Food security interventions have been difficult to measure. Although there are many reviews testing the effects of agricultural interventions with the aims of increasing food availability, diversifying diets, increasing incomes and supplementing essential vitamins and minerals, the effects on nutritional status are not well covered (see table 13 below). 

Table 13 Summary of reviews of the impact of agricultural interventions on nutrition

Source: Masset et al (2011)

A systematic review of agricultural interventions involving over 7200 papers (Masset et al, 2011) covered bio-fortification interventions, home gardens, aquaculture and small fisheries, dairy development and animal source food promotion, that aimed to improve children’s nutritional status by improving the incomes and the diet of the rural poor. The time frame was 1990 to the present. However, of these papers, only 23 were methodologically sound enough to draw concrete conclusions. Of these, 19 reported programme impact on the diet composition of the beneficiary population. The majority of studies found a positive impact of the interventions on the consumption of specific foods. As expected, home garden programmes increased the consumption of fruit and vegetables; aquaculture and small fisheries interventions increased the consumption of fish, while dairy development projects increased the consumption of milk. There are, however, a number of exceptions where no changes were observed.

Nineteen studies on the impacts of agricultural interventions are summarized here of which 12 showed a higher consumption of vegetables (mostly) and higher dietary diversity, significant at the 5% level or better. Of these, for six studies the observed population was preschool children. Broadly speaking, this says that there are interventions in home gardens that have led to improved dietary diversity of young children. Their effectiveness in the semi arid areas of the NW states will be questionable, as they require a stable water supply. Green vegetables are abundant in the markets in these states and these crops are often grown on low lying swamp (fadama) land.

Four of the studies that were assessed investigated the impact of the interventions on iron intake. The findings of these studies cannot be aggregated in a summary figure of impact because iron intake measurement were taken and reported in different ways. One study (Talukder et al. 2010) reported a statistically significant reduction in anaemia prevalence among non-pregnant women in project areas and no change in non-intervention areas. The other three studies found no statistically significant impact of the interventions on iron intake

With regards to Vitamin A, nine studies reported mean concentration of serum retinol in blood samples from project and control areas. Here the results are also ambiguous: only four of these studies reported means and standard deviations of children in project and control areas.

Finally, in assessing impact on nutritional status, anthropometric data were collected by 13 of the 23 studies included in the review. However, four of these studies had further deficiencies. The remaining studies calculated prevalence rates of under nutrition with statistical tests of significance. One study (Gunaratna et al. (2010)) employed rates of growth and found positive and statistically significant impact on nutrition by the interventions. However, only one study found a statistically significant impact on prevalence of stunting, while 3 studies (out of 8) found an impact on prevalence rates of underweight and two found an impact on wasting. The relatively greater success of agricultural interventions in reducing the prevalence of underweight and wasting compared to stunting can be explained at least in two ways: (i) the interventions may be better suited to addressing short-term under nutrition rather than chronic under nutrition, and (ii) the studies assessed impact shortly after the interventions had taken place and therefore could not capture longer term impact.