Doubts cast over value of low-calorie sweeteners

Professor David Benton of the University of Wales, Swansea, conducted a review of the scientific evidence looking at the effect of artificial sweeteners in weight control and energy intake.

Publishing his findings in Nutrition Research Reviews, he concluded that there would appear to be little long-term benefit for people of normal body weight.

It is widely believed that replacing sugars with artificial sweeteners can help reduce calorie intake and aid weight loss. As a result, sales of foods and drinks sweetened with artificially sweeteners are at an all time high.

According to market analysts Freedonia, the sweetener market is set to grow at around 8.3 per cent year on year until 2008: considerably higher than growth in the ingredients industry currently at about 3 to 4 per cent.

Tate & Lyle's Splenda sucralose product is currently winning the battle of the sweeteners. Nearly fifty per cent of the 942 new food and drink product launches featuring sweeteners contained only sucralose, according to market analyst Mintel, for January to June 2005.

By comparison, 300 products (32 per cent) were made with the amino acid sweetener aspartame, and 184 (about 20 per cent) products with the high intensity sugar replacer Acesulfame K, roughly 200 times sweeter than sugar.

This would appear to be just the tip of the iceberg more and more artificially sweetened products are continually hitting the shelves. But if Benton is correct, then this low-calorie craze could end up having little or no impact on the current obesity crisis.

This is becoming a significant problem. Data from the UK's National Diet and Nutrition Survey suggests that 42 per cent of men and 32 per cent of women are overweight with a further 25 per cent of men and 20 per cent of women being obese.

Low-calorie sweeteners have been championed as a possible tool to fight this epidemic but as Benton points out, little is known about the long-term impact of artificial sweetener consumption on energy intake and body weight. Although it would make sense that replacing sugar with artificial low calorie sweeteners would help achieve weight loss, Benton says that the science is not as straight forward as it may seem.

He argues that the body is capable of sensing and adapting to a reduced energy intake, and as a result people may compensate for this by eating more later.

Benton says that the consumption of artificial sweeteners or low-energy foods tends to be followed by an increase in energy intake to make up for the lost energy in people of a normal bodyweight. However, people who exercise dietary restraint may benefit from artificial sweeteners, as they tend not to compensate for energy intake.

This research will please the sugar industry, which maintains that there is a lack of convincing evidence regarding the role of artificial sweeteners in long-term energy intake and body weight regulation.

The Sugar Bureau, a trade association funded principally by British Sugar and Tate and Lyle with smaller contributions from Irish Sugar and the UK Sugar Merchants Association, says that as sugar is not the primary concern when considering causes of obesity, replacement with artificial sweeteners does not dramatically affect weight control compared with a reduction in fat intake.