Transcript Lecture notes week 1 Powerpoint presentation

Module title An introduction to the role of Food and
Nutrition in Health
Module Code: NS140
Module Credits: 5
Lecturer: Dr. Mary Rose Sweeney
Room HG269 School of Nursing, DCU.
email: [email protected]
Telephone: 00 353 1 700 7786
Module content
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Human Nutrition: Introduction to Nutrition. Normal nutritional requirements in
health
Normal calorific requirements
The role of water in the maintenance of normal growth and development
Macronutrients in normal human growth and development
Micronutrients in normal human growth and development
Research methods used in nutrition
Obesity
Economic impact of obesity
Impact of marketing on food choices
Impact of global warming on food security
Under-nutrition
Module assessments- 3parts –
specific details to follow
• MCQ: due end of week 4
• Practical assessment : due end of week 7
• Essay: due end of week 12
INTRODUCTION
• WHAT IS THE STUDY OF NUTRITION?
• Human nutrition describes the processes
whereby cells, tissues, organs, systems and
the body as a whole obtain and use
necessary substances obtained from food
(nutrients) to maintain structural and
functional integrity.
THE EVOLUTION OF NUTRITION AS A SCIENCE
• What are the landmark events historically ?
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1750- Scurvy treated by lime juice, the active agent was later identified as Vitamin C
1830-- rickets treated with cod liver oil or butter, active agent identified as Vitamin D
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1900- urbanization, city slums, working class recognised as being associated with
malnutrition. Malnutrition then became identified as a primary cause of ill health and
poor mental and physical performance. Not enough healthy recruits for the Boer war
lead to the defeat of Britain by the Dutch. Fear that this would lead to an “inferior
population” Hence school meals started in the UK to provide a daily single high quality
meal providing appropriate amounts of the more expensive nutrients such as protein
needed for normal growth and development – have they now gone full circle – Jamie
Oliver initiative
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1905- search and identification of vitamins and accessory food factors continued.
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1919- MRC vitamin group established in the UK – research continues until this day.
This group were the group who showed conclusively that folic acid supplements taken
in early pregnancy can prevent up to 72% of neural tube defects (e.g. spina bifida)
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1920- The UK Government started the promotion of milk and free milk supplied to
school children. In addition cod liver oil added to prevent rickets.
1940 - successful food rationing policy established in UK ensured distribution, supply
and a balanced diet adequate for the prevention of deficiency in the majority of the
population thereby preventing mass starvation, ill health and death during war-time.
1950- Food safety, food technology, food labelling, RDAs, vitamin and biochemical
research flourished
1970- Agricultural research priorities were to increase meat, milk and butter production.
Intensive rearing of pigs and chickens resulting in cheaper food, blossoming of food
industries, convenience stores and supermarkets.
1980- Western food mountains
- Developing countries adopt western diets and develop western diseases e.g.
Japan and Eastern Europe countries begin to develop Coronary Heart Disease
and Type II diabetes not traditionally seen in these countries.
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1990- growth of research into nutrient-genetic links continued leading to important
findings such as folic acid/genetic link in the prevention of Spina Bifida in early
pregnancy and in the prevention of Colorectal Cancer.
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1993- Importance of nutrition in the Health Care setting as a result of the KINGS FUND
REPORT in the UK was illustrated. This research showed major savings in the NHS
budget, up to 1.3 billion pounds annually if pre-op nutrition was optimised. Resulted in
fewer post-op complications, such as infections, improved wound healing, shorter
hospital stays and reduced number of re-admissions into hospital. This major saving
made the government sit up and listen for the first time and a renewed emphasis was
placed on the role of nutrition in the hospital. The use of nutrition support eg. Enteral
and Total Parenteral Nutrition became much more widespread.
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2000s- Nowadays it is recognised in order to understand the process from eating food to
the metabolism and catabolism of nutrients the study of nutrition requires a knowledge
of a much wider scientific spectrum including molecular biology, genetics,
biochemistry, chemistry, physics, food science, microbiology, physiology, pathology,
immunology, psychology and sociology.
The focus of nutrition in 2011 is
placed firmly on
1)“optimum nutrition” correct balance of all
nutrients
2) Prevention of obesity and obesity
associated disorders eg. Coronary Artery
Disease & Type 11 Diabetes
3) Feeding the starving nations
NUTRITION & HEALTH
• People eat food, not nutrients; however it is the
combination and amounts of nutrients consumed in foods
that determine health.
• To understand nutrition one must understand nutrients
• But first we will discuss food
The main food groups are
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Cereals
Dairy
Vegetables and Fruit
Meat/fish etc
Other – sugars, preserves, sweet spreads,
confectionary, soft drinks, fats and oils
Factors in food variations
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Of all the animal and plant species that could be safely
consumed, humans choose from a from a relatively narrow
range of foodstuffs. Reasons for this include
Biological factors
Economic factors
Cultural and religious factors
Food factors – taste, smell etc
Extrensic factors – media, time, season, availability etc
Personal and psychological factors
Celebrations
Methods of preparing/processing
foods
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Baking
Frying
Grilling
Boiling
Microwaving
Canning
Pasteurisation
Fermentation
Methods of storing foods
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Refrigeration
Freezing
Drying
Freeze- drying
Salting
Irradiation
Digestion and absorption of food –
organs involved
• Mouth – grinds food, moistens food, some digestion by
lipase and amylase enzymes in saliva
• Stomach – acid secretion, further moistening, further
enzyme digestion by pepsin and rennin, delivery of
nutrients to small intestine. Satiety feedback mechanism
kick in
• Small intestine – more enzymatic digestion by pancreatic
enzymes. Absorption of water, nutrients and minerals.
More satiety feedback messages sent to brain
• Colon- final salvage of water and electrolytes, fibre
fermented by bacteria
Recommended Reading
• Read chapter 1, 2 and 3 Gissler and Powers
To understand nutrients we must embark on a study of …
 The chemical and physical structure and characteristics of the nutrient
 The food source of the nutrient, including food composition, the way in which
the foods are grown, harvested, stored, processed and prepared and the effects
of these on nutrition value
 The digestion, absorption, circulatory uptake of the nutrient, as well as
regulation of these processes
 The metabolism of the nutrient, its functions, storage and excretion
 Physiological needs (demands or requirements) for the nutrient in health and
disease, and during
 special circumstances (pregnancy, lactation, sports events, disease states) as
well as individual needs
 Interactions with other nutrients, non-nutrients, anti-nutrients and drugs
 The consequences of under- and over-nutrition
 The therapeutic uses of the nutrient
 Factors influencing food supply and starvation i.e. famines, poverty
 Food safety
NORMAL REQUIREMENTS
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Food is essential for health and survival
Without sufficient energy and nutrients the body’s ability to function normally is
impaired
If starvation occurs, life can only be stained for a matter of weeks
A healthy diet should fulfill 2 objectives
It must provide sufficient energy and nutrients to maintain normal physiological
functions, and permit growth and replacement of body tissues
It should offer the best protection against the risk of disease
Relationship between nutrition & health
Nutrition status
Optimum nutrition
Secure food supply
Balanced & prudent diet
Undernutrition
Insecure food supply
Poverty, ignorance,
Unstable political envirns
Disrupted societies, war
Overnutrition
Overconsumption of food
Low physical activity
Smoking, stress etc
Consequences
Health, well being, normal development
Decreased physical and mental development
compromised immunity
increased risk of infection
vicious circle of undernutrition, underdevelopment and poverty
obesity, metabolic syndrome, cardiovascular disease, type II diabetes,
certain cancers, chronic non-communicable diseases,
Malnutrition
double burden of infectious plus non-communicable diseases
Some undernourished,
Somer overnourished
Often characterised by too many
Macronutrients but not enough micronutrients
NORMAL NUTRITION REQUIREMENTS IN HEALTH
• Requirements for nutrients differ from one individual to another, between
males and females, age, disease state and with pregnancy and lactation.
Additionally they vary with alterations in the composition and nature of the
diet of a whole, because such factors may affect the efficiency with which
nutrients are absorbed and utilized for example vitamin C enhances the
absorption of iron and a derivative of vitamin D enhances the absorption of
calcium
• Traditionally the requirement for a nutrient has been the amount of a nutrient
required to prevent clinical signs of deficiency. However it was later
recognised that that some allowance should be made where appropriate for a
degree of storage of the nutrient to allow for times of low intake or increased
demand without detriment to health.
The criterion for estimation of requirement
is now based on
 The intake of a nutrient needed to maintain a given circulating level or degree
of enzyme saturation or tissue concentration
 The intake of a nutrient by individuals and by groups which are associated
with the absence of any signs of clinical disease (population based)
 The intake of a nutrient needed to maintain balance
 The intake of a nutrient needed to cure clinical signs of deficiency
 The intake of a nutrient associated with the appropriate biological marker of
nutritional adequacy e.g. Serum ferritin is a marker of iron status
– There are more than 50 nutrients (including
amino acids and fatty acids) and many more
chemicals in food required for normal human
function and health. These nutrients are broadly
classified as follows
– Name some of them?
Class/category
Subclass/category
Nutrient examples
Carbohydrates
Monosaccharides/disac
charides
Protein (macronutrient)
Plant and animal source
proteins
Saturated fatty acids.
Glucose, fructose,
galactose, sucrose,
maltose, lactose
Amino acids
Fats and oils (lipids)
(macronutrients)
Monounsaturated fatty
acids
Polyunsaturated fatty
acids
Minerals
(micronutrients)
Minerals and electrolyte
Palmitic and stearic
acid
Oleic and elaidic fatty
acids
Linoleic, arachidonic,
eicosapentanoic,
docosahexanoic acid.
Calcium, sodium,
phosphate,
Trace elements
Vitamins
(micronutrients)
Fat soluble
Water soluble
Water
Water
Source: Introduction to Human Nutrition. Gibney MJ(2002). Blackwell Publishing.
potassium, iron, zinc,
selenium. Copper,
manganese,
molybdenum, fluoride,
chromium
Retinols (A), calciferols
(D), tocopherols (E),
vitamin K
ascorbic acid (C),
thiamine (B1),
riboflavin (B2), Niacin
(B3), pyridoxine (B6),
folate. cobalamin (B12)
Water
Recommended browsing
Dietary Allowances for Ireland (1999).
Published by: Food Safety Authority of
Ireland. Abbey Court Lower Abbey Street
Have a look at the document
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Nutrients do not exist in isolation, except for water and others in some pharmaceutical
preparations. In foods, in the gut during digestion and absorption, in the blood during
transport, and in cells during metabolism, nutrients interact with each other. Therefore
nutrients should never be studied in isolation for e.g., vitamin C enhances the absorption
of iron and calcium absorption is enhanced by a derivative of vitamin D.
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knowledge of nutrients and their functions will enable the nutritionist to advise
individuals what to eat
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however this knowledge is not enough to understand and address the global problem of
malnutrition facing mankind today
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This has resulted in other disciplines such as social sciences, geneticists, molecular
biologists, ethical experts and public health specialists joining in the race to improve
knowledge in this area globally
Nutrition in the Clinical Setting
Nutrition in the hospital setting normally involves an
assessment of nutrition status by measuring dietary intakes,
anthropometry measurements, assessing body composition,
measuring biochemical markers indicative of nutrition
status, and observing for clinical signs of malnutrition.
We wont be covering this in this module however
How do we assess nutrition status?
These will be covered in more detail in a later class
Includes the following
 By measuring food and drink intake, using diet history interviews,
weighed food records, 24-hour recall
 FOOD COMPOSITION TABLES
 RECOMMENDED DIETARY ALLOWANCES (RDAs), Irish
guidelines or DIETARY REFERENCE VALUES (DRVs)
 BIOCHEMICAL ANALYSIS. Blood / Urine/CSF levels of a given
nutrient i.e. vitamin B12, folic acid, iron, sodium etc. can be
measured.
 HUMAN STUDIES AND TRIALS: Absorption studies, intervention
studies, metabolic studies are frequently used tools in human nutrition
research.
 Anthropometry – Wt, Ht. BMI, waist/hip circumference
 Body composition – lean versus fat mass, skinfold thickness,
 Energy expenditure -
Water
• Go to part 2 lecture notes
REFERENCES
Department of Health (1991). Dietary Reference Values
for Food Energy and Nutrients for the United Kingdom.
HMSO, London.
MJ Gibney, HH Voster, KJ Kok (2002). Chapter one.
Introduction to Human Nutrition: A Global Perspective
on Food and Nutrition. In. Introduction to Human
Nutrition. Blackwell Publishing.
Food Safety Authority of Ireland (1999). Recommended
Dietary Allowances for Ireland 1999.