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TOPIC 4:NUTRITION part 1
Learning outcomes
1. Iden4fy the func4ons of nutrients. 2. Compare intracellular and extracellular
diges4on.
3. Describe the func4on of diges4ve systems in animals.
4. Iden4fy the needs of nutri4on in plants. 5. Describe the transporta4on of water and
nutrients in plants.
Part 1 Content
1. Nutri4on 2. Classes of nutri4on 3. Introduc4on to nutri4on
1. Carbohydrate 2. Lipids 3. Protein 4. Minerals 5. Vitamins
4. Intracellular diges4on 5. Extracellular diges4on
Nutri0on
• A nutrient is a component of food that is needed for a specific physiological func4on.
• All aspects of bodily func4on depend upon proper nutri4on.
• Deficiency disorders occur when the body lacks a nutrient required for a func4on.
The Classes of Nutrient • There are six classes of essen4al nutrient.
1. Carbohydrates 2. Lipids 3. Proteins and amino acids 4. Minerals 5. Vitamins 6. Water
• A balanced diet contains all the 6 classes of nutrient which includes fibers
• These nutrients may be needed in large amounts (macronutrients) or small amounts (micronutrients).
Introducing the Nutrients
CLASS ROLE Macro or micro?
Carbohydrates Energy, fiber Macronutrient
Lipids Energy, insula4on, vitamin D synthesis
Macronutrient
Proteins Provides essen4al amino acids Macronutrient
Minerals Homeostasis, water balance, cofactors
Micronutrient
Vitamins Metabolism and development Micronutrient
Water Hydra4on, temperature control -‐
CARBOHYDRATE
Carbohydrates • Carbohydrates include sugars, starches and fiber. • Sugars can be present as monosaccharides such as glucose or
disaccharides such as sucrose. • Glucose is metabolized for energy
• Starch is complex carbohydrates stored by plants
• Fibers-‐ preven4ng cons4pa4on
Fiber (Cellulose)
• Fiber or cellulose is the indiges4ble carbohydrates derived from plant material.
• Fiber is not considered a nutrient for human because it cannot be digested to smaller molecules in human diges4ve system.
• Insoluble fiber is important because it s4mulates movement of feces in the bowel.
• Soluble fiber binds to compounds in the intes4ne to deter their absorp4on and enhance their excre4on.
Can Carbohydrates Be Harmful?
• Carbohydrates are important because they provide about 45% of the body’s energy needs.
• In our diet, about 1 g of carbohydrates provide 4 calories of energy (compared to 1 g of fat ~ 9 calories)
• Excess carbohydrates in the diet can contribute to obesity, diabetes, and other diseases.
A low-‐GI food will release glucose more slowly and steadily, which leads to more suitable postprandial (a[er meal) blood glucose readings. A high-‐GI food causes a more rapid rise in blood glucose levels and is suitable for energy recovery a[er exercise or for a person experiencing hypoglycemia.
LIPID
Lipids • There are different forms of lipids
that influence nutri4on.
• Lipid (3 fa^y acids + glycerol) called triglyceride
• Triglycerides:
– such as fats and oils supply cells with energy.
– Fat is a long-‐term storage form for lipids.
– necessary for nutri4on. – fats and oils should provide
30-‐35% of the body’s energy. – contain essen4al fa^y acids
that the body requires for proper func4on.
Can Lipids Be Harmful? • Cholesterol is a lipid that
serves an important func4on in cells..e.g. to make certain hormones, bile & vitamin b.
• However, elevated levels of cholesterol and fats in the blood can be detrimental to health.
• Lipids should not be eliminated from the diet, but should be consumed in modera4on from more nutri4onal sources.
PROTEIN
Proteins
• Proteins consumed in the diet are broken down to liberate amino acids, nine of which are essen4al in the diet.
• While all foods contain protein, plant proteins are considered “incomplete” because they generally lack one or more of the essen4al amino acids.
• This limita4on can be overcome by ea4ng specific combina4ons of plant foods.
Can Proteins Be Harmful?
• Proteins should supply no more than 10-‐15% of the calories consumed in the diet.
• Excess protein in the diet cannot be used produc4vely and is generally excreted as urea in the urine.
• High protein diets can lead to some health problems, such as dehydra4on, calcium loss, and kidney stones.
MINERALS
Minerals
• The term minerals is applied to the 20 elements that are required for nutri4on.
• Mineral are necessary for regulate energy metabolism, maintain fluid balance, produce certain structure, enzymes & hormones.
• • Absence of a specific mineral can
lead to mineral deficiencies. – Low iron can lead to anemia. – Low calcium can lead to
osteoporosis.
• Excess minerals in the diet, such as sodium, can also have harmful effects.
Minerals (cont.)
Major minerals Primary Functions
Calcium Strengthen bones, nerve function
Phosphorus Bone growth, energy metabolism
Potassium Nerve function, muscle contraction
Sodium Nerve function, pH and water balance
Magnesium Nerve and muscle function
Chloride Water balance
Minerals (cont.)
Trace minerals Primary Functions
Zinc Protein synthesis, immune function
Iron Hemoglobin synthesis
Copper Hemoglobin synthesis
Iodine Thyroid hormone synthesis
Selenium Antioxidant
Vitamins • Vitamins are essential organic compounds other than carbohydrates, lipids, and proteins that regulate metabolic activities.
• Vitamins contribute primarily to energy metabolism and antioxidant defenses.
• Vitamin deficiencies can lead to serious disease.
Vitamins (cont.)
Water-soluble vitamin Primary functions
Vitamin C Antioxidant, maintains capillaries, bones, & teeth
Thiamine (B12) Important coenzyme, activity of nervous system
Riboflavin (B2) Coenzyme for energy, fat, & protein metabolism
Niacin Coenzyme for energy, fat, & protein metabolism
Vitamins (cont.)
Water-soluble vitamin Primary functions
Folic acid Helps form hemoglobin
Vitamin B6 Helps form hemoglobin
Pantothenic acid Coenzyme for fat & carbohydrate metabolism
Vitamin B12 Coenzyme for DNA synthesis
Biotin Coenzyme for amino acid and fatty acid metabolism
Vitamins (cont.) Fat-soluble vitamin Primary functions
Vitamin D Bone and teeth development
Vitamin E Antioxidant
Vitamin K Synthesis of clotting factors
Intracelullar & Extracelullar Diges0on
Diges0on
Intracellular Digestion
Extracellular Digestion
Single opening Two openings
Intracellular Diges0on
• referring to hydrolysis of food inside vacuoles in a single cell.
• Examples of intracellular diges4on:
i)process of phagocytosis (engulf solid
food)
ii) process of pinocytosis (liquid food).
Extracellular Diges0on (single opening)
• Simple organism having single pouch (gastrovascular cavity) with single opening.
• Examples: -‐Cnidarian (hydra form)
-‐Flatworm
Extracellular Diges0on (two openings)
• Common in most animals. • The diges4ve tube having two openings at each end (mouth and anus).
• Also known as complete diges-ve tract or alimentary canal.
END OF PART 1