Chapter 10 Notes PDF

Fat-soluble vitamins include Vitamins A, E, K, and D - They are closely associated with the absorption and transport of lipids - Most fat-soluble vitamins are stored in the body, with varying amounts stored 1. Vitamin A is a nutritional term for a family of essential, fat-soluble dietary compou...

Fat-soluble vitamins include Vitamins A, E, K, and D - They are closely associated with the absorption and transport of lipids - Most fat-soluble vitamins are stored in the body, with varying amounts stored 1. Vitamin A is a nutritional term for a family of essential, fat-soluble dietary compounds - In the diet, vitamin A also includes pro-vitamin A carotenoids - Retinoids are a subgroup of vitamin A that includes retinol and its related compounds - Animal foods, liver, dairy products, fatty fish, and fish liver oils are sources of retinoids - Carotenoids are another subgroup of vitamin A found in bright red, yellow, and orange pigments of plants - Carotenoids can be split into carotenes and xanthophylls based on their chemical structure - Carotenoids like β-carotene, lutein, and zeaxanthin are considered conditionally essential nutrients - Carotenoids in the diet are commonly found in fruits, vegetables, and some animal products - Specific foods like beef liver, sweet potatoes, and spinach are rich sources of vitamin A - Intestinal absorption of vitamin A involves steps like emulsification, solubilization, and cellular uptake - Cellular uptake of vitamin A involves the absorption of retinol and carotenoids through specific transporters - Metabolism of carotenoids and retinoids occurs in enterocytes and involves conversion and incorporation into chylomicrons - Vitamin A is stored mainly in the liver and released into the blood when needed - Functions of retinoids include vision, cellular differentiation, gene expression, bone metabolism, and growth - Carotenoids act as antioxidants to protect against free radicals - The Visual Cycle is a process involving retinoids in the retina for vision and light perception - Retinoids like all-trans retinoic acid help regulate gene expression and cellular differentiation - Retinoids also play a role in stimulating growth, maintaining cell structure, and affecting immune system activities - Carotenoids are important for protecting cell membranes and lipoproteins from free radicals by inactivating them- Light energy can transfer energy in enzymatic reactions - Damage to proteins, lipids, and DNA can occur from reactions involving light energy - Carotenoids with double bonds like β-carotene and lycopene can quench singlet oxygen and reactive oxygen species (ROS) such as peroxyl radicals - Carotenoids make LDL (low-density lipoprotein) resistant to oxidation and may protect against cancers and heart disease - Carotenoids like zeaxanthin, lutein, β-carotene, lycopene, and α-carotene play roles in eye health, heart disease prevention, and cancer influence - Carotenoids and their metabolites have various biological functions including acting on nuclear hormone receptors and oxidative metabolites - Detrimental levels of carotenoids can result from factors like cigarette smoking, excessive alcohol drinking, and interactions with procarcinogens - Excessive intake of certain nutrients like vitamin A can interfere with the absorption of others like vitamin K or vitamin E - Nutritional units for vitamin A are expressed in terms of equivalents, such as International Units (IU), Retinol Equivalents (RE), and Retinol Activity Equivalents (RAE) - Recommended intake of vitamin A ranges from 700 to 1300 µg RAE/d for pregnant and lactating women - Vitamin A deficiency can lead to various effects such as anorexia, impaired growth, and vision issues like nyctalopia (night blindness) and xerophthalmia - At-risk populations for vitamin A deficiency include those with fat malabsorption, chronic nephritis, or acute infections - Toxicity from vitamin A can lead to symptoms like anorexia, dry skin, liver damage, and even teratogenic effects - Assessment of vitamin A levels can be done through eye examinations, plasma retinol concentrations, or relative dose response tests 2. Vitamin E, originally discovered as α-tocopherol, plays essential roles in antioxidant function and various health processes - Sources of vitamin E include nuts, seeds, oils (rich in α-tocopherol), animal products, and supplements like tocotrienols - Different forms of vitamin E like tocopherols and tocotrienols have varying biological activities and sources - The FDA requires the use of milligrams on labels for vitamin E supplements, and IU conversions depend on the specific form of the vitamin - Food sources rich in Vitamin E include wheat germ oil, sunflower seeds, almonds, and plant-based oils - Let me know if you need more information on a specific topic!- ½ cup mango slices contain 1.28 grams of vitamin E - 1 medium raw tomato provides 0.75 grams of vitamin E - 1 cup of raw spinach contains 0.64 grams of vitamin E - Daily Value (DV) for vitamin E: 15 mg - Common oils rich in vitamin E: Sunflower oil (37% DV per serving), Almond oil (36% DV), Cottonseed oil (32% DV), Safflower oil (31% DV), Rice Bran oil (29% DV), Grapeseed oil (26% DV), Canola oil (16% DV), Palm oil (14% DV) - Intestinal absorption of vitamin E occurs through passive diffusion and involves various enzymes such as duodenal mucosal esterase - Vitamin E is mainly found in cellular membranes where it acts as an antioxidant - Vitamin E is stored in plasma as alpha-tocopherol and in small amounts in various tissues including the liver, lungs, heart, and brain - Functions of Vitamin E include its role as an antioxidant in maintaining membrane integrity and protecting against peroxidation of unsaturated fatty acids - The redox cycle of Vitamin E involves interactions with lipid peroxides and stabilized oxygen species - Vitamin E is known for its potential benefits in preventing various diseases associated with oxidative stress such as cardiovascular disease, cancer, cataracts, Alzheimer's disease, and aging - Vitamin E may have non-antioxidant properties, including regulatory effects on gene expression, anti-inflammatory effects, and interactions with other vitamins like vitamin A - Recommended daily intake of Vitamin E for adults is 15 mg of RRR alpha-tocopherol, with different requirements for lactating women and smokers - Vitamin E deficiency is rare but can lead to various symptoms such as retinal degeneration, anemia, muscle weakness, and neurological problems - Assessment of Vitamin E status can be done through plasma concentrations and other tests like the erythrocyte hemolysis test 3. Henrik Dam discovered Vitamin K in the 1920s, which plays a crucial role in blood clotting and is necessary for post-translational carboxylation of specific proteins - Vitamin K is found in different forms in plant and animal sources, and its digestion and absorption involve passive diffusion and specific receptors in the intestines - Vitamin K is stored in tissues like the lungs, kidneys, bone marrow, and brain, with a rapid turnover rate compared to other vitamins - Functions of Vitamin K include its role in blood clotting by activating specific factors and anticoagulant proteins - The Vitamin K cycle involves the conversion of Vitamin K from hydroquinone to epoxy forms, which are essential for its biological activities - Anticoagulants like warfarin inhibit the activity of Vitamin K and are used in the treatment of blood clotting disorders - Vitamin K is also essential for bone health and is involved in the carboxylation of bone proteins that aid in bone matrix formation - Excess intake of vitamins A and E can interfere with the absorption and metabolism of Vitamin K - Recommended daily intakes for Vitamin K are set as Adequate Intake levels, with no established Upper Limit due to the rarity of toxicity from natural sources - Vitamin K deficiency is relatively rare in healthy adults but can lead to abnormalities in blood coagulation and bone health- VK deficiency is likely induced by a low intake of around 10 μg/d of phylloquinone. - Signs of VK deficiency include serum concentrations >0.2 ng/mL (which drop within 2 weeks of inadequate intake), elevated blood clotting prothrombin time, and undercarboxylated osteocalcin ≥4.0 ng/mL. - VK deficiency in adults is associated with bleeding, especially mucosal bleeding such as epistaxis, gastrointestinal hemorrhage, menorrhagia, and hematuria, as well as bruises. - Treatment for VK deficiency includes oral doses (5-10 mg/d) or injections of menadione or phylloquinone (2-5 mg/d). - At-risk groups for VK deficiency include breastfed newborn infants, individuals on very low-fat diets, those with malabsorption syndromes, and individuals on chronic antibiotic therapy. 4. Vitamin D plays a crucial role in skeletal growth and maintaining strong bones. - Sources of vitamin D include sunlight exposure for photoactivation in the skin, as well as dietary sources like fatty fish, liver, egg yolks, and fortified foods. - Absorption of dietary vitamin D does not require digestion and follows fat digestion to become part of micelles. - Vitamin D is transported in the blood bound to vitamin D-binding protein (DBP), and its metabolism involves activation in the liver and kidney to its active form, calcitriol. - Factors affecting photoactivation of vitamin D include age, sunscreen use, clothing, latitude, skin pigmentation, and time of day. - The functions of vitamin D include calcemic roles, regulating blood calcium and phosphorus concentrations in the intestine, bone, parathyroid, and kidney, as well as non calcemic roles in cell differentiation and proliferation in various tissues. - Vitamin D is involved in gene transcription, acts as a steroid hormone in tissues, and plays a role in cell differentiation, growth, and bone health. - The recommended daily intake of vitamin D is 15 μg (600 IU) for adults under 70 years old and 20 μg (800 IU) for adults over 70 years old. - Vitamin D deficiency can lead to conditions like rickets in children and osteomalacia in adults, with symptoms such as bone deformities, soft bones, and bone pain. - Toxicity can occur with excessive sun exposure or supplementation exceeding the tolerable upper intake level of 100 μg (4000 IU) per day.- Taking 16 times the Recommended Daily Allowance (RDA) of a nutrient chronically can lead to toxic effects - In infants, excessive intake can cause hypercalcemia resulting in symptoms like anorexia, nausea, vomiting, hypertension, renal insufficiency, and failure to thrive - Adults may experience calcification of soft tissues (e.g. kidney, heart, lungs, blood vessels), hyperphosphatemia, hypertension, anorexia, nausea, weakness, polyuria, polydipsia, azotemia, nephrolithiasis, renal failure, and potentially death