by Brian T. Lynch, MSW
More and more people are looking to purchase organic foods in the belief that organically grown food is healthier. There has been growing concern about possible health impacts from the agrochemicals used in traditional crop production. These chemicals have included pesticides growth regulators and various petrochemical fertilizers. Many of these synthetic chemicals are not permitted in organically grown food. This often requires organic farmers to adopt different methods of crop production including mechanical weeding and different schedules of crop rotation. The question has been whether the absence of agrochemicals and the differing methods of food production actually produce safer or more nutritious crops.
A recent meta-analysis of 343 peer reviewed studies was published in the British Journal of Nutrition. This analysis uncovered that there are indeed significant differences between organically grown and traditionally grown crops. It was found that organically grown crops have higher antioxidants and lower concentrations of trace metals such as cadmium. I higher intake of antioxidants, such as those found in organic foods in this study, have been found to reduce the risk of cardiovascular disease and certain types of cancer such as colon cancer. Antioxidants have also been linked to a lower risk of certain degenerative neurological conditions. Low dose, long-term exposure to cadmium can be damaging to the kidneys and can lead to the formation of kidney stones.[http://www.epa.gov/osw/hazard/wastemin/minimize/factshts/cadmium.pdf]
For more detailed information on this study the abstract has been appended below along with a link to the original study.
News that organically grown food is richer in antioxidants is especially encouraging news since there continues to be little evidence that antioxidant supplements have a beneficial effect on health. it appears that not all substances with antioxidant properties have beneficial effects, and in some cases the effects of certain anti-oxidant chemicals can be harmful. What seems to be important for receiving health benefits from antioxidant substances is to obtain them through fresh fruits and vegetables rather than through supplements.
The school of Public health at Harvard has published a good review of the benefits of antioxidants, the just of which reads:
Free radicals contribute to chronic diseases from cancer to heart disease and Alzheimer’s disease to vision loss. This doesn’t automatically mean that substances with antioxidant properties will fix the problem, especially not when they are taken out of their natural context. The studies so far are inconclusive, but generally don’t provide strong evidence that antioxidant supplements have a substantial impact on disease. But keep in mind that most of the trials conducted up to now have had fundamental limitations due to their relatively short duration and having been conducted in persons with existing disease. That a benefit of beta-carotene on cognitive function was seen in the Physicians’ Health Follow-up Study only after 18 years of follow-up is sobering, since no other trial has continued for so long. At the same time, abundant evidence suggests that eating whole fruits, vegetables, and whole grains—all rich in networks of antioxidants and their helper molecules—provides protection against many of these scourges of aging. [ http://www.hsph.harvard.edu/nutritionsource/antioxidants/ ]
Demand for organic foods is partially driven by consumers’ perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences.
In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods.
Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95 % CI 5, 33) %, 69 (95 % CI 13, 125) %, 28 (95 % CI 12, 44) %, 26 (95 % CI 3, 48) %, 50 (95 % CI 28, 72) % and 51 (95 % CI 17, 86) % higher, respectively.
Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd.
Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons.
[ http://csanr.wsu.edu/m2m/papers/organic_meta_analysis/bjn_2014_full_paper.pdf ]
The Authors 2014. The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution licence http://creativecommons.org/licenses/by/3.0/
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