Special Nutrition


Notes On Type 2 Diabetes and Insulin Resistance

Criteria for diagnosis of Diabetes:

  • Symptoms of diabetes plus one random plasma glucose >11.0mmol/L, or
  • Fasting plasma glucose of 7.0mmol/L, or
  • Diagnostic values during an oral glucose tolerance test (75g glucose dissolved in water), see below

Diagnostic glucose values for diabetes, impaired fasting glucose (IFG) or impaired glucose tolerance IGT) with a glucose tolerance test

Fasting 2-Hours post glucose
Diabetes 7.0mmol/L or >11mmol/L
IFG >6.0, <7.0mmol/L and <7.8mmol/L
IGT <7.0mmol/L and >7.8, 11.0mmol/L

Symptoms of Diabetes


  • Polydipsia (increased thirst)
  • Polyuria
  • Unexplained weight loss
  • Fatigue
  • Repeated Infections
  • Blurred vision

Potential Dietary Factors and Risk of Diabetes

The following are a list of dietary factors that have been looked at in relation to the risk of developing diabetes.

No Evidence

n-6 Polyunsaturated fats: There is no evidence to date to relate diabetes and n-6 polyunsaturated fats.

No Evidence/Some Evidence

Sugars and Sucrose: Some biological and epidemiological evidence suggests a link between sugars and sucrose and diabetes. Other studies suggest no link. Despite this weak evidence, there remains the public perception that sucrose and sugars cause diabetes.

Some Evidence

cis-Monounsaturated Fat: There is some epidemiological evidence suggesting that a higher monounsaturated fat intake may be related to a lower risk of diabetes. Some of the biological evidence suggests no link.

More Evidence

Carbohydrate: There is epidemiological evidence of a relationship between a higher carbohydrate intake and a reduced risk of diabetes. There is also some biological evidence, which is not quite as strong as the epidemiological evidence.

Total Fat: There is both biological and epidemiological evidence of a link between increased fat intake and increased risk of diabetes.

n-3 Polyunsaturated Fat: There is both biological and epidemiological suggesting that a higher intake of n-3 polyunsaturated fatty acids reduces the risk of diabetes

Strong Evidence

Saturated Fats: There is strong biological and epidemiological linking a higher saturated fat intake with the increased risk of diabetes.

Dietary Fibre: There is strong biological and epidemiological that a high fibre intake is protective against diabetes.

Low Glycaemic Index Foods: There is biological and epidemiological suggesting that low glycaemic Index foods may reduce the risk of diabetes.

 

Other Factors

Body weight and body fat levels are significant predictors of the risk of diabetes. The waist circumference is the measure which is well correlated with diabetes risk. See cut-offs in anthropometry section.

Summary of major predictors of Type II Diabetes

  • Familial predisposition
  • Excess adiposity C centrally distributed
  • Lack of physical exercise
  • High saturated fat intake
  • It is somewhat controversial whether the intake of foods with a high glycaemic index increases risk

Treatment

  • Achieve and maintain weight loss. Optimal achievement is a BMI of 18.5-25kg/m2
  • Even modest weight reduction is beneficial
  • Aim for a reasonable target
  • Prevention of weight gain is important if weight loss is not possible
  • Exercise for at least 20-30 minutes each day

Carbohydrate

  • Total carbohydrate: 45-60%
  • Use low glycaemic index carbohydrates and those rich in fibre
  • Vegetables, fruits, legumes and cereal derived foods are preferred
  • Sucrose <10% of total energy
  • The timing of intake is essential for those on insulin

Fat

  • Total fat 25-35% of total energy
  • Saturated and trans-fatty acids <10% of total energy, if LDL raised <8%
  • Polyunsaturated fats <10% of total energy
  • Cis-Monounsaturated fat from vegetable sources (e.g. olive, canola, nuts and seeds) 10-20% of total energy
  • At least 1 serving of oily fish per week
  • Plant sources of n-3 polyunsaturated fats (e.g. canola, sunflower, soy, nuts, seeds)
  • Cholesterol <300mg/day

Rationale for Recommendations

  • Saturated and trans fatty acids increase LDL cholesterol and coronary heart disease
  • Saturated fat of around 18% of total energy can adversely affect the insulin receptors and decrease insulin sensitivity
  • High fat diets which are energy dense may promote obesity
  • High fat diets may increase fasting triglycerides (very high carbohydrate diets with high amounts of simple sugars may also increase triglyceride levels)
  • Polyunsaturated fat >10% of total energy may increase lipid oxidation and decrease HDL-cholesterol
  • A wide range of monounsaturated fat is acceptable

Protein

A protein intake at the lower end of the normal range (0.7-0.9g/kg/day) is recommended for those with incipient or established nephropathy

Vitamins and Antioxidants

Foods rich in tocopherol, carotenoids and vitamin C (i.e. a wide range of fruits and vegetables) are recommended

Minerals

A sodium intake of less than 6g per day is recommended

Weight loss should achieve:

  • Improved blood glucose levels
  • Lower blood pressure
  • Improved blood lipid profile

NOTE

Your diabetic or insulin resistant clients should have notes on the glycaemic index, and ways to decrease cholesterol levels, as well as weight loss notes if appropriate.