It is commonly believed that carbohydrates, particularly sugar, are a cause of insulin resistance and type 2 diabetes. However, such thinking has been challenged following the publication of a thorough appraisal of the evidence, in the latest edition of Nutrition Research Reviews.
Dr Neville McClenaghan, from the University of Ulster, conducted a large review and suggests that diets rich in carbohydrates, which tend to be naturally low in fat may help improve insulin control. Furthermore it is well established that high fat diets, particularly those rich in saturates, not only interfere the normal action of insulin but also encourage weight gain, which itself increases risk of insulin resistance.
Many people with type 2 diabetes wrongly restrict the amount of carbohydrate in their diet. This paper adds weight to current dietary advice which recommends that meals should be based around carbohydrate rich foods, such as bread, pasta or rice, that there is no need to restrict sugars specifically, and that the amount of saturated fat in the diet is restricted.
Insulin resistance is a common but often silent disorder which occurs when the body does not respond appropriately to the effects of insulin (see below). Insulin resistance can lead to, and is a feature of, the more serious condition, type 2 diabetes.
Insulin, a hormone produced by the pancreas, is needed for normal glucose, fat and protein metabolism. Insulin controls the amount of glucose in the blood by enabling glucose to enter cells (e.g. muscle and liver cells) which need glucose for fuel. With insulin resistance the body either can not produce enough insulin or the body's cells do not respond fully to its effects. This ultimately leads to a raised blood glucose. Having blood glucose that is either too high (hyperglycemia) or too low (hypoglycemia) is dangerous to health, for example, long-term hyperglycemia is associated with an increased risk of kidney and eye problems.
Fat metabolism is also affected by insulin resistance raising the risk of heart disease, the most common cause of death amongst people with diabetes.
On a global scale, insulin resistance and type 2 diabetes are becoming increasingly common. Whilst genetics account for some degree of susceptibility to these disorders, lifestyle factors such as diet and physical activity levels can have a large impact on risk. Insulin resistance is closely involved in type 2 diabetes, and is thought to be a precursor to the disease. In people with and without type 2 diabetes, a diet rich in carbohydrate and low in fat appears to offer protection against insulin resistance. Being of a healthy body weight and also maintaining an active lifestyle will help reduce the risk of developing type 2 diabetes.
Funded by the Sugar Bureau which is the trade association for the UK sugar industry. gars in the diet.