Varshil Mehta

A new systemic review and meta-analysis published in the BMJ suggest that sugar-sweetened beverages has a potential of causing more harm as compared to any other sugar containing foot item.

Sugar plays a key role in the development of diabetes and other cardiovascular diseases, which attracts widespread debate and increasing evidence suggests that fructose could be particularly harmful to health.

“These findings might help guide recommendations on important food sources of fructose in the prevention and management of diabetes,” said study author and Dr. John Sievenpiper.

Some salient points of the study:

  • This systematic review and meta-analysis of 155 controlled intervention studies suggests that most food sources of fructose-containing sugars do not have a harmful effect on glycaemic control in energy matched substitutions for other macronutrients;

  • However, several food sources do have harmful effects when adding excess energy to the diet, especially Sugar-sweetened beverages;

  • Until more information is available, public health professionals should be aware that harmful effects of fructose-containing sugars on glycaemic control seem to be mediated by energy and food source

Fructose often occurs naturally in a variety of foods, including whole fruits and vegetables, honey and natural fruit juices. Even man-made food items such as  soft drinks, breakfast cereals, baked goods, sweets, and desserts have a major proportion of sugar. Current notion and huidelines recommend reducing free sugars, especially fructose from sweetened beverages, but it is unclear whether this holds for all food sources of these sugars.

The article analysed the results of 155 studies that assessed the effect of different food sources of fructose sugars on blood glucose levels in people with and without diabetes monitored for up to 12 weeks. Results were based on four study designs: substitution (comparing sugars with other carbohydrates), addition (energy from sugars added to diet), subtraction (energy from sugars removed from diet), or adlibitum (energy from sugars freely replaced). Outcomes were glycated hemoglobin or HbA1c (amount of glucose attached to red blood cells), fasting glucose, and fasting insulin (blood glucose and insulin levels after a period of fasting). The results show that most foods containing fructose sugars do not have a harmful effect on blood glucose levels when these foods do not provide excess calories. However, a harmful effect was seen on fasting insulin in some studies.

Analysis of specific foods suggest that fruit and fruit juice when these foods do not provide excess calories may have beneficial effects on blood glucose and insulin control, especially in people with diabetes, whereas several foods that add excess “nutrient poor” energy to the diet, especially sweetened drinks and fruit juice, seem to have harmful effects. The low glycaemic index (GI) of fructose compared with other carbohydrates, and higher fibre content of fruit, may help explain the improvements in blood glucose levels, by slowing down the release of sugars, according to the researchers.