WHO may revise guideline on sugar to combat tooth decayBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g21 (Published 06 January 2014) Cite this as: BMJ 2014;348:g21
The World Health Organization may recommend halving the level of sugar in the diet, prompted by a review of the link between sugar consumption and tooth decay.1
The present WHO guidelines say that sugar should not exceed 10% of dietary energy—but the review, led by Paula Moynihan of the WHO Collaborating Centre for Nutrition and Oral Health at Newcastle University, found evidence that a lower limit of 5% may be justified to reduce the risk of caries.
A WHO spokesman confirmed that new guidelines were being drafted but could give no information on timing. Public consultation would be sought when the draft guidelines are published by the WHO Nutrition Guidance Expert Advisory Group, he said.
The sugar industry is expected to strongly oppose any change to the existing WHO guideline, which was set out in 2003. The WHO advisory group had originally planned to finalise its recommendations on sugar intake in relation to weight gain and dental caries at a meeting in March 2013, and it did not expect any change.
A review published in the BMJ in January 2013 by Jim Mann and colleagues from Otago University in New Zealand concluded that sugar consumption had a small but significant effect on weight gain.2 It said that the existing 10% guideline was compatible with the evidence from cohort studies and made no recommendation to reduce it.
The December publication of the Moynihan review in the Journal of Dental Research has reportedly prompted a rethink, or at least a delay in publishing the draft guideline. The review concluded that there was evidence “of moderate quality” to support the 10% guideline and some evidence, “albeit classified of very low quality,” to indicate the benefits of a reduction to 5%.
The review looked at evidence regarding the amount of sugar consumed and not the frequency of consumption, which earlier research had shown to be more important. The reason for this, it explained, was to help WHO establish recommendations on the basis of the amount consumed, not the frequency of consumption.
The review found no randomised controlled trials; the only evidence backing the call for a lower limit was three Japanese population surveys, published in 1959 and 1960, showing lower dental decay in children who consumed less than 5% of their dietary energy in the form of sugar.
A commentary on the NHS Choices website concluded that, such was the quality of the evidence, it was “debatable” whether current advice would be altered.3 All three studies were in populations with low fluoride exposure, but the authors said this did not mean that fluoridated populations would not also benefit.
Only three worldwide ecological studies were found to enable comparison of dental decay in children consuming higher or lower levels of sugar; one of these showed that lower sugar intake was associated with less tooth decay.
The WHO advisory group has yet to publish any recommendation on these findings. Sugar Nutrition UK, which is sponsored by the industry, said there was no evidence to show that reducing intake below current levels would be beneficial to health, and that the studies being cited to justify the 5% limit had several limitations.
The World Sugar Research Organisation has denied that sugar was responsible for obesity. It said in a position statement, “WSRO, in agreement with many reviews undertaken by international bodies, does not consider the evidence to support a convincing direct relationship between sugar intake via foods and drink and obesity. Excessive energy intakes, in any form, or inadequate physical activity will encourage weight gain.”
In the United Kingdom the Scientific Advisory Committee on Nutrition is conducting a review of the relation between carbohydrates and health that will include a chapter on sugar. The review is chaired by Ian Macdonald of the University of Nottingham, who told the Guardian, “As far as sugar goes, it’s difficult to know where to start because there are people who believe it is the cause of all our problems. John Yudkin started this in the 1960s with his book Pure, White and Deadly and other people have picked it up at intervals since. The consumption rates are a bit higher than they were in the 1960s, but not excessively so.”
Cite this as: BMJ 2014;348:g21
bmj.com Feature: Sugar and the heart: old ideas revisited (BMJ 2013;346:e7800, doi:10.1136/bmj.e7800)
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