July 19, 2016

expert reaction to study looking at sugar, childhood obesity and heart disease risk factors

Publishing in the journal Atherosclerosis a group of scientists have reported that reducing sugar, but not calories, in obese children can reduce markers of cardiovascular disease risk.

Dr Gavin Sandercock, Reader in Clinical Physiology (Cardiology) and Director of Research, University of Essex, said:

“The study included a small and very specific group of children – obese, Hispanic or African American children with existing metabolic problems who were already high consumers of sugar, and is not generalisable to most of the general population.

“This is not a high quality study as it only lasted 9 days, and there was no control group, meaning the effects could have been to changes in other behaviours like physical activity – which wasn’t measured – or the way the authors dealt with weight loss.

“The claim in the press release that reducing sugar lowers blood pressure is not supported by evidence in the paper – not only did they measure lots of things then only mention a few that did change, but without a control group you cannot say such things.

“The wording of the press release is misleading as it talks about reducing ‘sugar’ – they actually reduced fructose, not sugar. All carbohydrates are types of sugar and the one most people think about, the sugar in your bowl at home, is sucrose, not fructose.

“Statements such as “Sugar is uniquely metabolized to fat in the liver” (in the press release) are misleading; table sugar (sucrose) and starchy foods such as bread and potatoes (which are broken down into glucose) are stored in the muscles and liver as glycogen which we use for energy.

“The subtitle of the press release – ‘sweets, not calories, are culprits…’ is misleading as there is little or no fructose in sweets.”

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

“This is a small, short-term uncontrolled trial in obese children.

“It is already known that fructose – a component of sucrose (table sugar) – as well as honey increases fat synthesis in the liver because it cannot be metabolised outside the liver.

“This study measured changes in blood fats and did not measure heart disease.

“Reducing fructose intake had a modest effect on lowering serum triglyceride levels and a protein associated with fat synthesis in the liver, which is what would be predicted from current knowledge.

“There was a very small change high density lipoprotein concentration. The authors also claim a change in the small dense LDL (low density lipoprotein) fractions when sugar was cut, but this was only significant in a subgroup of 10 of the participants and not for the whole cohort. On average participants also lost weight, which is known to reduce the level of small dense LDL.

“Children are at very low risk of heart disease. Heart attacks occur mainly in those over the age of 50 years.

“The major problem with this study is that there was no control group, which makes the claim in the title of the press release invalid.”

Prof. Naveed Sattar, Professor of Metabolic Medicine, University of Glasgow, said:

“Whilst this study is of interest and undoubtedly refined sugar intake in excess is to be avoided, the present study overstates the potential importance as it small in size and not properly controlled, and if children were having less calories at the time of subsequent tests (which seems likely), results always tend to overestimate benefits of any intervention.

“We must not concentrate only on cutting refined sugar, but also to lessen fat intake, especially saturated fat, and at the same time increase intake of fibre rich foods in the form of fruit and vegetables. The present paper therefore does not change my opinion about current dietary advice.”

‘Short-term isocaloric fructose restriction lowers apoC-III levels and yields less atherogenic lipoprotein profiles in children with obesity and metabolic syndrome’ by Alejandro Gugliucci et al. published in Atherosclerosis on Tuesday 19 July 2016. 

Declared interests

Dr Gavin Sandercock: “No conflicts of interest to declare.”

Prof. Tom Sanders: “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’s 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.  Tom was a member of the FAO/WHO Joint Expert Committee that recommended that trans fatty acids be removed from the human food chain. Tom has previously acted as a member of the Global Dairy Platform Scientific Advisory Panel and Tom is a member of the Programme Advisory Committee of the Malaysian Palm Oil Board. In the past Tom has acted as a consultant to Archer Daniel Midland Company and received honoraria for meetings sponsored by Unilever PLC. Tom’s research on fats was funded by Public Health England/Food Standards Agency.”

Prof. Naveed Sattar: “Prof Sattar was senior author on a trial which was funded by Coca-Cola on a placebo-controlled RCT of a novel flavonoid rich beverage – the trial was negative.”