Health Effects of Consuming Vegetables Grown in the Presence of Salt: A Systematic Review ()
1. Introduction
In arid and semi-arid areas, salinity problems are common due to several factors. In Africa, salinity and alkalinity affect 24% of the continent’s arid and semi-arid areas [1] and about 30% of the African population depends on these lands [2]. Salinized irrigated land accounts for about 10% and nearly 50% of this land is found in arid areas [3].
Soil salinization is a concern worldwide. According to Pérez, globally, about one third of cultivated land is affected by salinity [4]. This situation could thus lead to a global catastrophe. Salinization is not without enormous consequences for food crops. It causes an increase in oncotic pressure which makes water difficult to mobilize by plants, a toxicity of certain ions for plants, in particular Cl− and Na+ ions [3]. The salt concentration in plant tissues increases as water is lost during the transpiration process [5]. On the other hand, salinization also negatively affects plant growth, reduces land yield, and can make soils unproductive [3] [6]. In the coastal countries of West Africa, in addition to cereal crops, the cultivation of vegetables plays an important role in agriculture to meet the needs of the population. However, the severity of the alteration of the quality of vegetables by salt also depends on the species and cultivar [7] [8]. The objective of this paper is to review the results obtained on the health of rats from different experiments on the consumption of vegetables or mutants of vegetables grown under salt stress.
2. Methods
2.1. Data Sources
Literature searches were conducted in the online databases of: PubMed, Google scholar, Cochrane and African Journal Online (Table 1). The articles selected were those published in English or French between 2011 and 2021. Different papers were also considered by exploiting the dissertations and theses produced in Benin, in particular those from the University of AbomeyCalavi. The research ended on December 31, 2021. The research question was formulated according to the PICO criteria (P = population, I = intervention, C = comparison group and O = results) (Table 2).
Table 1. Search equations used in the different databases.
Table 2. Research question formulated according to the PICO criteria.
2.2. Selection of Studies
The original studies related to the effect of consumption of vegetables or vegetable mutants grown under salt stress were those that should be included according to the selection criteria. The selection of studies from the electronic databases was done by the authors (AG and SE) in isolation. No discrepancies were observed.
2.3. Data Extraction
The information collected depends on the type of study, the population, the duration of the intervention and the results obtained.
3. Main Results
Figure 1 presents the literature search process. The initial selection of studies was 436, of which 109 were excluded as duplicates. After analyzing the titles of the articles, 323 articles had titles that were not relevant to the topic of this review. However, three articles addressed the nutritional aspects of vegetables grown under salt stress but none of the articles addressed the health effect of consuming these vegetables (Figure 1).
4. Discussion
Based on the literature search, there are no articles that have discussed the health effect of consuming vegetables grown under salt stress or articles that have discussed the health effect of consuming mutants of vegetables grown under salt stress.
Studies that have addressed the nutritional aspects of vegetables grown under salt stress have presented beneficial results reported in Table 3 [8] [9] [10]. However, these studies did not focus on the analysis of all the nutrients of these vegetables. Therefore, it is difficult to rule on the precise impact of salt stress on nutritional quality and in turn on the correlation between the consumption of vegetables grown under salt stress and the alteration or not of health status. It is therefore important, even if benefits seem to exist, to investigate whether there are any drawbacks before recommending their consumption.
5. Conclusion
The present literature review reveals that salt stress could have a beneficial effect on the levels of some B-complex vitamins and iron content. However, the current literature does not contain available information on the effect of salinity on the complete nutritional values of vegetables and sodium levels have not been measured, let alone the effect of consumption of these vegetables on arterial
Table 3. Status of studies that addressed nutritional quality.
health. Further research is needed to investigate the mineral content, especially sodium chloride.