Some known side effects caused by omega-3 fatty acids include cough, dizziness, headache, itching and tightness in the chest, claims Drugs.com. Side effects of omega-3 fish oil include nausea and an upset stomach, notes WebMD. Omega XL is a concentrated omega-3 essential fatty acids supplement, according to OmegaXL.com.
Omega-3 essential fatty acids are vital in preventing and regulating heart disease, states WebMD. Omega-3 fatty acids can lower blood pressure, reduce triglycerides and lessen plaque development in arteries. Omega-3 fatty acids also reduce the chances of a stroke, a heart attack or an irregular heartbeat. The American Heart Association recommends people to consume fish at least twice a week, as fish are high in omega-3.