Nutrition biochem - Lecture notes 3 PDF

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Summary

This will come up on all exams. always does every year...

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Nutrition = balances diet, requires proper absorption of food and proper conversion and storage by metabolism Staple foods are the main sources of energy in the diet Body is always being modified = old cells being replaced by new cells – digestion supplies a source of raw materials, whilst metabolism provides the chemical supervision, storage, modification and when necessary, the mobilization of tissue products. Nutrients are needed for growth and development, and for the maintenance of healthy tissues as a fuel to sustain metabolism. When we cant eat or the nutrients we intake aren’t in the correct ration, the immune system breaks down. This we don’t heal as efficiently as we should, and our bones become brittle. Diet essentials – as well as providing fuel for ATP production, a diet must also provide the building blocks for biosynthesis. Nutrients are needed to build molecules for growth, repair and reproduction. If we have a source of organic carbon and organic nitrogen, they can synthesise everything else. Diet must provide essential nutrients eg: ascorbic acid (vitamin C) Lacking in this is malnourished Excess = malnourished 6 classes of nutrients: Carbs, lipids, proteins, minerals, vitamins and water. < calories = under nourishment > calories = over nourishment Conversely, if there is too little - stores will be used. Eg glycogen broken down to produce glucose but this can only temporarily be offset Amino acids are not ‘stored’ and therefore constant supply of protein is needed in the diet. This is why the most common states of malnutrition seen are related to a def in protein as well as calories Calorie deficiency – Stores of glycogen and fat are broken down Break down of proteins Leads to loss of muscle mass Brain is protein deficient Overnourishment – When calories are in excess: primarily, fat is stored rather than used as fuel Bmr = basal metabolic rate Intake < BMR = starvation Intake > BMR = obesity

Nutrients – Fats Carbs Proteins Amino acids Vitamins

Minerals Trace elements

organic

inorganic

Fat + carbs = major sources of energy molecules, which are used to generate ATP for use of other metabolic processes in the body. Proteins = majority of amino acids that cells need to make their own proteins Macronutrients = CHO, fats and proteins Micro nutrients = vitamins and minerals Essential fatty acids – Unsaturated fatty acids that cant synthesise directly Essential for membrane structure and fuction Deficiency normally presents as saly skin and eczema Example of...