Nutrition and Public Health

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By Origin

Food of animal origin e.g. beef, chicken, pork, Egg, milk, cheese, fish etc.
Food of vegetable origin e.g. Yam, potatoes, lettuce, Oranges, Carrot, Beans, Rice etc.

By Chemical Origin

Protein
Fats
Carbohydrate
Vitamins
Minerals

By Predominant Function

Body building food e.g. milk, meat, poultry, fish, eggs, groundnut etc
Energy giving food e.g. Cereals, Sugars, Roots and tubers, fats and oils.
Protective food e.g. vegetables, fruits, milk.

By Nutritive Value (hallmark)

Milk group

This is made up of all dairy product e.g. fresh milk, skimmed milk, condensed milk, powdered milk, local and foreign cheese, butter, yoghurt and ice-cream. They are good for infants and adults
Lactose Intolerance people could take cheese, yoghurt and so on but can’t take milk.
It contains high concentration of Ca+, Mg+, Riboflavin, Cobalamine and high quantity of protein but low in Iron and Vitamin C.

Meat group

E.g. meat, poultry, eggs, fish, snails, shrimps, termites and other sea foods, legumes, seeds and nuts,
Although the nutritional contribution of each member of the group varies, they all provide valuable amount of energies, protein, iron and B-complex vitamins.
Since large amount are consumed, legumes are the most important source of protein in many African diet, because they are cheap, palatable and keep well. Usage of legumes, nuts, fish and poultry also reduce the intake of saturated fat that is in abundance in meat.

Cereals/millets group

These include maize, guinea corn, wheat, rice, barley, oat etc.
They contribute carbohydrate, B-complex vitamins, Iron, Mg+, and protein to the diet.
Although the protein content is very small, they constitute the most important staple food all over the world.

Starch/tuber group

E.g. yam, cocoa yam, cassava, plantain, Irish and sweet potatoes, bread fruit.
They are seasonal and contain large quantity of starch but are perishable. They can supply about 385 kilocalories/100g of dry matter but with low amount of other nutrient.
They are inferior to cereals because they contain about two-third water and less protein, vitamins, minerals compare to cereal.

Fruit & vegetable group

The term vegetable is used to include some fruit like tomatoes and pawpaw, leaves like spinach, bitter leaf etc., roots like carrots, stalk like celery and flower like cauliflower etc. They provide water-soluble vitamin, carotene (vitamin A) and minerals.
In addition to that, they contribute to roughages in the diet in the form of cellulose. They have very low protein contents. Mushrooms also provide vitamins.

Others (Not well defined in our settings)

Legumes e.g. Peas, Beans
Nuts and oilseeds e.g. linseed, cottonseed
Sugar and jaggery e.g. refined sugar, unrefined
Condiments and spices e.g salt, pepper, mustard, curry, nutmeg, ginger etc.
Miscellaneous foods – usually empty caloric food e.g. carbonated drinks, beverages, alcohol etc.
Some classification split Fruits and Vegetables into 2

There are about 50 different nutrients which are normally supplied in the food we eat, each of which has specific functions in the body

Classification

Based on quantity required in the body

Macronutrients

Protein (7-15%)
Fats (10 – 30%)
Carbohydrates (65-80%)

Micronutrients

Vitamins
Minerals

Based on function

Energy giving nutrients: Proteins, Fats & Oils, Carbohydrates.
Body Building nutrients: Proteins, Fats, Carbohydrates, Minerals (because of Ca+ and water.
Body process regulatory substances: Vitamins, minerals, proteins (enzymes & hormones).

Under laboratory conditions the essentiality of the nutrients can be established when:

A deficiency state occurs in a diet considered adequate in all respect except the nutrient under study.
The deficiency state correlate with sub-normal level of the nutrients in the blood or in certain tissues.
There is significant growth restoration in growing animals in repeated demonstration after supplement of the nutrient under study. When consumed in the correct amount and proportions, one is placed in the best position to maintain the highest level of health.
A deficiency and excess or imbalance is the intake of their nutrient result in aberration in health.

They are classified into:

Monosacharides: simple form of carbohydrates, e.g glucose, manose, fructose, pentoses, ribose
Dissacharides: maltose, lactose, sucrose
Polyssacharides: more than 10 monossacharides. The most complex, therefore they must undergo digestion before they can be absorbed into the blood and utilized in the body e.g.

Starch which is the stored form of polysaccharides in plant.
Glycogen- stored polysaccharides in mammals.

Cellulose- stored polysaccharides in green plants. Mammals do not have the beta-amylase that can digest cellulose.

Function of carbohydrate

Source of metabolic energy: if carbohydrate intake is sufficient in the diets, proteins may not be used to provide energy.
They are the starting minerals for the synthesis of several compounds in the body. Mucopolysaccharide, Glycoprotein etc.
Cellulose, heme-cellulose and pectin provide bulk in the intestine and aids in the excretion of waste products.
Minimum daily carbohydrate for human adult is 100g and can be obtained from yam, cassava, cocoyam, sweet and Irish potatoes, honey, jam, vegetables and fruits.

Several substances that are water-insoluble but soluble in ether or other fat solvents such as chloroform and benzene.
Oil liquid at room temp while Fat solid at room temp
There are 3 categories:

Simple lipids/dietary lipids: (most important to human), consists 98% of Triglycerides – best known of TGR are fats and oils or fatty acids esters of glycerol
Compound lipids: phospholipids and lipoprotein
Derived lipids: sterols and fatty acids

Forms of Lipids

Based on degree of hydrogen saturation

Saturated
Unsaturated: common unsaturated FA are liquid at room temperature e.g. oleic, palmitoleic, linoleic, linolenic acids.

Availability

Visible: seen in butter or vegetable oils
Invisible: dispersed in foods – meat, nuts etc

PUFA – cannot be synthesis in the body = EFA e.g. linoleic, linolenic & arachidonic acids. Deficiency of them can cause eczematous dermatitis, sparse hair growth, poor wound healing, decrease blood platelet.

Functions of Lipids

To provide energy and heat. It contains 9kcalories/g compared to carbohydrates and proteins which contain 4kcalories/g.
For transport of the fat-soluble vitamins. (A, D, E, K)
Essential for the formation of nerve sheath, cell membranes.
Act as lubricants in the intestine.
Add flavour to food.
Required for the production and secretion of bile.
Serves as packing materials in the body to prevent heat loss and to support the kidney, eyes and other internal organs.

Clinical Application

Conditions requiring fat metabolism or reduction are:

Malabsorption syndromes (cystic fibrosis)
Fatty liver
Diabetes mellitus
Hyperlipidemia and
Obesity

Such patient should select foods low in fat.
Condition that required addition of fat to their diet e.g underweight condition.
Note that dietary fat is a risk factor in coronary heart disease, colon and breast cancer.

Most abundant compound in the body, exceeded by water.
About 18-20% of the body weight = protein. One-third of which is in the muscle, one-fifth in the bones and cartilage, one-tenth in the skin while the remaining ones are in the other tissues and body fluids except urine and bile.
During digestion - broken down into 23 different amino acids. 8 are essential for adults, infants and children - histidine is added to the 8
Animal foods contain greater amount of essential amino-acids than plant foods.
The value of quality of a protein is determined by the amino acid composition.
Biological Value (BV) of a protein - an indication of the ability of protein to support growth and repair of tissue cells in childhood and later in life.
Proteins of animal origin have higher biological value. Plant foods contain insufficient amount of one or more of the following amino-acids; lysine, threonine, tryptophan and methionine.
The correction of amino-acid deficiencies in plant protein is made through a process called protein complementarity. In this case, 2 different protein, 2 essential amino-acids which are low in one food are complemented in the other food eaten with it.

Function of Protein

For growth: From birth to death
For building and maintenance of body tissues
For synthesis of enzymes, hormones, antibodies, haemoglobin and antitoxins.
Contribute to blood osmotic pressure: Albumin
For the production of calories especially when insufficient energy is provided in the diet.

Individuals who consume more plant foods are vegetarians.

Vegetarians who include eating eggs and diary food are called lacto-ovo-vegetarians.

Those taking only dairy product are called lacto-vegetarians.

Both groups are capable of maintaining perfect health although children on such diets may have protein-energy deficiency.

They must take vitamin B12 as supplement to prevent pernicious anaemia.

Protein Requirement

Males - 56g/day
Females - 46g/day
Infants –

2.2g/kilogram body weight (0-6 months)
2g/kilogram body weight (6 mths-1 yr)

Sources

Meat, fish, eggs, beans, snail, locust beans, wheat, rice, etc.
Plant proteins provide more than 50% of human protein supply.

Quality of Food Protein

Food proteins vary in efficiency of their utilization for the synthesis of tissue proteins. The efficiency of dietary protein is usually measured by any of the following:

Protein Efficiency Ratio (PER)
Biological value (BV)
Neat protein utilization (NPU)

PER: refers to amount of body weight gained per gram of protein consumed.

BV:

Amount of protein incorporated into the body tissue. That is total protein ingested- protein that has become part of the body. Calculated as: Nitrogen retained/nitrogen intake x 100
The most important single factor that influences the quality of a protein is the quality of essential amino acids in the proteins.

NPU:

A measure of protein quality based on the percentage of ingested nitrogen that is retained by the body.
Because NPU does not take into account differences in the digestibility of proteins, it gives a poorly digested but good-quality protein a false low value.
It is the ratio of amino acid converted to proteins to the ratio of amino acids supplied.

Clinical Application

Deficiency of protein result in disease condition in children such as marasmus, kwashiorkor, intermediate marasmus-kwashiokor.
Retarded growth in children and loss of weight for the adult.
Delayed wound healing in adult and children
Impaired haemoglobin synthesis resulting in anemia
In extreme cases of protein deficiency, excess amount of fat may accumulate in the liver, resulting in fatty liver and fibrosis of the liver.
Prolonged deficiency results in inadequate synthesis of plasma protein leading in edema.
Resistance to infection may be lowered as a result of impaired capacity for antibody production.
In severe conditions, certain hormones or enzymes may be absent or synthesize in little quantity leading to a complete upset of the biochemistry and physiology of the body.

The BMR energy requirement of man is met by three classes of organic food stuff: carbohydrate, proteins and fats.

The metabolism of carbohydrate supplies more than half of the energy required for the day e.g. a sedentary woman requires 2000 kcal/day. Her carbohydrate intake must be designed to contribute more than half of this requirement otherwise fat and proteins may be required to supply the deficiency.

Energy expenditure maybe classified as follows:

Basal metabolism:

When a subject is at complete rest and no physical work is being carried out energy is required for the activity of the internal organ and to maintain body temperature.
This is refers to as basal or resting metabolism and it is estimated by measuring the basal metabolism rate.
It is fairly constant for a given individuals and it is influenced by such factors as age, sex, weight, environmental temperature, pressure, rate of growth, endocrine activity, sleep, state of nutrition, physiological state e.g. last trimester of pregnancy is increased by 15-25%, lactation can also increase it.

Specific Dynamic Action:

Some food items usually generate heat when consumed.
The effect of such food substances in raising the metabolic rate above the basal rate is referred to as specific dynamic action. It has been shown that metabolism might increase.
The heat produced by the SDA of protein contributes to the maintenance of body temperature.

Muscular Activity:

This is the most important variable under normal condition. It depends on the type of work individuals engage in.
Sedentary woman requires about 2000kcalories while manual worker is 4500kcalories.

If energy provision is not sufficient to meet the demand, the body tissue is called upon to supply body energy. In prolonged starvation, the adipose tissue is depleted and ketosis result.

The body becomes emaciated and this can lead to marasmus. When a child is over fed with carbohydrate with little or no protein, the needed protein will be drawn from the blood and this result in reduction of Osmotic Pressure and consequently oedema.

While fat can be synthesized from dietary carbohydrate, carbohydrate can be derived from amino acids in proteins. The protein required by the body is usually derived by dietary sources.

A nutritional disorder results from an imbalance between the body’s requirement for nutrient and energy and the supply of this substrate of metabolism.

A nutritional deficiency, whether primary or secondary begin with the inadequate availability of one or more nutrient to the body.

An insufficient intake will lead to a decrease in serum level of nutrient consequently decrease in biochemical functions for the nutrient resulting in manifestation of a clinical deficiency disease.

When there is an excessive intake, it results in the building up of these nutrients in the body resulting in a nutritional disease referred to as the Disease of Affluence e.g. Obesity.

The most widespread of these diseases especially in Nigeria are:

Low birth weight
PEM (Protein-energy malnutrition) (kwashiorkor and marasmus)
Obesity
Endemic Goitre
Iron-deficiency anaemia
Ricket/osteomallasia
Pellagra
Scurvy
Beriberi

Low Birth Weight

Low birth weight is not a genetic characteristic but is due to maternal malnutrition possibility associated with protein deficiency especially in the last trimester
Study in South Africa showed that the deficiency found in the birth weight of Europeans, colored, Bontus and Indians were attributable to economic status of the parent.
Another study also showed that symptomless maternal malaria in hyperendemic tropic areas is often associated with placental infection which resulted in lowering of birth weight.

PEM Deficiency Diseases

This results when the body’s need for protein and food energy are not met by the diet.
The manifestation depends on the intensity of proteins or energy deficit, the severity and duration of the deficiency, the age of the host and the associated nutritional diseases, kwashiorkor and marasmus.

Kwashiorkor

A clinical syndrome caused by a deficiency of protein. Occur when the intake of energy is inadequate. Diarrhoea and infection are often the predisposing causes.
The infections may divert the meagre amino acids to the production of globulins and acute phase reactant proteins, instead of albumin and transport proteins.
Protein catabolism and nitrogen losses are enhanced by viral and bacterial infections. Protein losses can amount to 2% of muscle protein per day.
Kwashiorkor occurs among children between 6months to 3years with the 2nd year being the most vulnerable. It also coincides with the weaning period when the diet is low of energy and proteins.

Symptoms

Painless petting oedema
Lack of growth, muscle waste
Retention of subcutaneous fat and psychomotor changes.
The patient is irritable; cry easily and have an expression of misery and sadness
Biochemically, there may be increased fatty infiltration of the liver leading to hepatomegaly.
Oedema could be caused by reduction in renal blood flow and glomerular filtration rate due to decrease plasma volume and decrease cardiac output as consequences of hypo-albuminemia, this result in sodium retention and production of rennin and aldosterone, which will increase reabsorption of Na and water leading to oedema.
Patients with severe energy deficiency are usually unable to maintain the supply of tissue and cell energy supply and a serious decompensation occurs causing hypo-glycemia, hypo-thermia and impaired circulatory and renal functions which results in coma and death.

Marasmus

It is an extreme form of under-nutrition due to lack of calories and protein.
It is characterized by generalized muscle wasting, absence of sub-cutaneous fat which gives the skin and bone appearance.
The children have marked retardation in longitudinal growth and lack of physical wellbeing, abnormal behaviour and poor mental development.
The hair is sparse, thin and without normal shine. The cheeks are sunken by the disappearance of the Bichat fat packs giving it the appearance of a monkey or little old man’s face.
It develops slowly to allow for better adaptation to energy inadequacy. A decrease energy intake is followed by a decrease energy expenditure which account for shorter periods of play and physical activity in children
Consequently for longer rest periods and less physical work in adult. When the decrease in energy expenditure cannot compensate for inadequate intake, body fat is mobilized at a faster rate than lean body mass with a decrease in adiposity and weight loss.
Where dietary proteins are of poor quality, body proteins will not be synthesized and body protein losses arise from skeletal muscle breakdown.
Initially, some essential proteins are lost but this soon stabilizes until the non-essential tissue proteins are depleted, the loss of visceral proteins accelerates and death may occur.
Seventy-five percent of the free protein of the body from dietary and tissue proteins are utilized for protein synthesis.
The remainder are broken down for other metabolic purposes. When dietary intake is decreased, all these decrease too, there is then a shift of albumin from intravascular to the extravascular pool which lead to decrease in intravascular oncotic pressure and outflow of water into the extravascular space, this contribute to the development of oedema seen in kwashiorkor patient.
Underweight individuals are more likely to be ill and then recovery from illness is out to take longer time than with normal person. There is need for a gradual adjustment to normalcy since the introduction of a high calorie diet may be fatal to a severely malnourished marasmic patient.
Diarrhoea which is the primary cause of death for under 5 children in the less developed countries occurs much more frequently among the marasmic patient than among the well fed.

Obesity

Obesity has been classified by WHO as a disease of epidemic proportion.

In the poor countries, it is the most prevalent among the rich but in developed countries they look at obesity as undesirable development and a form of malnutrition.

It is characterized by an excess accumulation of body fat when an individual’s energy intake consistently exceed its expenditure, weight gain occurs and this result in obesity.

Garrow’s methods used to calculate obesity

Body Mass Index = Weight (kg)/Height (m) 2

25 – 29.9 - Grade 1
30 – 40 - Grade 2
Over 40 - Grade 3

Normal adult value is between 20 – 24.9. Since being overweight is not synonymous with being obese. It has become necessary to adopt the term desirable and ideal weight which is the weight that conform to the longest life span.

Tricept-Skin fold thickness

Since more than half of the fat in the body is deposited under the skin and its percentage increases with age, Seltzer and Steare proposed the figures of 23mm and 30mm for males and females as the minimum for defining obesity.

In general an adult obese person is one who, with the exception of muscular athlete is

9kg or more above her desirable weight or
Who weighs ≥ 15-20% more than the attained weight at age 20 under nutritional consideration.
Whose tricep skin fold thickness is more than 23mm for men and 30 for women at the age of 30-40 years or
Someone whose BMI exceeds 25.

Some studies have shown that there is increased mortality with increasing BMI with the higher mortality in men than in women.

When obesity occur in early ages of 20-40 years, it has a greater influence on cardiovascular disease than later onset obesity.

Hypertension occurs more often among the obese than among the non-obese and the mortality rate of those who are obese and hypertensive is higher than for those who are only obese or hypertensive.

Extreme obese individuals develop respiratory difficulty called Dickwickian Syndrome which produces lethargy and somnolence.

Causes of Obesity

Genetic
Physical Activity
Physiological factors
Psychological Factor
Socio-cultural Influences
Dietary Factors
Environment

Genetic:

If neither parent is obese, the risk of obesity may be less than 10% but if one of them is obese, the risk of fatness is 40% but if both parents, 80%.

Endomorphic (soft and roundish) have much fat storage capacity.
Mesomorphic (bony and muscular) are in between.
Ectomorphic (lean, fragile, thin, slender with long finger) have low fat storage capacity.

Genes can directly cause obesity in disorders such as Bardet-Biedl syndrome and Prader-Willi syndrome
Energy-thrifty genes- genes that helped our ancestors survive occasional famines: Now with abundance food, it program us to keep growing fat all year round

Physical Activity:

This constitutes a measure of an individual’s lifestyle. Modern technology has ways of reducing this eg use of automobile, television.
These conveniences have turn the population to sedentary people where physical activity is not highly priced the genetic potential obesity has greater opportunity to be expressed.

Physiological factors:

The food intake regulation is located in the hypothalamus of the brain.
A short term regulation of the glucose sensitive receptors found in the ventro-media nucleus of the hypothalamus when blood glucose is high, the lateral nucleus is shut off and activated again when glucose levels are low.
The obese compulsive person seems 2 have lost this normal control mechanism. His appetite is controlled by external influences and find it difficult to stop eating.

Psychological Factor:

Many obese persons eat to derive certain type of satisfaction or to compensate for certain person deficiency.

Socio-cultural Influences:

There is a belief that is associated with heavy eating with a change in fortune with occupational success but this comes at an age when caloric expenditure is decreased because of the modern conveniences and less physical activity. In Nigeria, generally, urban dwellers are fatter than rural dwellers.

Dietary Factors:

Over feeding in infancy may be a factor in the incidence of obesity later in life. Formular – fed babies are usually fatter than breast fed babies.
Infant who gain excessive weight during the first 6months of life have a greater likelihood of being obese later in childhood than infants who gain weight normally.

Environment:

The major contributing factor is the obesogenic environment – urbanization, fatty foods become increasingly accessible and physical activity decreases

Obesity in Childhood

Fat cells (Adipocyte) grow by increase in number and size. N obese adult, it is the number of weight increased and when they lose weight it is the cell size that decrease.
Infant growth occurs by increase in number and size. Obesity which results from an increase in fat cell number is called Hyperplastic obesity but that of increase fat cell size is called Hypertophic obesity.
Obesity is early multiplication of adipocyte appears to take place during the first 3 years of childhood and adolescent period.

Prevention and treatment

The best and most effective treatment is prevention. Losing weight and keeping off the weight is extremely difficult especially for those who are 25% or more overweight.

A gain of 2kg of above one’s ideal weight should be a signal to start curtailing energy intake. The modes of treatment vary from one individual to another.

The doctor or nutritionist must first conduct investigation to show whether it is due to endocrine problem or it is accompanied by diabetes or other health problem.

These factors are;

Psychological counselling
Exercise and drugs
Diet and Dietary advice

Each patient should receive specific guideline
They must eat breakfast
Avoid late night eating
Increase the amount of water, fruit and vegetable intake because these will lower the total amount of food energy and saturated fat consumed. Fish or chicken should be substituted for beef and decreased amount of refined sugar and snacks. There is a liquid formula diet which can lead to a loss of weight within 2-4 weeks but it is not sustainable.
Some proposed total fast especially for Type II obese but here both fat and lean body mass which may not be easy to regain are lost. In general, a recommended pattern should permit a gradual loss of weight of not more than 0.9kg/week. For a woman, the diet should provide 1000-1500kcalories. For a man, 1500-2000kcalories which supply the basal metabolism per day.

Psychotherapy (Behaviour Modifications)

The belief is that eating habits are learned behavior, so the focus is to change eating habit especially emotional and environmental factor that can lead to over eating.

Exercise

If energy can be increased by implemental physical activity and energy intake is constant, weight will drop. However, it requires a significant amount of physical effort to expend a significant amount of energy.

Drugs

Some drugs are given for weight control on a mix theory of appetite control and stimulation of the body to burn more fats.

Surgical treatment

A short bowel is created to produce mal-absorption of ingested calories. This can be done by having a small stomach, Truncal vagotomy, Jaw wiring.

Iron Deficiency

This is due to decrease in the total red cell mass due to fewer red blood cells or to smaller red blood cell which contain fewer haemoglobin.
Nutritional anaemia depends on nutritional factors involve in their formation e.g. iron, folic acid and vitamin B12. Iron deficiency anaemia is the most common and it is characterized by hypochromia and microcytosis of the red blood cell.
It results from inadequate diet, impaired absorption, blood loss or repeated pregnancy.
The anaemia is prevalent in pregnancy because requirement is so large and greater than the dietary intake, therefore it must be supplemented
In the adult, intestinal parasites like hookworm can cause anaemia, also accident, surgery, menstruation or blood donation are the ways of losing blood and consequently iron deficiency. Iron deficiency is also common among cereal eating population because it is poor in iron.
Non-heme iron is the major source, therefore enhancing the absorption will combat the deficiency.
This is found in cereal and vegetables, meat, vitamin c improve its absorption. Iron pot also contributes to its absorption.
Iron excretion is limited since it depends on absorption, its being used and reserved. It is stored in the liver, spleen and bone marrow, used for erythropoiesis.

Goitre (Iodine deficiency)

More common in women than in men and it is often noticed at the onset of puberty, during pregnancy or at menopause.
It is an iodine deficiency disorder. Iodine found in nature resides in the sea and ocean, hence its deficiency is much more in elevated region.
In Nigeria, hilly regions where food supplies comes from crops grown in iodine deficient land, the thyroid gland contain about 70-80% of total body iodine used for the synthesis of thyroid hormones.
It has to trap about 60ug of iodine to maintain an adequate supply of thyroxine. Where cassava is poorly processed goitogenes such as thiocynate may make iodine unavailable.
Where there is a congenital defect in the biosynthesis of MIT and DIT it may result in congenital form of goiter and hypothyroidism.

Rickets/Osteomalacia

The biochemical and physiological consequencies of inadequate vitamin D intake results in rickets in growing children and osteomalacia in adult.
Rickets occur when newly synthesized organic matrix fails to mineralize resulting in soft bone. Since the vitamin is essential for calcium absorption, it may also function in the prevention of osteoporosis later in life.

Scurvy

The name for a vitamin C deficiency
It can lead to anaemia, debility, exhaustion, spontaneous bleeding, pain in the limbs, and especially the legs, swelling in some parts of the body, and sometimes ulceration of the gums and loss of teeth
Common among people with High alcohol intake, tobacco use, Low income, on dialysis
Scurvy affects more men than women, and because vitamin C is found in whole fruits and vegetables, a deficiency is associated with poor nutrition

Xerophthalmia/Keratomalacia

This is a deficiency disease of vitamin A. Under normal circumstances the receptor cell or cone of the retina require constant replenishment of constant amount of vitamin A. When there is a deficiency of vitamin A, it expresses itself in a progressive manner.
First, the vitamin A deficient person experience history of night blindness called nyctalopia which result from a reduced concentration of low serum vitamin A. This is followed by a sequence of abnormality of the conjunctiva and cornea termed Xerophthalmia, in which the protective secretion of the eye is lost with consequent keratinization of the epithelia cell. The eye becomes dry and loses its sensitivity. Severe irreversible changes in the cornea which perforate the blood of aqueous.
PEM and zinc deficiency may also lower the rhodopsin content of the eye. Even viral infections such as measles may also worsen the condition. Vitamin A deficiency also produces skin changes of extra ocular manifestation including perifollicular hyperkeratosis.

Beriberi

Disease caused by a vitamin B-1 deficiency, also known as thiamine deficiency.
A serious and potentially life-threatening condition that develops if a person has a severe thiamine deficiency
There are two types of the disease: wet beriberi and dry beriberi.
Wet beriberi, which mainly affects the cardiovascular system, causing poor circulation and fluid build-up in the tissues.
Dry beriberi, which primarily affects the nervous system, leading to the degeneration of the nerves. Degeneration typically begins in the legs and arms and may lead to muscle atrophy and loss of reflexes
Rare in developed countries but because of poverty in LMICs and lack of policy to fortify stable food with thiamine, beriberi may go undiagnosed

Inadequate nutrition occurs from several biological, socio-cultural and economic aberrations among which are poverty, inadequate knowledge of nutrition and inadequate and unsafe water supply which may predispose individuals to diarrhoea diseases.

The problems are presented in a triad of agent, host and environment.

Agent

In a deficiency state, there is an insufficiency of nutrient at the cellular level to satisfy metabolic need. When there is an inadequate protein intake or an essential amino acid is missing, the body react as if all essential amino acid are deficient in the food and their utilization will not occur until all the essential amino acids are available at appropriately.

Host

Within a given environment, some individuals are more susceptible than others to malnutrition. Host factors are age, sex, activity, growth, pregnancy, lactation and pathological state.

Infant and Preschool Children
Pregnant Women: As a result of inadequate diet and increased nutritional requirement which combine to compromise the development of the foetus.
The Elderly: As a result of loneliness, decrease in income, inability to chew highly nutritious food.
The Sick: With poor appetite, infection, diarrhoea and increased nutritional requirement.

Environment

Poverty: This limit the choice of food and it generates a circle, inadequate diet-malnutrition- illness-inability to work-poverty.
Lack of nutrition education: Affect people of low income and educational level. Nutrition education programs help people learn about nutrient, food sources, better purchasing and better food preparation.
Cultural Factors: Under the guides of religious taboos which prohibit eating of certain nutritious foods eg milk causes diarrhea, meat maybe held from children, mothers withhold solid food from children when they are ill.
Rural-Urban Migration: Unable to accommodate the migrant in term of employment, housing, food and other services.
Inadequate Food Supply: The food to population ratio is very critical. Nigeria, is not producing enough food distribution of food and this is also uneven worldwide. Government may not be able to finance irrigation program to have food all the year round.
The income to purchase good food is another problem. Also, misplaced priority and poor budgeting can further aggravate this problem eg spending more money on arms, poor road network, expensive project, poor storage and distribution of foods, families having children by chance and not by choice.
In Nigeria, polygamy further enhances its lack of knowledge of nutrition due to literacy and semi-literacy, insufficient food production, food storage and distribution.

Causes of Malnutrition in Nigeria

Causes of malnutrition and food insecurity in Nigeria are multifaceted:

Poor infant and young child feeding practices
Lack of access to healthcare water, and sanitation
Armed conflict, particularly in the north
Irregular rainfall
High unemployment and poverty
Chronic and seasonal food insecurity
Volatile and rising food prices
Cultural practices
Ignorance, illiteracy, female education

Malnourished children are susceptible to infection and the relationship is synergistic.
Infection and diarrhoea diseases must be controlled through immunization, total maintenance of a health environment by the provision of adequate and safe water supply at the ease of all citizens.
Poor food storage and distribution also contribute a problem of malnutrition in Nigeria e.g. Fish produced in Calabar barely get to Jos before they get spoilt.
Fruits produced in villages rarely get to the city. Most foods produced are casual.
The culture of buying and selling as opposed to production.

Nigeria’s commitment to improving nutrition; aligned with the government’s Vision 20:2020 and the National Strategic Health Development Plan (2009–2015):

National Policy on Food and Nutrition (2013)
National Strategic Plan of Action for Nutrition (2014–2019)
National Policy on Infant and Young Child Feeding in Nigeria (2010)
Agricultural Sector Food Security and Nutrition Strategy

Nigeria has set the following targets between 2014 and 2018:

Reduce the number of under-5 children who are stunted by 20 percent
Reduce low birth weight by 15 percent
Ensure no increase in childhood overweight
Reduce and maintain childhood wasting to less than 10 percent
Reduce anaemia in women of reproductive age by 50 percent
Increase exclusive breastfeeding rates in the first 6 months to at least 50 percent.

In April 2016, Nigeria launched its “Zero Hunger Initiative” to achieve the goal of eliminating undernutrition by 2025— ahead of the 2030 deadline of the UN’s SDGs

Comprehensive legislation is in place for the implementation of the International Code of Marketing of Breast Milk Substitutes.

The addition of vitamin A to wheat flour, maize meal, vegetable oil, and sugar, as well as the addition of iron, zinc, folic acid, B vitamins, niacin, thiamine, and riboflavin to wheat, are mandated by law.

Nigeria received Universal Salt Iodization certification in 2005 (Kuku-Shittu et al. 2016).

A multi-sectoral National Committee on Food and Nutrition (NCFN) scaling up nutrition and convening government ministries and departments including the Ministries of Health, Education, Agriculture, Women Affairs, Finance, Information, Science and Technology, and Water Resources, and the Planning Commission.

Because of its multifactorial causation the solution too must be multifaceted and multisectoral.
A permanent elimination of malnutrition cannot be accomplished without first overcoming poverty and mal-distribution of national wealth which makes health care available to all citizens.
Government must create a political-economic system which will enable all or most of the citizen work and earn meaningful wages, thus providing decent living standards.
Government at all level must implement food and nutritional policies which will promote adequate food production and improve the stability of adequate food supply
Food availability / Food security
Rural and agrarian community development
Family planning to decrease number of children
Pregnant and lactating mothers must be encouraged to institute breast feeding both monitoring activity and the use of local inexpensive weaning food.
Infectious diseases control through immunization and healthy environment.
Food fortification
Food supplementation
Food diversification
Bio-fortification - new concept (Gambia conference) OFSP – Orange Fortified Sweet Potato

The following international organizations are concerned with global problems of nutrition;

FAO – Food and Agricultural Organization
WHO – World Health Organization
UNICEF – United Nation Children Emergency Fund
USAID – US Agency for International Development
UNESCO – United Nations Education and Scientific Community Organization
World Bank.

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