Is Aspartame a safe alternative to sugar?Thursday 27 June 2019
Unfortunately, Jersey has a growing problem with cardiometabolic diseases: diabetes, obesity, hypertension, coronary disease which are known to be linked to excess sugar consumption. One line of products that are been marketed as a safe alternative to sugar that promote weight loss is nonnutritive sweeteners (NNS) such as Aspartame, Sucralose and Stevioside. So it was with interest that I read a 2017 article that looked at the evidence in support of such claims.
The 2017 article was a systematic review and meta analysis of randomised controlled trials (RCTs) and prospective cohort studies (PCS). Included in the study were 7 RCTs (comprising 1003 participants; median follow-up 6 months) and 30 cohort studies (405,907 participants; median follow-up 10 years). It is worth noting that RCTs are usually funded by large industry and therefore tend to support outcomes favourable to the sponsor.
Questions arising from the 2017 article:
Do nonnutritive sweeteners help reduce BMI?
Evidence was inconclusive- two RCTs involving hypertensive participants and 1 RCT involving obese subjects showed no reduction in BMI over 6- 24 months. Two cohort studies with healthy subjects showed a slight reduction in BMI but, three long term cohort studies showed an increase in BMI. Therefore, the evidence did not support the assertion that NNS help lower BMI.
Effect of NNS on weight
Long term (4 to 9 year follow-up) cohort studies showed that higher intake of NNS was associated with increased waist circumference, higher incidence of abdominal obesity.
RCTs did not report on incidents of metabolic syndrome or diabetes or cardiorenal syndromes. Pooled data from cohort studies with 4 to 24 year follow-up showed an increased risk of diabetes metabolic syndrome and cardio renal syndromes.
Why would Aspartame increase the risk of metabolic or cardiorenal syndrome?
According to the Dr Axe article https://draxe.com/aspartame/ one must look at the chemical components of Aspartame. Aspartame breaks down into three components: phenylalanine, aspartic acid and methanol.
Phenylalanine is a naturally occurring amino acid that is usually bound to other molecules and absorbed slowly during digestion. However, in Aspartame, phenylalanine is bound to other compounds and immediately crosses the blood/brain barrier where it can lower serotonin levels. Serotonin is a multifaceted neurotransmitter produced by nerve cells. It influences cognition, learning, memory and modulates many biological processes.
Aspartic acid is a non essential amino acid meaning that the body makes its own as and when it is required. Its importance lies in the neuroendocrine system.
Methanol occurs in many fruit but is bound to pectin (a form of fibre) and is harmlessly excreted from the body. This is not the case in Aspartame, where it is weakly bound to phenylalanine. If heated beyond 27 degrees the bond is broken even before it enters the body and 'free methanol' is created which then forms formaldehyde. Some sources including the article on the Dr Axe website https://draxe.com/aspartame/ claim that the formaldehyde from Aspartame is a cause for concern as it is carcinogenic and can cross the blood/ brain barrier. However, the counter claim is that "The metabolic pathway is well-understood and well-documented in the scientific literature. First, the methanol from the intestinal tract goes to the liver via portal blood, where the liver enzyme alcohol dehydrogenase converts methanol into formaldehyde. The body very rapidly uses formaldehyde and so formaldehyde never builds up in the body. If the body doesn't need it, formaldehyde is converted to formic acid within seconds. The formic acid will be either excreted in the urine or broken down to carbon dioxide and water."
The build up of formic acid in the blood stream could be dangerous however, it is countered that this would be very unlikely to happen through Aspartame consumption: "To put this into perspective, studies in healthy adults and infants consuming up to 200mg per kg of body weight (50 times the amounts Americans consume on average), showed no change in the levels of formic acid in the blood"
The evidence suggest that NNS such as Aspartame:
1) will not help reduce BMI, and
2) is associated with increased waist circumference, higher incidence of abdominal obesity; and
3) more high quality research into the long term effects of Aspartame on humans is required.
Nonnutritive sweeteners and cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies. Meghan B. Azad, Ahmed M. Abou-Setta, Bhupendrasinh F. Chauhan, Rasheda Rabbani, Justin Lys, Leslie Copstein, Amrinder Mann, Maya M. Jeyaraman, Ashleigh E. Reid, Michelle Fiander, Dylan S. MacKay, Jon McGavock, Brandy Wicklow and Ryan ZarychanskiCMAJ July 17, 2017 189 (28) E929-E939