General Biochemistry
BIOC 201
CHAPTER I
Nutrition and Metabolism
Chapter Objectives
1. The main objective of this chapter is getting the student to understand the
fundamental constituents of human food.
2. The chapter is designed to familiarize the student with the basic classification of each constituent.
3. To provide the student with the
fundamental concepts and terminology of nutrition and metabolism.
BIOCHEMISTRY Definition of
NutritionIt is the science of food and its relationship to health and diseases.
The science deals with nature and
distribution of nutrients in food, metabolic effects and the consequences of
inappropriate food intake.
Nutrients are chemical compounds in foods, absorbed and promote health.
Human Food
(6 main nutrients)
1.
Carbohydrates
2.
Fats
3.
Proteins
4.
Vitamins
5.
Minerals
6.
Water
Human Food
(cont.,)(6 main nutrients)
Essential nutrient:
Vitamins Minerals
Amino acids Fatty acids
Some carb. (energy) Nonessential nutrients:
Synthesized inside the body from other cpds.,
Carbohydrates nutrient
Food carbohydrates:
Simple, derived from fruits, sugar.
Complex, derived from grains, veggies, fruits and beans.
Represents 55-60% of total caloric intake.
Main fuel source, supplying 4.1 calories/g
Lipids as nutrient
Represent 30% of total caloric intake.
Supply 9.3 calories/g
Act as body insulator against heat loss.
Protect internal organs.
Carry fat soluble vitamins.
Lipids as nutrient
Polyunsaturated fatty acids:
Fish and oils (corn & sunflower).
Mono-unsaturated fatty acids:
Nuts and oils (olive, peanut, canola).
Saturated fatty acids:
Meats, dairy products, and tropical oils(coconut &
palm).
Raise blood cholesterol (shouldn’t exceed 10% of the daily intake).
Liver, meat and egg yolk limited to 300 mg/day.
Proteins as nutrient
Represent 15% of the total caloric intake.
Supply 4.7 calories/g
Participate in building and repair body tissues.
Form enzymes, hormones and antibodies.
Found in meat, eggs, fish, poultry, beans, nuts and dairy products.
Vitamins as nutrient
Essential organic substance needed in small quantities.
Needed for growth, health and life!
Needed for vision, DNA formation, bone ossification, RBCs formation, maintenance of skin, blood clotting, general metabolism.
Vitamins as nutrient
Fat soluble vitamins:
A, D, E, and K
Water soluble vitamins:
B complex and C.
True vitamin deficiency is rare.
Vitamins are necessary for certain
populations (infants, elderly, pregnant and patients).
Minerals as nutrients
Principal elements:
Sodium, Potassium, Calcium, Phosphorus, magnesium, sulfur and chlorine.
Trace elements:
Iron, copper, zinc, manganese, iodine, fluorine, selenium, cobalt, molybdenum, and chromium.
Supplied by food and water.
May be necessary for certain populations.
Protein-Energy Malnutrition (PEM)
WHO definition: The cellular imbalance
between the supply of nutrients and energy and the body’s demand for them to ensure growth, maintenance, and specific
functions.
Applied to a group of related disorders:
Marasmus Kwashiorkor
Intermediate states of both.
Protein-Energy Malnutrition (PEM)
It is a problem in many developing countries.
Affects children between 6 months – 5 years.
It’s a result of lack of food or infections cause loss of appetite.
Protein-Energy Malnutrition (PEM) cont.,
Children between 12 and 36 month are
always at risk (vulnerable to gastroenteritis and measles).
Children with severe PEM are at risk of
hypoglycemia, hypothermia, serious
infections and severe electrolyte
disturbances.
METABOLISIM
It is the sum of all chemical reactions occurring in the cells of an organism.
It involves the changes that occur to foodstuffs.
Carried out by ENZYMES.
ENZYMES are proteins that functions as biological catalysts.
ENZYMES changes the rate of reaction without being consumed.
METABOLISIM
ANABOLISM
(constructive metabolism)
CATABOLISM
(destructive metabolism)
