Diet Drink Diabetes Risk

Sugar-free may not be better

Sugar-laden drinks have earned themselves a bad rap over the years for their role in promoting tooth decay and, more recently, weight gain and its associated risks of type 2 diabetes, heart disease and certain forms of cancer. This has seen many of us opt for 'diet' or 'light' alternatives, which use artificial sweeteners in preference to kilojoule-heavy sugar.

But a recent study from France has revealed that drinking artificially sweetened beverages – like fizzy soft drinks, cordials and sweetened fruit juices – in preference to sugar sweetened varieties may not reduce your risk of developing types 2 diabetes, it may actually be worse.

Published in the American Journal of Clinical Nutrition, the study involved more than 66,000 middle-aged or older women over a 14-year period from 1993. Participants completed a detailed diet questionnaire at the beginning of the study, listing their daily consumption of sugar-sweetened and artificially sweetened drinks and 100 per cent fruit juice. Their health was then monitored periodically for the remainder of the study.

The researchers concluded that women who drank artificially or sugar sweetened beverages had a greater risk of developing type 2 diabetes than women who avoided sweetened drinks. This association remained even when adjustments were made for participants' body mass index (BMI) and total energy intake (from all foods and drinks).

What was interesting, though, was that fans of artificially sweetened drinks were more likely to develop type 2 diabetes than those who drank beverages sweetened with sugar. In fact, compared to drinking equal amounts of regular soft drink, drinking half a litre of diet drink per week was associated with a 15 per cent greater risk of developing diabetes while the risk was 59 per cent greater for women who drank 1.5 litres of diet drink each week.

Despite their relatively high levels of natural sugar and energy, pure fruit juices (either freshly squeezed or with no added sugar) were not associated with increased risk of type 2 diabetes in this study.

Sugar and diabetes risk

Previous studies have linked consumption of sugar sweetened soft drinks with type 2 diabetes, but it was always thought this was due to the effects of these drinks on weight gain. Energy-dense drinks don't satisfy your appetite in the same way that food does, making you more likely to eat and drink more kilojoules than you need, and gain weight as a consequence.

When you are overweight, your body becomes less sensitive to insulin, so your pancreas needs to produce more to control your blood glucose levels. Likewise, sugary drinks cause a rapid increase in blood glucose that triggers a big spike in insulin levels, further increasing the demand on the pancreas. Eventually, this can lead to type 2 diabetes.

Artificial sweetener theories

Artificially sweetened drinks are substantially lower in kilojoules, and therefore don't have the same effect on weight as do those sweetened with sugar. So if they don't in themselves promote weight gain, what are some possible explanations for the association between artificially sweetened drinks and type 2 diabetes?

The study authors put forward some theories:

• People who eat or drink 'light' or artificially sweetened foods or drinks tend 'overcompensate' by eating and drinking greater quantities of food and drink overall, which can lead to weight gain and increased risk of type 2 diabetes. You know how it goes: 'This dip is reduced fat so I can have twice as much' or 'I'm having a diet cola so I'll upgrade to the large fries'. In this study, diet drink aficionados guzzled an average of 2.8 glasses each week compared to the 1.6 weekly glasses downed by regular soft drink fans.
• Some artificial sweeteners, such as aspartame, have been shown to trigger similar increases in insulin levels as regular sugar, placing more demand on the pancreas and increasing type 2 diabetes risk.
• Artificial sweeteners are sweeter to taste than sugar, and ongoing consumption can increase the preference for sweet-tasting foods which are high in kilojoules and can contribute to weight gain. Sweet drinks can also stimulate appetite so that you eat more.
  

Study limitations

Of course, this observational study doesn't prove that artificially or sugar sweetened soft drinks cause type 2 diabetes; the investigators themselves acknowledged that other unknown factors may have contributed to the higher diabetes risk among the participants who consumed these beverages. However, it does raise some interesting, and potentially concerning, aspects about artificially sweetened drinks in particular that are worthy of further investigation. Until then, your best bet is to avoid sweetened drinks altogether, and quench your thirst with some good old-fashioned water.