Obesity, Insulin Resistance and NIDDM

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Obesity, Insulin Resistance and NIDDM
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NIDDM

• Prevalence has increased in last 10 years
• Much more common over age of 60 years
• In Surrey, 2 of population are diabetic, of
  these 90 are type 2 NIDDM
• Men have a greater death rate relative to the
  prevalence

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Genetics

• In monozygotic twins the concordance rate for
  NIDDM is approximately 90
• In siblings of patients with NIDDM the lifetime
  risk of developing diabetes is almost 40

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Ethnic Groups

• Naura 20 years 24.3 of the population
• Asian (UK) 12.4 men 11.2 female
• White (UK) 3.2 men 4.7 female

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NIDDM and Exercise

• lt 500 kcal/wk risk of NIDDM increases in both
  high and low risk groups
• gt2000 kcal/wk risk of NIDDM decreases in both
  high and low risk groups

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Aetiology of NIDDM

• Malnutrition in the pre natal and early infant
  years
• Beta cells increase 130 times betweeb 12th
  uterine week and 5th post natal month
• Malnutrition
• Obesity in later life
• Syndrome X
• Thrifty genotype

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Impaired glucose tolerance

• Asymptomatic and do not have diabetes
• Do not suffer the microvascular complications
• Diagnosis is important because
• High rate of macrovascular disease
• A number will eventually become diabetic
• Secondary prevention may reduce morbidity and
  mortality

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Insulin Resistance

• Early metabolic defect precedes and predicts
  impaired glucose tolerance and NIDDM
• Carbohydrate and fat intakes influence
  development insulin resistance
• Glucose and insulin responses are determined by
  the amount of CHO consumed and its rate of
  absorption

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• Low glycaemic index foods are slowly absorbed,
  with increased HDL cholesterol and reduced risk
  of NIDDM
• Improve glucose sensitivity
• Low CHO diets reduce postprandial insulin

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• High CHO (Sucrose)
• impairs insulin sensitivity
• increases plasma triacylglycerol

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• High fat diets
• increase body weight
• impair membrane function through losing fluidity,
  impaired recruitment and motility of insulin
  receptors

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Management of NIDDM

• Diabetes is a disorder of metabolism involving
  the handling of fat, carbohydrate and protein
• Aim of diet is to reduce glycaemia and
  dyslipidaemia
• Traditional diet provides 60 of the calories
  from carbohydrate and 20 from protein remainder
  from carbohydrate

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• Dietary management should be individual
• Growing evidence that CHO intake should be
  reduced, and main source should be slow releasing
  with a low glycaemic index
• Fat content should be MUFA and PUFA with a
  reduction in saturated fats

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PUFAs

• PUFA derived from fish (N3) and plants (N6) are
  known as essential fatty acids.
• Change membrane fluidity and influence receptors
• Direct glucose towards glycogen
• Directs fatty acids towards fatty acid oxidation
  and not triglyceride synthesis

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• PUFAs can inhibit cytokine production and reduce
  damage to Islet cells.
• PUFAs enhance Nitric oxide production

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• Diabetes is a disorder of metabolism
• It affects all the macronutrients, fat,
  carbohydrate and protein
• Traditionally carbohydrate has been the main
  influence on glycaemia