A literature‐based comparison of nutrient and contaminant contents between organic and conventional vegetables and potatoes

Abstract

Purpose: The increasing demand for organic foods is explained mainly by consumers' concerns about the quality and safety of foods and their perception that organically produced foods are healthier and safer than conventional foods. Based on internationally available concentration data of organic and conventional vegetables (carrots, tomatoes, lettuce and spinach) and potato, it was aimed to investigate the scientific validity of nutrition claims as "no vegetable/potato has higher amounts of nutrient X than organic vegetables/potatoes" and "no vegetable/potato has lower amounts of contaminant Y than organic vegetables/potatoes".Design/methodology/approach: Detailed nutrient and contaminant databases were developed for organic and conventional vegetables separately. Non-parametric (Mann-Whitney test) methods were used to detect significant differences between both types of vegetables. A chisquare test was used to compare the incidence of pesticide residues in organic and conventional vegetables.

Effect of Organic Potato Farming on Human and Environmental Health and Benefits from New Plant Breeding Techniques. Is It Only a Matter of Public Acceptance?

“…The main features of organic farming are claimed to be sustainability, low-impact cropping methods, use of non-chemical fertilizers, and high-quality production; nevertheless, an objective and exhaustive assessment on the supposed higher nutritional value of organic food and on the benefits on consumers' health is still missing. Generally, organic food presents lower nitrates and higher content in vitamin C, but this is not true for all species; spinach, for example, accumulates more nitrates under organic farming than other farming systems [6][7][8]. A literature-based study including potato [7] revealed that organic vegetables are not significantly better than conventional ones and, in addition, experimental findings are often contradictory due to the influence of environmental factors and large genetic diversity among potato varieties tested.…”

“…Generally, organic food presents lower nitrates and higher content in vitamin C, but this is not true for all species; spinach, for example, accumulates more nitrates under organic farming than other farming systems [6][7][8]. A literature-based study including potato [7] revealed that organic vegetables are not significantly better than conventional ones and, in addition, experimental findings are often contradictory due to the influence of environmental factors and large genetic diversity among potato varieties tested. Up to date, only few studies focused on organic potatoes and most of them investigated target beneficial (vitamin C, flavonoids, vitamin B1, phenolics) and harmful compounds (heavy metals, glycoalkaloids, nitrates, residues of pesticides), organoleptic properties, and agronomic parameters (yield, tuber size, germination of tubers, starch content).…”

“…Up to date, only few studies focused on organic potatoes and most of them investigated target beneficial (vitamin C, flavonoids, vitamin B1, phenolics) and harmful compounds (heavy metals, glycoalkaloids, nitrates, residues of pesticides), organoleptic properties, and agronomic parameters (yield, tuber size, germination of tubers, starch content). Surprisingly, a high vitamin C content, typical of most organic food, is not always confirmed in organic tubers [7,[9][10][11][12] that, indeed, frequently show high content of vitamin B1 [11]. Organic restrictions on fertilization causes a reduced nitrogen availability, resulting in a lower N content in organic tubers, that could strongly influence the vitamin C content, together with the concentration of nitrate and total proteins [6,7] and the content and composition in free amino acids.…”

“…Surprisingly, a high vitamin C content, typical of most organic food, is not always confirmed in organic tubers [7,[9][10][11][12] that, indeed, frequently show high content of vitamin B1 [11]. Organic restrictions on fertilization causes a reduced nitrogen availability, resulting in a lower N content in organic tubers, that could strongly influence the vitamin C content, together with the concentration of nitrate and total proteins [6,7] and the content and composition in free amino acids. Lysine, the most abundant free amino acid in potato, was often found significantly higher in organic tubers [10,13].…”

Importance of health and environment as quality traits in the buying decision of organic products

“…For each of the two quality traits (health or environment), two attributes were included in the choice experiment, of which one triggers desirable (positive) expectations and the other undesirable (negative). The choice of the attributes (and their levels) was the result of careful deliberation between the choice experiment preconditions and objective scientific boundaries, the latter based upon an extensive literature review (Hoefkens et al, 2009 andMondelaers et al, 2009). …”