Wine contamination scare

Phtalates found in wine (Photo: boo_licious)

Phtalates found in wine (Photo: Boo Lee)

It is Friday evening and you are relaxing and enjoying a glass or two of a ten year old red wine. You roll the wine on your tongue and you detect a bouquet of raspberry and leather with a slight hint of phthalate. Hang on, what is phthalate? There shouldn’t be any phthalates in wine, should it? It is bad enough to have the sulfite preservative in the wine if you belong to the 5-10% of the population that is allergic to sulfite. But phthalates are hormone disrupting chemicals added to plastics to increase their flexibility and durability. They are considered carcinogenic, mutagenic and reprotoxic by the European Chemicals Agency. They don’t belong in wine, so what’s the story here?

Chinese consumer vigilance

Let’s go back a couple of years to 2012 and China. Following the catastrophic melamine-contamination scandal of 2008, Chinese consumers started to worry about other possible contamination problems. Thus, when elevated levels of phthalates were found in leading Chinese baijiu brands in November 2012, it caused a dramatic slump in sales. Baijiu is a popular white spirit produced from sorghum with 40-60% alcohol. Chinese authorities immediately lowered allowable phthalate levels in alcoholic drinks and clamped down on the maximum levels permitted in all wines and spirits. In March 2013, Chinese customs impounded containers of French wine and cognac on suspicion that they might contain phthalates. And they did, causing a flurry of testing, with laboratories in South West France suddenly swamped with samples from anxious exporters.

You may remember a previous scare regarding phthalates in cling film or glad wrap in the 1990s. They were found to migrate easily to fatty food products like cheese and meat.  Studies suggested that phthalates might be a factor in some cases of breast cancer, asthma, diabetes and attention deficit hyperactivity disorder in children. It is a group of chemicals that provoke universal anxiety, since they are now almost everywhere from household dust to the nasogastric tubes and surgical gloves used in hospitals.

New study quantifying the problem

Now a new study published in Food Additives and Contaminants provide some clarity of the extent of the problem of phthalates in a variety of French wines and spirits. The research showed that 59% of the wines analysed contained significant quantities of one particular form of phthalate, known as dibutyl phthalate, and only 17% did not contain any detectable quantity of at least one of the reprotoxic phthalates. Perhaps a more worrying statistic is that 11% of the wines analysed did not comply with EU specific migration limits (SML) for materials in contact with food, the only regulation applicable since no specific limits for phthalates in wine have yet been set in Europe.

Wine aged in oak barrels might be a safer bet (Photo: Ken Whytock)

Wine aged in oak barrels might be a safer bet (Photo: Ken Whytock)

So what is the origin of the phthalates in wine? The study analysed a variety of materials frequently present in wineries and found phthalates in winery equipment, especially tank linings, plastic vessels used in racking processes, the plastic tubing used to pump must or wine from one vessel to another, and pump components themselves. And ethanol as a solvent is a perfect way of extracting phthalates from plastics. That, of course, is why spirit producers need to be particularly vigilant.

As it happened, the French government stepped in to reassure consumers that this was an administrative issue and nothing to do with dangerous contaminant levels, adding that the change in the Chinese legislation affected tens of wine and spirit shipments from Bordeaux, Spain and Argentina, not only Cognac.

Should you be worried?

This might be an issue of limited toxicological impact in the overall scheme of things with so many other potential sources of phthalate exposure. More expensive wines aged in oak barrels might carry less risk. Australian wines have so far not been implicated in the contamination scare so there might be ample choices available to still enjoy a glass or two of wine on Friday evening.

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Aspartame deemed safe after a mammoth effort

Aspartame - EFSA's most comprehensive risk assessment ever

Aspartame – EFSA’s most comprehensive risk assessment ever

After its most extensive effort ever the European Food Safety Authority (EFSA) deemed aspartame to be safe at current use levels in an opinion just published in December 2013. This is a mammoth effort not only reviewing most of the available literature on aspartame and its breakdown products, but also consulting widely with the public before finalising the opinion. It will be seen as a breakthrough effort in improving consumer confidence in the scientific process of evaluating controversial food additives. But of course not everyone will be pleased, that is the nature of the beast.

The question could be raised why EFSA didn’t do as thorough a job in its previous evaluations of aspartame, but why be critical now when it is done. The work raises the bar for future opinions and I am thinking in particular of the Bisphenol A opinion in the immediate pipeline. That issue will be even more difficult to resolve with the low-dose hypothesis causing considerable angst among scientists. Another question is if EFSA can spend so much time on only one opinion without hampering overall progress on the many issues on EFSA’s plate. But that is an issue for their political masters.

So what did EFSA find

We all know that aspartame (E 951) is a sweetener authorised for use as a food additive in many countries. It is used extensively in diet soft drinks in particular. Chemically it is a dipeptide, that is the molecule is formed by the two amino acids, aspartic acid and the methyl ester of phenylalanine, binding together. In the gastro-intestinal system it is rapidly hydrolysed and fully degraded into its primary constituents of aspartic acid, phenylalanine and methanol with little or no aspartame available to be absorbed by the body. The amount of intact aspartame that enters the bloodstream has actually been reported as undetectable. Thus  potential toxic effects must be caused by any or all of these three major metabolites.

EFSA stated that it was clear from their literature review that the acute toxicity of aspartame as tested in mice, rats, rabbits and dogs was very low. Similarly, sub-acute and sub-chronic studies did not indicate any significant toxic effects in rats, mice or dogs. Neither did available data indicate a genotoxic concern for aspartame. Results from three chronic toxicity and carcinogenicity studies in rats and one in mice revealed no aspartame-related increase in any type of neoplasms at the doses tested.

There was a caveat though with debate raging about tumour findings reported by the European Ramazzini Foundation. However, EFSA and other authorities are of the view that many of the malignant neoplasms and the lymphoid dysplasias diagnosed in the studies were hyperplasias related to unknown chronic infection in the animals and not related to aspartame intake. Also hepatic and pulmonary tumour incidences reported fell within the institute’s own historical control ranges for spontaneous tumours.

There was also a problem with birth weight data from several reproductive and developmental toxicity studies performed in rabbits. However, EFSA stated that the findings were confounded both by a decrease in feed intake in the treated group and poor health of the animals.

What about human studies?

Artificially sweetened soft drinks a common source of aspartame

Artificially sweetened soft drinks a common source of aspartame

Looking at human studies, EFSA noted that there was no epidemiological evidence for possible associations of aspartame with various cancers in the human population.

A large prospective cohort study in Denmark found no consistent association between the consumption of artificially sweetened beverages in general (of which some might have been using aspartame) during pregnancy and the diagnosis of asthma or allergic rhinitis in children. Though they did find a small but significantly elevated risk of medically induced pre-term delivery in women with higher reported consumption of artificially sweetened drinks. This was countered by findings in another prospective study in Norway showing a barely discernible association between pre-term delivery and artificially sweetened soft drinks but a stronger association with consumption of sugar-sweetened soft drinks.

And the metabolites specifically

Methanol was cleared from any effects after aspartame consumption since it only contributes to a very small part of methanol exposure. Fruit and vegetables play a more important part in methanol exposure and it is also naturally produced by the body. It is only toxic at fairly high levels, such as from consumption of some home-distilled alcoholic spirits.

Neither did aspartic acid raise any human safety concerns. The body can convert aspartic acid into the neurotransmitter glutamate which, at levels very much high than can be derived from aspartame consumption, can have harmful effects on the nervous system.

Phenylalanine is the remaining potential culprit. It is known to be toxic at high intake levels, in particular to the developing foetus in women suffering from the medical condition phenylketonuria (PKU). EFSA considered that it was plausible that phenylalanine could be responsible for some or all of the adverse effects reported for aspartame in rat and rabbit developmental toxicity studies. However, phenylalanine blood levels reached after realistic dietary intake of aspartame were well below conservative estimates of the levels necessary to cause harm.

So all clear for everyone except PKU patients where total control of dietary phenylalanine intake is necessary to manage the risk from elevated phenylalanine blood levels. Fortunately, it is a requirement in many countries that products containing aspartame should indicate through labelling that they contain a source of phenylalanine to protect the small minority unable to metabolise the compound.

And the conclusion?

All-in-all EFSA considered aspartame safe at normal use levels and retained an Acceptable Daily Intake of 40 mg/kg bodyweight. Some dubious results remain but scientific studies are seldom perfect. It seems clear that all doubtful results can be explained without casting a shadow over aspartame. At least according to the EFSA evaluation.

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