Introduction to

Public Health
Nutrition
Dr. Hamza Alduraidi
Community Medicine

Adapted from: Krause’s Food & Nutrition Therapy

 Nutrition: definition

“The science/study of nutrients that come from

food, their action, interaction, and balance in
relation to health and disease; and the process by
which the organism (body) ingests, digests, absorbs,
transports, utilizes and excretes food substances.”
 Public Health

Public Health is defined as “the art and science of

preventing disease, prolonging life and promoting health
through the organized efforts of society” (Acheson, 1988;
WHO).
b

The main mission of public health is "to assure

conditions in which people can be healthy" (Institute of
Medicine, The Future of Public Health).
 Public Health and Nutrition

 Since nutrition is an essential aspect of the

conditions in which people can be healthy,
public health nutrition is part of the public
health system.
Nutrition
 Assessing Eating Behaviors

 What drives people to eat?

 Hunger
 Appetite
 Cultural and social meaning of food
 Habit or custom
 Emotional Comfort
 Convenience and advertising
 Nutritional value
 Social interactions
 Background definitions

 Nutrients: “Chemical substances in food that nourish

the body by providing energy, building materials,
and factors to regulate needed chemical
reactions.”
 Essential nutrients: Must be provided by food
because the body does not produce them in
sufficient quantities or can not make them at all.
 Nonessential nutrients: Healthy, well-nourished
bodies can make them in sufficient quantities to
satisfy their needs.
 Essential Nutrients

Nutrients are essential to the human diet if they meet

two characteristics.
 First, omitting the nutrient from the diet leads to a
nutritional deficiency and a decline in some aspect
of health.
 Second, if the omitted nutrient is put back into the
diet, the symptoms of nutritional deficiency will
decline and the individual will return to normal,
barring any permanent damage caused by its absence.
 Essential Nutrients cont’d:

The essential nutrients are:

• Some forms of carbohydrate (glucose)
• Certain constituents of fat [the essential fatty
acids: linoleic acid (omega-6) and linolenic acid
(omega-3)]
• Certain constituents of protein (the essential
amino acids such as lysine, histidine, etc)
• 15 vitamins
• About 25 minerals
• Water
Functions of nutrients in food:

a. Provide energy sources

b. Build tissue

c. Regulate metabolic processes

 Six categories of nutrients

1. Carbohydrates: contain carbon, hydrogen, and oxygen

combined in small molecules called sugars and large
molecules represented mainly by starch.
2. Lipids (fats and oils): contain carbon, hydrogen, and
oxygen as do carbohydrates, but the amount of oxygen is
much less. Triglyceride is the main form of food fat.
3. Proteins: contain carbon, hydrogen, and oxygen, plus
nitrogen and sometimes sulfur atoms arranged in small
compounds called amino acids. Chains of amino acids
make up dietary proteins.
 Six categories of nutrients
(cont’d):

4. Vitamins: are organic compounds that serve to

catalyze or support a number of biochemical
reactions in the body.
5. Minerals: are inorganic elements or compounds
that play roles in metabolic reactions and serve as
structural components in body tissues such as
bone.
6. Water: is vital to the body as a solvent and lubricant
and as a medium for transporting nutrients and
waste.
Nutrients are classified into :

 A. Macronutrients (carbohydrates, fats, and proteins).

Provide calories for energy
Needed in large quantities

 B. Micronutrients (vitamins, minerals, and water).

Needed in smaller amounts
Nutrient Classification

There are six major classes oin food:

 carbohydrates,
 proteins,
 lipids (fats and oils),
 vitamins (both fat-soluble and water-
soluble),
 minerals, and
 Water.
General FACTORS AFFECTING NUTRITION

 Age and gender

 Lifestyle
 Food habits
 Ethnicity, Culture, and Religious Practices
 Social Interaction
 Availability of food
 Peer pressures
 Economy
Social Determinants (factors) of Nutrition

Demographic characteristics of those with a more healthful diet

vary with the nutrient or food studied. However, most people
need to improve some aspects of their diet.
Social factors thought to influence diet include:
 Knowledge and attitudes
 Skills
 Social support
 Societal and cultural norms
 Food and agricultural policies
 Food assistance programs
 Economic price systems
 Public health nutrition

 Public Health Nutrition strives to improve or

maintain optimum nutritional health of the
whole population and high risk or vulnerable
subgroups within the population.

 Public Health uses multiple, coordinated

strategies to reach and influence the community,
and organizations and individuals that make up
the community…. with leadership provided by
the government.
Public health nutrition

 Community nutrition efforts involve a wide

range of programs that provide:
 increased access to food resources
 nutrition information and education
 health-related care
 efforts to change behavior and environments
 initiate policy
Public Health Practice Compared to
Clinical Nutrition Practice

Public Health Clinical Nutrition

Practice Practice

Focus Prevention Disease treatment

Target Populations Individuals

Setting Country, district & Clinics & Hospitals

Communities
Strategies Multiple, Counseling and
Reinforcing education
Ecological Framework for Influences on What People Eat
Basic issues related to health and nutrition

These issues include:

 Iodine and vitamin A deficiencies.
 Starvation and widespread chronic hunger.
 Under-nutrition, especially among children, women and
the elderly.
 Other important micronutrient deficiencies including iron.
 Diet-related communicable and non-communicable
diseases.
 Impediments to optimal breastfeeding.
 Inadequate sanitation and poor hygiene, including unsafe
drinking water.
Food and Nutrition Policy

 A food and nutrition policy is a policy with a preventative and

clinical health perspectives based on human rights.
 The basic idea is that all members of the society should be
granted enough food to grow and develop without disorders
due to malnutrition (under or over nutrition).
 The food and nutrition policy should adopt an integrated
approach with collaboration among all relevant government
ministries, non-governmental organizations (NGOs) and UN
agencies.
Refrence: Nutrition in Jordan, Updates and plan of Action. Health Promotion Program,
WHO.
Improving nutritional status is a global
health challenge

 It is a challenge that requires effective action

across a number of areas (food, health, social
welfare, education, water, sanitation, and gender
equity)
 and across a number of actors (government, civil
society, private sector, research, and international
development partners).
Improving nutritional status is a global
health challenge

 Poor nutrition is a challenge that casts a long-term shadow:

its consequences flow throughout the life cycle and cascade
down the generations affecting everyone— especially
children, adolescent girls, and women—and include
mortality, infection, cognitive impairment, lower work
productivity, early onset and higher risk of non-
communicable diseases (NCDs), stigma, and depression.
 Dietary factors are associated with
five of the ten leading causes of death

 Coronary heart disease, some types of cancer, stroke, non-

insulin dependent diabetes (type 2 diabetes), and
atherosclerosis are associated with dietary factors. Dietary
excesses and imbalances contribute to the development of
these diseases.
 Overweight and obesity which are estimated to affect nearly
one third of the world population and it is an important
contributing factor for disease and disability.
Major Nutritional Problems in Childhood

 Overweight and obesity

 Iron deficiency
 Dental caries
 Allergies
 Lactose intolerance
 Overweight/Obesity

 Increasing prevalence
 Influence of access to food, eating tied to leisure activities,
children making food decisions, portion sizes, and
inactivity.
 Consequences: discrimination, negative self-image,
depression, decreased socialization.
 Increases cardiovascular risk factors (hyperlipidemia,
hypertension, and hyperinsulinemia) and type 2 diabetes.
Interventions for Childhood Obesity

 Family involvement
 Dietary modifications
 Nutrition information
 Physical activity
 Behavioral strategies
 Prevention
 Nutrition and Nutritional Problems
in Adolescence

 Adolescence is a period of tremendous physical and

cognitive changes.
 Teens are nutritionally vulnerable because of increased
need for all nutrients at a time when changes in lifestyle
and food habits greatly affect nutrient intake.
 Educating adolescents about the optimal energy and fat
intake and level of physical activity helps them to develop
a healthy body and lifestyle and avoid overweight, obesity
and its co-morbidities of hypertension and hyperlipidemia.
Nutrition and Nutritional Problems
in Adolescence

Growth and Development:

 Physiologic changes
 Puberty, sexual maturity
 Growth velocity
 Independence and autonomy
 Body image
Food Habits

 Irregular meals
 Excessive snacking
 Eating away from home (especially fast
foods)
 Dieting and meal skipping
Factors Influencing Food Habits

 Decreasing influence of family

 Increasing influence of peers
 Increasing media exposure
 Increasing prevalence of employment
outside home
 Increasing responsibilities (less time to
eat with families)
Obesity

 Increasing prevalence of overweight and

obese teenagers
 Multi-factorial health issues
 Short-term and long-term health outcomes
 Importance of early identification and
intervention
Hyperlipidemia and Hypertension

 Onset of CVDs during youth

 Many risk factors are comorbid
conditions
 Diagnosis and treatment