July 21, 2015

expert reaction to study investigating sugar-sweetened drinks, artificially-sweetened drinks and type 2 diabetes incidence

Striking the right balance of components in our diets is an important but controversial area of research, and potential links between sugar, sweeteners and type 2 diabetes are explored in a paper published in The BMJ. The authors report an association between sugar-sweetened beverages and type 2 diabetes, and also an association when examining artificially-sweetened drinks or fruit juices, though they suggest that there may be some biases causing the two latter links.

Dr Alasdair Rankin, Director of Research, Diabetes UK, said:

“This study adds to evidence that sugary drinks are bad for health and can increase the risk of Type 2 diabetes. This study does not, though, provide strong evidence about whether this is because of the calories they contain or if there is something else going on in the body that is leading to an increase in risk.

“The researchers also suggest that artificially sweetened drinks and fruit juices are of no benefit in the prevention of Type 2 diabetes, but these findings are based on limited data and need further investigation.

“We would advise people to limit the amount of sugary drinks they have as part of a healthy diet in order to reduce their risk of Type 2 diabetes. There is very strong evidence that a healthy diet, together with regular physical activity, can help maintain a healthy weight and so help prevent Type 2 diabetes.”

Prof. Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:

“I have reservations regarding the basis of the calculations that suggest sugar sweetened beverages would cause 80,000 cases of diabetes over ten years in the UK. The conclusion that high consumers of soft drinks are at increased risk of type 2 diabetes is based on records reporting soft drink consumption several years before a diagnosis of diabetes. A problem with prospective studies such as these is that the early stages of developing type 2 diabetes are characterized by increased fluid consumption. This might explain part of the association particularly that with artificially sweetened drinks. It is also well known that people who are obese are more likely to use artificially sweeteners and drinks containing them.

“The study reports on average a 0.13 increase in relative risk associated with high sugar sweetened beverage consumption after adjusting for adiposity (the relative risk is 1.13 for high consumers of sugar sweetened beverage, that is a 0.13 increase in relative risk, which is 13%). But this is a relatively small effect compared to the larger effects of being overweight or obese (3-20 fold increases, which is a 300 to 2000% increased risk) or physically inactive. It appears that this small relative risk has been applied across the population to account for 3.6% of the 2.6 million new cases of type 2 diabetes predicted to occur over a ten year period in the UK. Age, obesity and physical inactivity are the main risk factors for developing type 2 diabetes and most new cases of type 2 diabetes are recorded in people over the age of 50 years old, who are not major consumers of sugar-sweetened beverages (with exception of sugar added to tea).

“Completely avoiding sugar-sweetened beverages in the UK would reduce the average intake by 115g/day of beverage (1/3 of can/day) providing 10% sugar (about 11g of sugar/day) or 44 kcal/day which by itself is a minor effect on energy intake. However, the benefit would be greater for high consumers i.e. 3 cans/day. It is important to stress that this study does not prove a cause-effect relationship and there are no trials as yet showing that reducing sugar sweetened beverages decreases the incidence of type 2 diabetes. However, there is good evidence from trials that type 2 diabetes can be prevented by increased physical activity and weight loss, which includes restricting the intake of sugary drinks as part of a more comprehensive dietary package that reduces energy intake.”

‘Consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice and incidence of type 2 diabetes: systematic review, meta-analysis, and estimation of population attributable fraction’ by Fumiaki Imamura et al. published in the BMJ on Tuesday 21 July 2015.

Declared interests

Dr Alasdair Rankin declares no interests.

Prof. Tom Sanders is a Scientific Governor of the charity British Nutrition Foundation, member of the scientific advisory committee of the Natural Hydration Council (which promotes the drinking of water), and honorary Nutritional Director of the charity HEART UK.  Prof Tom Sanders is now emeritus but when he was doing research at King’ College London, the following applied: Tom does not hold any grants or have any consultancies with companies involved in the production or marketing of sugar-sweetened drinks.  In reference to previous funding to Tom’s institution: £4.5 million was donated to King’s College London by Tate & Lyle in 2006; this funding finished in 2011. This money was given to the College and was in recognition of the discovery of the artificial sweetener sucralose by Prof Hough at the Queen Elizabeth College (QEC), which merged with King’s College London. The Tate & Lyle grant paid for the Clinical Research Centre at St Thomas’ that is run by the Guy’s & St Thomas’ Trust, it was not used to fund research on sugar. Tate & Lyle sold their sugar interests to American Sugar so the brand Tate & Lyle still exists but it is no longer linked to the company Tate & Lyle PLC, which gave the money to King’s College London in 2006.  Tom also used to work for Ajinomoto on aspartame about 8 years ago.