Energy Requirement Flashcards
What are nutrients?
Substances that must be supplied by the diet
What are macronutrients?
Substances which are needed in gram quantites in the diet, including carbohydrates, fats and proteins
What are micronutrients?
Substances which are needed in milligram or microgram quantities in the diet, such as vitamins and minerals
What nutrient requirements need to be met in the diet?
Calorie intake
Essential amino acids
Essential fatty acids
Micronutrients such as vitamins and minerals
What are conditionally essential nutrients?
Not required in the diet under normal conditions
Which groups of people must conditionally essential nutrients be provided to?
Individuals who do not synthesize them in adequate amounts such as:
1. People with genetic defects
2. Pathologc states
3. Developmentally immature infants
What is a calorie (cal)?
Amount of heat energy necessary to raise the temperature of 1g of water by 1°C
1000 cal = ?
Kilocalorie (kcal) or Cal
Capital C on Cal represent 1000 cal
1 Cal = x kJ
1 Cal = 4.2 kJ
How do the nutrients provide energy to the body?
Oxidation of dietary protein, fat, carbohydrate and alcohol through ATP
What are the major components of energy utilization?
Basal Energy Expenditure (BEE)/Basal Metabolic Rate (BMR)
Physical activity
Energy cost of metabolizing food (thermic effect of food or diet induced thermogenesis)
Additionally: Shivering thermogenesis, growth, repair of damaged tissues and other normal functions
How can Total Energy Expenditure be calculated?
Total Energy Expenditure = BEE + DIT + Physical activity + Expenditure through shivering thermogenesis
What is BMR?
Energy required by an awake individual during physical, emotional and digestive rest
Metabolic rate during sleep is less than BMR
What vital functions are sustained during BMR?
Working of heart
Circulation
Brain function
Respiration
Urine formation
Maintenance of body temperature
In what conditions should BMR be measured?
Highly standardized conditions while the subject is resting after overnight sleep in a comfortably warm room, not having eaten for 12 hours
Subject should be emotionally relaxed.
What are some factors which affect the BMR?
Age: Maximum in children minimum in old age
Gender: Women have lower BMR than men
Body Surface Area: BMR proportional to surface area
Climate (Environmental Temperature): BMR is increased in cold climate
Exercise: Trained athletes and manual workers have a higher BMR than the sedentary workers
State of Nutrition: BMR is lowered during fasting, starvation and in wasting diseases as a compensation to decreased intake
Pregnancy: The BMR is raised in the last trimester of pregnancy
Hormones: Thyroid hormone have stimulant effect on BMR. In hyperthyroidism BMR increased while in Hypothyroidism BMR is decreased
Pathological conditions: Fever, diseases and drugs like caffeine, alcohol and other medications can affect BMR
What is the importance of BMR estimation?
Diagnostic Aid: Used to be done to assess thyroid function
Calculation of Calorie Requirements: BMR is used to plan nutrition keeping in view their calorie requirements
Effect of Food & Drugs: Effect of different types of foods and drugs on BMR
BMR in adult men and women
Men = 1600 cal/day
Women = 1400 cal/day
What equation is used to estimate the BEE?
Harris-Benedict Equation
What are the four possible physical activity levels?
Light work
Moderate work
Heavy work
Very heavy work
What is diet induced thermogenesis/specific dynamic action?
Energy needed to digest, absorb, distribute and metabolize nutrients after ingestion of food
What percentage of total calorie intake comes from DIT?
10%
SDA of major macronutrients?
Proteins = 30%
Lipids = 15%
Carbohydrate = 5% calories injested
What are the methods of measuring energy expenditure?
Direct calorimetry
Indirect calorimetry
