In the U.S., the amount of harmful fats from processed foods in people’s blood dropped by more than half between 2000 and 2009, likely because food labels and restaurant rules changed to cut down on these fats.

Scientific Claim

Plasma levels of trans-fatty acids (TFAs) in non-Hispanic white U.S. adults decreased by 58% between 2000 and 2009, with the sum of four major TFAs (elaidic, vaccenic, linoelaidic, and palmitelaidic acids) dropping from 54.1 µmol/L to 22.4 µmol/L, reflecting a substantial population-level reduction in industrial TFA exposure.

Original Statement

“The weighted geometric mean of the difference for the sum of all 4 TFAs was 54.1 µmol/L (95% CI, 43.4–64.7 µmol/L) or 58% lower in samples from 2009 compared with samples from 2000.”

From study:Levels of plasma trans-fatty acids in non-Hispanic white adults in the United States in 2000 and 2009.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

The claim describes an observed change in biomarker levels over time using direct measurements from representative samples. The study design supports this descriptive claim, and the language accurately reflects the data without implying causation.

Evidence from Studies

Supporting (1)

Levels of plasma trans-fatty acids in non-Hispanic white adults in the United States in 2000 and 2009.

Cross-Sectional Study

Human

2012 Feb 8

The study found that the amount of harmful trans fats in people’s blood dropped by more than half between 2000 and 2009, which means people were eating less of them—likely because food labels started showing trans fat content and restaurants changed their recipes.

Contradicting (0)

No contradicting evidence found

Source Study

Levels of plasma trans-fatty acids in non-Hispanic white adults in the United States in 2000 and 2009.

Score: 42

DOI: 10.1001/jama.2012.112

Similar Assertions

Three other types of trans fats found in processed foods also dropped sharply in people’s blood between 2000 and 2009, showing the decline wasn’t just one type — it was a widespread change.

81%

This study only looked at white adults in the U.S., so we don’t know if the same drop in trans fats happened in Black, Hispanic, or younger people — the results only apply to this group.

78%

One of the main types of trans fat in people’s blood — called vaccenic acid — dropped by more than half in just nine years, showing that people were eating less of these harmful fats overall.

78%

Not all trans fats are the same — some might be more harmful, and others might be less harmful, depending on where they come from.

71%

Eating foods with artificial trans fats, like some fried or baked goods, is linked to higher bad cholesterol in people on tightly controlled diets.

71%