Nutritional Assessment - Nutrition - Lecture Slides, Slides of Nutrition

Download Nutritional Assessment - Nutrition - Lecture Slides and more Slides Nutrition in PDF only on Docsity! Nutritional Assessment of Minerals How much is too much How much is not enough How can we tell the difference Docsity.com Evaluating Individual Need Evaluating Individual Status Setting Standards for optima Experimental Balance Studies Biomarkers Functional tests Population Approach NUTRITIONAL CONCERNS Docsity.com Problems With Balance as a Criterion of Amount 1. End Point is in doubt 2. Excretion is episodic not continuous 3. Multiple connecting pools of the same mineral 4. System adaptation Docsity.com Experimental and Clinical Approaches 1. Experimental generally applicable to animal studies 2. Clinical approaches generally applicable to humans a. Semi Purified diet approach b. Make quantity of mineral in diet limiting c. Measure rate of growth, changes in a biomarker d. Assess quantity needed to suppress symptoms e. Assess quantity needed to reverse symptoms a. Correlate symptoms with diet record of patient b. Determine level needed to suppress or reverse pathologies Docsity.com Standards of Excellence Correlate amount needed with a high quality food source Example: Human or Bovine Milk to determine mineral levels for optimal health Problems: 1. Milk is poor in iron and copper 2. Milk contains whey protein that blocks calcium absorption Docsity.com Biomarkers of Nutritional Adequacy Dynamic storage intestine Functional pool Plasma Excretion Rapid turnover Slow turnover Docsity.com Selenium A good mineral to assess Docsity.com Plasma Selenium (8-10 g/L) 1. Glutathione peroxidase (GPX3) 2. Selenoprotein P (plasma), W (white muscle disease) Selenomethionine (major dietary source) CH3-Se-CH2CH2C-COOH NH3 H CH3-S-CH2CH2C-COOH NH3 H L-Methionine + + Most selenium absorbed goes into muscle and is not under homeostatic control But, plasma selenium rises on selenium intake Docsity.com Biomarkers urinary deoxypyridinoline (DPD) collagen-type 1 N-telopeptide (NTX) Bone Resorption Other markers of calcium-related bone Formation serum osteocalcin (OC) bone-specific alkaline phosphatase (Bone ALP) Ca2+ Its all about bone Docsity.com CH2 CH2 CH COOH N C O H Vitamin K CH CH2 CH COOH N C O H HOOC Osteocalcin Osteocalcin makes up about 10-20% of the non-collagenous protein in bone. Synthesized by osteoblasts it functions in calcium homeostasis, binding tightly to hydroxyapatite mineral surfaces. Serum levels of osteocalcin have been correlated with bone mineral density. ( a small 49 residue Ca2+-binding protein that binds tightly to hydroxyapatite) Ca2+ HA GLA (carboxy glutamic acid) Docsity.com Copper Acceptable but in need of repair Docsity.com Experimental Data Feeding postmenopausal women a diet of 0.57 mg Cu/day for 3 months did not depress plasma Cu or ceruloplasmin. Platelet and leukocyte cytochrome c oxidase activity, however, was suppressed. But feeding adult men 0.38 mg Cu/day for 6 weeks did depress serum Cu and ceruloplasmin. (Milne and Nielsen Am. J. Clin. Nutr. 63, 358- 364, 1996) Healthy adult volunteers fed 50-60 ug additional Cu/kg/day for 3 months failed to show any rise in superoxide dismutase activity or serum ceruloplasmin. These concentrations failed to change the range of Cu homeostasis. (Araya et al. Biometals 16, 199-204, 2003. Docsity.com Peptidylglycine-alpha amidating monooxygenase (PAM) Pep C N O H C COOH H H Pep C N O H H PAM Cu + HOOC-CHO glyoxylate Active hormone Docsity.com PAM Galanin (monoaminergic neurons) Pancreastatin (Insulin control) Gonadotropin releasing hormone (sex hormones) Substance P (emotions) Calcitonin (osteoporosis) Neuropeptide Y (hunger, obesity) Vasopressin (water homeostasis) Gastrin (gastric acid) Thyrotropin releasing horomone (thyroid hormone) Cu Docsity.com Molybdenum Biomarkers for deficiency 1. Decrease urinary sulfate and uric acid 2. Elevated sulfite, hypoxanthine and xanthine Adenine Hypoxanthine Xanthine Uric Acid Xanthine oxidase a Mo2+ enzyme Docsity.com Chromium Biomarkers of Deficiency Impaired glucose tolerance A rough History Plasma not a good indicator Urinary excretion controversial Docsity.com EAR RNI UL Acceptable range of intake Risk of deficit Risk of excess 0.5 1.0 Intake Cumulative Risk NOAEL 50% 2.5% 0% % at Risk LOAEL Docsity.com