by Meredith Beil BPharm MNutr & Alice Downing APD, MDiet & BHumNutr
GOOD NUTRITION FOR TYPE 2 DIABETES
Approximately 1.5 million Australians1
have been diagnosed with Type 2 Diabetes, and it is believed that a similar number
are yet to be diagnosed. It is the fastest growing chronic disease in Australia,
yet up to 60% of cases can be prevented. Many more of our population have
glucose intolerance and insulin resistance, which are pre-diabetic states that can
lead to Type 2 Diabetes. The incidence of this lifestyle related disease is
increasing rapidly in our community as a direct result of people being overweight
and obese, and reduced physical activity.
Diabetes can have serious implications for health.
The aim of diabetes management is to prevent complications, including permanent
damage to the eyes, kidneys and nerves through peripheral vascular disease, heart
attack and stroke. Damage to the body occurs when blood glucose levels are
continuously elevated. Proper management of diabetes, including diet and
exercise, results in a more “normal” fasting blood glucose level between
4.0-7.9mmol/L. This can prevent lifelong damage and disease complications.
Diet and Lifestyle
Diet and lifestyle are the two factors that we can
control. Weight management, a healthy diet with plenty of physical activity,
avoidance of smoking and moderation of alcohol consumption are essential in the
management of diabetes. Exercise and physical activity can assist greatly in
reducing blood glucose levels as the working muscles use the blood’s glucose
for energy. Having a higher muscle mass also assists in the maintenance of
normal blood glucose levels, as skeletal muscles readily take up and store
glucose.
Lifestyle intervention studies in individuals with
diabetes and pre-diabetes show a major impact in preventing and slowing the
development of diabetes. These studies incorporate physical activity such as
brisk walking, cycling or jogging (for a minimum of 30 minutes on most,
if not all days of the week), reducing body weight if overweight, increasing
dietary fibre and reducing saturated fat intake. Lifestyle intervention studies
show a significantly greater benefit in the reduction of diabetes progression
than taking metformin, a commonly prescribed diabetes medication. Discuss
lifestyle and medication interventions with your GP, dietitian and pharmacist
to find an option that is best for you.
Research suggests that smoking is associated with
an increased risk of developing Type 2 Diabetes, as well as increasing the
complications of diabetes, such as cardiovascular disease, leg ulcers and
amputations. Your pharmacist can provide
advice on smoking cessation treatments that are most effective.
Dietary Recommendations
Weight Loss
Type 2 diabetes most commonly occurs as a result of
being overweight or obese. In particular, abdominal adiposity is the major
factor in insulin resistance and drives the development of diabetes. A waist
circumference of >80cm for females or >90cm (Asian) / >94cm
(Caucasian) for males is associated with an increased risk of Type 2 diabetes.
A reduction in body weight 5-10% makes a significant difference, even if that
does not achieve a body weight within the healthy weight range.
Weight loss, if overweight or obese, should be slow
and gradual and include sustainable changes in eating habits. It is essential
to exercise during weight loss to maintain muscle mass and prevent the slowing
of metabolic rate. Strategies for weight loss in diabetics include significant reduction
in the intake of fats (particularly saturated fats), sugars and processed
foods. Increasing in the proportion of high fibre foods, such as vegetables and
wholegrain products is important in sustainable weight loss. Discuss diet
modification with a dietitian before making major changes to your diet.
Carbohydrates
A portion of low glycaemic index (GI) carbohydrates
should be consumed at each main meal and snack to manage and maintain your
blood glucose level. GI ranks foods according to their ability to raise blood
glucose levels; a high GI meal produces a rapid rise in glucose levels. It is
also important to consider glycaemic load (GL). GL takes into account both the
amount of carbohydrate in the food as well as its GI. The nutritional quality
of the food is also a factor, just because a food is low GI does not mean it is
a good food choice. The GI and GL of commonly eaten foods, as well as useful
advice on their relationship to blood glucose levels, can be found at www.glycemicindex.com.
Fat Intake
The dietary intake of saturated and trans fats
should be minimised. These fats are mainly found in animal products and
processed or deep-fried foods. Replace these fats with healthier monounsaturated
and polyunsaturated fats; e.g. olive oil and almonds. A major dietary
intervention study found that a diet with a higher proportion of
monounsaturated fats reduced fasting blood glucose levels, whilst the
low fat diet and ‘usual’ diet lead to increased blood glucose levels and
progression of diabetes. High levels of monounsaturated fats are found in
olive, canola and peanut oils, while whole grains, avocados, nuts, legumes and
seafood also contain healthy fats.
Dietary Fibre
A fibre intake of 14g per 4200KJ (or 30g per day)
can assist in the stabilising of blood glucose levels. Insoluble fibre from wheat
bran and wholegrain breads helps to keep bowel motions regular. Soluble fibre
from vegetables, fruits, and legumes helps us to feel full and also slows down
the absorption of blood glucose in the small intestine. Soluble fibre can
assist in regulating blood glucose levels and also lower blood cholesterol
levels.
Alcohol
Alcohol has many risks for those with diabetes,
such as increasing blood pressure, affecting blood sugar levels and reducing
the ability to achieve or maintain a healthy weight. Consumption of alcohol should be moderate,
which means no more than 2 standard drinks per day for males and females. Try
to have at least two alcohol free days per week. When consuming alcohol, you
should eat a carbohydrate containing meal or snack to ensure blood glucose
levels do not drop too low and result in a ‘hypo’.
Enjoying Life
Having diabetes doesn’t have to prevent you from
enjoying life and eating tasty, nutritious food. You may find that making diet
and lifestyle changes to manage your diabetes also results in positive mental
health benefits. Enjoy life to the fullest whilst knowing that you are taking
care of yourself as best you can. Remember; it is the person with diabetes who
is ultimately responsible for managing their diabetes and maintaining positive changes.
Seek support from your GP, pharmacist, dietitian and physiotherapist to assist
you in making lifelong positive changes to your diet and lifestyle.
References
1. Diabetes association of Australia.
www.diabetesaustralia.com.au
2. Ausdiab: www.diabetes.com.au/research.
3. Lachin et al 2002. New Engl Journ
Medicine:346; 393-403.
4. Tuomilehto et al 2001. New Eng J
Med;344:1343-50.
5. ADA Diab Care 2008;31(suppl 1):s61-s78.
6. Willi C et al 2007 Active smoking and the
risk of T2D. JAMA; 298(22):2654-2664.
7. www.cochrane.org/reviews/en/ab003054.html.
8. Due A et al. Comparison of the effects on
insulin resistance and glucose tolerance of 6mo high monounsaturated fat, low-fat
and control diets. Am J Clin Nutr. 2008;87:855-62.
9. NHMRC
Clinical Practice Guidelines: Management of overweight and obesity in adults
2003.
