Carbohydrates and diabetes
It is common knowledge that carbohydrate foods affect our blood sugar levels. To explain this further, it is important to first understand carbohydrates. The carbohydrate food group includes fruits, breads and cereals, rice, pasta, lentils, certain starchy vegetables like potato and corn, and dairy. When we eat carbohydrate-containing foods our pancreas secretes the insulin hormone. This takes the glucose from carbohydrates. In normal circumstances, the cells are unlocked so they take the glucose up and use it as energy. Type 2 diabetes is a chronic condition which affects the ability of the cells in the body to react to the insulin being secreted and take up the glucose. As a result, the glucose remains in the blood and this is what causes high blood sugar levels.
However, this does not mean a diabetic patient has to avoid carbohydrates entirely. It does come down to the type of carbohydrate being consumed. For example, refined carbohydrates such as biscuits, confectionery, fruit juice, sugar and rice malt syrup would cause a spike in the blood sugar, but healthier carbohydrate options such as wholegrain breads and cereals, lentils and dairy cause a more steady release of glucose. Carbohydrates are ranked from 1-100 according to their effect on the blood sugar levels. This is known as the glycaemic index. Carbohydrates with a higher glycaemic index tend to cause a spike in blood sugar levels while carbohydrates with a lower glycaemic index cause a steady release of glucose.
What about fruit and diabetes?
Fruits have a low glycaemic index and do not need to be completely avoided to manage diabetes. In fact, consuming fruit can promote better management of diabetes. There are a number of plausible explanations for this:
- Fruits contain fibre which promotes satiety and prevents unnecessary grazing throughout the day. Fruits are low in calories and can therefore help with weight management. Excess weight especially around the abdomen is one of the main causes of diabetes.
- Fruits are rich in vitamins and minerals. Fruits are rich in antioxidants that protect the cells of the body from damage caused by free radicals. Free radicals are molecules containing oxygen which can easily react with other molecules through a process known as oxidation. In normal circumstances, the free radicals help protect the body against disease. However, when there are not enough antioxidants in the body and therefore more free radicals than needed, they can cause damage to the cells of the body. This is known as oxidative stress which is commonly observed in patients with diabetes.
In fact, a study found that there was no benefit of decreasing fruit intake on the Hbac1c levels (3 month aggregate blood sugar levels) of diabetes patients.
How much fruit can a diabetic person consume?
Although fruit has a low glycaemic index, the portion size does matter. Too many carbohydrates can spike up the blood sugar level. This is because the GI of a carbohydrate-containing food is not the only factor that influences the blood sugar level. It is also the glycaemic load.
Glycaemic Load = GI of food * carbohydrate ( g) content per portion ÷100
Furthermore, filling up in excess on one food means that you are not eating other food groups that could provide valuable nutrients. Hence, the Australian dietary guidelines recommend having not more than two servings of fruit and it is advisable to spread it out in the day. One serving of fruit could be one apple/one banana/two small apricots/two kiwi fruit/a cup of diced fruit. It is also important to watch out for differently sized fruits sold in the supermarket.
For example with banana, 1 medium banana constitutes as one serve. Larger sized bananas would constitute as more than one serve.
What about fruit in other forms?
- Fruit juice: causes a higher rise in the blood sugar level compared to fruit. For example, the glycaemic index of an orange is 6.2 and glycaemic index of juice is 13.4.This is because of the low fibre intake and higher sugar content in juice compared to the natural fruit.\
- Don’t count wine as part of your fruit intake: Wine is made from grapes and does contains resveratol, an antioxidant found in fruit. However, it does not contain all the other antioxidants found in fruit because they are insoluble and lost in the process of making wine. Wine is also loaded in calories compared to fruit.
- Smoothie: A better option to juice as the fibre is retained in making a smoothie. However one has to be careful to not add more sugar from fruit juice and instead opt for reduced fat milk. It is advisable to go for homemade smoothies rather than store brought.
Whether you’re diabetic or not, include two serves of fruit everyday as part of a balanced diet to obtain the amazing vitamins, minerals and fibre that fruit has to offer!
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This article was written by our dietitian and nutritionist Juhi Bhambhaney. If you have any questions regarding health and nutrition, make an appointment with one of our dietitians. We‘ll provide you with a simple and effective routine targeted to your concerns. Contact us today.