Diabetes is thought to affect 2½ million people in the UK and is the third leading cause of death behind cardiovascular disease and cancer. The condition is becoming more common, with the number of diabetics in the UK expected to double in the next 10 years. Never has there been a more important time to focus on effective ways to stem the tide of diabetes we are currently experiencing. A recent article published in the New England Journal of Medicine (NEJM) offers real hope in this respect. This study showed that dietary changes, coupled with an increase in activity, reduced the risk diabetes by more than half. This conclusive evidence that diabetes us a preventable illness has enormous public health and economic implications. Here, we look at how can we assess our own risk of developing diabetes, and discuss effective ways of protect ourselves from this condition.
Diabetes (full name diabetes mellitus) is characterised by higher than normal levels of sugar in the bloodstream. 90 p.c. of diabetics have what is termed ‘Type 2’ diabetes. This condition is generally related to an inability of the body to respond to insulin; the main hormone responsible for controlling sugar levels in the body. Type 2 diabetes used to be called ‘mature-onset’ diabetes, on account of the fact that it typically came on in middle or old age. However, this form of diabetes is now being diagnosed in younger and younger individuals, sometimes in children as young as 10. Being aware of the factors which appear to put us at increased risk of Type 2 diabetes can alert us to the need to take preventative action.
Individuals who have one or more family members (e.g. a parent, uncle, aunt, grandparent or sibling) with diabetes are at increased risk compared to individuals with no family history of the condition. Excess weight is another important risk factor. This is especially the case if surplus pounds tend to be focused around the middle of the body (often referred to as ‘abdominal’ obesity). Many individuals who go on to develop Type 2 diabetes have symptoms of fluctuating levels of blood sugar well before the condition becomes manifest. Blood sugar imbalance can lead to episodes of low blood sugar (also known as hypoglycaemia) which can cause symptoms such as cravings for sweet and/or starchy foods, sudden hunger, mood swings, and fatigue. The presence of skin tags (little pouches of skin which can grow in the neck, armpit and groin regions) is also thought to be a risk factor for diabetes. Anyone with one or more of these risk factors can take effective steps to protect themselves from diabetes with specific lifestyle changes.
The study on diabetes prevention published in the NEJM examined the effect of lifestyle changes on a group of overweight, middle-aged individuals with evidence of a condition known as ‘insulin resistance’. Insulin resistance is essentially a halfway house between normal blood sugar control and diabetes. The subjects in the study were asked to cut down on their intake of fat (particularly saturated fats found in animal products such as meat, cheese and butter), increase their intake of fibre, and take more exercise (at least 30 minutes per day). After four years, their risk of developing diabetes had fallen by an impressive 58 p.c..
This study clearly offers great promise, but perhaps failed to highlight other potentially effective strategies in the prevention of diabetes. One very important principle in this respect is the need to base the diet around foods which release sugar relatively slowly into the bloodstream. Conventional medical wisdom dictates that starchy foods such as bread, potato, rice, pasta and cereals release sugar more slowly than sugary foods. The theory here is that starches need to be broken down into sugar (which theoretically takes time) before they can be absorbed from the gut. However, during the last 20 years a wealth of research has shown that starches often release sugar very quickly into the bloodstream. This is particularly true for potatoes and refined starches such as white bread, white rice and regular pasta.
A study published in the Journal of the American Medical Association in 1997 found that women whose diets were rich in these foods had 2½ times the risk of developing diabetes compared to women eating a diet rich in whole grains such as wholewheat pasta and wholemeal bread. I note that the Diabetes UK (formerly the British Diabetic Association) website is still advising diabetics to eat meals based on starchy foods such as bread, pasta, chipatis, potatoes, rice and cereals�. While fibre is mentioned, this is only in relation to digestive health and the prevention of constipation. Individuals wanting to prevent diabetes (and those with the condition as well) need to know that many of the starchy foods doctors and dieticians advise us to eat are simply bad for blood sugar control and appear to increase diabetes risk. A better diet is one based on moderate amounts of unrefined starch, along with other food which release sugar relatively slowly into the bloodstream including fresh fruits, vegetables, beans and pulses. There is evidence that a diet rich in high-fibre, slower sugar-releasing foods such as these can lower diabetes risk.
While the NEJM study recommended that individuals reduce their intake of saturated fat, the latest evidence published last month in the American Journal of Clinical Nutrition (AMJN) is that saturated fat is not the problem. It appears that other fats known as ‘trans fatty acids’ found in many processed foods, margarines, baked goods and fast foods substantially increase the risk of diabetes. However, polyunsaturated fats, such as those found oily fish (e.g. salmon, trout, tuna, mackerel, herring) and many unrefined vegetable oils (e.g. corn oil, sunflower oil), appear to reduce diabetes risk. The authors of this study concluded that even a relatively modest replacement of trans fatty acids in the diet with healthier polyunsaturated fats would reduce diabetes risk by about 40%.