Longitudinal cohort study of canola composition demonstrates changes in the climate and the food system are decreasing the essential fatty acid content of canola

Abstract

Background

Canola oil represents a vital source of essential fatty acids (EFA), linoleic (LA), and α-linolenic acid (ALA). In assessing EFA intake, clinicians and nutritionists consult food composition databases; however, nutritional composition data may not reflect changes in food composition due to environmental factors. As the leading global exporter, Canada annually monitors canola quality in Manitoba, Saskatchewan, and Alberta using the Canadian Grain Commission’s Harvest Sample Program, providing a geographical cross-section of canola composition which may provide empirical evidence for changes in EFA content for canola oil.

Objective

Use fatty acid composition data from 2010 to 2022 to determine 1) regional variability, 2) temporal variability, and 3) estimate how much of the observed variability can be related to differences growth temperature.

Method

Using the Harvest Sample Program and contemporaneous climate data, we constructed a model relating EFA composition with mean daytime high temperatures during flowering and seed development.

Results

Data for this cohort showed the average mean ALA content decreased from 9.93 ± 0.78 mass % (average mean± standard deviation) to 8.16 ± 0.46 mass %, with a concomitant increase in oleic acid. LA content was less variable, with a maximum of 19.21 ± 0.52 mass % in 2012 and a minimum of 18.06 ± 0.32 mass % in 2022. LA and ALA content are negatively correlated to daytime high temperature.

Conclusion

Compared our observations to publicly available food composition databases, the observed systemic changes in fatty acid composition from the field can be detected on grocery store shelves.