February 19, 2025

expert reaction to study looking at aspartame artificial sweetener and insulin levels and blood vessel inflammation in mice

A study published in Cell Metabolism looks at the artificial sweetener aspartame, insulin levels and blood inflammation in mice. 

Prof Naveed Sattar, Professor of Cardiometabolic Medicine/Honorary Consultant, University of Glasgow, said:

“This seems like worrying findings but of course, before it can taken seriously, the findings have to be replicated in man.  There is no good evidence from trials that exogenous insulin increases cardiovascular risks in people with prior cardiovascular disease AND in people with type 1, by improving glucose levels, exogenous insulin lowers many risks.  Whether excess pancreatic insulin occurs with aspartame in amounts regularly consumed occurs and then accelerates vascular risks in man is also not proven.  For now, I remain happy to take sweeteners and related diet beverages instead of sugar filled drinks as the former limits excess calorie intake.”

Prof James Leiper, Director of Research, British Heart Foundation, said:

“This study has revealed much more about the known potential risks of artificial sweeteners.  In these mice, a diet that included an artificially high level of aspartame did exacerbate the size and number of fatty plaques in their arteries.  The effect of these plaques was not measured here, but they are known to greatly increase the risk of a heart attack or stroke.

“While it is important to note that these findings have not yet been seen in humans, the results highlight the importance of further research to determine whether these additions to our food, and their effect on insulin levels, are contributing to an increased risk of cardiovascular events.

“These sweeteners are now found in many foods and drinks, and people are probably consuming more than they realise.  But this research is not a green light to have more sugar instead.  We all need to reduce our intake of the processed foods and beverages that contain high levels of fat, sugars, sweeteners and salt.  This is the best way of ensuring a healthy diet and a lowered risk of heart and circulatory disease.”

Prof Oliver Jones, Professor of Chemistry, RMIT University in Melbourne, said:

“I have several concerns about this study.

“The authors claim that the consumption of Aspartame by adults and children “often exceeds those levels recommended by the FDA” – this is extremely unlikely in my view.  The FDA-acceptable daily intake of Aspartame is 50 mg per kg of body weight per day.  I weigh 80 kg, so this means this means the FDA-based safe dose for me is 4000 mg (or 4 grams) of Aspartame per day, every day, for life.  Given a diet drink contains about 200 mg of Aspartame, I would have to drink the equivalent of 20 cans of diet soda a day to get this dose.  A child of 40 kg would have to drink 10 cans a day, every day.  Even then, the 50 mg/kg dose has a safety factor of 100 built-in.

“The study design also has some issues.  The main one is that the authors used a particular type of lab mouse called an ApoE mouse, which is bred to be prone to heart disease.  They also fed it a high-fat, high-cholesterol diet, which itself increases the risk of heart disease.  They also don’t seem to have measured how much of the Aspartame water the mice drank, or the Aspartame level in the blood, so it is unknown what the mice actually received.

“To my mind, the authors’ admission that feeding mice that are already genetically susceptible to heart disease with a high-fat, high-cholesterol diet that is known to cause heart disease “diminishes clinical relevance” is somewhat of an understatement.

“Contrary to the paper’s claims, it is quite well-established that Aspartame doesn’t stimulate glucose or insulin levels in humans [1, 2].

“Aspartame is essentially just two common amino acids (aspartic acid and phenylalanine) joined together.  In the gut, it is broken down to aspartic acid and phenylalanine.  There is no reason to think amino acids from Aspartame would be worse than those from any other source.

“The authors would appear to think little work has been done on safety testing in Aspartame; this is just not true.  All food ingredients are rigorously tested and safety assessed before they are approved for use.  Aspartame is one of the most researched ingredients in the world.  It is just that a lot of the data is in safety assessments for regulatory approval, not the academic literature.

“Finally, even if Aspartame did cause some increase in cardiovascular risk (which this study does not prove), then that risk would likely be very small compared to things like high fat/high sugar diets and lack of exercise, etc.

“In short, I don’t think this study itself gives us more reason to worry about diet drinks or aspartame.”

References

1 Santos, N. C., de Araujo, L. M., De Luca Canto, G., Guerra, E. N. S., Coelho, M. S., Borin, M. de F. (2017). Metabolic effects of aspartame in adulthood: A systematic review and meta-analysis of randomized clinical trials. Critical Reviews in Food Science and Nutrition, 58(12), 2068-2081. https://doi.org/10.1080/10408398.2017.1304358

2 Stern S.B., Bleicher S.J., Flores A., Gombos G., Recitas D., Shu J. Administration of aspartame in non-insulin-dependent diabetics. (1976) Journal of Toxicology and Environmental Health,. 2(2):429-39. https:// 10.1080/15287397609529444

‘Sweetener aspartame aggravates atherosclerosis through insulin-triggered inflammation’ by Weijie Wu et al. was published in Cell Metabolism at 16:00 UK time on Wednesday 19 February 2025. 

DOI: 10.1016/j.cmet.2025.01.006

Declared interests

Prof Naveed Sattar: “Takes occasional diet drinks.

Has consulted for several companies that make diabetes medicines but also contributed to several lifestyle trials.

“For Novo Nordisk: have consulted for company in advisory boards but not on any of their weight loss drug trial committees; am on steering committee for ZEUS trial but this is not a weight loss trial product but anti-inflammatory.  Do not have any shares either for any product in health etc.

“N.S. declares consulting fees and/or speaker honoraria from Abbott Laboratories, Afimmune, Amgen, AstraZeneca, Boehringer Ingelheim, Eli Lilly, Hanmi Pharmaceuticals, Janssen, Merck Sharp & Dohme, Novartis, Novo Nordisk, Pfizer, and Sanofi; and grant support paid to his university from AstraZeneca, Boehringer Ingelheim, Novartis, and Roche Diagnostics.”

Prof James Leiper: “No conflicts of interest to declare.”

Prof Oliver Jones: “I have no conflicts of interest to declare.”