Biomarkers of Fruit and Vegetable Intake in Human Intervention Studies: A Systematic Review

Abstract

Observational evidence consistently shows that consumption of a diet rich in fruit and vegetables may offer protection against diseases such as cardiovascular disease and cancer. Assessment of dietary intake is complex and prone to many sources of error. More objective biomarkers of fruit and vegetable intake are therefore of interest. The aim of this review is to examine the usefulness of the main biomarkers of fruit and vegetable intake to act as objective indicators of compliance in dietary intervention studies. A comprehensive search of the literature was conducted using six databases. Suitable papers were selected and relevant data extracted. The papers were categorized into 3 sub-groups: whole diet interventions; mixed fruit and vegetable interventions; and studies involving individual varieties of fruits or vegetables. Ninety-six studies were included in the review. Overall, the most commonly measured, and most consistently responsive, biomarkers were the carotenoids and vitamin C. Based on the results of this systematic review, it remains prudent to measure a panel of biomarkers in fruit and vegetable intervention studies. The only possible exception to this is "fruit only" intervention studies where assessment of vitamin C alone may suffice.

Effect of fruit and vegetable intake on oxidative stress and inflammation in COPD: a randomised controlled trial

“…A 12-week period was chosen for this study as this has been shown to be sufficient time to ensure an increase in micronutrient status [11] in response to FV interventions, and also to induce changes in plasma C-reactive protein (CRP) and urinary isoprostanes [12,13]. Interleukin (IL)-8 has recently been shown to be responsive to 10-week dietary interventions (with bread [14] and cheese [15]).…”

Dietary fiber intake and risk of colorectal cancer and incident and recurrent adenoma in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

“…However, because flexible sigmoidoscopy-which only assesses the distal (left-sided) colon and rectum-was used for screening, proximal adenoma could not be evaluated, and the results observed for distal or rectal adenoma may not be generalizable to proximal adenoma. Dietary assessment is also complex and FFQs are not a perfect measure of habitual dietary intakes; therefore, intakes of some foods, including fruit and vegetables, may have been underestimated because of difficulty in the accurate recall of usual intakes (32). Whereas the misreporting and misclassification was likely equal between groups, it may still have reduced the ability to detect associations and resulted in residual confounding.…”

Carotenoids and alkylresorcinols as objective biomarkers of diet quality when assessing the validity of a web-based food record tool and a food frequency questionnaire in a middle-aged population

“…; lutein, zeaxanthin, β-cryptoxanthin, lycopene, α-carotene and β-carotene) were used as biomarkers of fruit and vegetable intake [17,18]. The plasma concentrations were determined with high-performance liquid chromatography (HPLC).…”

“…Although the available recovery or prediction biomarkers do not capture total intake of these food groups on an absolute scale, it is possible to distinguish between high and low intakes of these food groups using concentration biomarkers. Plasma carotenoids are considered to reflect the intake of fruits and vegetables in a satisfactory manner [17,18] and are amongst the most commonly used concentration biomarkers in dietary validation studies today. In a "western diet", approximately 80 to 90 % of the total carotenoid intake derives from fruit and vegetable consumption of which yellow-orange fruits and vegetables and dark green leafy vegetables are particularly rich in carotenoids [17].…”