Some of the food sources of ω-3 and ω-6 fatty acids are fish and shellfish, flaxseed (linseed) , hemp seed, soya oil, canola (rapeseed) oil, chia seeds, pumpkin seeds, sunflower seeds, leafy vegetables, and walnuts.he term essential fatty acid refers to fatty acids required for biological processes but does not include the fats that only act as fuel. Essential fatty acids should not be confused with essential oils, which are essential in the sense of being a concentrated essence.