The Study
Aspartame Metabolism in Normal Adults, Phenylketonuric Heterozygotes, and Diabetic Subjects
This study didn't do any experiments itself — it just looked at other studies and said, 'Some people who ate aspartame had changes in their blood, but we don't know if it was because of the sweetener or something else.' So we can't say aspartame causes those changes — only that they might be linked.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
Scientists looked at old studies to see what happens when people eat aspartame, a sugar-free sweetener.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 51 / 100
Quality score
Based on clinical experience or non-systematic literature reviews. The lowest level of evidence as they are most susceptible to bias and personal perspective.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The changes in blood chemicals are small and not known to harm people, but the studies were not strong.
- 2Aspartame raises phenylalanine and methanol in blood, but doesn't change blood sugar, insulin, or fats in diabetics.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Diabetes Care
Year
1989
Authors
L. Filer, L. Stegink
Related Content
Claims (5)
When your body breaks down aspartame (an artificial sweetener), it turns into three things you already get from foods like meat, beans, and fruit—and your body doesn’t store them up over time.
When people eat or drink things with aspartame (like diet soda), their blood phenylalanine goes up — and this happens more if they haven’t eaten recently, even if they don’t have the genetic condition PKU.
Eating or drinking things with aspartame doesn’t seem to raise or lower blood sugar, insulin, or fat levels in people with diabetes, according to some small studies.
Eating or drinking things with aspartame might raise the amount of methanol in your blood, but we don’t yet know if that’s actually harmful or just a harmless blip.
Some studies say eating aspartame doesn’t mess up your metabolism, but the studies aren’t very strong or many — they just watched people instead of testing them in controlled experiments.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.