British Journal of Nutrition

Full Papers

Nutritional Immunology

β2-1 Fructans have a bifidogenic effect in healthy middle-aged human subjects but do not alter immune responses examined in the absence of an in vivo immune challenge: results from a randomised controlled trial

Amy R. Lomaxa1, Lydia V. Y. Cheunga1, Kieran M. Tuohya2 p1, Paul S. Noakesa1, Elizabeth A. Milesa1 and Philip C. Caldera1 c1

a1 Institute of Human Nutrition and Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, IDS Building, MP887 Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK

a2 Food Microbial Sciences Unit, Department of Food and Nutritional Sciences, School of Chemistry, Food Biosciences and Pharmacy, The University of Reading, Whiteknights, Reading RG6 6AP, UK


β2-1 fructans are considered to be prebiotics. Current literature indicates that β2-1 fructans may modulate some aspects of immune function, improve the host's ability to respond to certain intestinal infections, and modify some inflammatory outcomes in human subjects. However, there is a need to find out more about the modulation of immune markers by β2-1 fructans in humans. Healthy human subjects aged 45–65 years were randomly allocated to β2-1 fructans (Orafti® Synergy1; 8 g/d; n 22) or the digestible carbohydrate maltodextrin as placebo (n 21) for 4 weeks. Blood, saliva and faecal samples were collected at study entry and after 4 weeks. Immune parameters were measured using the blood and saliva samples and bifidobacteria were measured in the faecal samples. Faecal bifidobacteria numbers increased in the Orafti® Synergy1 group (P < 0·001) and were different at 4 weeks from numbers in the placebo group (P = 0·001). There was no significant effect of Orafti® Synergy1 on any of the immune parameters measured (blood immune cell subsets, total serum Ig, salivary IgA, neutrophil and monocyte phagocytosis of Escherichia coli and respiratory burst in response to E. coli or phorbol ester, natural killer cell activity, T cell activation and proliferation, production of six cytokines by T cells). It is concluded that, compared with maltodextrin, Orafti® Synergy1 has a bifidogenic effect in healthy middle-aged human subjects but does not alter immune responses examined in the absence of an in vivo immune challenge.

(Received August 03 2011)

(Revised November 30 2011)

(Accepted December 06 2011)

(Online publication January 16 2012)

Key Words:

  • Prebiotics;
  • β2-1 Fructans;
  • Immune function;
  • Bifidobacteria


c1 Corresponding author: P. C. Calder, fax +44 2380 795255, email

p1 Present address: Nutrition and Nutrigenomics Group, Research and Innovation Centre, FEM-IASMA, 38 010 San Michele a.A, Trento, Italy.


  Abbreviations: CFSE, carboxyfluorescein succinimidyl ester; ConA, concanavalin A; FCS, fetal calf serum; FIFC, fluorescein isothiocyanate; MFI, median fluorescence intensity; PBMC, peripheral blood mononuclear cells; RPMI, Roswell Park Memorial Institute; sIgA, secretory IgA