Opinion: What the WHO aspartame findings mean for your diet
Editor’s Note: Dr. Francesco Branca is the director of the Department of Nutrition and Food Safety at the World Health Organization. He was previously a scientist at Italian Food and Nutrition Research Institute and a lecturer in public health nutrition at Rome University. The views expressed here is his own. Read more opinion on CNN.
One in six deaths each year is due to cancer. If we want to reduce this statistic, it is imperative that we delve deeper into the potential causes and contributing factors of this devastating disease.
In an effort to do just that, last week, the International Agency for Research on Cancer (IARC), the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) Joint Expert Committee on Food Additives (JECFA) released assessments of the health impacts of the non-sugar sweetener (NSS) aspartame, commonly found in food and drinks such as diet sodas and tabletop sweeteners. These assessments shed light on the limited evidence surrounding the possible carcinogenic hazard of aspartame and emphasize the need for further scientific studies to fully understand this widely used sugar substitute’s effects on human health.
Aspartame, an artificial sweetener that has been used in many food and beverage products dating back to the 1980s, has now been classified by the IARC as “possibly carcinogenic to humans” (at hazard level Group 2B, which also includes gasoline engine exhaust and lead). It is the first time that aspartame has been assessed by IARC. This classification is based on limited evidence for cancer in humans and experimental animals, and we have a limited understanding of the potential mechanisms through which aspartame could cause cancer.
Based on these findings, the JECFA, which assesses the safety of food additives, concluded that the data did not provide sufficient reason to change the established consumption safety limits, and reaffirmed the acceptable daily intake of aspartame to be 40 milligrams per kilogram of body weight.
To reach the threshold of 40 milligrams per kilogram of body weight per day, an adult weighing 70 kilograms (or around 155 pounds) would need to drink 14 cans of diet soda (each containing 200 milligrams of aspartame) or consume 62 sweetener tablets (with each tablet containing around 45 milligrams of aspartame). A 20-kilogram child (around 45 pounds) would need to drink four cans of soda. These are large amounts for most consumers.
At the same time, WHO has indicated that using NSS does not help in controlling body weight in the long term. So, weighing the absence of benefits of consuming NSS and the potential risk associated to high consumption levels, limiting the amount you consume is advisable. This does not mean, however, we should replace NSS with traditional sugars. Consuming free sugars is linked to gaining weight more easily. We need to reduce the use of sweetened drinks altogether and adapt our taste buds to less sweetness.
How do we do that? Opt for water for drinks and fruit for desserts. Do not have the soda bottle on the table as the main drink. Get accustomed to first reducing and then eliminating the addition of a sweetener to your cup of tea or coffee.
As is the case with science, our understanding of aspartame and other sweeteners can — and should — continue to evolve. IARC and WHO encourage independent research groups to develop better studies (including longer follow-up and repeated dietary questionnaires in observational studies) and randomized controlled trials, including studies of how the human body processes and responds to sweeteners.
It is reassuring that the IARC and JECFA assessments were based on data collected from a range of sources, including peer-reviewed papers, governmental reports and studies conducted for regulatory purposes. The thorough review process by independent experts ensures the credibility and reliability of the evaluations.
However, the limitations in the available evidence for the health effects of aspartame, especially its impact on cancer risk, underscore the need for more scientific studies with improved designs. The reality is that there is still a lot we don’t yet understand about aspartame and how it impacts the human body. So, while the daily acceptable intake guidelines have not changed, consumers would be wise to start trading in their sweet treats for healthier options.
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