Nutrition and Biochemistry(Lecture No. 1)

NUTRITION AND BIO CHEMISTRYToday’s common health Problems are D.M, HTN, CHD, Certain Cancer, and Obesity are Nutritional disorder. These Nutritional Disorders result from nutritional imbalance (in our life style) to understand Nutritional Disorders (to acquire Perfect Health). Scientific based knowledge is essential. Today scientific based knowledge of human Nutrition is the most important contribution of BIOCHEMISTRY.

DIET AND NUTRITIONA diet consists of energy yielding, body building and protective food which we eat to maintain normal growth function and optimal health.

DIETETICS:- The science of food and nutrients, their action inter- action and balanced use in health science for normal growth function and optimal health is dietetics.

NUTRITION:-Is the study of all the process of growth, maintenance and repair of living body which depends upon digestion and utilization of food for normal growth, function and optimal health.

METHODOLOGY OF NUTRITION:-Most of existing knowledge on nutrition is derived from animal experiments. In spite of the fact that there may be several difference in biochemical composition between man and animals e.g. some animals can synthesize ascorbic acid but a man cannot.

STUDY OF NUTRITION:- Ideal Nutrition: - It is Concern of everyday. Under Nutrition: - Concern of developing countries e.g. Rickets, kwashiorkor Over Nutrition: - Serious Concern of developed Countries e.g. obesity ,cancer WHAT IS NUTRIENT?

Chemical substance or constituent of food – Necessary to sustain normal function of body or a chemical substance which helps to maintain body to build tissue and regulate body function.

PRINCIPAL NUTRIENTS: - Carbohydrates, Proteins, Fats EFA. EAA, Vitamins minerals roughage water. TYPES OF NUTRIENTS: -

Macro – Nutrients or Bulk NutrientsMicro – Nutrients

Macro – Nutrients: - Those primary foods needed in bulk or larger amounts e.g. carbohydrates, fats and proteins these are energy yielding nutrients.

Micro – Nutrients: - Needed lesser amounts these are Vitamins + Minerals do not provide energy so

no source of energy and have no caloric value. VARIABLE WHICH EFFECT NUTRIENT REQUIREMENT:

Age Activity state levelSex Physiological state of nutrients e.g. pregnancy lactationClimate Health status

 DIETARY REFERENCE INTAKE (DRI)

Committees of US and Canadian experts organized the Food & Nutrition Board of National Academy of sciences has compiled in 1941.Basically these are the terms which are frequently used in diet & Nutrition

DRI Estimated Average Requirements EAR Recommended Dietary Allowance RDA Adequate Intake AI Tolerable upper intake level ULESTIMATED AVERAGE REQUIREMENTS EAR

ERA is average daily nutrient intake level that is estimated to meet the requirement of one half ½ healthy individual in particular life stage and gender, Useful to estimate actual requirements in groups ERA sets foundation for RDA.

RECOMMENDED DIETARY ALLOWANCE RDARDA is average daily dietary intake level that is sufficient to meet requirement for nearly all (97 – 98%) individuals in particular life stage and gender.

ADEQUATE INTAKE AIAI is a set instead of RDA when sufficient Scientific evidence is not available to calculate ERA or RDA e.g. AI for young infants who are healthy, full term infants and exclusively are breast fed.

TOLERABLE UPPER INTAKE LEVEL ULUL is highest average daily nutrient intake level that is likely to pose no risk or adverse health effect to almost all individual in general population.

ENERGY REQUIREMENT IN HUMANFood is the only source of body which undergoes Metabolism and liberate / Generates Energy – required for vital activities of the body i.e. main function of nutrient is to provide Energy and Heat i.e. Chemical Stored Energy ATP.

Caloric value of CHO = 4 Kcal / gm energyProtein = 4 Kcal / gm energyFat = 9 Kcal / gm energyThe energy is governed by some Laws i.e. Laws of thermodynamic.

FIRST LAW OF THERMODYNAMICS:-Its states that energy can never be created nor destroyed but can be change from one form of energy to other form of energy e.g. Potential energy to Kinetic energy and other various form of energy are thermal, chemical, electrical, mechanical. They all are inter- convertible.

SECOND LAW OF THERMODYNAMICS:- Impacts on Transformation of energy, precede spontaneously from less stable to move stable energy and dissipate as heat.

MEASUREMENT OF ENERGY:- Is measured as calories / gram small ‘c’Standard Calories:- Is amount of heat required to raise temp of 1gm H2O /0c (i.e. from 150c - 160c)Large Calories:- Denoted Capital ‘C’ i.e. 1000 Cal = 1 kilo Cal1 kilo = 4.2 Kilo Joules (KJ)

CALORIC REQUIREMENT OR REQUIREMENT OF ENERGYESTIMATED ENERGY REQUIREMENTEstimated Energy Requirement is the average energy to maintain balance energy i.e. energy consumed = energy utilized of healthy adult of define age, gender, height, weight, and level of physical activity i.e. sleeping, sitting, walking up stairs, fast running, cycling or swimming.Mild or light doctor, lawyer Moderate, student tailor Severe black smith minerAdult 30 Kcal/ Kg / day 35 Kcal/ Kg/ day 40 Kcal/ Kg/ dayAverage: 2000 Kcal/ day

HOW ENERGY IS USED IN BODYEnergy generated / Liberated by metabolism of nutrients is used in three forms:- Resting Metabolic Rate: BMR / RMR

RMR is minimum amount of energy required by body to maintain basic metabolic activities in post absorptive phase i.e. when person is in complete Mental & Physical rest (or RMR is energy utilized is to carry out body function at rest) e.g. blood flows, Ion transport, Maintenance of Cellular integrity.Basal condition,post absorptive phase, wear light clothes, lying posture at complete Mental & Physical rest etc.Adult of 70 Kg = 1800 Cal Women 50 Kg = 1300 CalFactor Affecting RMR = Surface of body, Sex, Climate, Habits, Good Health or Diseased

Thermic Effect of food or diet induced (Effect) thermogenesis:-About 30% more heat as compared to body at resting condition is needed during digestion and absorption this extra heat required is called diet induced thermogenesis or specific dynamic action (SDA).

Extra physical Activity:-The amount or quantity of energy consumed during physical activity depends on:Duration of exercise Intensity of exerciseAbout 30% - 50% more energy is required than normal at resting conditions so more duration of exercise, more energy is required, more intensity of exercise, more energy needed.Beside above Three processes extra calories are required duringGrowthPregnancyLactation

Oxidation + Reduction:-Oxidation reduction reactions plays a key role in flow of energy in biological system.Gains of O2 or loss of H+ ions is --- Oxidation Gains of H+or loss of O2 ions is --- Reduction

Redox:- Combination of oxidation and reduction, electrons lost by some ones must be gained by other ones.

RESPIRATORY QUOTIENTRespiratory Quotient is the ratio of volume of CO2 produced or liberated to, volume of O2 used, for complete oxidation of energy yielding nutrients (fats, CHO, Proteins)

Formula RQ = Volume of CO2produced / Volume of O2 usedRQ = Carbohydrate C6 H12 O6 + 6O2 -------- 6CO2 + 6H2O6/6 = 1So volume of O2 used from oxidation is equal to volume of CO2 produced.But in respiratory quotient of fats and proteins found less than 1 it means that volume of O2 used for oxidation is GREATER than CO2 production.RQFats = 0.7Proteins = 0.8Mixed Diet (Balanced Diet)= 0.85Carbohydrates = 1RQ of mixed diet (or balanced diet depends on its component i.e. amount of CHO fats proteins present in diet. 

BIO MEDICAL IMPORTANCE OR RQ:-RQ changes in certain physiological & pathological states e.g. D.M prolonged starvation.When energy is mainly derived from fats (Ketone bodies) ↓Alkalosis = ↓Acidosis = ↑So RQ helps in Diagnosis of D.M, Alkalosis & Acidosis