Presentation on theme: "Nutrition Basics Food defined culturally : –A person’s diet is the result of: Genetics - taste ability (PTC test) Personal life experiences Culture Nutrients:"— Presentation transcript:
Nutrition Basics Food defined culturally : –A person’s diet is the result of: Genetics - taste ability (PTC test) Personal life experiences Culture Nutrients: biological requirement
Role of Food/ nutrients –Food - supplies nutrients: carbohydrate, protein, vitamin, mineral, fat/oils –Food/nutrients important for: growth, development, reproduction etc –Food/nutrition plays a major role in human adaptation because: it is an independent stressor modifier of other stressors (disease)
Nutrition Basics Nutrients function to: –Sustain life –Promote growth –Replace loss –Provide energy: growth, maintenance, work, respiration, reproduction
Energy Intake Energy Expenditure Food freq. quest. 24-hr recall Food records Food weighing Direct observation Gas exchange calorimetry Heart rate monitoring Estimated from activity –Motion sensors –Activity diary –Direct observation Doubly labeled water (D218O)
Macronutrients Protein Carbohydrate Lipids (fats & oils)
Protein structural materials enzymes hormones source of amino acids used to make protein in the body contributes to immune function can provide some energy can make glucose from amino acids 20 aa used in human protein – 9 are essential (they must be obtained from food). Complete protein contain all essential a a
Carbohydrates Historically nutritionists have classified carbohydrates as either simple or complex, however, the exact delineation of these categories is ambiguous. Today, simple carbohydrate typically refers to monosaccharides and disaccharides complex carbohydrate means polysacchrides (and oligosaccharides).
Carbohydrates: major functions 1.Providing energy and regulation of blood glucose 2.Sparing the use of proteins for energy 3.Breakdown of fatty acids and preventing ketosis 4.correct working of our brain, heart and nervous, digestive and immune systems. 5.Fiber, which is also a form of carbohydrate, is essential for the elimination of waste materials and toxins
Lipds: Fats & Oils Production of fatty acids for the production of phospholipids – in structure of cell membranes. Cholesterol is also made from fatty acids and is used for prod of sex and adrenal hormones. Lubrication, especially in joints and around muscles. Temperature regulation through the insulation they provide. They are also important for the transport of certain vitamins (fat-soluble vitamins).
Vitamins Catalysts for metabolic processes Required in small quantities Absorption mechanisms –fat soluble (A, D, E, K) –water soluble (C, B complex) Storage capacity –greatest for fat soluble vitamins, with potential for overdosage Food sources
Vitamin A Deficinecy Night blindness,(earliest manifestation) –rhodopsin reduced in rods –reduced ability to see in dim light Early eye lesions –conjunctival xerosis conjunctiva becomes dry, thickened, wrinkled, pigmented, loses shiny luster –Bitot’s spots bilateral, triangular, raised whitish plaques plaques appear as fine foam with bubbles
Epidemiology-Vitamin A Deficiency Distribution –Poor, rice-eating populations world wide –W. Africa-spared; red palm oil, those eating small, (entire), fish spared as vit A concentrates in liver –Affluent societies; alcoholics, malabsorbtion Prevalence –251 million children <5 years with mild to moderate deficiency –2-3 million children with xerophthalmia >50% become blind or have serious visual damage significant mortality from infection, decreased immunity and decreased epithelial integrity
SCURVY Scurvy is the term to describe ascorbic acid or vitamin C deficiency in the diet, manifest by – weakness, –anemia, –spongy swollen gums, James Lind a British naval surgeon born 1739, is credited with having empirically evaluated the effect of diet on scurvy, (the first reported controlled clinical trial!).
Rickets: childhood Dental changes in childhood rickets –delayed dental eruption small, pointed teeth susceptible to early caries Complications –growth retardation –pulmonary infection –high childhood mortality Osteomalacia: adults Vitamin D Deficiency
Sunlight- education re: swaddling Vitamin D supplementation –prophylactic supplementation of the institutionalized Prevention-Vitamin D Deficiency
Summary- Vit D deficiency Rickets- childhood Osteomalacia- adults Primary skeletal changes due to bone softening Lack of cutaneous synthesis or intake and utilization of Vit D required for calcium absorbtion
Pellagra Diagnosis Clinical- Four D’s –dermatitis, diarrhea, dementia, death Laboratory –urine N’-methyl- nicotinamide
PELLAGRA Clinical Presentation –Dermatitis confluent over sun exposed areas collar of Casal, dermatosis around neck –Progression erythema, desquamation, hyperpigmentation, atrophy –Seasonality worst after sun exposure
PELLAGRA MANIFESTATIONS Gastrointestinal –stomatitis, glossitis, gastritis, enteritis, malabsorbtion (edematous, painful mucosa, desquamation, glossy- scarlet tongue) Neuropsychiatric (late stage) –confusion, irritability –depression, delusions, suicidal ideation there were asylums in the southern US for victims of central nervous system pellagra/ niacin deficiency
Mineral Deficiencies Iron- anemia Iodine- goiter Fluoride-caries Trace elements
Iron Metabolism Etiology –insufficient dietary iron (most common) absorbtion/binding may be affected –anemia from blood loss hookworm and other parasites in developing world Prevalence –~50% of developing world may have iron deficiency – 56 - 70% of pregnant women in developing world compared to 18% of pregnant women in developed world associated with 50% of maternal deaths, retards fetal growth –60% of children < 5 yrs in developing world
27 ANEMIA Definition Anemia is defined as a decrease in the concentration of circulating red blood cells or in the hemoglobin concentration and a concomitant impaired capacity to transport oxygen. WHO Diagnosis Hemoglobin below 12gm/dl in non pregnant females, 11gm/dl for pregnant women, 11gm/dl in pre school children. Etiology –insufficient dietary iron (most common) absorbtion /binding may be affected –anemia from blood loss hookworm and other parasites in developing world
High Iron Bioavailability Blood products Beef, pork, chicken, fish Liver, spleen, kidney Oysters, clams, mussels Spinach, alfalfa shoots
Iodine Deficiency Requirement- sources –150 micrograms/day in adolescent and adults –seafood, soil, milk products –iodized salt, 60% of world’s salt is iodized, but not targeted to those at risk Prevalence –1 billion at risk –655 million with goiter –11 million with cretinism –high mountainous areas; away from sea
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