Discussion

In the present study, based on comparison of data from the Dietary and Nutritional Surveys of British Adults, there was an increase in the proportion of adults who consumed 5 or more portions of fruit and vegetables per day from 12·7 % in 1986–1987 to 16·5 % in 2000–2001. Improvements were seen across social class groups. Differences between men and women and between regions reduced between 1986–1987 and 2000–2001. Those on benefits, those unemployed or economically inactive and couples or lone parents with dependant children were less likely to comply than their comparators in 1986–1987 and 2000–2001.

The survey data are of high quality, being based on nationally representative samples, weighed dietary records and validated methods. Our observations were based in the first instance on comparison of findings in two cross-sectional surveys and subsequently strengthened by formal testing in logistic regression analysis including survey year as a variable. The sample from 2000–2001 contained a greater proportion of older people and people in upper social classes than did the 1986–1987 sample. In both surveys response rates were calculated for the number of respondents completing full 7 d weighed dietary records as a proportion of the number of eligible respondents. As the response rate fell from 70 % to 47 %, bias introduced by self-selection of participants pursuing a healthier lifestyle is possible. Extensive analysis of response rates by sociodemographic group, region and recruitment waves showed consistent changes in response rates across the entire population⁽ Reference Gregory, Foster and Tyler ^{16 ,} Reference Hoare, Bates and Prentice ^{17 )}; and we note that the changes in age distribution and social class are consistent with demographic trends and that independent effects for age, region, employment status, marital status and survey year are confirmed in logistic regression analyses. In both years surveys were conducted in four rounds across spring, summer, autumn and winter. It was not possible to formally adjust for seasonality as date of the survey was only made available for the later data set. However, given the systematic sampling approach which included consideration of geographic units and similar response rates across rounds in each survey, we are not anticipating that a residual seasonality effect will have caused an important bias in our results.

A study comparable to ours is that of Roos et al.⁽ Reference Roos, Talala and Laaksonen ^{21 )} looking at socio-economic differences in daily vegetable intake from 1979 to 2002 among Finish adults. In that study, daily consumption of vegetables was more common among those with higher income or higher education level, and among women, during the whole study period. However, the increase was higher in the lower educational and lower income groups during the study period, meaning that the socio-economic divide narrowed for vegetable intake during this period. In contrast, analyses of the Dutch National Food Consumption Surveys for 1987–1988, 1992 and 1997–1998 demonstrated a decrease in consumption of fruit and vegetables over the period⁽ Reference Hulshof, Brussard and Kruizinga ^{22 )}. Socio-economic differentials were present at baseline, which were more marked in women than in men, and changes towards lower consumption of fruit and vegetables were seen in all socio-economic groups in later years.

Meanwhile, in the USA the proportion complying with fruit and vegetable goals appears to have remained static through the same time period. Casagrande et al.⁽ Reference Casagrande, Wang and Anderson ^{23 )} examined data from the National Health and Nutrition Examination Survey and found that 24·3 % complied with the recommended 5 or more portions of fruit and vegetables per day in 1988–1994 and 23·6 % in 1999–2002. Blanck et al.⁽ Reference Blanck, Gillespie and Kimmons ^{24 )} used a different data source (the Behavioral Risk Factor Surveillance System) to show for both men and women that the percentage who met 5 or more per day did not change: 20·6 % in 1994 and 20·3 % in 2005. Complementary analyses of the same data indicated that there were actually increases in fruit and vegetable consumption in 1990–1996⁽ Reference Ruowei, Serdula and Balnd ^{25 )}, but these fell away in 1994–2000⁽ Reference Serdula, Gillespie and Kettel-Kahan ^{26 )}.

The years between the Dietary and Nutritional Surveys of 1986–1987 and 2000–2001 were at the beginning of a phase of food policy direction reinforced by statements of explicit recommendations^{( 7 , 8 )} and characterised by early selective and universalist approaches towards improving fruit and vegetable consumption in the UK. The former were driven by and large by the voluntary sector and public sector groups, and ranged in character from supplying food to teaching cooking and budgeting skills. At the same time various retailers were beginning to accept a notion of social responsibility and introduce economy ranges of food and business models that did not depend exclusively on out-of-town supermarkets^{( 8 )}. In England, there was little by way of centrally coordinated food policy, with the Department of Health and the Ministry of Agriculture, Fisheries and Food adopting principally a monitoring role⁽ Reference Nelson ^{27 )}. Lack of leadership could be less true for the devolved administration in Scotland and it is interesting to speculate whether the changes in regional differentials between the two surveys reflect the effective implementation of elements of the Scottish Diet Action Plan^{( 7 )}.

Some encouragement should be taken from the findings of our research in that there has been an increase in the proportion of ‘compliers’ between 1986–1987 and 2000–2001 and closure of the gender gap. The data also indicate the continuing challenge of social class, where a fourfold difference in the proportion of ‘compliers’ persists between social class I and social class V. The evidence base for interventions directed towards individuals and groups has grown considerably in the last decade and policy can be framed around selective and universalist interventions that are evidence based⁽ Reference Pommerleau, Lock and Knai ^{28 )} and/or can build on work that has gone before in communicating messages to the public and to specific segments of the population in particular circumstances⁽ Reference Pollard, Miller and Daly ^{29 ,} Reference Bremner, Dalziel and Evans ^{30 )}.

We hope that momentum has not been lost since 2001 and note that Dowler⁽ Reference Dowler ^{31 )} has recently presented a framework for addressing households’ nutritional needs, summarising the range of policy responses in the UK to inequalities in diet and nutrition broadly under the remit of ‘health’, ‘education’ and ‘commercial food access’. Data from the Dietary and Nutritional Survey for 2008–2009 are now available and early indications are that there has been a further improvement in compliance with fruit and vegetable goals^{( 32 )}. We hope it may be possible eventually to see an extended analysis similar to the work presented here, using systematic methods to examine trends across all three surveys.