Is sugar the only sweet poison?

Have you heard sugar being referred to as ‘sweet poison‘? Probably. You’ve likely also heard rumours that the sugar alternatives (such as Equal and Splenda) could potentially be worse for our health in the long term, yet (like I did), brushed off the propaganda-type campaigns that suggested our insides would rot and we’d grow a second head. There was a time not so long ago (err… 18 months prior) where I used to use a LOT of artificial sweetener. To the point that it could have been considered a food group all on its own. For a good 22 years. So I wasn’t sure how to react when my friend Helen forwarded me an email from The Lancet Journal of Oncology this week that reported the International Agency for Research into Cancer (IARC) have made investigating the carcinogenic effects of Aspartame and Sucralose a priority over the next couple of years.

Aspartame is a methyl ester comprised of phenylalanine and aspartic acid, two amino acids found naturally in foods such as meat and dairy, and certain fruit. It’s used as a replacement for sugar in products such as diet soft drinks, sugar free gum and other artificially sweetened foods. A quick google search brought up this list of foods in New Zealand containing Aspartame and while many of these have changed to using Splenda, the active sweetener in Splenda is Sucralose – the other sweetener under the spotlight (which I’m not talking about in this post). You will notice that many of the products on the list are pharmaceutical and in fact that was how these products originally entered the food supply – as a way to make medicine more palatable. Stevia – a non sugar sweetener which I’ve actually been using of late due to the ketogenic diet (usually I would use rice malt syrup or another sugar alternative if making anything sweet) – has been used for 1000s of years. More recently sweeteners were developed to make pharmaceuticals more palatable and the first to be manufactured was saccharin in the 1890s. Aspartame specifically has been in the food supply since its creation in the 1960s, with the Food and Drug Administration (FDA) approval for wide-spread use since 1996 in all food types.

If Aspartame has been approved by the FDA as safe (and it’s touted that the level in the average diet is approximately 1/50th that considered to be the acceptable daily intake (ADI) limit – 50 mg/kg body weight (BW) in the US, 40 mg/kg BW in Europe), why now is the IRAC announcing that the safety of it (and Sucralose) is being called into question? I did a bit of digging around the literature and found a review paper based on the current evidence that was released earlier this year. This isn’t going to be an indepth review of all literature pertaining to aspartame – that would take me more time than I have on a Sunday to write the blog and, let’s face it, I’m no brainiac. I did, though, want to share the take-home messages I got from this review, in an effort to understand the sudden interest of the IARC into aspartame. Interestingly, this review paper was written in light of another organisation’s interest in the safety of aspartame, the European Food Safety Authority (EFSA). Along with a re-examination of the trials conducted using animal models, more recent trials showing a dose-response relationship between aspartame and cancer lesions in rats, their investigation also evaluated evidence from two large scale population-based studies.

The first of these evaluated dietary data from the National Institute of Health—American Association of Retired Persons surveillance, and included 473,984 individuals aged 50–71 who were surveyed in 1995, and followed until 2000 for signs of gliomas (a malignant tumor found in the nervous system) (315 cases) and hematopoietic tumors (tumours in the blood, 1,888 cases). The authors reported that for a daily intake of aspartame  greater than 900 mg/day (equivalent to 1.5 L a coke – yes, a lot!) no significant increase in risk of hematopoietic neoplasms (RR 0.98, 95% CI 0.76–1.27) or of gliomas (RR 0.73, 95% CI 0.46–1.10) was observed.

However, despite the large number of people followed, this conclusion has been criticised due to the limited duration of exposure and  follow-up, and the low exposure levels that reduced the statistical power to detect an effect. Because of the overly simple evaluation of the exposure (measured as the consumption of products containing aspartame during the 1 year immediately prior to the start of the 5 years follow-up), there were concerns about the validity of the results.

The second study examined data from the Nurses’ Health Study and the Health Professional’s Study – two large scale population-based studies where the intake of diet soft drink was observed across a 22y time period (1984-2006) every four years. In total, consumption levels were evaluated in over 77,000 women and close to 48,000 men. The researchers concluded there was a statistically increased risk of both multiple myeloma and non-Hodgkin’s lymphoma in men who consumed more than 1 serving diet soda per day. No clear effect was seen in women, which the authors speculated may be due to the increased activity of the alcohol dehydrogenase type 1 (ADH1) enzyme in men that is responsible for converting methanol (a constituent of aspartame) to formaldehyde. Remember, these are correlational studies and cannot establish cause and effect. However, it is from this foundation that we form questions in order to test in a more rigorous setting. In nutritional research, this would be by conducting a randomised controlled experiment where participants consume either a predetermined amount of a beverage containing aspartame or a placebo daily for 20 years, whilst observing the incidence of newly formed cancer. Hmm. There-in lies the problem. Studies like that are clearly unethical (and not mention hideously expensive!!) Much like the research related to the increased risk of lung cancer with tobacco smoking, many people argue that there is enough research now to recommend lowering our overall exposure to aspartame in the food supply.

Despite what might appear to be worrying reports based on quite a small dose of aspartame, the EFSA‘s review concluded that the base of the evidence was not strong enough to recommend a lower dose of aspartame and future animal model studies should be set up to determine the effect of aspartame with regards to reproduction and development (not cancer lesions). They also recommended the evidence base that would warrant a change in position stance should come from animal models and not epidemiological research. If they had decided that carcinogenic tumours were the endpoint of interest, would they have decided differently?

Now, then, the IARC are set to review the evidence for and against the use of aspartame in our diet. In light of what I learned through reading the review paper I’m both relieved that I no longer have it a regular part of my everyday diet, and slightly concerned of the effect that my long term consumption of foods containing it could have on my overall health. But  I’m not going to dwell on that as it’s completely beyond my control. My other thought is around the focus we’ve had on sugar in the diet of late. Many soft drink manufacturers have jumped on board the ‘no sugar’ bandwagon and have started heavily promoting their ‘no sugar wares’, Of course, the alternative could, down the line, be far worse for the health of the consumer. The best option? Choose real food and beverage options. If you like to cook and would normally use a sweetener, why not cut back the amount you use and choose a natural product over Splenda? Better yet, begin to reduce the amount of sweet foods in your diet (artificial or otherwise) so you can begin to retrain your palate and adapt to a diet that is high in nutrients, and lower in all types of the sweet poison.