2. Course Objectives
• Upon successful completion of this course, student will be able to:
• Define the theory and practice of public health nutrition
• Describe methods for evaluating community nutrition status and identify
current community nutrition problems
• Characterize populations at the greatest risk for malnutrition and nutrition
related disease, including principal biological, cultural, socioeconomic,
and nutritional determinants of diet-related disease risks
• Identify methodologies for nutrition intervention from an individual,
community, program and policy level including similarities and
differences
• Identify educational resources and public nutrition services available in
the US, identifying which programs target food insecurity, hunger,
nutritional deficiencies, over nutrition and diet-related chronic disease.
• Describe the strengths and weaknesses of current nutrition services and
resources
• Develop audience specific nutrition education messages
4. Module 1: Concept and Principlesof Public Health
• Module objectives: At the end of this modules, students will be
able to understand the:
• Basic Concepts and Scope of Public HN
• Theories of PHN
• PHN principles related to Dietary nutrients requirements,
health maintenance, and factors influencing nutritional
requirements at population level
• Principles related to public health nutrition requiremetns
5. • What is Public Health - Introduction
• Public health refers to those aspects of health that affect the population as a
whole, their study and the services that aim to deliver it.
• Public health nutrition is where these two concerns – population health and
nutrition – interact or overlap
• ‘The science and art of promoting and protecting health and well-being,
preventing ill health and prolonging life through the organized efforts of
society’ or
• Public Health is the science of promoting health and preventing
disease of a population by systematic efforts of society, communities
or individuals, usually in the presence of limited financial resources.
• The Science and art of helping people change their lifestyle
to move toward a state of optimal health’’.
6. The three main public health roles are:
● The assessment and monitoring of the health of
communities and populations at risk to identify health
problems and priorities.
● The formulation of public policies designed to solve identified
local and national health problems and priorities.
● To assure that all populations have access to appropriate
and cost-effective care, including health promotion and disease
prevention services.
7. • Current Role of Nutrition in Public Health
• Socio-demographic changes are affecting many parts of the globe
• Transition from traditional diets typical ‘westernised’ patterns
• In less economically developed countries, there is a rising burden of
cardiovascular disease, and some cancers breast, colorectal and prostate –
related to nutritional factors
• In more affluent nations, with increasing age the major non-communicable
disease group is predicted to be cancers, many of which are related to
dietary patterns, body fatness and physical activity levels
• Meanwhile malnutrition – stunting and wasting in children, short stature in
adulthood, as well as specific micronutrient deficiencies – remains prevalent.
Even in richer countries, where food security is less of a problem, rickets
remain persistent in vulnerable groups, and are possibly increasing
8. • Principles of Public Health Nutrition
• Effective public health nutrition requires three discrete functions
• the acquisition, synthesis and dissemination of knowledge relating
nutrition to health and disease;
• surveillance programmes to detect potential nutritional problems
across the life course among the population, and to monitor
• and to monitor change; evidence-informed policy development and
implementation.
9. Principles of Public Health Nutrition
Overview
• Public Health Nutrition
• Nutrition is essential for life, encompassing biological and sociological
aspects of accessing necessary substrates and cofactors.
• Public health nutrition focuses on promoting and protecting health,
preventing illness, and prolonging life through organized societal
efforts.
• Historically, undernutrition has been a major concern in both
economically developed and less developed countries.
• Undernutrition manifests as micronutrient deficiencies, wasting, and
stunting in childhood and nutrition-related chronic diseases in
adulthood.
• Nutrition-related chronic diseases, like obesity, type 2 diabetes,
cardiovascular disease, and common cancers, now dominate the
global nutrition-related disease burden.
10. • Human Nutrient Requirements
• Characterizing human nutrient requirements is crucial in public health
nutrition.
• Professional nutritional practice requires training and experience to
apply nutrient requirements in clinical and public health settings.
• Nutritionists play a significant role in addressing undernutrition and
chronic diseases globally.
• As societies undergo nutritional transition, there is a rising burden of
nutrition-related chronic diseases in less economically developed
countries.
• Public health nutrition interventions are vital for promoting well-being
and reducing the burden of nutrition-related diseases.
•
11. Food as Medicine: Historical Perspective
• Ancients viewed food and medicine as interconnected aspects
of health.
• James Lind's 18th-century demonstration of lime juice curing
and preventing scurvy emphasized the importance of
appropriate food for health.
• Despite lacking detailed knowledge of nutritional demands, it
was evident that food is vital for growth, development, and well-
being.
• Lack of nutrition knowledge hindered the formulation of rational
nutrition policies, as seen during the disruption of food imports
in the First World War in the UK.
12. • Principles of Dietary Nutrient Requirements
• Understanding the body's nutritional demands and how different
foods meet them is essential for formulating effective nutrition
policies.
• Nutrition science applied to policy-making ensures a coherent
response to maintain a healthy food supply during disruptions.
• In the Second World War, despite similar food import
disruptions, the application of nutritional science enabled an
equitable distribution of food, securing the population's health.
13. • Dietary Nutrient Requirements in Policy-Making
• Knowledge of dietary nutrient requirements plays a critical role
in ensuring an adequate and balanced food supply.
• Evidence-based policies help maintain the nutritional well-being
of the population during challenging times.
• Integrating nutrition science into policymaking ensures effective
food distribution to meet the health needs of the population
14. • Principles of Public Health Nutrition
• The primary prevention of disease relies on the identification of the
causes of disease
• The identification of infectious causes has led to the development
of vaccination and antibiotics, and of means to control their
vectors, such as the mosquito for malaria.
• The identification of a deficiency of the essential nutrients allowed
for dietary approaches to their prevention, and policies such as
food fortification.
• In all health practice:
• epidemiological information
• clinical trial data or laboratory evidence,
• or less reliable forms
15. • Components of PHN
● Health protection through Nutrition - protection against
infectious / chronic such as metabolic diseases and
environmental threats
● Health promotion through Nutrition - target individual
behaviour or promote health by education, legislation
• Health-care services - provide, analyse and improve /
optimise health-care services
16. • Prevention Approaches for Optimal Health:
Personal prevention involves people at individual level; for instance,
educating and supporting a breastfeeding mother to promote the
health of her infant.
Community-based prevention target groups; for example, public
campaigns for low fat diets to decrease the incidence of obesity or
heart disease.
System-based prevention deals with changing policies and laws in
order to achieve the objectives of prevention practice; laws regarding
childhood immunization, food labels, food safety and sanitation.
17. Level of Prevention
Each part of prevention itself has three levels.
• Primary prevention is aimed at preventing disease by controlling
risk factors that are related to injury and disease.
• For example, low-fat cooking classes, help people change their
eating and cooking patterns to reduce their risk of
cardiovascular disease.
18. Level of Prevention
Each part of prevention itself has three levels.
• Secondary prevention focuses on detecting disease early
through screening and other forms of risk assessment.
• For example; public screening for hypertension at a health fair
identify people whose blood pressure is high, these individuals are
then referred to a physician or other health professional for follow-up
and treatment.
19. Level of Prevention
Each part of prevention itself has three levels.
• Tertiary prevention aims to treat and rehabilitate people who
have experienced an illness or injury.
• Education programs for people recently diagnosed with diabetes
help prevent further disability and health problems, such as
blindness and end-stage renal disease.
22. Reducing
Risk Through
Prevention
• Socioeconomic
models have been
used to develop
policies and dis-
ease prevention
strategies, such as
the Mackenbach
model, which can
be used as a basis
for developing
policies and
intervention
strategies
25. Role of Health Professionalsin UpliftingPHN
CLASSACTIVITY
26. • Role of health professionals in uplifting PNH
• Health professionals must be a member of an
interdisciplinary team in order to provide an effective nutrition
program. An interdisciplinary team is a collaboration
among personnel representing different disciplines of public
health workers (nurses, social workers, physicians, daycare
workers, dietitians, and dietetic technicians).
27. ● Role of health professionals in uplifting PNH
● Various approaches are used to diagnose and ad- dress public or community issues,
including:
● Utilizing interventions that promote health and prevent communicable or chronic
diseases
● Channeling funds and energy to problems that affect the lives of the largest
numbers of people in a community
● Seeking out unserved or underserved populations (due to income, age, ethnicity,
heredity, or lifestyle) and those who are vulnerable to disease, hunger, or
malnutrition.
● Collaborating with the public, consumers, community leaders, legislators, policy
makers, administrators, and health and human service professionals to assess
and respond to community needs and consumer demands.
● Monitoring the public or community’s health in relation to public health
objectives, and continuously addressing current andfuture needs.
● Planning, organizing, managing, directing, coordinating, and evaluating the
nutrition component of health agency services.
28. Factorsaffectingnutritionalrequirementsthroughlifecycle
• Low per capita income
• Low and unequal distribution of income
• Poor and highly unstable growth performance especially in agriculture
• Unemployment and underemployment
• Low and declining farm size
• Inequalities in land distribution
• Low land utilization
• Social discrimination
• Population growth
• Access to market
• Food taboos: certain restrictions in the food consumption due to cultural and social norms.
• Poverty
• Climate induced insecurity: climate change, deforestation, landslide, declining soil fertility
• Political instability
• Poor, marginalized, ethnic group & lower caste groups
• High maternal and infant mortalities
31. • Module Objectives:
• Understand Food Security and its major pillars
• Major challenges in Food security to sustainable, safe, and equitable
food supplies,
• Different conceptual frameworks in food security
• Food security assessment tools
• the role of the UN, government, and private sector actors in relation
to food production, trade, access and consumption,
• Current policies to establish safe and equitable food supplies,
Factors such as the impact of climate change on food supplies.
32. Food Security– History & needs
• In 1974, the Committee on World Food Security (CFS) was
established in the United Nations (UN) system recognising the need
for an intergovernmental body to review food security policies.
• CFS was reformed in 2009 to maximise stakeholder input. In 2015, a
work stream on nutrition was established with the aims:
• Formulate policy recommendations, international strategies, voluntary
guidelines, principles and other policy frameworks; share lessons and
good practices that are relevant to CFS work on nutrition and food
systems; report on the implementation of the ICN2 recommendations for
sustainable food systems promoting healthy diets; raise awareness of
CFS stakeholders in nutrition.
35. Food Security–Availability
• Food availability addresses the “supply side” of food security
and is determined by the level of:
• food production,
• stock levels and
• net trade.
36. Food Security–Accessibility
• An adequate supply of food at the national or international level
does not in itself guarantee household level food security.
• Concerns about insufficient food access have resulted in a
greater policy focus on incomes, expenditure, markets and
prices in achieving food security objectives.
• Major factors:
• Purchasing power, income of population, transport and market
infrastructure
37. Food Security– Utilization
• It essentially translates the food available to a household into
nutritional security for its members.
• Utilization is commonly understood as the way the body makes
the most of various nutrients in the food.
• Sufficient energy and nutrient intake by individuals are the
result of good care and feeding practices, food preparation,
diversity of the diet and intra-household distribution of food.
• Combined with good biological utilization of food consumed,
this determines the nutritional status of individuals.
38. Food Security– Utilization
• Utilization also covers food safety, hygiene and manufacturing
practices applied in primary agricultural production, harvesting and
storage; food processing; transportation, retail, households, diet
quality and diversity: meeting needs in terms of energy, macro and
micronutrients
39. Food Security– Stability
• Stability of the other three dimensions over time:
• Even if your food intake is adequate today, you are still considered to
be food insecure if you have inadequate access to food on a periodic
basis, risking a deterioration of your nutritional status.
• Adverse weather conditions, political instability, or economic factors
(unemployment, rising food prices) may have an impact on your food
security status.
42. CLASSACTIVITY
Why is Food a Security Issue?
- Elaborate through a Flow-Chart / Schematic demonstration
43.
44. FoodSecurity:Duration
• Food security analysts have defined two general types of food insecurity
in term of DURATION:
CHRONIC FOOD INSECURITY TRANSITORY FOOD INSECURITY
Is….. long-term or persistent. short-term and temporary.
occurs
when...
people are unable to meet their
minimum food requirements over a
sustained period of time.
there is a sudden drop in the ability to produce or
access enough food to maintain a good
nutritional status.
Results
from ….
extended periods of poverty, lack of
assets and inadequate access to
productive or financial resources.
short-term shocks and fluctuations in food
availability and food access, including year-to-
year variations in domestic food production, food
prices and household incomes.
can be
overcome
with...
typical long term development
measures also used to address
poverty, such as education or access
to productive resources, such as
credit. They may also need more direct
access to food to enable them to
raise their productive capacity
transitory food insecurity is relatively
unpredictable and can emerge suddenly. This
makes planning and programming more difficult
and requires different capacities and types of
intervention, including early warning capacity
and safety net programmes
45. FoodSecurity:seasonalfoodsecurity
• The concept of seasonal food security falls between chronic and
transitory food insecurity. It is similar to chronic food insecurity as it is
usually predictable and follows a sequence of known events.
• However, as seasonal food insecurity is of limited duration it can also be
seen as recurrent, transitory food insecurity.
• It occurs when there is a cyclical pattern of inadequate availability and
access to food.
• This is associated with seasonal fluctuations in the climate, cropping
patterns, work opportunities (labour demand) and disease.
46. Vulnerabilityto Food Insecurity
• Vulnerability is defined in terms of the following three critical
dimensions:
• vulnerability to an outcome;
• from a variety of risk factors;
• because of an inability to manage those risks
• Indeed, a person can be vulnerable to hunger even if he or she is not
actually hungry at a given point in time.
• Vulnerability analysis suggests two main intervention options:
• Reduce the degree of exposure to the hazard
• Increase the ability to cope
47. FoodSecurity:OvercomingStrategies
• Early Warning Systems (EWS) alert to the presence of food crises
and related drivers, informing decision makers and saving lives.
• The Early Warning Hub brings together information from across
Early Warning Systems in one place.
• There is a range of Early Warning Systems (EWS) relevant for food
security.
48. FoodSecurity:OvercomingStrategies
• Safety Nets
• Measures to enhance direct access to food are more likely to be
beneficial if these are embedded in more general social safety net
programmes.
• Safety nets include income transfers for those chronically unable to
work—because of age or handicaps—and for those temporarily affected
by natural disasters or economic recession
49. FoodSecurity:OvercomingStrategies
• Safety Nets – Options
• Targeted direct feeding programmes. These include school meals;
feeding of expectant and nursing mothers as well as children under five
through primary health centres, soup kitchens and special canteens
• Food-for-work programmes. Food-for-work programmes provide
support to households while developing useful infrastructure such as
small-scale irrigation, rural roads, buildings for rural health centres and
schools
• Income-transfer programmes. These can be in cash or in kind,
including food stamps, subsidized rations and other targeted measures
for poor households
Sources:
Stamoulis, K. and Zezza, A. 2003. A Conceptual Framework for National Agricultural,
Rural Development, and Food Security Strategies and Policies. ESA Working Paper No.
03-17, November 2003. Agricultural and Development Economics Division, FAO, Rome.
www.fao.org/documents/show_cdr.asp?url_file=/docrep/007/ae050e/ae050e00.htm
50. TheSeverityofFoodinsecurity– ToolsforAssessment
• Different ‘scales’ or ‘phases’ to ‘grade’ or ‘classify’ food security
have been developed by food security analysts using different
indicators and cut-off points or ‘benchmarks’
• Measuring the Severity of Undernourishment
• The measure for hunger compiled by FAO, defined as
undernourishment, refers to the proportion of the population whose
dietary energy consumption is less than a pre-determined threshold.
• This threshold is country specific and is measured in terms of the
number of kilocalories required to conduct sedentary or light activities.
• The undernourished are also referred to as suffering from food
deprivation.
• The severity of undernourishment indicates, for the food deprived, the
extent to which dietary energy consumption falls below the pre-
determined threshold.
52. Food Insecurity – Poverty– Hunger Cycle
• Hunger, Malnutrition & Poverty:
• Hunger is usually understood as an uncomfortable or painful
sensation caused by insufficient food energy consumption.
Scientifically, hunger is referred to as food deprivation
• Simply put, all hungry people are food insecure, but not all food
insecure people are hungry, as there are other causes of food
insecurity, including those due to poor intake of micro-nutrients
53. Food Insecurity – Poverty– Hunger Cycle
• Hunger, Malnutrition & Poverty:
• Malnutrition results from deficiencies, excesses or imbalances
in the consumption of macro- and/or micronutrients. Malnutrition
may be an outcome of food insecurity, or it may relate to non-
food factors, such as:
• inadequate care practices for children,
• insufficient health services; and
• an unhealthy environment.
54. Food Insecurity – Poverty– Hunger Cycle
• Hunger, Malnutrition & Poverty:
• Poverty is undoubtedly a cause of hunger, lack of adequate
and proper nutrition itself is an underlying cause of poverty.
• A current and widely used definition of poverty is:
• “Poverty encompasses different dimensions of deprivation that
relate to human capabilities including consumption and food
security, health, education, rights, voice, security, dignity and
decent work.”
Reference:
Organisation for Economic Co-operation and Development (OECD)
55. Food Insecurity – Poverty– Hunger Cycle
• Food insecurity, malnutrition and poverty are deeply
interrelated phenomena
57. Learning Objectives
• At the end of this module, students will be able to understand:
• The overall burden of all forms of malnutrition at global and country
level
• Nutrition Specific and Nutrition Sensitive interventions with
examples
58. Burden of malnutrition at global level – Under-nutrition
• Malnutrition is one of the world’s most serious but least-addressed
development challenges.
• In 28 countries, at least 30 per cent of children were still affected by
stunting in 2022
Source: UNICEF, WHO, World Bank Group Joint Child Malnutrition Estimates, 2023 Edition
60. Learning Objectives
• At the end of this module, our students will be abke to
understand:
• a range of different types of dietary assessment methods used for
estimating food consumption of individuals
• strengths and weaknesses of each methods
• The selective issues that are applicable to many or all dietary
assessment methods such as portion size assessment, nutrient
calculations and measurement error
61. DietaryAssessment Methods
• Dietary Assessment
• Measurement of nutrient intake is probably the most widely used
indirect indicator of nutritional status.
• Approaches to Measuring Diet
• Dietary Records
• 24 hours dietary recall
• Diet History
• FFQ
• Biomarkers for Intake
• Automatic image capture methods
62. • Dietary Records
• In the dietary record method, the subject is asked to record
all food and beverages immediately before or after they are
consumed.
• The food diary in which the recording is done can be open,
semi-open or closed.
• A closed form is a precoder list of all of the commonly
eaten foods in units of specified portion size.
• A semi-open form may be meal based and prestructured
with many foods and amount options listed but including
sufficient space for other foods.
63. • Other example include
• NutriNet-Santé is an online dietary record for use with adults.
• It is a meal-based record, whereby participants log on and record
all foods and drinks consumed for each eating occasion (breakfast,
lunch, dinner and others) along with portion size estimates using
food photographs
• Nutrisurvey
• It offers a user-friendly interface and a comprehensive database of
food items, making it easy for healthcare professionals to
accurately assess the diets of clients and patients
64. • Strength
• Respondents must be literate and have some level of food
knowledge.
• High burden on respondents may lead to response bias and
changes to diet to facilitate recording.
• May result in underestimation of intakes due to
underreporting or undereating
• Weaknesses
• Does not rely on memory.
• Can provide accurate information on foods and drinks
consumed during the reporting period
65. • 24-h dietary recall
• The principle of a 24-h dietary recall is that a participant
recalls actual food and beverage consumption for the past 24
h or the preceding day
• The recalled day is defined as from when the respondent
gets up one day until the respondent gets up the next
66. • Strengths
• The administration time can be short, and
the respondent burden is relatively small.
• In the case of interviewer administration,
literacy is not required.
• Weaknesses
• A respondent's recall depends on short-term memory, and it
is known that omission and intrusions occur
• Portion size is difficult to remember and might be
misestimated; and intakes tend to be underreported
67. • Diet History
• The dietary history is used for assessment of usual meal
patterns and details of food intake of an individual.
• A short version of this method with a limited checklist of foods is
often used in the clinical setting for diagnosis and as a basis for
therapeutic dietary guidelines
• In 1947, Burke developed the dietary history technique in three
parts: (1) an interview about the subject's usual daily pattern of
food intake with quantities specified in household measures,
• (2) a cross-check using a detailed list of foods and
• (3) a food diary in which the subject recorded food intake for 3
days
68. • Diet History– computerized online version
• A number of computerized/online versions of the diet history
have been developed; for example, DISHES98 (Mensink et al.,
2001)
• Audio-guided self-administered diet history questionnaire
developed by Slattery et al. (2008)
• These still require a dietitian or nutritionist to be present to
assist the respondent due to the complexity of the method. In
the case of interviews, highly trained nutritionists with well-
developed social skills are required to conduct the interview,
and the interview is very liable to evoke socially desirable
answers.
69. • Strengths
• The dietary history method allows assessment of intake over a
longer time period.
• In the case of a cross-check dietary history, the different
checks likely improve quality of the dietary data obtained.
• Weaknesses
• Respondents are asked to make many judgments about the
usual food intake and the amounts of those foods, and the
recall period is difficult to conceptualize and remember
accurately.
• This is particularly the case for participants with an irregular
dietary pattern.
• Reports covering a longer period may be influenced by present
consumption
70. • Food Frequency Questionnaires
• The FFQ is a preprinted list of foods on which subjects are
asked to estimate the frequency and very often also the
amount of habitual consumption during a specified period.
• FFQs vary in the foods listed, length of the reference period,
response intervals for specifying frequency of use, procedure
for estimating portion size (pictures, household measures,
units) and manner of administration.
• The most optimal food list depends on the research questions
and study population.
71. • Food Frequency Questionnaires
• The first FFQs were developed for large epidemiological
studies; for instance, on the relation between diet and chronic
disease
• The food frequency method estimates the usual food (group)
intake of an individual. Individuals can be ranked according to
nutrient intake, but the absolute level of intake is often not
estimated well
72. • Strengths
• A self-administered questionnaire may require little time to complete
and to code;
• The response burden is generally low and response rates, therefore,
are relatively high.
• The method can be automated easily and is not very costly.
• Weaknesses
• Memory of food use in the past is required and that the respondent’s
burden is governed by number and complexity of foods listed and
• quantification procedure.
• The listing of foods may be incomplete or missing details.
• Longer food lists and longer reference periods often lead to
overestimation of intake.
• Because of these problems, relationships in epidemiological studies
may be attenuated, obscuring relationships that might exist.
73. • Biomarkers of Intake
• Biomarkers of intake are biochemical indicators measured in
biological specimens (e.g. urine, blood (fractions)) that are associated
with dietary intake.
• Dietary biomarkers can be divided into several classes; that is,
• Recovery biomarkers, predictive biomarkers, concentration
biomarkers and replacement biomarkers
• Recovery biomarkers provide an estimate of absolute intake levels,
and predictive biomarkers show a dose relationship with intake levels.
• Whereas concentration and replacement biomarkers cannot be
translated into absolute levels of intake, the biomarker concentrations
do correlate with intakes of corresponding food components.
• Examples are urinary nitrogen, sodium and potassium, and doubly
labelled water. Vitamin and mineral levels in blood fall in the class
of concentration biomarkers.
74. • Biomarkers of Intake
• Biomarkers for intake are often used as an objective reference
measure to validate other dietary assessment methods.
• Sometimes biomarkers are used as a (better) substitute for
dietary assessment.
• For example, accurate assessment of total sodium intake
using self reported methods is very difficult because people
cannot quantify discretionary salt well, and because sodium
contents in foods differ largely between brands, whereas food
composition tables are usually not brand specific.
75. • Strengths
• The main strength of dietary biomarkers is that they are objective
measures and are independent of all the biases and errors
associated with self-reported dietary assessment.
• Weaknesses
• They are available only for a limited number of nutrients and
foods.
• Genetic variation and other factors may influence nutrient
metabolism and may affect the utility of a dietary biomarker to
properly reflect dietary exposures.
• Biomarkers can tell us about the intake of specific nutrients or
foods but cannot provide detailed information on the rich variety of
foods and nutrients which make up an individual's total dietary
intake.
• The requirement to collect blood and/or urine samples making it
difficult to achieve a representative sample
76. Other Methods
• Image-Capture-Based Methods
• Records digital images of food intake along with where food
and drink are bought and time spent in various activities
• Combined Methods
• Combination of two dietary assessment methods might balance
the shortcomings and strengths of different methods.
• Self-reporting of dietary intake is always subject to error, and
biomarkers do not provide insight into the dietary sources of
nutrient intake.
• Combining self-reporting methods with biomarkers, therefore,
has important advantages.
