Vitamins and fat-soluble vitamins

Vitamin Malabsorption

As a result of pancreatic enzyme insufficiency and mucus blocking passageways throughout the body, fat-soluble vitamin digestion and absorption is often impaired in cystic fibrosis. Vitamin A is involved in immunity, and poor immune response is a concern of people with cystic fibrosis because they are already prone to frequent respiratory infections. Although vitamin A supplementation could benefit people with the disease, more research is needed to develop specific guidelines for use of supplemental vitamin A in persons with cystic fibrosis. Vitamin D deficiency is almost universal in cystic fibrosis patients. Over 20 studies have documented low blood levels of vitamin D in patients with cystic fibrosis, even after supplementation with the micronutrient. Adequate sun exposure should also be encouraged for those who have cystic fibrosis.

Functions of Vitamin K

Blood contains inactive clotting factors and cell fragments called platelets that are necessary for blood clotting to occur. When a blood vessel is cut, blood in the injured area undergoes a complex series of steps to form a clot that stops the bleeding. A clot is comprised of strands of the protein fibrin that traps blood cells, forming a mesh. The liver synthesizes several blood-clotting factors, and the organ needs vitamin K to produce four of them, including prothrombin, properly. In addition to vitamin K's role in blood clotting, it is also a coenzyme for an enzyme that is essential for bone-building cells to produce osteocalcin, a protein needed for normal bone mineralization.

Rickets

Breast milk contains insufficient amounts of vitamin D to prevent rickets. Young children who are most likely to develop rickets are breastfed, and they have dark skin, minimal sunlight exposure, and little or no vitamin D intake. Exposing breastfed infants to sunlight reduces their risk of the disease, but medical experts do not know how much sun exposure is necessary. Thus, breastfed infants should consume a supplement containing 400 IU of vitamin D per day soon after birth. While infants being formula-fed are at low risk for rickets, health care providers should ensure that the formula is fortified with vitamin D and that the infant is consuming enough formula each day to meet needs. Healthy children should continue to consume at least 400 IU of the vitamin per day through adolescence.

Vitamin A and Chronic Diseases

CVD and Cancer Results of clinical studies have not provided support for taking vitamin A or beta-carotene supplements to reduce the risk of cardiovascular disease (CVD). Age-related macular degeneration (AMD) is the leading cause of impaired vision among people over 55 years of age. The macula contains the carotenoids lutein and zeaxanthin. Diets supplying high amounts of carotenoids (beta-carotene, lutein, and zeaxanthin) may lower the risk of AMD. However, there was no clear scientific evidence that taking antioxidant supplements prevents healthy people from developing AMD. Additionally, the long-term use of these supplements could be harmful, and more research is needed.

Vitamin A Deficiency

Epithelial cells are among the first to become affected by a deficiency of vitamin A. In skin, vitamin A-deficient epithelial cells produce too much keratin, a tough protein found in hair, nails, and the outermost layers of skin. Keratin accumulates within the skin and makes the tissue rough and bumpy. Keratin also forms in tissues that do not normally contain the protein, such as the cornea, the clear covering over the iris of the eye. The epithelial cells that line the inner eyelids secrete mucus that helps keep the cornea moist and clean. In a person suffering from chronic vitamin A deficiency, these cells accumulate keratin, become hardened, and stop producing mucus. This condition is called xerophthalmia or "dry eye". Corneas affected by xerophthalmia can be damaged easily by dirt and bacteria. Unless a person with xerophthalmia receives vitamin A, the condition eventually leads to blindness. Vitamin A deficiency also reduces the effectiveness of the immune system, and many children suffering from vitamin A deficiency die from infections such as measles. The results of animal studies suggest that women who are vitamin A deficient during pregnancy may give birth to infants with circulatory, urinary, skeletal, and nervous system defects. However, a pregnant woman should not take a vitamin A supplement without consulting her physician. When taken in excess during pregnancy, vitamin A is a teratogen, an agent that causes birth defects.

Vitamin A

Family of compounds that includes retinol, retinal, and retinoic acid, together called retinoids (preformed vitamin A). Retinol is the the alcohol form and most active form of the vitamin in the body. The body often stores retinol as retinyl esters. Although retinol, retinyl esters, and the other retinoids are only found in animal foods, plants contain hundreds of yellow-orange pigments called carotenoids. Over 600 forms of carotenoids exist, but only alpha-carotene, beta-carotene, and beta-cryptoxanthin can be converted into a biologically active retinoid.

Food Sources of Vitamin D

Fish liver oils and fatty fish, especially salmon, herring, and catfish, are among the few foods that naturally contain vitamin D. Milk is routinely fortified with vitamin D, and some brands of ready-to-eat cereals, orange juice, and margarine have the vitamin added to them as well.

Vitamin D classification

Vitamin D, calciferol, comes from both plant and animal sources. The plant form of vitamin D is called vitamin D2, or ergocalciferol, whereas the animal form is vitamin D3, also called cholecalciferol. Vitamin D is unique among all other vitamins because it is not considered an essential nutrient. The body can make vitamin D when skin cells are exposed to the sun's ultraviolet radiation, which explains why the nutrient is also considered a hormone and referred to as the "sunshine vitamin."

Vitamin E

Vitamin E exists in one of eight forms; four of the forms are tocopherols. Only the alpha-tocopherol form of the vitamin is maintained in plasma and used by the body. Alpha-tocopherol is in many foods and vitamin E supplements; gamma-tocopherol is also in foods, including vegetable oil. However, the biological activity of gamma-tocopherol is significantly lower than that of alpha-tocopherol.

Does vitamin give you energy?

Vitamins, are not a source of energy, because cells do not metabolize them for energy. Although not used directly for energy, many vitamins participate in the chemical reactions that release energy from glucose, fatty acids, and certain amino acids.

Toxicity of vitamins

When cells are saturated with a vitamin, they contain all they need and cannot accept additional amounts of the micronutrient. In this situation, continuing to take the vitamin can produce a toxicity disorder, because exposure to the excess micronutrient or its by-products can damage cells. Liver damage can also occur as a result of the intake of toxic levels of some vitamins. Most people do not need to be concerned about vitamin toxicity unless they are taking excessive amounts (megadoses) of vitamin supplements or consuming large amounts of vitamin-fortified foods regularly. In their natural states, most commonly eaten foods do not contain toxic levels of vitamins. Taking a "once daily" type of multivitamin supplement regularly is unlikely to cause toxic effects in adults because these products usually contain less than two times the Daily Values of each micronutrient component.

Bioavailability of Vitamins

Food processing and preparation, as well as digestion and absorption, all affect the bioavailability of a vitamin, the amount of that vitamin that is actually available for use by the body. Factors that affect vitamin bioavailability include: -Changes to the normal GI transit time. When foods move too quickly through the GI tract, such as in cases of frequent diarrhea, vitamin bioavailability is decreased. -Health conditions that affect absorption of fats also affect fat-soluble vitamin absorption, reducing vitamin bioavailability. -Food processing and preparation techniques. -Source of the vitamin. Most vitamins are more bioavailable from natural food sources, but that is not always the case. For example, folate is nearly two times as bioavailable from synthetic sources as from food sources.

Food Sources of Vitamin K

Major food sources of vitamin K are green leafy vegetables such as kale, turnip greens, salad greens, cabbage, and spinach; broccoli; and green beans. Other reliable sources of the vitamin are soybean and canola oils, and products made from these oils, such as salad dressing.

Vitamin D

Major functions in the body: Absorption of calcium and phosphorus, maintenance of normal blood calcium, calcification of bone, maintenance of immune function. 15-20 μg Vitamin D-fortified milk, fortified cereals, fish liver oils, fatty fish Rickets in children, osteomalacia in adults: soft bones, depressed growth, and reduced immune system functioning UL = 100 μg/day Poor growth, calcium deposits in soft tissues

Vitamin A

Major functions in the body: Normal vision and reproduction, cellular growth, and immune system function. Adult RDA/AI 700-900 μg RAE. Major Dietary Sources: liver, milk, fortified cereals Provitamin: yellow- orange and dark green fruits and vegetables. Major deficiency signs: Night blindness, xerophthalmia, poor growth, dry skin, reduced immune system functioning. Major Toxicity signs: Upper Level (UL) = 3000 μg/day. Nausea and vomiting, headaches, bone pain and fractures, hair loss, liver damage, interference with vitamin K absorption.

Deficiency of vitamins

A diet that contains adequate amounts of a wide variety of foods, including minimally processed fruits, vegetables, and whole-grain breads and cereals, can help supply the vitamin needs of most healthy people. Vitamin deficiency disorders generally result from inadequate diets or conditions that increase the body's requirements for vitamins, such as reduced intestinal absorption or higher-than-normal excretion of the micronutrients. Many Americans, however, consume less than recommended amounts of vitamins A, D, E, and K. Vulnerable people include alcoholics, older adults, and patients who are hospitalized for lengthy periods. Additionally, people who suffer from the eating disorder anorexia nervosa, have intestinal conditions that interfere with vitamin absorption, or have rare metabolic defects that increase their vitamin requirements are more likely to develop vitamin deficiency disorders than people who do not have these conditions.

Vitamin A functions

All cells in the body need vitamin A to develop and function properly. Vitamin A participates in the processes of cell production, growth and development, function, and maintenance. As one example, the vitamin is necessary for the production, maturation, and maintenance of epithelial cells, cells that form protective tissues that line the body, including skin and linings of the digestive, respiratory, and reproductive tracts. Certain epithelial cells secrete mucus, a slippery and sticky fluid that keeps the tissue moist and forms a barrier against many environmental pollutants and infectious agents. When the mucus-secreting epithelial cells do not have vitamin A, they deteriorate and no longer produce mucus. Lack of Vitamin A can also reduce fertility because the vitamin is required for maintaining the epithelial cells that line the female and male reproductive tracts. Certain white blood cells produce antibodies, which are proteins that participate in the body's immune response. Antibodies help destroy infectious agents such as bacteria. Vitamin A plays a role in the production and activity of white blood cells.10 Thus, people deficient in vitamin A are at greater risk of infections than those with adequate levels of the vitamin in their bodies. Normal bone growth and development also require vitamin A. Although bones do not appear to change their shape, they are constantly being remodeled by processes that involve tearing down and rebuilding the tissues to meet the physical demands that are placed on them each day.

Differences between vitamins and carbs, fats and proteins

Although vitamins are organic molecules in foods, they are distinctly different from carbohydrates, fats, and proteins. For example, carbohydrates, fats, and proteins are metabolized for energy, but vitamins are not. In addition, foods generally contain much smaller amounts of vitamins than of macronutrients. A slice of whole-wheat bread, for example, weighs 28 g. Of that weight, only about 0.005% (1.48 mg) is comprised of vitamins; carbohydrate, water, protein, fat, and minerals make up the remaining weight of the bread. Furthermore, the body requires vitamins in milligram or microgram amounts, but it needs grams of macronutrients.

Food source of vitamin A

Animal foods such as liver, butter, fish liver oils, and eggs are good sources of preformed vitamin A, including retinyl esters. Vitamin A-fortified milk, yogurt, margarine, and cereals are important sources of the nutrient for Americans. Carrots, spinach and other leafy greens, pumpkin, sweet potatoes, broccoli, mangoes, and cantaloupe are rich sources of beta-carotene, a carotenoid that the body can convert to vitamin A. However, the body obtains only 1 μg of retinol from every 12 μg of beta-carotene in a food. Vitamin A precursors in plant foods are not as well absorbed as retinol in animal foods. Once absorbed, vitamin A is transported with lipids in chylomicrons to tissues for use or storage. Over 90% of vitamin A is stored in the liver. When needed, vitamin A is transported in the blood bound to retinol-binding protein (RBP).

Vitamin E

Antioxidant 15 mg (alpha- tocopherol) Vegetable oils and products made from these oils, certain fruits and vegetables, nuts and seeds, fortified cereals Loss of muscular coordination, retinal damage, hemolysis of red blood cells resulting in anemia (premature infants) UL = 1000 mg/day Excessive bleeding as a result of interfering with vitamin K metabolism

Vitamin D

Children with rickets have bones that are soft and can become misshapen. Leg bones, for example, bow under the weight of carrying the upper part of the body. Additionally, the affected child's joints, rib cage, and hips (pelvis) become deformed, and the child may complain of muscle pain.

Cystic Fibrosis and Fat-Soluble Vitamins

Cystic fibrosis is caused by a defective gene that was first identified in 1989.65 Experts estimate that more than 10 million Americans are carriers of the faulty cystic fibrosis gene.65 The presence of this gene leads to the overproduction of thick and sticky mucus that negatively affects the lungs, pancreas, liver, intestines, sinuses, and sex organs. Respiratory and digestive problems are common in cystic fibrosis as the thick mucus builds up, often leading to lung infections. Left untreated, children with cystic fibrosis usually experience delayed growth and malnutrition.

Vitamin A Toxicity

Excessive consumption of vitamin A can damage the liver because the organ is the main site for vitamin A storage. Toxicity signs and symptoms include headache, nausea, vomiting, visual disturbances, hair loss, bone pain, and bone fractures. Carotenemia, a condition characterized by yellowing of the skin, can result from eating too much beta-carotene-rich produce or taking too many beta-carotene supplements. This condition occasionally develops in infants who eat a lot of baby foods that contain carrots, apricots, winter squash, or green beans. In most instances, carotenemia is harmless. The skin's natural color eventually returns to normal when the carotenoid-rich foods are no longer eaten.

Preserving the Vitamin Content of Foods

Fruits and vegetables, especially berries and leafy vegetables, are highly perishable. Therefore, these foods should be eaten soon after they are harvested or purchased to ensure maximum vitamin retention. Some vitamins, such as niacin and D, resist destruction by usual food storage conditions or preparation methods. Others—particularly vitamin C, thiamin, and folate—are easily destroyed or lost by improper food storage and cooking methods. Generally, fresh produce retains its natural vitamin content better when stored at temperatures near freezing, in high humidity, and away from air. Tomatoes, bananas, and garlic should be stored at room temperature. Exposure to excessive heat, alkaline substances (such as baking soda), light, and air can destroy certain vitamins, especially vitamin C. To reduce such losses, wait to trim, peel, and cut raw fruits and vegetables until just before eating or serving them. Keep in mind that the darker leaves of vegetable greens generally contain more vitamins than the paler inner leaves or stems. Water-soluble vitamins can leach out of food and dissolve in the cooking water, which is often discarded. Cooking vegetables in small amounts of water and reusing that water for soups or sauces helps retain those water-soluble nutrients. Cutting produce into large pieces reduces the amount of surface area exposed to heat, water, and other conditions that can increase vitamin losses. Cooking fruits and vegetables with their skins on helps keep nutrient content, as does consuming edible skins. Quick cooking methods that involve little contact between produce and water, such as microwaving, steaming, and stir-frying, can conserve much of the vitamin content of the food. According to the Food and Drug Administration (FDA), microwave cooking does not reduce the nutrient content of foods any more than do conventional cooking methods. Microwave cooking may help conserve more vitamins in food because the method cooks quickly and without the need to add much water. Stir-fried vegetables should be cooked briefly to retain their nutrients as well as their appealing textures, flavors, and colors. Produce that is frozen immediately after being harvested and then properly stored can be just as nutritious as fresh produce. Frozen fruits and vegetables are often economical alternatives to fresh produce, but they need to be cooked without thawing to conserve much of their vitamin content.

Carotenoids (lutein, zeaxanthin , and lycopene)

Green, leafy vegetables, such as spinach and kale, have high concentrations of lutein and zeaxanthin. Tomato juice and other tomato products, including pizza sauce, contain considerable amounts of lycopene. Although lutein, zeaxanthin, and lycopene are carotenoids, the body does not convert them to vitamin A. Nevertheless, these plant pigments may function as beneficial antioxidants in the human body. Darkly pigmented fruits and vegetables usually contain more beta-carotene and other provitamin A carotenoids than lightly colored produce. For example, carrots, sweet potatoes, and peaches contain more beta-carotene than celery, white potatoes, and bananas.

Dietary Adequacy for Vitamin D

Many Americans do not consume enough vitamin D to meet the RDA.7 According to findings of a nationwide survey, approximately 41% of American adults had low blood levels of vitamin D. Individuals who were female, black, or Mexican-American were more likely to be vitamin D deficient than white, non-Hispanic males. Other factors that were associated with low vitamin D status included having excess body fat; using electronic media or games for more than 4 hours daily; and drinking milk less than once a week.

Symptoms and Diagnosis

Most children with cystic fibrosis are diagnosed by the time they are 2 years old. People may be diagnosed with the condition when they are teenagers or young adults; however, these individuals have a much milder form of the disease. At this time, most states in the United States conduct newborn screening for cystic fibrosis. A blood sample is sent to a lab for detecting genetic abnormalities that are characteristic in cystic fibrosis. If the blood test comes back positive, a sweat test follows. A high level of salt in sweat is a positive sign for cystic fibrosis.

Vitamin E Deficiency and Toxicity

People who have diseases that interfere with fat absorption may become deficient in vitamin E because dietary fat enhances intestinal absorption of the micronutrient. Long-term vitamin E deficiency damages the nervous system and results in nerve damage, loss of neuromuscular control, and blindness. Taking dietary supplements that supply excessive amounts of the vitamin may interfere with vitamin K's role in blood clotting and lead to uncontrolled bleeding (hemorrhage)

Sources of vitamins

Plants, animals, fungi, and even bacteria supply natural forms of vitamins in our diets. In addition to foods, vitamin supplements are another source of these micronutrients. Although chemists can synthesize vitamins, certain types of bacteria and algae produce vitamins. These organisms can be grown in laboratory settings for the purpose of "harvesting" their vitamins to use in supplement production. Regardless of whether a particular vitamin is naturally found in foods or synthesized in a laboratory, it generally has the same chemical structure and works equally well in the body. Exception: synthetic folic acid, the type of folate that is added to flour and many ready-to-eat and cooked cereals, has almost twice the biological activity as the natural form of the vitamin (it is more potent)

Vitamin K

Production of active blood-clotting factors 90-120 μg Green leafy vegetables, canola and soybean oils, and products made from these oils Excessive bleeding UL = undetermined Unknown

Food Sources of Vitamin E

Rich food sources of vitamin E include sunflower seeds, almonds, and plant oils, especially sunflower, safflower, canola, and olive oils. Products made from vitamin E-rich plant oils, such as margarine and salad dressings, also supply the micronutrient. Other important dietary sources of the vitamin include fish, whole grains, nuts, seeds, and certain vegetables. Meats, processed grain products, and dairy products generally do not contain much vitamin E. Although many American adults do not consume recommended amounts of vitamin E, vitamin E deficiency is rare. A healthy body stores the vitamin in body fat, skeletal muscle, and the liver.

Osteomalacia

The adult form of Vitamin D deficiency is called osteomalacia, or literally, "soft bones." The bones of people with osteomalacia have normal amounts of collagen, the protein that provides structure for the skeleton, but their bones contain less-than-normal amounts of calcium. The bones are soft and weak, and bend and break easily as a result. Muscle weakness is also a symptom of osteomalacia. Adults who are confined indoors or almost fully covered when outside during the day, such as for religious or cultural reasons, are at risk for osteomalacia. Osteomalacia is a risk for adults who have kidney, liver, or intestinal diseases because these conditions may reduce both vitamin D production and calcium absorption.

Why is important to know what vitamins are water-soluble and fat-soluble?

The body generally has more difficulty eliminating excess fat-soluble vitamins because these nutrients do not dissolve in watery substances such as urine. As a result, the body stores extra fat-soluble vitamins, primarily in the liver and in adipose tissue. Over time, these vitamins can accumulate and cause toxicity. In contrast, the body stores only limited amounts of most water-soluble vitamins; vitamin B-12 is an exception. Furthermore, kidneys can filter excesses of water-soluble vitamins from the bloodstream and eliminate them in urine. Thus, water-soluble vitamins are generally not as likely to be toxic as fat-soluble vitamins.

Vitamin Enrichment and Fortification

The enrichment of grains helps protect Americans from developing the deficiency diseases associated with the lack of thiamin, riboflavin, niacin, folate, and iron. However, the enrichment does not replace the vitamin E, vitamin B-6, magnesium, several other micronutrients, and fiber that were naturally present in the unrefined grains. This is the major reason registered dietitian nutritionists and other nutrition experts promote regular consumption of whole-grain products, such as whole-wheat bread and brown rice.

Vitamin K Digestion and Absorption

The presence of dietary fat, bile, and pancreatic juice enhances vitamin K absorption in the small intestine. Following absorption, some vitamin K is stored in the liver and some is incorporated in lipoproteins for transport in the bloodstream. The liver also breaks down vitamin K and eliminates the vitamin's by-products by adding them to bile.

Vitamin A and vision

The retina, the light-sensitive area inside each eye, contains rods and cones, specialized nerve cells that are essential for vision. Rods enable adaptation to see in poorly lit environments. Cones are responsible for color vision and function in well-lit environments. Rods and cones both need vitamin A, particularly retinol, to function properly. Night blindness, the inability to see in dim light, can occur if retinol is unavailable. Night blindness may be an early sign of vitamin A deficiency.

Vitamin Absorption

The small intestine is the primary site of vitamin absorption. However, the intestine does not absorb 100% of the vitamins in food. Vitamin absorption tends to increase when the body's needs for the micronutrients are also higher than usual. The body's requirements for vitamins generally increase during periods of growth, such as infancy and adolescence, and during pregnancy and breastfeeding. Processes that normally occur during fat digestion facilitate the absorption of fat-soluble vitamins. For example, bile enhances lipid as well as fat-soluble vitamin absorption. In the small intestine, the presence of fat stimulates the secretion of the hormone cholecystokinin (CCK) that causes the gallbladder to release bile. Therefore, adding a small amount of fat to low-fat foods, such as tossing raw vegetables with some salad dressing. Diseases or conditions that affect the GI tract can reduce vitamin absorption and result in deficiencies of these micronutrients. People with the inherited disease cystic fibrosis are unable to digest fat properly. Blockages form in ducts that convey pancreatic enzymes to the small intestine, reducing fat absorption. People suffering from the disease often develop deficiencies of fat-soluble vitamins.

Treatment

Treatment for cystic fibrosis includes diet and medications. Nutritional management of cystic fibrosis improves disease management and prevents serious complications of the disease. Such complications include destruction of pancreatic tissue, blockage of the ducts leading to and from the pancreas, and reduced enzymatic activity that can cause nutrient malabsorption

Functions of Vitamin D

Vitamin D is necessary for the metabolism of the minerals calcium and phosphorus, and the production and maintenance of healthy bones. Vitamin D stimulates small-intestine cells to absorb calcium and phosphorus from food. When vitamin D is lacking, the intestine absorbs only 10 to 15% of the calcium in foods; with the vitamin, intestinal absorption of dietary calcium increases to 30 to 80%. Vitamin D also stimulates bone cells to form calcium phosphate, the major mineral compound in bone. Without adequate vitamin D, bone cells cannot deposit enough calcium and phosphorus to produce strong bone tissue. When blood calcium levels drop, vitamin D works with parathyroid hormone (PTH) to signal bones to release calcium. PTH also stimulates the kidneys to increase vitamin D production and decrease the elimination of calcium in urine. These actions help raise the level of calcium in blood to normal. Removing too much calcium from bones can weaken them, but calcium is essential for normal heartbeat and other muscle contractions. If bones did not supply calcium for such vital functions, a person could experience serious, even fatal consequences. Vitamin D has other roles in the body, including regulating neuromuscular and immune function and reducing inflammation. The vitamin may also reduce the risks of heart disease, cancer, diabetes mellitus, multiple sclerosis, asthma, and depression. However, more research is needed to clarify the vitamin's role in chronic disease prevention.

Vitamin D and Sunlight

Vitamin D is not widespread in food; therefore, the body depends on sunlight exposure to synthesize the vitamin. Those living south of the 33rd parallel and who are outdoors between 10 a.m. and 3 p.m., when sunlight is most intense, often obtain enough sun exposure to synthesize vitamin D during most of the year. The amount of time one needs to spend in the sun to form adequate amounts of vitamin D depends primarily on his or her location, the time of day and year, age, and skin color.

Functions of Vitamin E

Vitamin E protects polyunsaturated fatty acids in cell membranes from being damaged by free radicals. Such oxidative damage may be associated with the development of atherosclerosis, the process that occurs within arteries and contributes to heart attack and stroke, cancer, and premature cellular aging and death. Other roles for vitamin E include maintaining nervous tissue and immune system function.

Vitamin K Deficiency

Vitamin K deficiency, however, can develop in people who have liver diseases or conditions that impair fat absorption, such as cystic fibrosis. Additionally, long-term antibiotic therapy can reduce the number of bacteria in the colon that synthesize vitamin K and, as a result, contribute to a deficiency of the nutrient. The most reliable sign of vitamin K deficiency is an increase in the time it takes for blood to clot. Babies are generally born with low vitamin K stores, and a deficiency of the vitamin can occur soon after birth because of the newborn's immature GI tract. Vitamin K-deficient infants are at risk of serious bleeding because their bodies are unable to make certain blood-clotting factors. To prevent vitamin K deficiency from developing during infancy, newborns generally receive a single injection of vitamin K immediately after birth.

Vitamin K

Vitamin K is a family of compounds that includes phylloquinone from plants and menaquinones in animal food sources such as egg yolks, butter, and beef, as well as fermented foods, such as sauerkraut and miso. Bacteria that normally live in the intestinal tract also synthesize menaquinones that can be absorbed by the body. Bacterial menaquinone contributes about 10% to the body's vitamin K supply. The biological activity of phylloquinone is greater than that of menaquinone. A synthetic form of vitamin K, menadione, can be converted into menaquinone in the body.

Fat-soluble vitamins

Vitamins A, D, E, and K. These vitamins are found in the lipid portions of foods and tend to associate with lipids in the body. The fat-soluble vitamins are digested and absorbed with fats in the GI tract. Therefore, foods rich in fat often contain vitamins A (retinol), D (cholecalciferol or egocalciferol), E (alpha-tocopherol), and/or K (phylloquinones, menaquinones).

Vitamin D Toxicity

When excess vitamin D is consumed, the small intestine absorbs too much calcium from foods and the mineral is deposited in soft tissues, including the kidneys, heart, and blood vessels. The calcium deposits can interfere with cells' ability to function and cause cellular death. Other signs and symptoms of vitamin D toxicity include muscular weakness, loss of appetite, diarrhea, vomiting, and mental confusion. The body does not make toxic levels of vitamin D when exposed to sunlight because skin limits its production of 7-dehydrocholesterol.

Antioxidant

When many biochemical reactions take place, the compounds participating in the reactions lose or gain electrons. An atom or molecule that loses one or more electrons has been oxidized. An oxidizing agent or oxidant is a substance that removes electrons from atoms or molecules. An oxidation reaction can form a free radical, a substance with an unpaired electron. Free radicals are highly reactive, that is, chemically unstable, and they remove electrons from more stable molecules, such as proteins, fatty acids, and DNA. As a result, free radicals can damage or destroy these molecules. If the loss of electrons is uncontrolled, a chain reaction can occur in which excessive oxidation takes place and affects many cells. Many medical researchers suspect excess oxidation is responsible for promoting chemical changes in cells that ultimately lead to heart attack, stroke, cancer, Alzheimer's disease, and even the aging process. Some free radical formation in the body is necessary and provides some benefits. Free radicals, for example, stimulate normal cell growth and division. Additionally, white blood cells generate free radicals as part of their activities in destroying infectious agents. Under normal conditions, cells regulate oxidation reactions by using antioxidants such as vitamin E. Antioxidants protect cells by giving up electrons to free radicals. When the chemically unstable substance accepts an electron, it can form a more stable structure that does not pull electrons away from other compounds. By sacrificing electrons, antioxidants protect molecules such as polyunsaturated fatty acids in the membrane or DNA in the nucleus from being oxidized.

Vitamine

vita = necessary for life; amine = a type of nitrogen-containing substance. It is a complex organic compound that regulates certain metabolic processes in the body and meets the following criteria: -The body cannot synthesize the compound or make enough to maintain good health (it is an essential nutrient) -The compound naturally occurs in commonly eaten foods -Signs and symptoms of a health problem (deficiency disorder) eventually occur when the substance is missing from the diet or is not properly metabolized -Good health is restored if the deficiency disorder is treated early by supplying the missing substance.