Evidence suggests that many people do not ingest the correct ratio of n-6 to n-3 fatty acids, and as a result they develop chronic systemic inflammation that may cause disease and ill health. Current recommendation is to reduce dietary intakes of n-6 fatty acids and to increase intakes of n-3 fatty acids in order to rebalance the current n-6 to n-3 ratio from 6 to 10:1 to around 3:1. Eating fatty fish or consumption of fish oils have been shown to be effective at increasing plasma phospholipid concentrations of eicosapentanoic acid (EPA, C20:5 (n-3)) and docosahexanoic acid (DHA, C22:6 (n-3)). These two fatty acids can inhibit the formation of inflammatory eicosanoids which may reduce the risk of cardiovascular disease. However, vegetarians cannot consume n-3 fatty acids from fish, and current recommendation is to consume flax or other n-3 containing oils such as hemp and walnut.
However, these oils may not be effective at raising phospholipid levels of the beneficial EPA and DHA n-3 fatty acids. For example, researchers1 fed 86 healthy subjects either hemp oil, flax oil, fish oil or a placebo for 12 weeks. Plasma levels of DHA and EPA increased after the fish oil supplement and plasma levels of α-linolenic acid (ALA, C18:3 (n-3)) increased after consumption of flax oil. However, no changes in plasma levels of fatty acids were detected following consumption of hemp oil. While ALA is an n-3 fatty acid and may show some beneficial effects at inhibiting inflammation, consumption of ALA to rebalance the n-6 to n-3 fatty acid ratio is controversial because the conversion of ALA to EPA and DHA is not efficient in humans. Supplementation with DHA from tank grown algae is therefore a better alternative for vegetarians who cannot consume fish oils.
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