NUTRITION -1

NUTRITION -1

Is the process by which an organism provides itself or is provides itself or is provided with materials  necessary for energy release, growth and repair of body tissues and keeping the body in a good condition.

FOOD

Is any liquid or solid which provides the body with materials for growth and repair,  energy release or keeping the body in a good (healthy) condition.

KINDS OR MODES OF NUTRITION

Basically there are two kinds of nutrition

1. AUTOTROPHIC NUTRITION

2. HETEROTROPHIC NUTRITION

AUTOTROPHIC NUTRITION

This is mode of nutrition where by organisms can make their own food from simple inorganic substance, such as carbon dioxide and water using either light energy (photosynthesis) or chemical energy (chemosynthesis). Organisms which feed by this way are known as AUTOTROPHS

            Example

            1. Green plants

          2. Iron bacteria and sulphur bacteria

                                   HETEROTROPHIC NUTRITION

This is the mode of nutrition where by organisms use organic materials as the only source of food. Organisms which feed by this way are known as HETEROTROPHS. They feed on already made food.

There are three types of heterotrophic nutrition

1. Saprophytic nutrition
2. Symbiotic nutrition
3. Holozoic nutrition

1. Saprophytic nutrition

This is the mode of nutrition where by organisms feed on dead decaying bodies parts of animals or their excrete; Organisms feeding by this way are known as SAPROPHYTES



      2. Holozoic nutrition

This is mode of nutrition where by organism take food by mouth. It passes through a digestive system and broken down, finally absorbed into body tissue.

FORMS OF HOLOZOIC NUTRITION

1. Herbivores – Are animals which feed on plants only Example cow, goat and zebra       

2. Carnivores – Are animals which feed on flesh only e.g. lion, tiger.

3. Omnivores – Are animals which feed on varieties o food (flesh, plants, insect etc) example. Man, monkey, pig.

4. Insectivores – Are animals that feed on insects e.g. shrews, ant

      3. Symbiotic nutrition

This mode of nutrition in which an organism of different species exist in a nutrition relationship with other organism;

There are three kinds of symbiotic associations

1. Mutualism
2. Commensalism
3. Parasitism.

1. Mutualism

This is a nutritional relationship in which the two partners benefit each other by living together Example Nitrogen Fixing Bacteria in the roots of legumes.

      2. Commensalism

This is an association of two group where by the host does not get any partnership. Example Epiphytes (are plants that grow on other plants) e.g. Moses and algae which grow on upper parts of big trees to get sunlight easily

      3. Parasitism

This is a nutritional relationship between two organisms in which one organism live inside/on other living organism and depends on food. The parasite causes harm to the host. The host provides food and shelter for the parasite.

Endoparasites are living inside the body of the host e.g. tapeworm, roundworm and plasmodia.

Ectoparasites;Parasite that lives on host’s surface [outside the body] examples includes some mites, flea and body lice.

The importance of nutrition

1. Nutrition enables an organism to get nutrients and energy required for various life processes. These processes include growth and development of cells.
2. To protect body against diseases.
3. Enable in replacement of worn out tissue and dead cell.

NUTRITION IN MAMMALS

HUMAN NUTRITION
        
 FOOD SUBSTANCES

There are several types of substances that are needed by the human body for its proper functioning. The basic food substances include proteins, carbohydrates, lipids, vitamins, minerals, roughage and water.

1. CARBOHYDRATES.

These are compounds which contain the following elements

1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)

Carbohydrates are also known as SACCHARIDES

There are three groups of saccharides

1. Monosaccharides
2. Disaccharides
3. Polysaccharides

1. MONOSACCHARIDES

These are simplest form (basic unit of carbohydrates) which  are absorbed directly in the blood. These are also known as REDUCING SUGARS

           Their general formula is C₆ H₁₂ O₆

              Exampleof Monosaccharide

1. Glucose

Occurs freely in grapes, honey, tomato and germinating maize

2. Fructose

Occurs freely in all ripe sweet fruits E.g. banana, pineapple

      3.  Lactose

It is found in mammalian milk

(B) DISACCHARIDES

       These are also known as NON – REDUCING SUGARS. They are found when two molecules of monosaccharides condense and release molecules of water. Their general formula is C₁₁ H₂₂ O₁₁.Example of disaccharides.

            (1) Maltose is formed when two molecules of glucose condense.

                                                Glucose + glucose = maltose + water

            (2) Sucrose is formed by condensation of glucose and that of fructose.

                                                Glucose + fructose = sucrose + water

            (3) Lactose is found by condensation of galactose molecule and glucose molecule

                                                glucose + galactose = lactose + water

(C) POLYSACCHARDES                                                                           

These are formed when several units of monosaccharides linked together.

  Example of polysaccharides

   1) Starch

Starch is stored in plant cell, in the muscles and liver of vertebrates as (glycogen) in exoskeleton of arthropods and fungal cell as chitin

    2) Cellulose

It forms the building material of the plant cell walls.

Source of Carbohydrates

Cereals - e.g. maize, rice, wheat

Sugar – e.g. honey, sugar cane, glucose, sweet fruits.

Function of Carbohydrates in the body

1) To provide the body with energy.

2) Carbohydrates combine with proteins, glucose and lipids which are important components of cell membrane.

    2. PROTEINS

Proteins are compounds of carbon, Hydrogen, Oxygen and Nitrogen. Some protein also contains sulphur and phosphorus. Proteins are long chains of Amino acid formed through condensation.

Approximately there are twenty Amino acids that occur naturally. The human body makes ten of this amino acids. These are called NON – ESSENTIAL AMINO ACIDS. The other ten amino acids must be obtained from the diet they are called ESSENTIAL AMINO ACIDS. We get essential amino acids by eating food rich in protein. Food that contains all the essential amino acid is called first class proteins, animal protein most fall in these group. Second class protein lack one or one more essential amino acids, most plant proteins fall in this group.

Functions of protein

1. The body use proteins for tissue growth and repair such as healing of wounds and replacement of skin and mucus membranes.
2. Antibodies are made of proteins, Antibodies are important in offering immunity to the body
3. Enzymes which help us to digest food are protein in nature. In addition hormones, the chemical messengers in our bodies are also protein.
4. They are alternative source of energy in the body

  3. LIPIDS

Lipids are compounds of carbon, hydrogen and oxygen. They are insoluble in water the mean form of dietary lipids is fats and oil. Fats are solid at room temperature while oil is liquid at room temperature. Lipids are made up fatty acid and glycerol. Fatty acid can be essential or non – essential. The body can make non essential fatty acids, it is not able to produce essential fatty acids. We therefore need to eat food that contain essential fatty acid, Example of such food are oil fish, nuts oil seed (such as sunflower seeds, maize, avocados and olives.

Functions of lipids

1) Lipids are source of energy; they produce energy more than all foods substances.

2) They are important component of cell membrane.

3) Fat deposits protect delicate organs such as heart and kidney.

4) Stores of fat under the skin help to insulate the body against loss of heat.

5) Essential fatty acids are important for the formation of substances that help to control blood pressure.

  

 4. ROUGHAGE

This dietary fiber that is obtained from indigestive part of plants; Roughage does not have any nutrition at value as it is not digested and absorbed in the body. However it helps in the passage of food and faeces through the gut by avoiding contraction of the gut muscle.

Source of roughage : Whole grown cereals, fruits, beans, cabbage, spinach, cassava and whole baked potatoes.


   5. WATER

Water does not provide energy to body the but there are several ways through which it is important

(i)It used in the digestion and absorption of food.

(ii) It is a medium of transport for food and hormonies.

(iii) It acts as lubricants e.g. eyeball eyelids.

(iv)It helps in excretion of harmful by product of metabolic process e.g. urine, sweat.

(v)It helps in regulation of heat loss (evaporation of sweat on body surface causes the body to cool)

(vi)It is used in the manufacture of different secretions e.g. tears, saliva.

Water can be replaced in the body through

            a) Direct drinking

            b) Eating foods and fruits.




    6. VITAMINS

Vitamins are complex organic micro nutrient that is essential for growth and survival. Lack of vitamins in the body leads to deficiency disease. Vitamins can be grouped into two categories water- soluble and fat soluble vitamins.

• Fat soluble vitamin can be stored in the body and need not be consumed daily. Vitamin A, D, E and K are example of fat soluble vitamins.
• Water – soluble vitamins are not stored in the body. Therefore they should be consumed. Vitamins B and C are water – soluble. Vitamins B is named of various forms, namely vitamin B₁ B₂ B₆ and B₁₂

                       

                                      Source, functions and deficiency of vitamins

vitamins	source	Function	Sign of deficiency
Vitamin A (retinol)	Liver, milk, carrots, orange, and yellow vegetable	Essential for the formation of membrane of the eyes and the respiratory tract	Night blindness, increased risk of infection.
Vitamin B1 (thiamine)	Lean meat, liver, eggs, yeast extract and brown rice	Carbohydrate metabolism, Coordinate of muscle	Beriberi, a diseases characterized by loss of appetite, muscle cramps disorder and heart failure.
Vitamin B2 (riboflavin)	Liver, meat, whole, grain cereals, yeast extract.	Needed for metabolism of all food and release of energy to cell	Severe and cracking lips corner of the mouth.
Vitamin B3 (niacin)	Nuts, fish, meat, yeast, extract unpolished rice.	Needed by enzyme to convert food into energy	Pellagra a disease characterized by skin lesions, loss of appetite and muscle weakness
Vitamin B6 (doxine)	meat, vegetables, yeast, extracts, whole grown cereals	Essential in protein metabolism	Nerve irritability sores in the mouth, eyes and anemia.
Vitamin B12 (yanocobalamin)	Fish, meat, eggs, milk, and lever.	Builds genetic material, helps to form bloods cells.	Anemia nerve damage weights loss.
Vitamin C (ascorbic acid)	Citrus fruits, fresh green vegetables and tomatoes.	Antioxidant improves absorption of iron used in synthesis of collagen in the bones and gums.	Muscle weakness, easy bruising, joint pains, scurvy (bleeding gums), poor healing of wounds and  frequent infection.
Vitamin D	Egg yolk, milk oily, fish and liver	Helps to build and maintain teeth and bones.	Rickets in children, osteoporosis (soft bones) in adult
Vitamin E	Corn of sunflower oil, butter, brown, rice and peanuts	Antioxidant prevents damage of all membranes	Nerve abnormalities infertility in rats.
Vitamin K	Green vegetables and liver	Needed for normal clothing	Detective blood coagulation resulting in excessive bleeding.

       

  7.Minerals

Certain mineral elements are vital for the proper functioning of the body. Some are required in relatively large quantities and are therefore called macro minerals. Others are required in very small quantity are referred to as micro minerals or trace element.

The following are example of minerals, their sources and their functions in the body.

a) Macro minerals

Minerals	Source	Function	Deficiency symptoms
Calcium	Milk, yoghurt, cheese, sardines, egg, green vegetable	Helps build strong bones and teeth,  promote muscle and nerve functions, and important in clotting of blood.	Weak bones, bleeding easily
phosphorus	Meat, milk, fish, eggs and nuts	Builds bones and teeth, help muscle and nerve activity,  aids formation of genetic materials	Impaired nerve activity bone and teeth formation
potassium	Peanut, bananas, orange juice, green beans and meat.	Help maintaining regular fluid balance needed for nerve and muscle	Poor muscle contraction
Iron	Liver, meat, beans and green vegetables	Essential formulating hemoglobin [the red pigment in blood)	anemia
Zinc	Oysters, shrimp, crab, meat, yeast extracts	Activates enzymes, helps to heal wounds necessary for a healthy immune system	Impaired teeth, poor immune response, skin problems
Sodium	Table salt	Necessary for nerve and muscle activity	Muscle cramps
Chlorine	Table salt	Maintenance of water and ionic balance,  formation of hydrochloric acid in the stomach	Poor digestion of proteins
magnesium	Spinach, pumpkin seeds, sesame seeds and black beans	Relaxation of nerves and muscle strengthening of bones.	Muscle weakness, irregular heartbeat and weaker bones

b) Micro minerals

Iodine	Iodinated table salt and sea food	Production of thyroid hormone which regulate growth, development of bones and teeth, helps prevent tooth decay	Goiter (enlarged thyroid gland)
Fluoride	Fluorinated water and fluoride tables	Development of bones and teeth, helps prevent tooth decay	Poor development of bones and teeth , tooth decay
manganese	Kidneys, liver, tea, coffee nuts and fruit	Formation of bones and activation of enzymes	Nausea, dizziness, loss of heating loss of bone mass
Copper	Meat, fish, and liver	Synthesis of bones and haemoglobin, activation of enzymes	Bleeding under skin, easy rupturing of blood vessel, bones and joint problems, anemia

                                  

  A BALANCE DIET

A balanced diet refers to food containing all types of food nutrients in the correct proportion. We should eat a diet low in fats, sugar and salt but high in proteins, carbohydrates, vitamins, minerals, and roughage, more importantly we should take in large amounts of water.

However, it is recommended that we eat more fish, poultry products and legumes (such as pea, beans and peanuts)

Instead of taking red meat as protein sources. The following should be done in order to maintain a healthy body.

1. Physical activity can preserve and improve your health. Therefore, it is important to balance your food intake and exercise.

2. Minimize your intake of fats and oils by eating foods low in fats, sugars and salts. This will reduce your risk of heart attacks, tooth decay and high blood pressure respectively.

3. Include plenty of grains, fruits, and vegetables in your diet.

4. Eating a variety of food will provide the body with energy and nutrients that is required in maintaining proper health.

Nutritional requirements for different groups of people

Nutritional requirement differ for different groups of people. The ratio of nutrients varies depending state of the body. The following are some groups of people and the special nutritional needs.

          1. Expectant and lactating mothers.

Expectant and lactating (breast feeding) mother need to get enough nutrients.

 They should thus eat a balanced diet because they require nutrients for themselves and the growing foetus or babies.

Protein is needed for the build – up of the mother muscles, breast, uterus, blood supply and the baby or foetus tissue and organs.

Folic acid and vitamin B help to lower the risk of birth defects such as spina bifida. Spina bifida is a spinal disorder characterized by a hole in the spine.

It results from incomplete formation of the spinal cord and the bones of spine. Often the spine protrudes through the hole and sometimes a fluid filled sac may surround the protruding spinal cord.

Calcium helps in the development of the foetus or baby’s bones, if the mothers’ diet does not contain adequate calcium; it is derived from her bones for the foetus or baby. This weakens the mother bones.

Zinc is important for the proper progression of labour and proper growth and development of the baby.

The mother to be requires iron for her blood supply need, the foetus also needs to store iron for use during the first few months after birth.

Expectant mother requires adequate amounts of dietary fiber to reduce the likelihood constipation, which is a common complaints during pregnancy.

          2. Children

Children require enough proteins for the growth and development of body tissues. Inadequate of proteins can lead to stunted growth.

Minerals like calcium are necessary for the formation of strong bones and teeth. Zinc is important for body growth. The zinc resources in the body can be depleted by vigorous physical exercise.

Vitamin B₁₂ is required for the formation of red blood cells. Because a growing baby needs more oxygen and more blood) for growth while vitamin C helps children to build their immunity.

Children also require more energy – giving foods because they are active than adult.

         3. Adolescent

• Need food rich in carbohydrates because of high body metabolism
• Food rich in protein and mineral salt such as calcium, iron and phosphorus
• Adolescent girl require additional supply of iron to compensate for the blood loss during menstruation.

4.The elderly.

Elderly people require less energy – giving foods because they are generally less active than young people. This group should eat food that is rich in fiber in order to reduce constipation and bowel problems that come with age.

 They also need minerals such as iron, zinc and calcium. Iron is necessary because anemia is a frequent problem in older age; zinc is required for a healthy immune system and to increase the rate of healing of wounds.

Old age comes with the loss of calcium from bones leading to soft and weak bones that can break easily. Old people therefore require adequate amounts of calcium and vitamin D to counter the loss.

The elder often have problems of chewing tough  foods because of weakened teeth and swallowing because of the decreased production of saliva. It is therefore important to ensure they get food that are nutritious as well as easy to chew and swallow. For example they can get proteins from eggs or liver instead of meat.

       5. Sedentary workers

These are individuals who stay in one place for a long time while performing their daily occupational activities. They include workers potter’s weavers, clerk, receptionists and doctors.

Sedentary workers are encouraged to balance their diets with physical exercise. Due to their lifestyle and occupation obesity increasingly is common among them. Therefore, it is recommended that they limit their intake of foods rich in lipids.

       6. The sick

Sick people require plenty for nutrients to help recover their health, those who have incurable disease such as HIV and AIDS should get food that will help them to manage their conditions.

Proper nutrition helps to keep their immune system strong and helps the body to fight opportunistic infections and disease.

Rapid weight loss is a major problem in the late stage of AIDS. It is therefore important to get enough nutrients so as that the body can compensate for this.

Proper nutrition helps the body to withstand heavy medication.

Proper diet and exercise helps to combat symptoms such as fatigue, nausea, diarrhea and high blood sugar.

Excess caffeine sugar, dried foods, spicy foods and alcohol should be avoided because they are harmful to a body whose immune system is already weak.

They need to take plenty of fruits and water. Fruits provide vitamins which are required to fight disease. Water replaces the amount lost through diarrhea or vomiting.

It is advisable to use food guide pyramid to know what to eat. The food guide pyramid is a chart showing the recommended amounts of different food types that dietician considers healthy eating.

             

                                    
Nutritional deficiencies and disorders

Malnutrition

Malnutrition (limiting the intake of one or more essential nutrients) results from eating too little from eating the wrong food. There are different types of nutritional deficiencies and disorders in human beings, these deficiencies and disorders include obesity, rickets, kwashiorkor, marasmus, anorexia nervosa and bulimia nervosa.
 

Nutritional disorders

Nutritional disorders are conditions of ill health in a person which arise as a result of lifestyle (poor eating habits) as discussed below.

1. Obesity

Obesity is where by a person has excess body fat. A person sex, age and level of activity among other factor determine his or her ideal body fat. To maintain fertility, women need more body fat. Women also store more fat in their breasts, hips and thighs.

Another important influence of body fat is a person frame size. Individuals with larger bones carry more fat.

Obesity mostly results from eating too much and not exercising enough. Body weight and health risks associated with it are correlated by the body mass index (BMI). BMI gives the relationship between the estimated body fat and the risks of certain disease or conditions.

                        BMI = Body mass (in kilograms)
                                 persons height (in meters)²

                         OR
                       BMI =  Body mass (kg).
                                (Person's height)² (m²).

            For example if your height is 1.65 meters and your body mass is 60 kilograms your BMI can be calculated as

60/ (1.65)² = 60/ (2.7225) = 22.04

If an individual’s BMI falls in the range of 20 – 25, this is considered to be healthy. On the other hand if the BMI is over 30, one may be at risk of diseases associated with obesity.

The following table shows a general guide of how different values of BMI are used to define the condition of the body.

            Table BMI guide        

BMI	Body condition
Below 20	Underweight
20 – 25	Advisable range
25 – 30	Overweight
30 – 35	Obese
Above 35	Very obese

Obesity increases the like hood of conditions such as high blood pressure, diabetes and certain types of cancer, stroke, and respiratory problems.

Obesity can be prevented by eating properly and engage in regular exercise. The intake of calories should balance one’s physical activity. It is also important to avoid eating too much fat foods such as butter, fat meat, chips, margarine, sausage and vitumbua. Avoid also unhealthy dieting.

Anorexia nervosa and Bulimia nervosa

Anorexia nervosa is also called slimmer’s disease or self starvation syndrome. It occurs when a person intentionally refuses to eat enough, leading to a severe loss of body mass.

Sign and symptoms of anorexia

1. Muscle wasting (including weakening of heart muscle)

2. Excessive loss of body mass

3. Extreme fear of being fat.

4. Disturbed body image or feeling fat even when one is very thin.

Bulimia nervosa involves excessive eating followed by efforts to remove food from the body. This effort could involve self- induced vomiting, fasting, excessive exercising or taking drugs that stimulate, emptying of the bowels or excessive urination. Bulimics usually have a normal body mass and keeps their eating behavior secret. Hence it may be difficult to tell that they have a problem.

Causes of Anorexia and Bulimia

Both Bulimia and Anorexia have underlined psychological causes, such as depression, low self esteem and bottled up emotions and the need to fit contemporary standard of beauty Bulimia and Anorexia mostly affect women.

Effects of Anorexia and Bulimia

• The effects of Anorexia and Bulimia are demonstrated by heart problems due to weak cardiac muscles or an imbalance of mineral salts.
• There is an impaired mental function because the brain lacks adequate amount of glucose. Victims also exhibit dehydration. During vomiting, the acidic present in the stomach come into contact with the teeth and gums, the eventually causes, serious damage to the gum and erosion of the teeth. Other effects include anemia, stomach ulcers, abdominal cramping and inflammation of the gut, irregular or absent menstrual periods and dry skin.

Treatment for Anorexia and Bulimia