Al Neelain University Faculty of Medicine

Sem.(7)Primary Health Care Course-Nutrition

Nutrition and Health

Dr.Abeer Abuzeid Atta Elmannan Ali

Course contents:

1. Dietary constituents.2. Balanced diet.3. Assessment of nutritional status.4. Nutritional surveillance.5. Nutritional indicators.6. Common nutritional problems.7. Foodborne diseases.

Session Outlines

Section I: Introduction to Nutrition • What is Nutrition?• Dietary Constituents • Classification of foods.• What is a balanced Diet?• Principles of Balanced Diet.

Section II: Vitamin A Deficiency • Sources of Vit.A, & Requirements• Deficiency.• Treatment.• Prevention & Control.

Definitions:

Nutrition: The science of food and its relationship to health.

Good nutrition: Maintaining a nutritional status that enables us to

grow well and enjoy good health

Dietetics: Practical application of the principles of nutrition

Dietary constituents

Nutrients

Macronutrients:Proteins ,fats and carbohydrates.

Micronutrients:Vitamins and minerals.

Classification of foods

Classification by origin:1- foods of animal origin.2- Foods of vegetable origin.

Classification by chemical composition:1-proteins 2-carbohydrates3- fats 4- minerals5- vitamins.

Classification of foods

Classification by predominant function:

1- body-building foods.2- Energy-giving foods.3- Protective foods.

Classification by nutritive value:

1- cereals 2- vegetables3- fruits…….ect

Balanced diet:

Diet which contains a variety of foods in such quantities and proportions that the need for all nutrients is adequately met for maintaining health, and general wellbeing and also makes small provision for extra nutrients to withstand short duration of leanness.

Principles of constructing balanced diet:

• Daily requirement of protein should be met.(15-20% of daily energy intake).

• Fat s limited to 20-30%• Carbohydrates rich in natural fiber should

constitute the remaining food energy.• Requirements for micronutrients should be met.

WHO Dietary goals:

• Fat should be limited to about 20-30%.• Saturated fats should be not more than 10%.• High consumption of refined CHO should be

avoided.• Restrict sources rich in energy.• Salt intake should be reduced.• Proteins should account for 1—20%• Junk foods should be reduced.

Vitamin A deficiency

Vitamin A

Vit. A covers both - pre-formed vitamin, retinol - pro-vitamin ,beta carotene.

Functions: - Vision - Epithelial integrity - Immune response - Growth - Fertility

Sources of Vit.A

• Animal foods.• Plant foods.• Fortified foods

• Retinol is fat-soluble • naturally present in foods from animal

sources only, for example in dairy products and liver.

Sources

Sources:

• In plants, only precursors are found, i.e. the so-called pro-vitamin A substances, such as carotene .

• They are particularly common in green leafy

Vit.A Storage & Transport

• Stored in the liver mostly in firm of retinol palmitate.

• A well fed person has a reserve to meet his needs for 6-9 months.

• Free Retinol is highly active nd toxic, and therefore is transported in blood stream in combination with Retinol –binding protein.

• In severe protein deficiency ,mobilization of liver retinol reserves is impaired …… Why?

Vit.A Toxicity:

• Nausea• Vomiting• Sleep disorders.• Enlarged liver

Vit. A has teratogenic effects

What is Vit.A Deficiency?

• Vitamin A deficiency is a condition that results from inadequate quantities of vitamin A in the body.

• Lack of vitamin A (vitamin A deficiency) can damage the immune system, making people more likely to suffer from infections.

• Severe vitamin A deficiency can lead to eye problems, poor vision and irreversible blindness.

• Vitamin A deficiency is the major cause of blindness in children.

Who is at risk of developing vitamin A deficiency ?• Newborn babies who are not given collostrum

(first breast milk)• Infants who are not breastfed• Infants born or breastfed from mothers with

vitamin A deficiency• Infants born with very low weight (under 2.5

Kilos)• Children between 6 months and 6 years of age• Children who are malnourished and suffer from

measles, diarrhoea and other infections• School-age children, pregnant adolescent girls

and elderly people• People of any age who are malnourished and do

not have a diet rich in vitamin A

What causes vitamin A deficiency?

• Vitamin A deficiency is caused by a poor diet that does not contain enough foods rich in vitamin A to meet the body’s needs.

• Oil or fat in the diet is needed to help the body absorb vitamin A from foods.

• It is also caused by measles, diarrhoea and other infections and repeated illnesses that block absorption and cause the body to lose or use up stores of vitamin A more quickly.

• Contributing factor in 2.2 million deaths each year from diarrhea and 1 million deaths from measles among preschool children under five.

• Severe deficiency can also cause irreversible corneal damage, leading to partial or total blindness.

• Vit.A can reduce by half the number of deaths due to measles.

Magnitude of Vitamin A Deficiency

Magnitude of Vitamin A Deficiency

• Pre-school children• Clinically deficient: 3 million (Asia and Africa)• Subclinically deficient (low serum retinol): 100-

140 million• 250,000-500,000 become blind each year• 90 % case fatality among those who become

blind

• Pregnant women• 25%-30% cases of night blindness reported in

some countries

Assessment of Vit.A Deficiency

WHO Criteria (The presence of any one criteria should be considered as evidence of

Xerophthalmia problem in the community)

Criteria Prevalence in population at ris (6 months to 6 years)

Night Blindness More than 1%

Bitot`s Spots More than 0.5 %

Corneal xerosis/ulceration/Keratomalacia More than 0.01%

Corneal ulcer More than 0.05%

Serum Retinol less than 10 mcg/dl More than 5%

What are the effects of vitamin A deficiency?

• Eye problems, poor vision and in severe cases, permanent blindness.

• Diseases of the respiratory and digestive systems.

• Repeated illnesses, because the body’s defence mechanism is low, and general poor health.

• Poor growth and development in children.

Manifestations of Vit.A Deficiency:

• Predominantly Ocular• Extra-Occular

Xerophthalmia (Dry eye): Comprises all the ocular manifestations of vit.A

deficiency ranging from night blindness to keratomalacia

Ocular manifestations( Xerophthamia)

• Most common in children aged 1-3 years.• Related to weaning.• Often associated with PEM.• Risk factors include:1. Ignorance2. Faulty feeding practices.3. Infections.

Ocular manifestations( Xerophthamia)

• Night blindness• Conjunctival xerosis.• Bitot`s spots.• Corneal xerosis.• Keratomalacia..

Ocular Manifestations( Xerophthamia)

Night blindness:Inability to see in dim light.

Conjunctival xerosis: Drying of the conjunctival surface.

Bitot’s spots: Cheesy or foamy patches of keratinised cells.

Corneal xerosis: Drying and keratinisation of the corneal surface; hazy, opaque Appearance.

Keratomalacia: Liquefaction of the cornea. It is a grave medical emergency.It is also a major cause of Blindness. (softening of the cornea).

Extra-ocular manifestations:

• Follicular hyperkeratosis.• Anorexia.• Growth retardation.• Increased child mortality and morbidity due to

respiratory and intestinal infections. .

How can vitamin A deficiency be treated?

• Effective treatment of vitamin A deficiency depends on early identification of the problem. Blindness caused by severe vitamin A deficiency is preventable but not curable.

• Treatment of severe vitamin A deficiency:• A child with any signs of eye problems, such as

night blindness (chicken eyes) or dry eyes, needs urgent medical attention and vitamin A supplements.

• • People suffering from vitamin A deficiency need to eat foods rich in vitamin A and foods fortified with vitamin A.

• Proper treatment of diarrhoea, malnutrition, measles,malaria and tuberculosis.

Treatment:

• Early stages: 200,000 IU or 110 mg of retinol palmitate. Orally

on two successive days.

• All children with corneal ulcers should be given vit.A.

Prevention and control:

• Short-term action. (Supplementation)• Medium-term action. (Fortification)• Long-term action. (Reduction of factors

contributing to the disease)

Interventions to Control VAD

• In 1999, only 10 countries provided two rounds of VA supplementation with high coverage, this has increased to over 50 countries by 2004.

• Between 1998 and 2004, UNICEF estimates that about two million child deaths may have been prevented.

• Food Fortification - A number of countries are successfully fortifying foods with vitamin A (e.g. sugar, maize flour, wheat) reaching large populations.

•

70% or more

30 to 69% Less than 30% No data available

VA Supplementation CoverageWhere VAD is a public health problem (U5MR>70)

1 Percent of children aged 6-59 months who received at least one vitamin A supplement within the last six months

Source: UNICEF (2000)