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Effect of increasing fruit and vegetable intake by dietary intervention on nutritional biomarkers and attitudes to dietary change: a randomised trial.

Duthie, Susan J.; Duthie, Garry G.; Russell, Wendy R.; Kyle, Janet A.M.; Macdiarmid, Jennie I.; Rungapamestry, Vanessa; Stephen, Sylvia; Megias-Baeza, Cristina; Kaniewska, Joanna J.; Shaw, Lindsey; Milne, Lesley; Bremner, David; Ross, Karen; Morrice, Philip; Pirie, Lynn P.; Horgan, Graham; Bestwick, Charles S.


Garry G. Duthie

Wendy R. Russell

Janet A.M. Kyle

Jennie I. Macdiarmid

Vanessa Rungapamestry

Sylvia Stephen

Cristina Megias-Baeza

Joanna J. Kaniewska

Lindsey Shaw

Lesley Milne

David Bremner

Karen Ross

Philip Morrice

Lynn P. Pirie

Graham Horgan

Charles S. Bestwick


Low fruit and vegetable consumption is linked with an increased risk of death from vascular disease and cancer. The benefit of eating fruits and vegetables is attributed in part to antioxidants, vitamins and phytochemicals. Whether increasing intake impacts on markers of disease remains to be established. This study investigates whether increasing daily intake of fruits, vegetables and juices from low (approx. 3 portions), to high intakes (approx. 8 portions) impacts on nutritional and clinical biomarkers. Barriers to achieving the recommended fruit and vegetable intakes are also investigated. In a randomised clinical trial, the participants [19 men and 26 women (39-58 years)] with low reported fruit, juice and vegetable intake ( < 3 portions/day) were randomised to consume either their usual diet or a diet supplemented with an additional 480 g of fruit and vegetables and fruit juice (300 ml) daily for 12 weeks. Nutritional biomarkers (vitamin C, carotenoids, B vitamins), antioxidant capacity and genomic stability were measured pre-intervention, at 4-, 8- and 12 weeks throughout the intervention. Samples were also taken post-intervention after a 6-week washout period. Glucose, homocysteine, lipids, blood pressure, weight and arterial stiffness were also measured. Intake of fruit, fruit juice and vegetables was reassessed 12 months after conducting the study and a questionnaire was developed to identify barriers to healthy eating. During the study, intake increased significantly in the intervention group compared to controls, achieving 8.4 portions/day after 12 weeks. Plasma vitamin C (35%), folate (15%) and certain carotenoids [α-carotene (50%), β-carotene (70%) and lutein/zeaxanthin (70%)] were significantly increased (P < 0.05) in the intervention group. There were no significant changes in antioxidant capacity, DNA damage and markers of vascular health. Barriers to achieving recommended intakes of fruits and vegetables measured 12 months after the intervention period were amount, inconvenience and cost. In conclusion, while increasing fruit, juice and vegetable consumption increases circulating level of beneficial nutrients in healthy subjects, a 12-week intervention was not associated with effects on antioxidant status or lymphocyte DNA damage.


DUTHIE, S.J., DUTHIE, G.G., RUSSELL, W.R., KYLE, J.A.M., MACDIARMID, J.I., RUNGAPAMESTRY, V., STEPHEN, S., MEGIAS-BAEZA, C., KANIEWSKA, J.J., SHAW, L., MILNE, L., BREMNER, D., ROSS, K., MORRICE, P., PIRIE, L.P., HORGAN, G. and BESTWICK, C.S. 2018. Effect of increasing fruit and vegetable intake by dietary intervention on nutritional biomarkers and attitudes to dietary change: a randomised trial. European journal of nutrition [online], 57(5), pages 1855-1872. Available from:

Journal Article Type Article
Acceptance Date May 6, 2017
Online Publication Date May 30, 2017
Publication Date Aug 31, 2018
Deposit Date Jun 2, 2017
Publicly Available Date Jun 2, 2017
Journal European journal of nutrition
Print ISSN 1436-6207
Electronic ISSN 1436-6215
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 57
Issue 5
Pages 1855-1872
Keywords Fruit; Vegetables; Human intervention; Dietary change; Biomarkers; Attitudes
Public URL