This is a guest blog by Trudi Deakin from X-PERT Health.
Sugar-free is old hat in diabetes. Despite radical changes to the dietary guidelines for people with diabetes back in the 1980s, the myth that people with diabetes should avoid sugar still persists. Why is this? Because the term “blood sugar” is used to describe diabetes control, it is assumed that eating sugar in the diet leads to raised blood sugar levels and poor diabetes control. So what does diabetes mean these days?
There are three main nutrients in the diet, protein, fat and carbohydrate. Carbohydrate is made from building blocks of glucose and it is the only nutrient that directly impacts on diabetes control. When carbohydrate is digested, the glucose is released into the blood. Therefore the correct term to use is blood glucose and not blood sugar.
Research has shown that although different carbohydrate foods have different effects on blood glucose levels, it is the total amount of carbohydrate consumed that is the key factor for optimal diabetes control.
How much carbohydrate should you have? The latest dietary guidelines for people with diabetes do not provide an ideal amount of daily carbohydrate as it is acknowledged that requirements will differ depending on individual circumstances and lifestyle. For the general population, the minimum amount of carbohydrate is determined by the brain’s requirement for glucose which is 130 grams per day, and the Guideline Daily Amount (GDA) is 230g per day for women and 300g per day for men. It is recommended that the majority of carbohydrate is derived from fibre-rich starchy food. People with diabetes are advised to experiment to find an acceptable level of daily carbohydrate that enables them to manage their blood glucose levels and body weight.
How do you know how much carbohydrate there is in food? If the food is in packaging, you can look at the nutrition information table that is usually found on the back of the packaging. It will often provide the grams of carbs per 100g and per serving. There are also resources that help you become more carbohydrate aware and that can assist with carbohydrate counting such as the X-PERT Diabetes Handbook and Carbs and Cals book. These can be purchased from http://www.xperthealth.org.uk/shop
Are low carbohydrate diets beneficial for diabetes?
Reviews of lower carbohydrate diets have shown that weight loss is associated with the duration of the diet and restriction of calories but not with restriction of carbohydrates.Reviews of people with diabetes have demonstrated improvements in diabetes control in the short term but not over the longer term.
There is also evidence that a diet low in carbohydrate and deficient in wholegrains, vitamins and minerals, may result in nutritional deficiencies, heart disease and high blood pressure and may also adversely affect an individual’s general sense of wellbeing. It is therefore advisable for women to consume between 130-230 grams of carbs per day, and men between 130-300 grams per day, unless under medical supervision.
What about Glycaemic Index? Research has shown that carbohydrate foods have different effects on blood glucose levels and it’s not to do with how much sugar they contain. The ranking of carbohydrate foods according to their immediate effect on blood glucose levels is called Glycaemic Index [GI]. Carbohydrate foods that release glucose quickly are called high GI foods. Slow releasing carbohydrate foods are called low GI foods.
The effect a carbohydrate food has on blood glucose levels is dependent on a whole range of factors including how it is prepared, cooked and what it is eaten with. Key factors are discussed below.
- Physical form: The more processed food is, the more likely it is to have a higher GI.
- Food combinations: Adding protein or fat to a high GI food will decrease the rate of glucose absorption from the carbohydrate food – but all the glucose will still affect blood glucose levels but just at a slower rate.
- Cooking time: Cooking food for longer usually increases the glycaemic impact of food through breaking down carbs or starches. This lets it pass through the body much more quickly.
- Acidity: Food that’s more acidic will have a lower GI (example: food that contains lemon juice or vinegar, such as pickles)
- Physical entrapment: The fibrous coat around beans, seeds, and plant cell walls helps slow down digestion and break down of the carbs into glucose.
- Soluble fibre: In general, the higher the food is in viscous or soluble fibre, the lower its GI will be. Beans and oats are a great example of a food high in soluble fibre.
- The amount of glucose, fructose or lactose: Carbohydrate food is digestion down to its building blocks [glucose, fructose or galactose] and these are then released into the blood. Glucose is absorbed rapidly having a large impact on blood glucose levels whereas fructose and galactose are transported to the liver and stored as reserve energy for between meals or overnight.
Therefore, foods that contain fructose [such as fruit] or galactose [such as milk] have a less rapid impact on blood glucose levels. Sugar contains equal amounts of glucose and fructose and therefore has a lower GI than many starchy foods.
Does this mean that sugary food is better than starchy food? No. Sugar, or sucrose to give its correct name, does not provide the body with any nutrients except energy and can lead to tooth decay whereas starchy foods such as potatoes, rice, pasta, yam and bread can provide a host of nutrients and can be much more filling. Wholegrain starchy foods also release the glucose at a much slower rate than processed starchy carbohydrates such as white bread, cornflakes and standard white rice. However, it does mean than people can incorporate sugar into their diet without guilt or it deteriorating their diabetes control as long as their total carbohydrate intake remains the same. The UK Guideline Daily Amount (GDA) for sugar intake is 90g for women and 120g for men. Also consider that some foods that contain sugar also contain a lot of saturated fat such as chocolate, biscuits and desserts.
Key article points:
- People with diabetes do not need to have a sugar-free diet.
- Considering total carbohydrate intake is key to optimal diabetes control.
- Lowering the overall GI of the diet may offer additional benefits.