TEXTBOOK DIETARY/EXERCISE ANALYSES ESSAY OPTION

Lecture 2a- 20 September 2010 Overview of Nutrition

Overview of lecture 1)Introduction-nutrition in a nutshell/nutritional choices 2)Nutrients defined 3)Science of nutrition 4) Next lecture- Planning a healthy diet-chapter 2

Choices of quantity and quality of nutrition have significant impact on the longevity and quality of a person’s life.

Nutrition-defined-narrow- science of what we eat and its impact on us through: digestion, absorption, transport,metabolism and excretion

Nutrition-defined-broad Previous narrow definition plus psychology, economics, sociology, and culture of food and eating

Food and hence nutritional choices depend on: personal preference, habit, ethnic heritage or tradition, social interactions, availability, convenience and economy of food, positive and negative associations, emotional comfort, values, body image, nutrition for health

Nutrients defined: chemical substances obtained from food and used in the body to provide: -energy, structural materials and regulating agents to support growth, maintenance, and repair of the body -possible disease prevention and reduction

Nutrients classified Energy yielding Non-energy yielding Non-nutrients

Energy yielding nutrients -all organic-carbon containing Carbohydrates Lipids Proteins 4/9/4 kcal/gm – remember calories are really kcal 17/37/17 kjoules/gm -energy for warmth, body maintenance (build new compounds/turnover), movement

Non-energy yielding nutrients -but can assist in deriving energy Vitamins-organic Minerals-inorganic-non-carbon containing Water-inorganic

In food one has: Essential or indispensable vs. non essential nutrients vs conditionally essential Also have non-nutrients-helpful, neutral, or harmful Alcohols Phytochemicals Additives, etc How to page 9-Rolfes et al. – homework file:///D:/Media/Animations/chapter2/02ht2.html file:///D:/Media/Animations/chapter2/02nc2.html

file:///D:/Media/Animations/chapter1/01ht2.html file:///D:/Media/Animations/chapter1/01nc.html

Science of nutrition Separating fact from rumour via studies: fig 1-4 and table 1-3 Rolfes et al Epidemiological (no intervention) -case-control, cross sectional, cohort Experimental (intervention) - animal, in vitro (eg cell culture), human

Science of nutrition -all must follow good scientific method: question –hypothesis- data - interpret data -conclude –question (s) Figure 1-3 Rolfes et al-eg vitamin D

Animal and Human Studies all studies must take into consideration -controls -double/single blind, -subject/animal numbers, -randomisation of experimental and control groups, -placebos in some cases for controls -replication-so as to determine the validity of the variable(s) measured

SCIENCE OF NUTRITION DETERMINES : a) If people meet requirements (how much (minimum) needed in diet) or if one is deficient for one or more nutrients b) Nutrient recommendations-page 16 Rolfes et al DRI (EAR/RDA/AI/TUI) c) TUI-toxicity d) How to tell about adequate nutrition Watch out for hucksters