'Diet' soft drinks

Artificially-Sweetened or “Diet” Soft Drinks

Weight Status

Some studies have linked the consumption of food and beverages containing intense artificial-sweeteners to overeating and weight gain (Blundell and Hill 1986; Davidson and Swithers 2004; Swithers and Davidson 2008). Also data from the prospective Framingham Heart Study (Dhingra et al. 2007) and the San Antonio Heart Study (Fowler 2005; Fowler et al. 2008) recently showed a positive association between BMI and the consumption of regular and diet soft drinks. Similar findings have come from studies of elementary school children (Blum et al. 2005). It is hypothesised that artificially-sweeteners stimulate appetite or affect mechanisms that regulate hunger and satiety (Rolls et al. 1990; Black et al. 1991; Gougeon et al. 2004) and thus increase appetite for sweet foods. An alternative mechanism is that diet soft drinks might lead to weight gain by disrupting the sensory mechanisms associating sweetness with energy, although Appleton and Blundell (2007) have recently shown that this disruption of the sensory mechanisms might work towards reduced appetite for sweet tastes in habitually high consumers of artificially-sweetened beverages compared to low consumers (Appleton and Blundell 2007). Another explanation for a mechanism by which diet soft drinks might lead to weight gain is that of “consumer rationalisation”, i.e. diet soft drink consumers might consider that they are reducing energy intake through drinking diet drinks and hence might consciously feel that they can eat other energy-dense foods more freely than they might otherwise have done. A recent study in the US examined this possibility. The grocery purchases of buyers of diet soft drinks were compared to buyers of regular soft drinks with the aim of investigating the overall energy intake of the different buyers (Binkley and Golub 2007). The study results suggest that the use of diet soft drinks does not lead to compensation by increased purchase (and therefore assumed intake) of high-energy foods. However, the study did show that the highest purchasers of diet soft drink were also the highest purchasers of processed snack foods. Therefore it was considered that snacks have the greatest potential for undermining a strategy based on the control of energy intake through consumption of diet drinks. In contrast, two recent reviews concluded that intense sweeteners can have a measurable impact on satiety and lower energy intakes (Bellisle and Drewnowski 2007). De La Hunty et al (2006) conducted a meta-analysis of mainly short-term randomised controlled trials and demonstrated that consumption of drinks sweetened with aspartame instead of sucrose resulted in a significant reduction in energy intakes and body weight (de la Hunty et al. 2006). In a review of laboratory, clinical and epidemiological studies, Bellisle and Drewnowski (2007) suggested that humans compensate poorly for previously ingested energy due to an imprecise energy homeostatic mechanism (Bellisle and Drewnowski 2007). Consequently, they argue that diet beverages may represent a plausible strategy for weight control. A recent randomised controlled intervention trial involving the home delivery of non-calorific beverages including diet drinks and bottled water led to a reduction of 82 per cent in consumption of sugar-sweetened soft drinks in 103 adolescents (13–18 years) after a 25 week period (Ebbeling et al. 2006). The intervention was also associated with significant weight loss, particularly in those children with a higher BMI at baseline. However, the reduction in BMI could not be related directly to diet drinks as no data on the proportion of diet drinks versus bottled water was provided.

Other Health Effects

Diet soft drinks are often promoted as a healthy alternative but they retain some of the components of sugar-sweetened soft drinks which have been associated with ill-health consequences. Diet soft drinks also have high levels of acidity (from carbonic acid, phosphoric acid and citric acid in cola-type drinks) which may contribute to dental erosion when consumed regularly. In addition the diet cola drinks contain caffeine which has been linked to disturbances of the central nervous system (especially in children and adolescents) and to loss of bone mass (see Section 4.2.4).

Safety

The most prevalent artificial sweeteners used in diet drinks in Australia are aspartame and acesulfame potassium, used either singly or in combination (Food Standards Australia New Zealand 2003a). Both sweeteners have undergone rigorous toxicological studies and have been shown to be safe for consumption by humans including pregnant women, children and for people with diabetes (Leon et al. 1989; Yost 1989; Mukhopadhyay et al. 2000; Butchko et al. 2002). Regulatory groups in over 100 countries, including Australia have approved the use of these sweeteners (Food Standards Australia New Zealand 2003b). FSANZ commissioned a dietary survey in 2003 which indicated that the daily exposure of the population to all intense or artificial sweeteners is below acceptable daily intake (ADI), (Food Standards Australia New Zealand 2003a). However concern was expressed for the potential for high consumers of low-joule products to reach their ADI level of these intense sweeteners

Adapted from: NSW Centre for Public Health Nutrition – Soft Drinks, Weight Status and Health: A Review. NSW Department of Health 2009
https://www.health.nsw.gov.au/heal/Publications/soft-drinks-report.pdf