Organically grown fruit and vegetables are regularly ascribed beneficial health effects. Is this assumption actually substantiated by thorough scientific research or is it rather the result of a smart marketing team? FreshPlaza delved deeper into the literature and revealed two frequently submitted health claims.
Statement 1: organic is richer in important nutrients
To the naked eye, the difference between organic and conventional vegetables is negligible. You cannot decide whether you’re dealing with an organic or conventional product based on smell or flavour. It’s more helpful to look at nutritional value as a starting point. In an episode of Dutch TV show Broodje Gezond, which aired in May 2016, Wijnand Sukkel, researcher of biodynamic agriculture at the WUR, looked deeper into the question of whether organic vegetables are richer in health-promoting nutrients.
According to the researcher, there definitely are differences in the amount of active plant substances. For example, he explains that organic vegetables contain more antioxidants. These antioxidants protect the human body against free radicals, harmful substances known to disrupt cell structure and cause tissue damage. The antioxidant properties of polyphenols are often associated with a reduced risk of cardiovascular disease in scientific literature, and are also thought to have anti-carcinogenic effects.
Earlier research also indicates a higher presence of important nutrients in organic vegetables. In March 2008, the American Organic Center published a report comparing research into nutritional composition of organically and conventionally grown vegetables. The data used dates back to the early 1980s. In the study, 135 products were compared. In 62 per cent of the comparisons, the organic product scored higher in the field of antioxidants, vitamins and minerals than the conventional supply. However, the results appear to be strongly bound by product and region. By way of illustration, in that same year, a Danish publication also revealed that there was hardly any difference in minerals between conventional and organic cabbage, carrot, pea and potato. To some extent, the findings even spoke in favour of conventional cultivation.
Food experts practically unanimously agree that organic vegetables contain up to 20 per cent more dry matter. Due to the lower moisture balance, the nutrients are grouped more compactly in relation. On balance, organic vegetables are more nutritious than conventional ones. The fact remains that according to this reasoning, a 20 percent higher intake of conventional vegetables amounts to the same results.
American scientists, affiliated with the University of New Jersey, warn that excesses are harmful and moreover, they say that a dose that’s too high could possibly contribute to liver failure. Science therefore profits more from shifting the issue concerning the presence of health-promoting nutrients to finding an optimal balance in that. The dividing line for that is wafer-thin: a positive effect on human health can quickly turn into a negative one due to excessive use. That optimal balance — and whether organic and conventional can support each other — is still a controversial subject in the scientific literature.
Statement 2: organic contains fewer contaminants
The discussion regarding contaminants, or substances that end up in food inadvertently or unintentionally, focuses mostly on the presence of pesticides, fungal toxins and other environmental contaminants such as heavy metals and nitrate.
Both European and American research emphasises that people who consume organic fruit and vegetables have fewer (residues of) pesticides in their body. In an American study, 4,466 Americans were presented with a questionnaire that coupled their eating habits to the consumption of organic food. As a check, a urinary sample was taken from all respondents. On average, respondents with organic food in their diet had 65 per cent fewer pesticides in their urine. These results were published in scientific journal Environmental Health Perspectives. However, the same researchers emphasised that consumers who consume only conventional fruit and vegetables are not worse off. The observed residues in the study remained within the legal standards.
The opinions are divided on the amount of nitrate in organic vegetables. On average, organic vegetables contain a lower amount of nitrate than conventional cultivation. But there are some peaks. A Dutch monitoring study from 2008 in the scientific journal Food Additives & Contaminants, for example, suggested that organic carrot had a higher nitrate content than conventional carrots.
It has long been thought that organically grown vegetables have to create more anti-fungal substances to keep invaders at bay, because pesticides are out of the question, and they therefore have to rely on their ‘survival instinct.’ The Louis Bolk Institute indicates the contrary in the publication ‘Food Quality, Safety and Health of Organic Products,’ and talks about ‘clear indications that organic products would sooner contain less rather than more fungal toxins compared to conventional products.’
A contributing factor is that crops with a natural low sensitivity to fungi are selected in organic cultivation more often. The researchers posit that climatological circumstances and cultivation region have more influence on the creation of mycotoxins than the cultivation method itself.
The same report is resolute in its claim about the presence or absence of environmental contaminants in organic potatoes and vegetables. “There are no indications that potatoes and vegetables contain more heavy metals. Lead levels sometimes appear to be slightly higher, but the quantities remain below the norm,” the finding concludes.
However, in the Netherlands in August 2016, it was reported that there was excessive and unauthorised use of copper in organic potato farming. The question is how much of that claim remains when seen in that light.
Potato disease phytophthora infestans was very active last summer, which meant that several growers were forced to use copper oxichloride for fear of otherwise losing half their harvest. However, copper oxides can no longer be used as a pesticide since the turn of the century, only as a leaf fertiliser, and then only to a very limited degree (6 kg per hectare). Supervisor Skal, however, noted that some growers used this substance under false pretences, and he even spoke of abuse.
Some nuance required
The health claims regarding organic fresh produce remain strongly dependent on product group, variety choice, fertilising strategy, harvesting moment and the conditions after harvesting. Environmental factors such as cultivation location, soil type and weather conditions are also of influence for the presence or absence of important nutrients or contaminants.
