 percent or more of the recommended daily intake of vitamin A. Excessive vitamin A also poses a teratogenic risk. Excessive vitamin A during pregnancy can injure the spinal cord and other tissues of the developing fetus, increasing the risk of birth defects.

Thiamin (b1)

First B vitamin discovered Casimir Funk identified thiamin as the curative factor in unpolished rice in 1911. Dietary form converted to active coenzyme form thiamin pyrophosphate (T P P) It is destroyed in basic solutions; acid solutions protect it. Absorption In jejunum by passive diffusion Active transport is used with low intakes Transported through the blood and excreted through urine

Sources of Vitamin A

Fish, Liver, Cheese, Carrot Juice, Sweet Potatoes, Squash

How does Vitamin K affect newborns?

Newborn infants present a unique case of vitamin K nutrition. An infant is born with a sterile digestive tract, and some weeks pass before the vitamin K-producing bacteria become fully established in the infant's intestines. At the same time, plasma prothrombin concentrations are low (this helps prevent blood clotting during the stress of birth, which might otherwise be fatal). A single dose of vitamin K, usually in a water-soluble form, is given at birth to prevent hemorrhagic disease in the newborn.

Folate toxcity

No risk from eating foods with folate Excess intake from fortified food or supplements can mask a vitamin B12 deficiency.

Can Vitamins be synthesized enough in the body?

No, Chronic deficiency is likely to cause physical symptoms. Symptoms will disappear once the vitamin level in the body is restored. Deficiency can cause permanent damage.

Toxicity of Niacin

None known from normal dietary intake Excess supplements or too many overly fortified foods can cause: Reddish coloring of the face, arms, and chest Nausea, vomiting Heartburn Liver toxicity Raised blood glucose levels Certain forms of niacin supplements taken in doses three to four times the dietary recommendation or larger cause "niacin flush," a dilation of the capillaries of the skin with perceptible tingling that, if intense, can be painful.

What are the food sources of Vitamin K

Notable food sources of vitamin K include green vegetables such as collards, spinach, lettuce, brussels sprouts, and cabbage and vegetable oils such as soybean oil and canola oil.

Sources of Vitamin E

Olive oil, coconut oil, sunflower oil, broccoli, kale, spinach, avocado, almonds and peanuts

What are the metabolic functions of Pantothenic Acid?

Part of coenzyme A used in fat, carbohydrate, and protein metabolism. Fat: Synthesizes fatty acids and converts them to energy Carbohydrate: Converts pyruvate to acetyl C o A Protein: Converts amino acids to substrates in the T C A cycle Synthesis of: Cholesterol Steroid hormones Neurotransmitter acetylcholine

Pantothenic Acid

Part of the compound coenzyme A, which then is used to make acetyl C o A Sometimes referred to as B5. Pantothenic acid is involved in more than 100 different steps in the synthesis of lipids, neurotransmitters, steroid hormones, and hemoglobin. Absorption In the small intestine If intake is high: Passive diffusion If intake is low: Active transport Is not stored but high concentrations are found in the liver, kidney, adrenal glands, and brain

What role does riboflavin play in metabolism?

Participates in energy metabolism through oxidation F A D and F M N accept hydrogen ions. F A D H2 transports electrons to the electron transport chain to make A T P. Participates in beta-oxidation Participates in oxidation-reduction reactions that protect cells from oxidative stress Enhances the function of other B vitamins

Deficiency of Niacin

Pellagra (disease of the four Ds)- Dermatitis Diarrhea Dementia Death

What are the 3 forms of Vitamin K?

Phylloquinone is found in green plants. Menaquinone is synthesized by intestinal bacteria. Menadione is the synthetic form.

What is the medical use of niacin and cholesterol?

Physicians sometimes use diet and large doses of a form of niacin (nicotinic acid) to lower blood cholesterol in the treatment of atherosclerosis. When used this way, niacin becomes a pharmacological agent, a drug.

Function of Thiamin

Produces A T P from carbohydrate metabolism T P P activates decarboxylase to remove a carbon from pyruvate; forms acetyl C o A. T P P-dependent enzymes convert alpha-ketoglutarate to succinyl C o A in the T C A cycle. Converts branched-chain amino acids to acetyl C o A Makes pentoses used to synthesize D N A and R N A Transmission of nerve impulses

Recommended amount and food sources of B6

R D A for adults Males: 1.3 to 1.7 milligram/day Females: 1.3 to 1.5 milligram/day Tolerable upper limit: 100 milligram/day Variety of food sources Ready-to-eat cereals Meat, fish, poultry Fruits and vegetables Nuts and other legumes

What are the functions of vitamins?

Regulate metabolism Help convert energy in fat, carbohydrate, and protein into A T P Promote growth and reproduction

Vitamin C Toxcicity

Toxicity Consuming > 3,000 milligram can cause nausea, stomach cramps, and diarrhea. Overconsumption can lead to: Kidney stones False positive or false negative medical tests Those with hemochromatosis should avoid excess amounts.

nIACIN (b3)

Two active forms derived from food Nicotinic acid and nicotinamide Endogenous sources of Niacin The amino acid tryptophan can be converted to niacin in the body Bioavailability Less available in plant foods (wheat or corn) More available in dairy foods and meat Absorbed in the small intestine by simple diffusion Circulates through the blood to the liver Coenzyme in oxidation-reduction reactions Glucose, protein, fat, and alcohol metabolism Folate and vitamin C metabolism Keeps skin cells healthy and digestive system functioning properly In therapeutic doses: Lowers total cholesterol in the blood by lowering L p(a) lipoprotein Lowers triglycerides Raises H D L cholesterol Can be synthesized by the body from tryptophan 60 milligram of tryptophan = 1 niacin equivalent (N E) Conversion requires riboflavin, vitamin B6, and iron R D A for adults (N E) Males: 16 milligram/day Females: 14 milligram/day Upper level: 35 milligram/day

Metabolic Functions of B12

Two coenzymes Methylcobalamin: converts homocysteine to methionine; prevents homocysteine buildup Deoxyadenosylcobalamin: helps form succinyl C o A during the T C A cycle Activates folate Synthesis of new cells, especially red blood cells Maintains myelin sheath of nerve tissue Catabolism of amino acids and fatty acids for energy metabolism

Vitamin B12

Vitamin (B12) (in coenzyme form) stands by to accept carbon groups from folate as folate removes them from other compounds. The passing of these carbon groups from folate to vitamin regenerates the active form of folate so that it can continue its dismantling tasks. In the absence of vitamin , folate is trapped in its inactive, metabolically useless form, unable to do its job. When folate is either trapped due to a vitamin deficiency or unavailable due to a deficiency of folate itself, cells that are growing most rapidly—notably, the blood cells—are the first to be affected. Also called cobalamin Two forms Both forms contain cobalt.

What vitamin leads to night blindness?

Vitamin A

Fat-Soluble Vitamins

Vitamin A Vitamin D Vitamin E Vitamin K

Vitamin K

blood clotting and red blood cell synthesis, bone health,

B-12

blood clotting and red blood cell synthesis, energy production, and protein metabolism and synthesis

Vitamin A Functions

bone health, growth and reproduction, and immune function

Foods with lots of Vitamin C

citrus fruits, strawberries, kiwi, papaya, guava, watermelon, mangos, tomatoes

What can help preserve vitamins in food?

refrigerating, protecting from light and air, and prevent destruction or losses of water

The B Vitamins

thiamin, riboflavin, niacin, vitamin B6, folate, vitamin b12, pantothenic acid, and biotin

How are excess vitamins secereted?

through the urine

Vitamin D

Bone health, growth and reproduction, immune function

Vitamin C as an antioxidant

By being oxidized itself, vitamin C regenerates already-oxidized substances such as iron and copper to their original, active form Acceptance of unstable electrons from free radicals helps to reduce oxidative stress

Toxicity of riboflavin

nONE, EXCESSIVE AMOUNTS OF IT SECERETED IN URINE

Vitamin A

- A family of fat-soluble retinoids (retinol, retinal, retinoic acid) mostly related to the vision cycle and DNA synthesis The first fat-soluble vitamin to be recognized. More than a century later, vitamin A and its plant-derived precursor, beta-carotene -Preformed vitamin A (retinyl ester) is found primarily in animal foods. Some plants contain provitamin A compounds, which are converted to retinol in your body. Beta-carotene is split into two molecules of retinal. Carotenoids, including beta-carotene, are pigments that give color to carrots, butternut squash, and cantaloupe. -All forms of vitamin A are absorbed by active transport with bile salts and micelles. Beta-carotene is absorbed by passive diffusion. Reduced with high fiber intake Improved in cooked foods Most forms of vitamin A are packaged into chylomicrons → enter lymph. Retinoic acid is attached to albumin and transported to the liver via the portal vein. Stored in the liver -Participates in: Vision Protein synthesis and cell differentiation Reproduction Bone health A healthy immune system Retinal is active in vision, and retinoic acid acts as a hormone, regulating cell differentiation, growth, and embryonic development. Vitamin A exerts considerable influence on an array of body functions through its interaction with genes—hundreds of genes are regulated by the retinoic acid form of the vitamin. -The role that vitamin A plays in the skin and the linings of organs, where it works at the genetic level to promote protein synthesis and cell differentiation. All body surfaces, both inside and out, are covered by layers of cells known as epithelial cells. The epithelial tissue on the outside of the body is, of course, the skin—and vitamin A and beta-carotene help to protect against skin from damage. Vitamin A, by way of its role in cell differentiation, helps to maintain the integrity of the epithelial cells.

Overconsumption of Vitamin D

A high intake can cause loss of appetite, nausea, vomiting, and constipation. Overuse of supplements may lead to hypervitaminosis D. Hypercalcemia Can cause damaging calcium deposits in kidneys, lungs, blood vessels, and heart Can affect the nervous system and cause severe depression Too-high levels are rarely caused by food intake or overexposure to the sun. Vitamin D is among the vitamins most likely to have toxic effects when consumed in excess. Excess vitamin D raises the concentration of blood calcium. Excess blood calcium tends to precipitate in the soft tissues and form stones, especially in the kidneys, where calcium is concentrated in an effort to excrete it. Calcification may also harden the blood vessels and is especially dangerous in the major arteries of the brain, heart, and lungs, where it can cause death

What are the main differences between water-soluble and fat-soluble vitamins? (mainly bioavailability)

Absorption Bioavailability Bioavailability varies based on: Amount in food Efficiency of digestion and absorption of food Individual nutritional status Natural or synthetic Fat-soluble vitamins are generally less bioavailable than water-soluble vitamins. Vitamins from plant foods are generally less bioavailable than those in animal foods.

How is B12 absorbed?

Absorption of vitamin requires intrinsic factor, a compound made by the stomach with instructions from the genes. With the help of the stomach's acid to liberate vitamin from the food proteins that bind it, intrinsic factor attaches to the vitamin. and the complex is absorbed into the bloodstream.

Vitamin E needs

Adults need 15 milligrams of alpha-tocopherol equivalents. Upper limit is 1,000 milligrams/day Current suspicion that the upper limit may be too high

Vitamin C

Also known as ascorbic acid Humans lack the enzyme to make vitamin C. Absorption Small intestine by active transport Higher intakes absorbed by simple diffusion in the stomach and small intestine Absorption decreases 50 percent with intakes > 1 gram Excreted through kidneys Not stored in the body

deficiency of riboflavin

Ariboflavinosis Cells in tissues lining the throat, mouth, tongue, and lips become inflamed or swollen. Sore throat, stomatitis, glossitis, cheilosis

Water-Soluble Vitamins

B vitamin complex Vitamin C Vitamin C Eight B-complex vitamins Initially thought to be one vitamin Years of research uncovered it was several substances. Thiamin Riboflavin Niacin Vitamin B6 Folate Vitamin B12 Pantothenic acid Biotin

What are the functions of Vitamin D?

Bone growth Calcitriol stimulates intestinal calcium and phosphorus absorption. Maintains healthy ratio of calcium and phosphorus in the blood Controls interaction between osteoblasts and osteoclasts Potential for research in Parkinson's, Obesity, and Immunity Incidence of breast, colon, and prostate cancer, high levels of Morbid Obesity, and muscular diseases are higher in individuals living in sun-poor areas of the world. Potentially helps reduce risk of some neurologic and muscular disorders like Parkinson's Disease May prevent diabetes May reduce type 1 diabetes risk by 50 percent in adults Type 2 diabetes is associated with low blood vitamin D levels. May regulate blood pressure

Folate

Folate is active in cell division. During periods of rapid growth and cell division, such as pregnancy and adolescence, folate needs increase, and deficiency is especially likely. When a deficiency occurs, the replacement of the rapidly dividing cells of the blood and the GI tract falters. Not surprisingly, then, two of the first symptoms of a folate deficiency are a type of anemia and GI tract deterioration Folate is found in many foods. Folic acid is the synthetic form added to foods and in supplements. Most folate in foods is in the polyglutamate form. Absorption All but one glutamate is removed to form monoglutamate during digestion. In the small intestine, 5-methyl-tetrahydrofolate is formed and transported to the liver. Active form: Tetrahydrofolate Bioavailability Folic acid is more bioavailable than folate. Folate is destroyed with exposure to heat and light. Raw foods have more folate than cooked foods. Some foods contain enzymes that inhibit folate availability. Beans, legumes, and cabbage Alcohol-addicted people risk folate deficiency because alcohol impairs folate's absorption and increases its excretion Transfers single-carbon compounds to form new compounds D N A and amino acid synthesis. Key regulator for Homocysteine metabolism from Cystenine. As people's alcohol intakes rise, their folate intakes decline. Assists in neural tube development to prevent: Neural tube defects Anencephaly Spina bifida May prevent cancer and heart disease

Fortification of Foods

Fortified foods: Voluntary addition of nutrients by manufacturers to: Enhance the nutrient quality of food Prevent or correct dietary deficiencies Ensure adequate intake for some individuals Enrichment is a form of fortification. Fortification can contribute to health risks. Lead to vitamin excess Displace nutrient-rich foods

Vitamin A deficiency

In vitamin A deficiency, cell differentiation and maturation are impaired. The epithelial cells flatten and begin to produce keratin—the hard, inflexible protein of hair and nails. In the eye, this process leads to drying and hardening of the cornea, which may progress to permanent blindness. Chronic vitamin A deficiency causes night blindness. Prolonged vitamin A deficiency leads to xerophthalmia. Leading cause of preventable blindness in children, mostly in developing countries Deficiency can lead to keratinization of epithelial tissues. Epithelial cells don't secrete mucus. Cells are unable to function properly, promoting infection.

Folate deficiency

Interferes with normal red blood cell division Megaloblasts → macrocytes → macrocytic anemia Red blood cells are abnormally large. Macrocytic anemia Symptoms Fatigue Weakness Research studies confirm the importance of folate in preventing neural tube defects (NTD). The brain and spinal cord develop from the neural tube, and defects in its orderly formation during the early weeks of pregnancy may result in various central nervous system disorders and death. Folate supplements taken before conception and continued throughout the first trimester of pregnancy can prevent NTD. For this reason, all women of childbearing age who are capable of becoming pregnant should consume 400 micrograms (0.4 milligrams) of folic acid daily

Biotin

Made of sulfur-containing double rings and a side chain Absorption Biotinidase removes biotin from food. Active transport in the small intestine Absorbed into the liver Coenzyme for enzymes involved in energy metabolism Synthesis of fatty acids Replenishes oxaloacetate from pyruvate Amino acid metabolism D N A replication and transcription of genes Cell development and growth Maintenance of healthy hair and nails Major food sources Peanuts Yeast Liver and other organ meats Bacteria in the G I tract Egg yolks Whole grains Fish Deficiency Seen with: Overconsumption of raw egg whites (> 12/day for a prolonged time); avidin in raw egg whites can bind to biotin and cause deficiency symptoms Total parenteral nutrition Impaired absorption Rare genetic disorders Symptoms include hair loss, depression, conjunctivitis, dermatitis, lethargy, hallucinations

Food Sources of Niacin

Major food sources Meats, fish, poultry Enriched and fortified grains and cereals Amino acid tryptophan Stable in foods Not destroyed by heat or ultraviolet light Can leach if food is cooked or soaked in water

Where is Vitamin K made?

Most vitamin K is absorbed in the jejunum Like vitamin D, vitamin K can be obtained from a nonfood source. Bacteria in the intestinal tract synthesize vitamin K that the body can absorb, but people cannot depend on this source alone for their vitamin K. Ten percent of vitamin K is produced by bacteria in the colon.

Deficiency of Vitamin D

Rickets: Vitamin D deficiency disease in children Bones aren't adequately mineralized with calcium and phosphorus, causing them to weaken, leading to bowed legs. On the rise in the United States due to decreased milk consumption, fear of skin cancer from sun exposure, and air pollution Other vitamin D deficiency disorders Osteomalacia: Adult equivalent of rickets Osteoporosis: Condition where bones don't mineralize properly Muscle and bone weakness and pain

Who would need more Vitamin C?

Smokers As is true of all nutrients, unusual circumstances may raise vitamin C needs. Smoking has adverse effects on vitamin C status. Cigarette smoke contains oxidants, which deplete this potent antioxidant. Accordingly, the vitamin C recommendation for smokers is set high, at 125 milligrams for men and 110 milligrams for women.

What makes vitamins different from other compounds?

Structure. Vitamins are individual units; they are not linked together (as are molecules of glucose or amino acids). Function. Vitamins do not yield energy when metabolized; many of them do, however, assist the enzymes that participate in the release of energy from macronutrients. Dietary intakes. The amounts of vitamins people ingest daily from foods and the amounts they require are measured in micrograms (μg) or milligrams (mg).

What are provitamins?

Substances found in foods that are not directly usable by the body Converted to an active form once absorbed Example: beta-carotene → vitamin A

Function of Vitamin E

Vitamin E is a fat-soluble antioxidant. It protects other substances from oxidation by being oxidized itself. Vitamin E in the membranes of cells protects against exposed reactive substances, taking the brunt of any oxidative attack, protecting the lipids and other parts of the membrane. Acts as a powerful antioxidant Protects cell membranes; prevents oxidation of L D L cholesterol Vitamin E exerts an especially important antioxidant effect in the lungs, where the cells are exposed to high concentrations of oxygen. Vitamin E also protects the lungs from air pollutants that are strong oxidants. Vitamin E may also offer protection against heart disease by protecting low-density lipoproteins (LDL) from oxidation and reducing inflammation. The oxidation of LDL encourages the development of atherosclerosis; thus, in theory, halting LDL oxidation should reduce atherosclerosis

Vitamin K function

Vitamin K has long been known for its role in blood clotting, where its presence can make the difference between life and death. Vitamin K appropriately gets its name from the Danish word coagulation (coagulation, or "clotting"). The vitamin also participates in the synthesis of several bone proteins. At least 13 different proteins and the mineral calcium are involved in making blood clots. Vitamin K is essential for the activation of several of these proteins, among them prothrombin, the precursor of the enzyme thrombin. When any of the blood-clotting factors are lacking, hemorrhagic disease results. Promotes blood clotting Involved in synthesizing four blood-clotting factors Including synthesis of prothrombin which forms fibrin

Where is Vitamin K stored?

Vitamin K is incorporated into chylomicrons and transported to the liver. When a diet is deficient in vitamin K: Storage forms are transported by V L D L, L D L, and H D L. Stored mostly in the liver

Vitamin A Needs

Vitamin needs for adults Males: 900 micrograms (μ g) retinol activity equivalents (R A E) Females: 700 μ grams R A E Upper limit: 3,000 μ grams Beta-carotene: 3 to 6 milligrams daily Strict vegans need to meet vitamin A intake through carotenoids and beta-carotene-rich foods.

what are preformed vitamins?

Vitamins found in foods in their active form Do not need to be converted

Vitamin E deficiency

When blood concentrations of vitamin E fall below a certain critical level, the red blood cells tend to break open and spill their contents This classic vitamin E-deficiency symptom, known as erythrocyte hemolysis, is seen in premature infants born before the transfer of vitamin E from the mother to the fetus that takes place in the last weeks of pregnancy In adults, vitamin E deficiency is usually associated with diseases, notably those that cause malabsorption of fat. These include diseases of the liver, gallbladder, and pancreas.

Vitamin K and Bone Metabolism

Without vitamin K, the bones produce an abnormal protein that cannot effectively bind to the minerals that normally form bones. An adequate intake of vitamin K helps to decrease bone turnover and protect against fractures. Vitamin K supplements seem ineffective against bone loss, however, and more research is needed to clarify the links between vitamin K and bone health.

What does Vitamin C act as?

antihistimine

Vitamin E Functions

antioxidant

Vitamin C

antioxidants, bone health, immune function and protein metabolism and synthesis