Foundations of Health Introduction to Nutrition

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Foundations of Health Introduction to Nutrition

• Dr Frank Thies
• Department of Medicine Therapeutics
• December 2006

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Lecture Aims

• To define the Science of Nutrition
• To describe in broad terms the different
  components of Nutritional Science
• To emphasise the importance and relevance of
  nutrition in health and disease.

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What is Nutrition?

• O.E.D definition the action or process of
  supplying or receiving nourishment and that
  which nourishes food, nutriment
• To nutritional scientists it means the
  processes by which dietary constituents are
  converted into and sustain the body, and how
  these processes determine its development and
  composition, modulate and control its function
  and enable it to resist disease. Studies of the
  effects of each of these characteristics form the
  discipline of nutrition.

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To Continue

• Nutrition (with genetic constitution) determines
  the quality and quantity of the soil of the
  body in which the seeds of disease germinate the
  interaction between the nutritional soil and the
  seed will determine the course and cost of
  illness and is the reason that nutrition seems
  to form part, but only a part of many
  specialities.
• As a modifier of the quality and quantity of the
  body, nutrition emphasises positive health rather
  than simply the absence or treatment of disease

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In short

• The food we eat is one of the most intimate
  encounters we have with our environment
• It is fundamental to our existence
• Along with our genetic inheritance, the
  composition and quantity of the food we eat
  affects how our bodies function in the short and
  long term.
• Nutrition Matters!

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Nutrition is related to many scientific
disciplines

• Nutrition is a BROAD BASED science!
• It draws on many many different disciplines
• Nutritionists specialise depending upon their
  backgrounds and interests.

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Genes
Malnutrition
Diseases incidence (obesity, diabetes,
CVD, inflammatory diseases, cancer) Prevention Nut
ritional support
Nutrients
Athletic performance
Growth Development Pregnancy Childhood
adolescence Adult aging
Resistance to infection
Cognitive functions
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Nutrient intake Ene. Vit Prot Lip CHO Trace
elements
Dietary assessment
Malnutrition, diseases
Absorption
Biomarkers
Physiology, Biochemistry, Genetic
Circulation
Food composition
Metabolism
Diseases
Diseases
Excretion
Delivery/storage
Epidemiology used for the study of the relation
between diet diseases. May lead to intervention
studies.
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Examples of Disciplines Related to Nutrition

• Physiology and Biochemistry
• A basic understanding of how the body works at
  both the whole body and cellular level
• E.g. How food is digested and absorbed
  (physiology) and how the energy present in the
  food is converted into energy for the cells of
  the body (biochemistry)

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Genetics

• A great deal of new and exciting research in
  nutrition is oriented towards the effect of
  different dietary components on gene expression
  in relation to many different diseases- e.g.
  obesity, heart disease and cancer. It may be that
  in the future people will be given specific
  dietary advice depending on their genotype! e.g.
  fish oil may be beneficial in the treatment of
  arthritis in some patient but not others.

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Psychology

• Behaviour affects what we eat
• But what we eat may also affect our behaviour!
• E.g. Influence of supplementary vitamins,
  minerals and essential fatty acids on the
  antisocial behaviour of young adult prisoners.
  Gesch et al in the British Journal of Psychiatry
  (July 2002)

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Epidemiology

• This is the study of how often diseases occur in
  different populations and why.
• Much of our evidence relating diet and disease
  comes from large epidemiological studies of
  different populations.
• e.g. The European Prospective Investigation into
  Cancer and Nutrition (EPIC)
• e.g. Studies of Ancel Keys in the 1950s that led
  to the link between saturated fat and coronary
  heart disease.

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Cross Cultural Epidemiological Studies of CHD

• Ancel Keys - studies starting in the 1950s
  highlighted the differences in the prevalence of
  CHD across the globe. CHD was unusual in Japan,
  Crete and Corfu while it was a scourge in
  Finland, the USA and the Netherlands for example
• He demonstrated a link between blood cholesterol
  levels and CHD and dietary saturated fat

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Diet CHD

• Research into the relationship between diet and
  CHD is ongoing and complex.
• Many dietary factors have since been linked
• But first line public health advice is still to
  reduce the saturated fat content of the diet in
  order to reduce risk of CHD.

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Nutrition Related Problems

• Deficiency Diseases
• Some of these still exist in Europe today
  despite understanding of prevention. For example
  iron deficiency anaemia is surprisingly prevalent
  in Europe (10 of women and girls). Sub-clinical
  iron deficiency may affect around 1/3 of children
  adults and the elderly

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The Emergence of Adult Chronic Diseases

• Post War Agriculture Policy geared to provide
  high quality food to guarantee the absence of
  deficiencies so that children would grow well and
  nobody would go hungry. But as deficiencies were
  eradicated new disease patterns emerged with
  chronic adult diseases becoming epidemic

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Chronic Diseases

• According to the recent WHO/FAO Expert
  Consultation on Diet, Nutrition the Prevention
  of Chronic Diseases, (WHO, 2003), the growing
  epidemic of chronic diseases affecting both
  developed and developing countries is linked to
  diet and lifestyle changes.

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Chronic Diseases Considered in the WHO report

• Obesity
• Diabetes
• Cardiovascular Diseases
• Cancer
• Osteoporosis and Bone Fracture
• Dental Disease

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Obesity

• The main determinant of the obesity epidemic is
• The imbalance between declining energy
  expenditure due to physical inactivity and high
  dietary energy (i.e. excess calories).
• Action Increase physical activity and reduce
  intake of high fat foods and sugary drinks.

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Diabetes

• Escalating rates of type 2 diabetes due to
• Excess weight gain, overweight and obesity and
  physical inactivity
• Diabetes leads to increased risk of heart
  disease, kidney disease, stroke and infections
• Action Maintenance of healthy body weight.

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Cardiovascular Diseases

• Major killers worldwide. Due to a great extent
  to
• Unbalanced diets and physical inactivity
• Action
• Reduce the intake of saturated and trans fats,
  take sufficient polyunsaturated fats, enough
  fruits and vegetables, and less salt. Increase
  physical activity.

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Cancer

• Tobacco is the number 1 cause of cancer.
• But dietary factors contribute significantly to
  certain types of cancer
• Maintenance of a healthy weight will reduce the
  risk for cancers of the oesophagus, coloretum,
  breast, endometrium and kidney.
• Limiting alcohol intake will reduce risk fro
  cancers of the mouth, throat, oesophagus, liver
  and breast.
• Adequate intakes of fruit and vegetables will
  further reduce risk for oral cavity, oesophagus,
  stomach and colorectal cancer

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Osteoporosis and bone fractures

• Adequate intakes of calcium (500mg or more) and
  Vitamin D intakes helps reduce the risk as does
  exposure to sunlight and physical activity.

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Dental Disease

• Caries are preventable by
• Limiting the frequency and amount of consumption
  of sugars and by appropriate exposure to
  fluoride.

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Early Mediterranean Diet

• Associated with low rates of CHD and other
  chronic diseases
• Typified by high intakes of fruit and vegetables,
  low total fat, modest amounts of olive oil,
  substantial amounts of cereal based foods, small
  amounts of milk, meat fish and eggs and very
  little refined sugar.
• ? The optimal diet for health

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So what do we teach in nutrition?

• Dietary constituents
• Energy- expressed as either kcal or kJ
• Nutrients that can be split into
• macronutrients- protein, fat, carbohydrate (and
  alcohol)
• micronutrients- vitamins and minerals
• Other bioactive compounds
• Other- e.g. colours, flavours, toxins,
  carcinogens etc

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Nutrient Requirements

• E.g. the Reference Nutrient intake for Vitamin C
  in the UK is 40mg.
• How is this derived, what is the evidence for
  this recommendation..

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How the body process energy and nutrients

• From Digestion Absorption to Cellular
  Nutrition.
• Includes links with many different scientific
  disciplines and for many classes we draw on the
  expertise of the scientists at the Rowett
  Research Institute here in Aberdeen.

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Nutrition Development

• Pregnancy Lactation
• Infant Feeding
• Childhood
• Adolescence
• Adulthood
• Old Age

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Body Composition

• How nutrition determines the composition of the
  body
• E.g. proportion of lean tissue and fat free mass
• E.g. cell membrane composition and therefore cell
  function is affected by the food we eat

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Diet and Disease

• Obesity
• Heart Disease
• Cancer
• Diabetes
• Constipation
• Etc.

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Main Components of Nutrition Teaching at
Undergraduate Level
Nutrition the lifecycle
Dietary Constituents
Nutrient utilisation
Body composition nutritional assessment
Nutrient requirements
Diet and Disease