Poor nutrition is responsible for up to half of all deaths from heart disease, stroke, and type 2 diabetes, and this includes suboptimal intake of vital omega-3 fatty acids. Heart disease and diabetes costed the United States $650 billion in 2003, a number that is expected to increase to $1.96 trillion in 2023.
Both monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids can improve metabolic parameters like blood pressure, lipid profiles, and insulin sensitivity. Both types of fat have also been studied to reduce inflammation, although the evidence base is stronger between reduced inflammation and PUFAs like omega-3 fatty acids. Addressing excessive inflammation is associated with a reduced risk of chronic conditions like heart disease and stroke.[3-7]
Additionally, the Standard American Diet (SAD) usually contains more MUFAs, making it particularly important for the average individual to focus on consuming more PUFAs. Saturated fats and MUFAs can be synthesized in the liver, but omega-3 and omega-6 PUFAs are essential fatty acids that are good for health but cannot be synthesized in the body. Thus, it is necessary to obtain omega-6 and omega-3 fatty acids from the diet.
Omega-3 Deficiency in the Standard American Diet (SAD)
The ratio of omega-6 to omega-3 fatty acid intake is optimally around 2:1. However, with a disproportionate amount of omega-6 consumption compared to omega-3 consumption in modern American diets, the ratio can be as high as 20:1.  A balanced consumption ratio of omega 6 : 3 is important because omega-3 and omega-6 fatty acids compete for the same metabolic resources such as conversion enzymes in the body.
The conversion from omega-3 alpha-linolenic acid (ALA) to eicosapentaenoic acid (EPA) in our body is already very low (only 8-9%), and the conversion to docosahexaenoic acid (DHA) is even lower (<0.1%). A diet higher in omega-6 fatty acids and lower in omega-3 fatty acids could reduce the conversion rate even more, making it all the more important to consume DHA and EPA directly in the diet. 
The Omega-3 Advantage
Omega-3 fatty acids are associated with reduced risk of heart disease due to their ability to support key functional systems. For example, increased intake of omega-3s has been shown to have anti-arrhythmic effects.  EPA and DHA also help to lower triglyceride levels by reducing synthesis and secretion from the liver, and can improve blood pressure by stimulating the dilation of small arteries. 
Additionally, EPA and DHA improve cardio-metabolic parameters in a few key ways: 
- Address plaque buildup in arteries by reducing levels of cytokines and adhesion molecule levels near the artery wall
- Increase size of LDL, as low LDL particle size is associated with risk for heart disease [link to lipoprotein article]
- Reduce steatosis in non-alcoholic fatty liver disease (NAFLD)
Increasing omega-3 fatty acid intake through dietary choices and/or supplementation can be effective at improving the omega-6 to omega-3 ratio. The more optimized the ratio, the more health benefits that can be gleaned, including improving cardio-metabolic parameters.