Research & Your Health is a series of articles written in accessible, everyday language, focused on the latest scientific research of natural health products.
On April 22, 2016
Background: Various studies have shown there is still scientific uncertainty over whether, and to what extent, organic production results in significant and nutritionally relevant changes in food quality. To be certified organic, livestock must be reared outdoors for part of the year, must receive 60 per cent of their food intake from grazing, from fresh cut forage or from conserved forage such as silage or hay. Meat is an important source of protein, fatty acids, minerals and vitamins, yet studies to date, have focused on meat fat composition and less so on mineral and vitamin concentrations. Saturated fatty acids (SFA) are widely considered to have negative effects on health whereas polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) are thought to have positive effects and decrease the risk of cardiovascular diseases (CVD).
Objective: This review compared 67 independent studies to determine whether there were health benefits to eating organic meat over non-organic meat. It focused on concentrations of SFA, monounsaturated fatty acids (MUFA) and PUFAs between organic and inorganic meat products. Findings help determine whether the effects of livestock management practices (feeding practices) and potential health impacts of composition differences between organic and non-organic meat are worthwhile to human health.
Methods: This was a review paper where 707 initial and relevant publications were identified through database searching published between 1992 and 2014 and from eight EU countries and seven countries outside of the EU. All abstracts were examined to determine if they contained original data regarding organic versus conventional beef, lamb, goat, pork, poultry or rabbit meat, which narrowed the selected publications to 67. From these 67 publications, data was extracted and six analyses methods were utilized to compare relative differences between conventional and organic meat samples. In order to evaluate the fatty acid content (SFA, MUFA and PUFA), data was extracted from the original publications and was converted into a common unit (g/100g total fatty acid esters).
Results: When data for all meat types was analyzed together, significant differences in fatty acid profiles were detected between organic and conventional meat. Organic meat had similar SFA and higher PUFA concentrations compared with conventional meat. When data for different meat types was analyzed separately, no differences in SFA were detected for beef, lamb, goat or pork, but significantly lower SFA concentrations were detected for organic chicken. MUFA concentrations were found to be significantly lower for organic pork and chicken only. Last, in terms of PUFA concentrations, significantly higher concentrations were detected for pork and chicken meat, but not for beef and lamb meat, respectively.
Conclusion: Results of this review article report for the first time that there are significant and nutritionally meaningful composition difference between organic and non-organic meat when evaluating the fatty acid content of SFA, PUFA and MUFA. Production of organic livestock may change the fatty acid profiles and possibly other composition parameters that may be nutritionally desirable. This is contradictory to previous literature reviews stating there were no significant composition differences between organic and conventional livestock products.
Findings and perspectives: Although the overall findings from this review showed that there are significant and nutritionally meaningful composition differences between organic and non-organic meat, results for specific parameters were variable and serious deficiencies in the evidence resulted in considerable uncertainty. It would therefore be important to carry out additional studies to address the limitations in the current evidence base. If nutritionally relevant composition differences could be confirmed and/or linked to specific agronomic practices, it would then help justify dietary intervention or cohort studies designed to identify the impact of consuming meat with contrasting composition generated by switching to organic production or specific agronomic practices.
Srednicka-Tober, D., Baranski, M., Seal, C., et al. British Journal of Nutrition (2016), 115, 994-1011