FSN Chapter 12

How does absorption differ among fat soluble and water soluble vitamins?

-Fat-soluble vitamins are absorbed with dietary fats -- Adequate absorption depends on bile and pancreatic lipase -- 40 to 90% absorbed under optimal conditions -Water-soluble vitamins are not dependent on dietary fats -- 90 to 100% absorption rate

5. What kind of foods can you find Vitamin A?

-Retinoids are found in liver, fish, fish oils, fortified milk, and eggs -Carotenoids are found in dark-green and yellow-orange vegetables and fruits -Beta-carotene has greatest amount of pro-vitamin A activity -Retinoids (preformed vitamin A) are found in liver, fish, fish oils, fortified milk, and eggs. Margarine is fortified with vitamin A, as are fat-free, low-fat, and reduced-fat milks. The provitamin A carotenoids are found mainly in dark green and yellow-orange vegetables and fruits, such as carrots, spinach and other greens, winter squash, sweet potatoes, broccoli, mangoes, cantaloupe, peaches, and apricots.

What happens with too much vitamin A?

-not harmful, yellow-orange color of skin

What is the difference between provitamin A and preformed vitamin A?

Carotenoids—provitamin A -Found in dark-green and yellow-orange fruits and vegetables Retinoids—performed Vitamin A

What vitamins are considered fat soluble? Water Soluble?

Fat-Soluble Vitamins -A,D,E,K --Dissolve in organic solvents Water-Soluble vitamins -B-Vitamins and C --Dissolve in water

What are some of the sources of vitamin K?

a. 10% absorbed daily comes from bacterial synthesis in colon b. Remainder comes from food i. Green leafy vegetables ii. Broccoli iii. Peas iv. Green beans v. Vegetable oils

7. What are the functions of carotenoids?

a. Can be converted in the body to vitamin A b. Beta-carotene may act as antioxidant c. May also decrease risk of: eye-diseases like macular degeneration d. Cancers i. Influenced by immune and antioxidant properties ii. Carotenoids may decrease risk of lung and oral cancer iii. Lycopene may decrease skin and prostate cancer risk iv. Studies of male smokers show adverse effects of beta-carotene supplementation v. Effects seen with carotenoids from food, not supplements e. Cardiovascular disease i. Carotenoids are antioxidants ii. At least 5 servings per day of fruit and vegetables can decrease risk

Who is most at risk for vitamin K deficiency? Why?

a. Can occur in newborns i. Stores are low and bacteria not yet present in colon ii. All newborns are given vitamin K injection at birth

Be able to explain what can occur due to toxicity of vitamin D.

a. Excess blood calcium b. Deposits of calcium in kidneys, heart, and lungs c. Anorexia, nausea and vomiting, bone demineralization d. Weakness e. Joint pain f. Kidney dysfunction

Be able to explain the roles vitamin A plays in growth and development, cell differentiation, vision, and immune function.

a. Growth and Development i. Involved in the development of: 1. Eyes 2. Limbs 3. Cardiovascular system 4. Nervous system 5. Epithelial cells and mucous-forming in lungs, trachea, skin, and GI tract ii. Lack of vitamin A during early stages of pregnancy results in birth defects and fetal mortality b. Cell Differentiation i. Gene expression directs cell differentiation—the process in which stem cells develop into specialized cells with unique functions in the body. Vitamin A is especially important in maintaining normal differentiation of the cells that make up the structural components of the eye, such as the cornea (clear lens) and the retina (rod and cone cells). 1. Cell differentiation: Weakening of bones that occurs in adults as a result of poor bone mineralization linked to inadequate vitamin D status. 2. Stem cells: Unspecialized cell that can be transformed into a specialized cell. ii. Retinoids bind to retinoid receptors in the cell nucleus 1. RXR and RAR receptors regulate formation of messenger RNA, which results in gene expression iii. Gene expression directs cell differentiation 1. Stem cells develop into specialized cells c. Vision i. Vitamin A (as retinal) is needed in the retina of the eye to turn visual light into nerve signals to the brain. The sensory elements of the retina consist of the rods and cones. Rods are responsible for the visual processes that occur in dim light, translating objects into black-and-white images and detecting motion. Cones are responsible for the visual processes occurring under bright light, translating objects into color images. 1. Retina: Biologically active forms of vitamin A, including retinol, retinal, and retinoic acid. 2. Rods: Sensory elements in the retina of the eye responsible for visual processes occurring in dim light, translating objects into black-and-white images, and detecting motion. 3. Cones: Sensory elements in the retina of the eye responsible for visual processes that occur under bright light, translating objects into color images. d. Immune Function i. Increase of infection is an early symptom of vitamin A deficiency ii. Vitamin A helps maintain epithelium, the barrier that protects the body against entry of pathogens

Be able to name some of the vitamin A deficiencies.

a. Impoverished and older adults, people with alcoholism or liver disease (which limits vitamin A storage), and individuals with severe fat malabsorption, which may develop in gluten-sensitive enteropathy (celiac disease), chronic diarrhea, pancreatic insufficiency, Crohn disease, cystic fibrosis, and AIDS, may develop vitamin A deficiency. Premature infants also are at risk of deficiency because they are born with low stores of vitamin A. b. This sequence of changes in the eye—collectively known as Xerophthalmia—causes irreversible blindness in millions of people worldwide. i. Xerophthalmia: Condition marked by dryness of the cornea and eye membranes that results from vitamin A deficiency and can lead to blindness; specific cause is a lack of mucus production by the eye, which then leaves it more vulnerable to surface dirt and bacterial infections. c. Rare in North America d. Major public health problem in developing countries e. Worldwide, deficiency is leading cause of non-accidental blindness f. Blindness g. Poor growth in infants/young children h. Skin problems i. Bone development j. Reproduction

Name some of the good food sources of vitamin E.

a. Plant oils and products made from plant oils b. Wheat germ c. Avocado d. Almonds e. Peanuts f. Sunflower seeds

How does vitamin K help in the formation of blood cells?

a. Synthesis of blood clotting factors and conversion of pre-prothrombin to prothrombin, an active blood clotting factor

What are the best food sources of vitamin D?

a. The best food sources of vitamin D are fatty fish (e.g., sardines, mackerel, herring, and salmon), cod liver oil, fortified milk, and some fortified breakfast cereals b. Sources include i. Fatty fish ii. Cod liver oil iii. Fortified milk iv. Fortified breakfast cereals

What are free radicals and how does vitamin E affect them?

a. Vitamin E is an important part of the body's antioxidant network, which helps maintain the integrity of cell membranes by stopping chain reactions caused by free radicals. Free radicals are very unstable compounds that have 1 or more unpaired electrons.

In general, how does vitamin E function as an antioxidant in the body?

a. may reduce heart disease developments

21. Know the difference between phylloquinones and menaquinones.

a. phylloquinone from plants and menaquinone found in fish oils and meats. Menaquinones also are synthesized by bacteria in the human colon. A synthetic compound, called menadione, can be converted to menaquinone in body tissues. Phylloquinone, the main dietary form of the vitamin, is the most biologically active form.

How does vitamin D3 form in the skin?

i. Begins with 7-dehydrocholesterol in skin ii. Exposure to sunlight transforms 7-dehydrocholesterol to cholecalciferol (vitamin D3) iii. Cholecalciferol enters bloodstream and goes to liver and kidneys 1. Converted to calcitriol, its bioactive form vitamin D3 iv. Sun exposure provides 80-100% of required v. Amount of sun exposure depends on: a. Time of day b. Geographic location c. Season of year d. Age e. Skin color f. Use of sunscreen vi. Prolonged exposure to sun will not result in toxic amounts a. Excess amounts of previtamin D3 are degraded

What are some of the common vitamin D deficiencies?

i. Rickets 1. Abnormal mineralization of bones in children; bones will be weak and bow under pressure 2. Signs include a. Enlarge head, joints, and rib cage b. Deformed pelvis c. Bowed legs 3. Can be associated with a. Fat malabsorption b. Cystic fibrosis c. Dark skin d. Low milk intake e. Minimal sun exposure ii. Osteomalacia 1. Poor calcification of newly synthesized bones in adults 2. Results in fractures 3. Can be seen in adults with a. Kidney or liver disease b. Impaired fat absorption c. Dark skin d. Limited UV exposure

What is the most active form of vitamin D and what are some of its important functions?

i. Vitamin D (calcitriol) helps maintain blood levels of calcium and phosphorus, which maintains bone health. ii. Vitamin D increases intestinal absorption of calcium and phosphorus when calcium levels are low a. Minerals are incorporated into bone iii. Vitamin D releases calcium and phosphorus from bone to restore blood levels of these minerals a. Needed for many basic life functions iv. Vitamin D may also help regulate a. Immune function b. Secretion of hormones c. Cell cycle v. May also decrease risk of: a. Infections b. Autoimmune diseases vi. And protect against a. Diabetes b. Hypertension c. Dementia d. Cancer

What type of food is usually fortified with vitamin D?

milk and cereal