Blood tests for vitamin C and plant pigments stay accurate even after years in storage, making them trustworthy tools to measure how much fruit and vegetables people eat over time.

Scientific Claim

Plasma vitamin C and carotenoid levels are stable over long-term storage and show high reproducibility, validating their use as reliable biomarkers of long-term fruit and vegetable intake in epidemiological studies.

Original Statement

“The reproducibility for the measurement of these biomarkers was high for most biomarkers (r=0.89-0.93), and moderate for zeaxanthin (r=0.63).”

From study:Unknown Title

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The claim describes a methodological validation finding using 'are stable' and 'show high reproducibility' — appropriate for a descriptive finding based on direct measurement data.

Evidence from Studies

Supporting (1)

Unknown Title

Cohort Study

Human

The study found that people with higher levels of vitamin C and carotenoids in their blood ate more fruits and vegetables over time, and these blood levels stayed consistent enough to accurately show how much produce people were eating—making them reliable markers.

Contradicting (0)

No contradicting evidence found

Source Study

Unknown Title

Score: 59

DOI: 10.1136/bmj.m2194

Similar Assertions

People with more vitamin C in their blood — which comes from eating fruits and vegetables — are less likely to get type 2 diabetes, even after accounting for other healthy habits.

75%

People who eat about 66 grams more fruits and vegetables each day — roughly one extra apple or a cup of carrots — have a 25% lower chance of getting type 2 diabetes, according to blood tests that measure plant nutrients.

72%

When people who don't eat much fruit or veggies start eating about 8 servings a day for 3 months, the level of vitamin C in their blood goes up by 35%, meaning their body gets more of this important nutrient.

71%