Health professionals bypassed by trade associations once again

Here we go again: a not entirely unexpected piece of news bouncing out of the scientific sessions of EPI/NPAM 2013 (Epidemiology & Prevention and Nutrition, Physical Activity & Metabolism 2013), under way in New Orleans, has triggered the proverbial recommendations from Coldiretti which, teamed up from time to time with ISMEA, or with CENSIS or ISTAT, presents itself to the press and to consumers as the point of reference for accurate nutritional and food information for Italians.

It is time for the ownership of scientific information on nutrition to return to the professions that have studied, in the field, the relationships between food, nutrition and health, rather than being the exclusive domain of agricultural trade associations which, by their very mandate, must defend the interests of producers — interests that unfortunately do not always coincide with those of citizens/consumers. To each their own role! I fear, however, that this happens more because nutritionists are absent from the scene than because Coldiretti is overstepping.
It is up to us to take back what falls within our competence. With this reflection we wish to open a debate on the subject, hosted in a professional space such as Nutricity aims to be.

THE CASE
The message coming from New Orleans is objectively alarming: the consumption of sugary drinks may be associated with 180,000 deaths a year worldwide; countries in the Caribbean and Latin America show diabetes mortality rates linked to the consumption of sugary drinks; around 25,000 deaths a year in the United States may be associated with the consumption of sugary drinks.

THE STUDIES
The issue is nonetheless controversial — as demonstrated by a longitudinal study conducted in the UK (reported on the Eufic website) which examined, using data from the Avon Longitudinal Study of Parents and Children, the relationship between high intake of sugar-sweetened beverages by 521 five-year-old children and 682 seven-year-old children and body fat (measured by DEXA). Sugary drink consumption was calculated on the basis of a 3-day food diary and represented on average 15% of all beverages consumed and 3% of daily energy intake. The researchers used a statistical technique called "linear modelling" that could account for the possible effect of other variables (dietary fat, physical activity, etc.). The results showed no statistically significant association between body fat and sugar-sweetened beverages. Indeed, paradoxically, children with higher consumption of low-calorie or unsweetened drinks tended to be fatter than those who consumed few of them, although this could have been a bias linked to parents offering more low-calorie drinks to overweight children. (Johnson L et al. Is sugar-sweetened beverage consumption associated with increased fatness in children? Nutrition,2007 Vol 23, pages 557-563). A further consideration that may explain the differences from what was reported in New Orleans is that current US data put the calorie intake from glucose due to sugary drink consumption at 15% and 357 Kcal, far more than the 3% reported by the British study.

A systematic review published in 2010 in Obesity Reviews on the association between sugar-sweetened beverage consumption and body weight sought conclusive evidence on the subject. A group of US researchers from the University of Alabama carried out a meta-analysis of randomized controlled trials (RCTs), according to well-defined criteria (definition of a sugary drink, i.e. a beverage with nutritive sweeteners and not 100% fruit juice, unsweetened milk or light drinks; healthy, non-pregnant subjects; and studies that did not clearly state the aim of the research). Twelve usable studies were identified. The studies (4) that assessed the effect of adding sugary drinks to the habitual diet showed a dose-dependent increase in weight. The short duration (up to 12 weeks), the rather small sample and potential confounding factors suggest caution in interpreting the results.

Overall, the studies that attempted to reduce sugary drink consumption through educational methods failed to find any effect on BMI. However, in 3 of these, where additional statistical analyses were carried out, the intervention of reducing sugary drink consumption proved potentially useful for overweight individuals attempting to lose weight or to limit weight gain. Ultimately, the evidence does not clarify whether long-term consumption of sugary drinks can influence BMI. In short-term trials the increased energy intake linked to sugary drinks is not compensated for and can lead to weight gain. There is, however, a need for randomized, controlled and well-powered studies to verify the effectiveness on weight of programmes that reduce sugary drink consumption. (Mattes RD, Shikany JM, Kaiser KA and Allison DB. Nutritively sweetened beverage consumption and body weight: a systematic review and meta-analysis of randomized experiments. Obesity Review 2010s 12(5):346-365, doi:10.1111/j.1467-789X.2010.00755.x)

THE INTERPRETATION
To address the issue of the association between sugary drink consumption and chronic degenerative diseases with more recent scientific data, I will draw on a piece by Prof. Nisoli, president of the SIO, which cites an editorial by Dr Sonia Caprio published in the NEJM (N Engl J Med. 2012 Oct 11;367(15):1462-3) analysing 3 recent studies published in the same journal dealing with the problem of obesity and sugary drinks.

1. The first study (Qi and colleagues N Engl J Med 2012.DOI: 10.1056/NEJMoa1203039) examined the interaction between environmental factors (intake of such beverages) and genetic predisposition to obesity in 6,934 women participating in the Nurses’ Health Study, 4,423 men participating in the Health Professional Follow-up Study, and a control cohort of 21,740 women (Women’s Genome Health Study). Genetic predisposition was assessed on the basis of 32 gene loci associated with body mass index (BMI), and sugar-sweetened beverage consumption was examined prospectively in relation to BMI. The data analysis indicates that the greater the genetic predisposition, the more negative the adverse effects of sugary drinks on obesity and its associated diseases; the study thus provides an unequivocal example of gene-environment interaction. The other two are randomized controlled intervention studies describing the effects of sugar-sweetened beverages on weight gain in normal-weight children or in overweight and obese adolescents.

2. De Ruyter and colleagues (N Engl J Med 2012.DOI: 10.1056/NEJMoa1203034) carried out a highly reliable study, as it was conducted over a long period (18 months), double-blind, and with adherence to the study monitored by measuring sucralose (a calorie-free sweetener) in urine. 641 normal-weight children aged between 4 years 10 months and 11 years 11 months were given, at school, either a sugar-free, artificially sweetened drink or a similar drink containing enough sugar to provide 104 kcal. Despite one limitation (26% of participants did not complete the study for reasons that were not stated), the results clearly indicate that replacing, without the participants’ knowledge, a sugary drink with an unsweetened one limits weight gain and fat accumulation in normal-weight children.

3. Ebbeling and colleagues (N Engl J Med 2012.DOI: 10.1056/NEJMoa1203388) conducted a study of 224 overweight and obese adolescents who were regular consumers of sugary drinks. The subjects were randomized into two groups: a control group and a group that for 1 year received an intervention consisting of home delivery of unsweetened beverages. This group was followed for a further year with no additional intervention. In this way it was possible to analyse the effects of consuming caloric drinks at home, that is, in the setting where most of the consumption occurs. The results show that the overweight and obese adolescents in the experimental group gained less weight than those in the control group. The smaller weight gain was not maintained in the second year, that is, in the absence of the intervention.

These latest studies, rigorously designed from a scientific standpoint, therefore provide a strong impetus to issue recommendations and take policy decisions aimed at limiting the consumption of sugar-sweetened beverages.

The real problem, if anything, is another: is it really enough to go from a minimum of 12% to a 20% share of juice to tackle this health problem seriously? Moreover, are we sure that fructose (a simple sugar present at around 50% in orange juice) is less harmful than glucose in its effects on metabolism?
These are all assessments to be made regardless of the consumption concerns that are central to producers’ outlooks, consistent with their function.
I believe it is appropriate for nutrition professionals to reclaim their role and to be the ones proposing suitable solutions to the mass media, consumers and policymakers.