Fat-Soluble Vitamins: Vitamin A Properties

The four fat-soluble vitamins are vitamins A, D, E, and K. Good dietary sources of vitamin A include sweet potatoes, carrots, and dark leafy greens. Vitamin D can be found in fatty fish, fortified dairy products, and sunlight exposure. Vitamin E is abundant in nuts and seeds, such as almonds and sunflower seeds. Vitamin K is found in leafy greens, such as spinach and kale.

Vitamin A is essential for vision, immune function, and gene transcription. A deficiency in vitamin A can lead to night blindness, impaired immune function, and skin problems.

Vitamin K is necessary for blood clotting and bone health. It helps to activate proteins that bind to calcium, which is essential for bone mineralization.

<p>Excessive intake of fat-soluble vitamins can lead to toxicity, as they are stored in the body and can accumulate over time. This is in contrast to water-soluble vitamins, which are readily excreted in the urine.</p> Signup and view all the answers

<p>The RDAs for fat-soluble vitamins vary based on age, sex, and other factors such as pregnancy and breastfeeding. For example, the RDA for vitamin D is higher for older adults and pregnant women.</p> Signup and view all the answers

<p>Vitamin A is necessary for the production, maturation, and maintenance of epithelial cells, which form protective tissues that line the body, including skin and linings of the digestive, respiratory, and reproductive tracts.</p> Signup and view all the answers

<p>Vitamin A deficiency causes mucus-secreting epithelial cells to deteriorate and no longer produce mucus.</p> Signup and view all the answers

<p><strong>700–900 mcg RAE</strong></p> Signup and view all the answers

<p>Vitamin A plays a role in regulating the activity of the immune system.</p> Signup and view all the answers

<p>Vitamin D–fortified milk, fortified cereals, fish liver oils, and fatty fish.</p> Signup and view all the answers

<p><strong>1000 mg/day</strong></p> Signup and view all the answers

<p>Production of active blood-clotting factors.</p> Signup and view all the answers

<p>Vitamin A participates with other vitamins and minerals in the bone remodeling process.</p> Signup and view all the answers

<p>Reduced immune system function.</p> Signup and view all the answers

<p>Rods enable us to adapt to poorly lit environments and see objects as shades of black.</p> Signup and view all the answers

<p>Rickets in children and osteomalacia in adults, characterized by soft bones, depressed growth, and reduced immune system functioning.</p> Signup and view all the answers

<p>Some retinal is destroyed, and rods remove some retinol from the bloodstream and convert it to retinal to replace it.</p> Signup and view all the answers

<p>Night blindness is the inability to see in dim light, and it occurs if retinol is unavailable.</p> Signup and view all the answers

<p>Vitamin A is required for maintaining the epithelial cells that line the reproductive tracts of men and women, and a lack of vitamin A can reduce fertility.</p> Signup and view all the answers

<p>These darkly pigmented parts of the plants contribute more provitamin A carotenoids to our diet.</p> Signup and view all the answers

<p>Liver, butter, fish liver oils, and eggs are good sources of preformed vitamin A.</p> Signup and view all the answers

<p>The body obtains only 1 mcg of retinol from every 12 mcg of beta-carotene in a food.</p> Signup and view all the answers

<p>Cones are responsible for color vision and function in well-lit environments.</p> Signup and view all the answers

<p>Vitamin A helps to fight infections.</p> Signup and view all the answers

<p>Carrots, spinach, pumpkin, sweet potatoes, broccoli, mangoes, and cantaloupe are rich sources of beta-carotene.</p> Signup and view all the answers

<p>Plant cells break down and release carotenoids.</p> Signup and view all the answers

<p>They function as beneficial antioxidants in the human body.</p> Signup and view all the answers

<p>Because they contain more beta-carotene and other provitamin A carotenoids.</p> Signup and view all the answers

<p>Preschool children who do not eat enough vegetables, urban poor, older adults, and people with severe alcoholism, fat malabsorption, or liver diseases.</p> Signup and view all the answers

<p>They accumulate keratin and eventually harden and stop producing mucus.</p> Signup and view all the answers

<p>Blindness.</p> Signup and view all the answers

<p>It can cause blindness and reduces the effectiveness of the immune system, leading to death from infections such as measles.</p> Signup and view all the answers

<p>700 mcg RAE (women) to 900 mcg RAE (men).</p> Signup and view all the answers

<p>U.S. Department of Agriculture, Agricultural Research Service: FoodData Central, 2019.</p> Signup and view all the answers

<p>To reduce the prevalence of vitamin A deficiency in countries where it is widespread.</p> Signup and view all the answers

<p>Excess vitamin A can cause birth defects.</p> Signup and view all the answers

<p>3000 mcg/day</p> Signup and view all the answers

<p>Golden Rice was developed to provide a rich source of beta-carotene for vitamin A-deficient populations.</p> Signup and view all the answers

<p>Carotenodermia is a yellow-orange discoloration of the skin caused by consuming too much beta-carotene-rich produce or taking beta-carotene supplements.</p> Signup and view all the answers

<p>Vitamin A derivatives can cause miscarriage or severe birth defects in the offspring.</p> Signup and view all the answers

<p>Cod liver oil contains a fat-soluble factor that prevents and treats rickets.</p> Signup and view all the answers

<p>Soft and misshapen bones, particularly in the legs, which can bow under the weight of carrying the upper part of the body.</p> Signup and view all the answers

<p>Vitamin D is a hormone because it is a fat-soluble factor needed for proper bone health.</p> Signup and view all the answers

<p>Vitamin A toxicity damages the liver, causing symptoms such as headache, nausea, vomiting, visual disturbances, hair loss, bone pain, and bone fractures.</p> Signup and view all the answers

<p>To prevent excessive intake of vitamin A, which can cause birth defects and toxicity symptoms.</p> Signup and view all the answers

<p>It limits skin's ability to synthesize previtamin vitamin D3.</p> Signup and view all the answers

<p>Because breast milk contains insufficient amounts of vitamin D to prevent rickets.</p> Signup and view all the answers

<p>Soft and weak bones that break easily, and muscle weakness.</p> Signup and view all the answers

<p>Production of vitamin D3 in skin declines with age.</p> Signup and view all the answers

<p>Melanoma, the most deadly form of skin cancer.</p> Signup and view all the answers

<p>Because they have limited skin exposure to sunlight, leading to vitamin D deficiency.</p> Signup and view all the answers

<p>10 mcg (400 IU) of vitamin D per day.</p> Signup and view all the answers

<p>Because many Americans do not consume enough vitamin D to meet the RDA.</p> Signup and view all the answers

<p>15 mcg/day.</p> Signup and view all the answers

<p>It allows the body to make some active vitamin D.</p> Signup and view all the answers

<p>Because few foods are good sources of vitamin D, and she will need to maintain a healthy blood level of the fat-soluble vitamin for the rest of her life.</p> Signup and view all the answers

<p>Supplements, as the sun's rays are blocked by the atmosphere during this time.</p> Signup and view all the answers

<p>Because only a few foods are naturally rich in vitamin D, and many products are fortified with it.</p> Signup and view all the answers

<p>Soft and weak bones, as vitamin D is essential for bone health.</p> Signup and view all the answers

<p>Because vitamin D can be toxic in excess.</p> Signup and view all the answers

<p>Because she has red hair, which makes her more susceptible to sun damage.</p> Signup and view all the answers

<p>UV radiation triggers the production of previtamin D in the skin.</p> Signup and view all the answers

<p>Because the sun's rays are weaker and more oblique during the winter months, making it harder to synthesize vitamin D.</p> Signup and view all the answers

<p>They limit the amount of UV radiation that reaches the skin, making it harder to synthesize vitamin D.</p> Signup and view all the answers

<p>Because it is a rich source of vitamin D, which is essential for bone health.</p> Signup and view all the answers

<p>Some studies found a lower risk of hip fracture, while others indicated that supplementation with higher amounts of vitamin D might increase risks of hip fracture and heart disease.</p> Signup and view all the answers

<p>Vitamin D deficiency reduces calcium absorption, which contributes to osteoporosis.</p> Signup and view all the answers

<p>Excess calcium is absorbed from foods, deposited in soft tissues, and can cause cellular death, along with other symptoms such as muscular weakness, loss of appetite, diarrhea, vomiting, and mental confusion.</p> Signup and view all the answers

<p>Vitamin E is an antioxidant that protects polyunsaturated fatty acids in cell membranes from oxidative damage, which may be associated with atherosclerosis, cancer, and premature cellular aging and death, and also maintains immune system function.</p> Signup and view all the answers

<p>Rich sources include sunflower seeds, almonds, plant oils (sunflower, safflower, canola, and olive oils), products made from vitamin E-rich plant oils (margarines and salad dressings), fish, whole grains, nuts, seeds, and certain vegetables.</p> Signup and view all the answers

<p>To prevent rancidity and oxidative damage of vitamin E, store unopened containers of oil in a cool, dark cabinet or pantry, and refrigerate opened containers.</p> Signup and view all the answers

<p>Excess calcium is deposited in soft tissues, including kidneys, heart, and blood vessels, which can interfere with cell function and cause cellular death.</p> Signup and view all the answers

<p>To protect polyunsaturated fatty acids in cell membranes from oxidative damage, which may be associated with atherosclerosis, cancer, and premature cellular aging and death.</p> Signup and view all the answers

<p>Older adults are more likely to develop vitamin D deficiency, which increases the risk of bone fractures and osteoporosis.</p> Signup and view all the answers

<p>Vitamin E protects unsaturated fatty acids in cell membranes from oxidative damage, which can cause cellular death and contribute to atherosclerosis, cancer, and premature cellular aging.</p> Signup and view all the answers

<p>Harvesting, processing, storage, and cooking methods</p> Signup and view all the answers

<p>Because vitamin E is transferred from mother to fetus late in pregnancy</p> Signup and view all the answers

<p>Blood clotting</p> Signup and view all the answers

<p>1000 mg/day of alpha-tocopherol</p> Signup and view all the answers

<p>Because it may interact with vitamin K's role in blood clotting</p> Signup and view all the answers

<p>Reduced functioning of the nervous and immune systems</p> Signup and view all the answers

<p>Because it helps activate clotting factors in the liver</p> Signup and view all the answers

<p>A compound found in plants, particularly in fermented foods</p> Signup and view all the answers

<p>Development of signs of vitamin E deficiency</p> Signup and view all the answers

<p>Because it helps solubilize vitamin K, facilitating absorption in the small intestine</p> Signup and view all the answers

<p>Vitamin K helps bone-building cells produce osteocalcin, a protein needed for normal bone mineralization.</p> Signup and view all the answers

<p>Because vitamin K can interfere with warfarin’s ‘blood-thinning’ activity.</p> Signup and view all the answers

<p>Vitamin K–deficient infants are at risk of serious bleeding because their bodies are unable to make certain blood-clotting factors. It is prevented by giving newborns a single injection of vitamin K.</p> Signup and view all the answers

<p>Green leafy vegetables, such as kale, turnip greens, salad greens, cabbage, and spinach; broccoli; and green beans. Also, soybean and canola oils, and products made from these oils, such as salad dressing.</p> Signup and view all the answers

<p>120 mcg/day for men and 90 mcg/day for women.</p> Signup and view all the answers

<p>Liver diseases, conditions that impair fat absorption, such as cystic fibrosis, and long-term antibiotic therapy.</p> Signup and view all the answers

<p>An increase in the time it takes for blood to clot.</p> Signup and view all the answers

<p>Vitamin K is necessary for the production of certain blood-clotting factors, including prothrombin.</p> Signup and view all the answers

<p>The chemical structure of vitamin K is very stable and resists being destroyed by usual cooking methods.</p> Signup and view all the answers

<p>There is no reported harm to humans from ingesting amounts of natural forms of vitamin K that exceed the AIs.</p> Signup and view all the answers

<p>Eating their sled dogs' livers, which contained high amounts of vitamin A, toxic to humans.</p> Signup and view all the answers

<p>Sunlight exposure, which converts a cholesterol derivative into previtamin D3 in the skin.</p> Signup and view all the answers

<p>The kidneys convert 25-OH vitamin D into the active hormone, vitamin D.</p> Signup and view all the answers

<p>10-15%</p> Signup and view all the answers

<p>Bone cells cannot deposit enough calcium and phosphorus, leading to weak bones.</p> Signup and view all the answers

<p>Regulating neuromuscular and immune function, and reducing inflammation.</p> Signup and view all the answers

<p>Because her blood test showed that she didn't have enough vitamin D in her body.</p> Signup and view all the answers

<p>Sunlight exposure stimulates the production of vitamin D in the skin.</p> Signup and view all the answers

<p>Weak bones, and increased risk of certain diseases such as osteoporosis and certain cancers.</p> Signup and view all the answers

<p>Because it is synthesized in the skin upon exposure to sunlight, specifically UVB radiation.</p> Signup and view all the answers