The Claim

Consumption of aspartame is associated with increases in blood phenylalanine levels in normal adults and phenylketonuric heterozygotes, and the magnitude of this increase is influenced by feeding status.

Source: Aspartame Metabolism in Normal Adults, Phenylketonuric Heterozygotes, and Diabetic Subjects

What the research says

Roughly balanced

Support and challenge are close. The picture may shift as more studies come in.

Supports
1score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

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.

See the scientific wording

Aspartame consumption is associated with increases in blood phenylalanine levels in normal adults and phenylketonuric heterozygotes, with the magnitude influenced by feeding status.

What the research says

1 study
  1. Study: Aspartame Metabolism in Normal Adults, Phenylketonuric Heterozygotes, and Diabetic Subjects

    This study looked at what happens to a chemical called phenylalanine in people’s blood after they eat or drink aspartame, and it found that it goes up — just like the claim says. It also checked this in different situations, like when people are fed or fasting, which matches the claim too.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

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