Efficacy of food fortification for the prevention of vitamin D deficiency – results of a systematic review and meta-analysis

Abstract

Food fortification with vitamin D is a potentially effective public health strategy to address vitamin D deficiency. The aim of this systematic review was to evaluate the current evidence that food fortification can improve vitamin D status in the population by increasing circulating 25-hydroxyvitamin D (25(OH)D) concentrations in excess of the cut-off levels representing deficient or desirable status.Five medical and health databases (Medline OVID, PubMed, CINAHL, Embase, Cochrane Central Register of Controlled Trials) were searched for randomised controlled trials in free-living adults that used vitamin D-fortified foods and reported circulating 25(OH)D concentrations. A total of 440 abstracts were retrieved. Two reviewers independently screened papers for eligibility and extracted relevant data. Meta-analysis of the absolute mean change in circulating 25(OH)D concentrations was conducted using a random-effects model. Dose, latitude and baseline 25(OH)D were identified a priori as probable sources of heterogeneity. Fourteen trials were included (n 936; 483 treated and 453 controls), derived from eleven published studies (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11) , all of which showed a statistically significant beneficial effect of food fortification on circulating 25(OH)D concentrations. Individual treatment effects ranged from 10.00 (95% 23.20) to 36.25 (22.47, 50.03) nmol/l. There was moderate statistical heterogeneity across the fourteen trials (P = 0.002, I 2 = 60 %) which was not explained by subgroup analyses of dose, latitude and baseline 25(OH)D concentrations. These data suggest a beneficial effect of vitamin D-fortified food on circulating 25(OH)D concentrations. However, the treatment effect is influenced by a variety of factors, such as dose, latitude, baseline 25(OH)D concentrations, sun exposure, dietary vitamin D intake and age. Investigators did not typically report the change in prevalence of individuals with 25(OH)D concentrations below cut-off levels indicating deficiency, so it was not possible to evaluate the effectiveness of fortification in preventing vitamin D deficiency. There is a need for stronger data on the effect of vitamin D-fortified food on vitamin D status using controlled intervention studies and transparent reporting.

Consumer acceptance of and willingness to pay for food nanotechnology: a systematic review

“…Whilst there have been systematic reviews of the regulatory situation surrounding nanotechnology (Grobe 2008 ), to the best of the authors’ knowledge, no systematic reviews of research investigating consumer attitudes, perceptions and acceptance of agri-food nanotechnology have been conducted or registered on the PROSPERO 1 (PROPSERO 2012 ) database, nor on the databases of the Centre for Reviews and Dissemination (Centre for Reviews and Dissemination 2012 ; Besley et al 2008 ) The systematic reviews that have been conducted to date are in the general area of nanotechnology application (e.g. in relation to risk assessment) or have focused on specific food issues, such as vitamin D food fortification (Black et al 2011 ). A systematic review of research into consumer’s attitudes towards and acceptance of agri-food nanotechnology is timely and policy relevant, as simply considering attitudes to specific applications may not reflect general trends in attitudes and consumer priorities for development.…”