Do n-3 fatty acids work against CVDs?

Is it correct to promote daily intake of n-3 at 250mg/day ? as in here, table 1.



Probably not!

here is the latest etiology against n-3.  

Omega‐3 fatty acids for the primary and secondary prevention of cardiovascular disease

Cochrane Systematic Review - Intervention Version published: 29 February 2020 see what's new

https://doi.org/10.1002/14651858.CD003177.pub5

Authors' conclusions

This is the most extensive systematic assessment of effects of omega‐3 fats on cardiovascular health to date. Moderate‐ and low‐certainty evidence suggests that increasing LCn3 slightly reduces risk of coronary heart disease mortality and events, and reduces serum triglycerides (evidence mainly from supplement trials). Increasing ALA slightly reduces risk of cardiovascular events and arrhythmia.