NUTR 202 1nd Edition Lecture 14 Ch 7 Vitamins cont.Vitamin E• Alpha-tocopherol is most active form in body• Functions: • POWERFUL ANTIOXIDANT (protects lipids throughout the body) • Protects cell membranes• Red blood cells, brain, nerve cells, lungs• May prevents oxidation of LDL cholesterol• In large dose, reduces blood clotting• Daily needs: Adults need 15 mg of alpha-tocopherol equivalents• Too much or too little:• No known risk of excess vitamin E from natural food sources• Over-consumption from supplements and fortified foods:• Hemorrhage • Upper limit is 1,000 mg/day• Deficiency rare:• Nerve problems, muscle weakness, and free radical damage to cell membranes.Vitamin K• Two forms of vitamin K:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.• Menaquinone • Synthesized by intestinal bacteria• Phylloquinone• Found in green plants• Functions:• Important to bone health• Blood clotting • Involved in synthesizing four blood clotting factors (opposite of vitamin E)• No known problems of consuming too much vitamin K from foods or supplements• No UL• People taking certain anticoagulant medications such as warfarin (Coumadin):• Need to keep vitamin K intake consistent • Changes in intake can increase or decrease drug effectiveness• Severe vitamin K deficiency• May affect blood clotting, but this is extremely rare• Most not stored in the body in large amounts• B-vitamins:• Coenzymes for energy metabolism from macronutrients• Vitamin C:• Antioxidant• Connective tissue• Choline:• Vitamin B complexThiamin: First B vitamin discovered Deficiency condition in Asia related to diet change from brown rice to polished rice Functions• Coenzyme needed for breakdown of glucose to provide energy• Important for nerve function because:• Glucose is nerve cell energy source• Needed for synthesis of neurotransmitters (chemical signals from neurons) • Needed for metabolism of other sugars, certain amino acids and synthesis of ribose (in RNA)• Too much or too little:• No known toxicity, no UL set• Deficiencies:• BERIBERI• Symptoms include fatigue, weakness from not metab. glucose • Also, depression, poor coordination, paralysis• Who is at risk of Beriberi?• Affects population of poor countries with an inadequate food supply-non-enriched refined grains.Riboflavin• Forms two active coenzymes in reactions that: • Produce ATP from FAT, carbohydrates, and protein• Converts a number of vitamins to their active forms (coenzyme!):• Folate, Niacin, Vitamin B6, Vitamin K• Destruction of vitamin B2• UV light• Irradiation • Too much or too little:• No UL set• Deficiency symptoms not common:• Usually with other B-vitamin deficiencies• Deficiency first noted in tissues with rapid cell turnover:• Lining of mouth, lips • Symptoms: injuries heal poorly; cracking of lips and corners of mouth; sensitivity to light; eye burning, tearing, itching; skin flaking around nose, eyebrows, earlobesNiacin• Can be made from tryptophan (protein)• Functions: • Coenzyme for energy metabolism• Glucose and fat• SYNTHESIS OF CHOLESTEROL• Maintaining health of skin cells, digestive system, and NS • Daily needs: men: 16 mg/day; women: 14 mg/day• Toxicity from too much:• Not from food; supplementation a risk. Symptoms include flushing, nausea, tingling of extremities:• may be toxic to LIVER• UL is 35 mg/day• Prescribed in high doses by physicians• Decrease LDL cholesterol and triglycerides, increase HDL• Deficiency:• Pellagra (the four D’s)• Dermatitis, Diarrhea, Dementia, Death• Once common in South, due to corn-based diet Vitamin B6• Functions as coenzyme for over 100 enzymes in:• PROTEIN METABOLISM• To create nonessential amino acids• To create hemoglobin in red blood cells• To create neurotransmitters• Conversion of tryptophan to niacin• To break down glycogen for glucose• 3 forms: pyridoxal, pyridoxine, pyridoxamine• Active coenzyme: pyridoxal phosphate• Deficiency symptoms:• Poor growth, skin lesions, poor immune response, numbness or tingling in extremities• Because of its role with red blood cell synthesis:• **Microcytic anemia (smaller red blood cells, with less hemoglobin)Folate Folate Naturally occurring form in foods Folic acid Synthetic form of folate  Fortified to foods and found in supplements Absorbed more easily than folate Functions:  Amino acids metabolism Coenzyme for DNA synthesis• Particularly important for rapidly dividing cells Folate deficiency can lead to formation of abnormally large, immature red blood cells present; this is called: MACROcytic anemia  Inadequate intake of folate/folic acid before and during pregnancy can result in:  Neural tube birth defects Examples:  Incomplete development of brain, spinal cord and/or spine (can’t complete cell division) • Spina bifida  Incomplete development of brain, skull, scalp• Anencephaly  May reduce the risks of some cancers Colon, pancreatic, breast, ovarianVitamin B12• Also called cobalamine because it contains the element cobalt• ONLY water soluble vitamin STORED in body in significant amounts • Important for:• ATP production from certain fatty acids• Amino acid and protein metabolism• Homocysteine to methionine conversion• ? Prevention of heart disease?• Myelin coating of nerve