The truth about aspartame

Aspartame has been subject to more scare stories than any other sweetener, ranging from allergies and premature births to liver damage and cancer.

It is low calorie and up to 200 times sweeter than sugar. Aspartame is used all over the world as a sugar substitute in thousands of foods and drinks, including cereals, sugar-free chewing gum, low-calorie (diet) soft drinks and table-top sweeteners.

Aspartame has been extremely controversial since its approval for use by several European countries in the 1980s. A 1996 report suggested a link between aspartame and an increase in the number of diagnosed brain tumours. However, the study had very little scientific basis and later studies showed that aspartame was in fact safe to consume.

The European Ramazzini Foundation of Oncology and Environmental Sciences published several long-term studies in 2006 and 2007 linking the consumption of aspartame with an increase in cancers – namely lymphomas and leukaemias – in rats.

Following these studies, the US National Cancer Institute conducted a study of nearly half a million people, comparing those who consumed drinks containing aspartame with those who did not. Results of the 2006 study (PDF, 87kb) found aspartame did not increase the risk of leukaemia, lymphoma or brain cancer.

In 2013 the European Food Safety Authority (EFSA) conducted a comprehensive review of the evidence (PDF, 2.25Mb) and concluded that aspartame was safe for human consumption, including pregnant women and children.

In digestion, aspartame is quickly and completely broken down into by-products – including phenylalanine, aspartic acid and methanol – which then enter our system through normal routes. Hardly any aspartame enters the bloodstream.

However, the EFSA said the acceptable daily intake recommendations did not apply to people with phenylketonuria (PKU), a rare genetic disorder where the body cannot break down phenylalanine. People with this condition need to closely monitor their phenylalanine intake.

The EFSA report stated that, "PKU mothers with poorly controlled phenylalanine intake in their diet during pregnancy may give birth to babies with congenital heart diseases, microcephalus and impaired neurological function."

It is worth noting that phenylalanine occurs naturally in many protein-rich foods, such as milk, eggs and meat. Table-top sweeteners containing aspartame or aspartame-acesulfame K must be marked with "contains a source of phenylalanine".

Acceptable daily intake: 40mg per kg of body weight

Find out what the latest scientific evidence says about these other common artificial sweeteners:

Read The truth about sweeteners

Page last reviewed: 13/04/2016

Next review due: 13/04/2018

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