Sugar and diabetes
When we eat any digestible carbohydrates such as sugars and starches, our body breaks them down into single sugar molecules which, on absorption, give rise to an increase in blood glucose levels. Our body mainly utilises glucose with the aid of insulin, a hormone secreted by the pancreas in response to this rise in blood glucose. Insulin acts on the cells of the muscles and liver to allow the uptake of blood glucose, which is then metabolised to release energy with the excess being stored as glycogen.
1. Different forms of diabetes mellitus
There are two forms of diabetes with the most common being type 2 diabetes. This form occurs when there is a decline in sensitivity to insulin in target tissues leading to a progressive inadequacy of insulin production. As a result of this, blood glucose levels remain high in the blood and spill over into the urine. The other form of diabetes, known as type 1 diabetes, is usually diagnosed in children or young adults and occurs when there is a destruction of insulin- producing cells in the pancreas, so the body can no longer produce insulin. People who have this form of diabetes need to inject themselves with insulin to maintain blood glucose levels within the normal range. Although there may be no cure for either type of diabetes mellitus, it is possible to control the disease and live a normal and healthy life.
2. What causes type 2 diabetes?
Genetic susceptibility plays an important role in the development of type 2 diabetes. Those with a family history of the disease are at a higher risk, and some ethnic groups (South Asian, African, Mexican and Native Americans) have a much higher risk of developing type 2 diabetes. However, the disturbing increase in the prevalence of type 2 diabetes in recent years in both developed and developing countries is thought to be related more to sedentary lifestyles, coupled with too high an energy consumption, which have increased overweight and obesity in the population.
Although the disease can occur in people whose weight is within the normal range, obesity, particularly abdominal obesity, is a major risk factor in the development of type 2 diabetes. With the increase in prevalence of childhood obesity and inactivity, type 2 diabetes, once known as a disease of middle and old age, is now beginning to afflict younger age groups. Contrary to popular belief, consumption of sugar is not specifically involved in causing Type 2 Diabetes.
3. What is the role of the diet in controlling type 2 diabetes?
There have been changes in the recommended diet for people with diabetes in recent years. Flexible and less restrictive diets, similar to ones recommended for the general public, are now advised for people with diabetes. For people who have diabetes and who are overweight or obese, the main recommendation is to lose weight and undertake regular physical activity. There is no need for people who have diabetes to avoid sugar in their diet. However, advice from national expert organisations vary, with some organisations recommending that sugar can be included as part of the carbohydrate allotted in their diets, whilst others recommend intake should be minimised.
People with diabetes are also often advised to consume a low glycaemic index (GI) diet, ie one with foods that produce minimal fluctuations in blood glucose. It was once believed that starches, the so-called complex carbohydrates, had a lower GI than sucrose, a so-called simple sugar. However, research has shown that most sugars actually have a lower GI than cooked starch and there is often little-to-no difference between the GI of sweetened and unsweetened products. Studies have also shown that there is little variation in the GI of naturally-occurring sugars and the same sugars after refining. For these reasons, sucrose added to foods or used as a replacement for some starchy foods, can make an important contribution to the diet of diabetics by lowering the amount of fat in their diets.
4. Importance of physical activity
People who have Type 2 diabetes can also benefit from increasing their physical activity levels. Physical activity has a positive effect on increasing the sensitivity of tissues and cells to the hormone insulin and regular physical activity may even prevent or delay the development of diabetes.
It is increasingly recognised that avoidance of obesity by controlling total energy intake and increasing physical activity levels can help reduce the risk of developing type 2 diabetes. Most nutrition recommendations for people who have diabetes permit reasonable intakes of sugar in the context of a healthy balanced diet.