Omega-3 fatty acids improve heart attack survival in rats

The June, 2006 issue of the Journal of Nutrition published the findings of researchers at Indiana University-Purdue University in Indianapolis that consuming diets high in omega-3 polyunsaturated fatty acids (PUFAs) extends the period of survival in mice in whom heart attack was induced. Heart attacks are responsible for fifty percent of all cardiovascular deaths in the United States.

Seventy-four male rats who survived induced myocardial infarction via coronary artery ligation were divided to receive diets high in omega-3 or omega-6 fatty acids. The fat content of the high omega-3 diet consisted of 28 percent eicosapentaenoic and docosahexaenoic acids, while the high omega-6 diet provided 58 percent of its lipid content in the form of linoleic acid.

At six months, 33 of the rats on the high omega-3 diets were alive compared with 24 on the high omega-6 diets. Rats who died prior to six months appeared to be healthy, yet died from sudden death. Examination of plasma cardiac tissue from the surviving animals predictably showed higher levels of the polyunsaturated fatty acids from the diets they received. Total kinase activity was one-third lower in the group that received the high omega-3 than in the omega-6 group. Protein kinase pathways are associated with the generation of heart arrhythmias, which are the cause of most cases of sudden cardiac death.

The investigation is the first long-term dietary outcome study of sudden death utilizing a rat model of myocardial infarction. The authors speculate that “decreased activities of protein kinases induced by diets high in omega-3 PUFAs are associated with a decrease in sudden death after MI in rats.”



Health Concern

Arrhythmias

There are several kinds of arrhythmias, depending on the nature of the abnormal heart rhythm:

Tachyarrhythmias: rhythms that are abnormally rapid, with or without other abnormalities
Bradyarrhythmias: rhythms that are abnormally slow, with or without other abnormalities
Fibrillations: uncoordinated, very rapid and weak rhythms
Sometimes arrhythmias are also identified by where in the heart they arise. For example, atrial fibrillation describes a chaotic, quivering rhythm that occurs in the upper chambers of the heart, or the atria.

Extensive scientific studies, both animal and human, have shown that supplementing the diet with fish and their oils has a beneficial effect on the heart, particularly in preventing cardiac arrhythmias (Nair SS et al 1997). The omega-3 fatty acids in fish oils appear to stabilize the electrical activity of the heart muscle, reducing susceptibility even to ventricular arrhythmias and ultimately decreasing the risk of sudden cardiac death (Lee KW et al 2003; Kang JX et al 2000).

The GISSI-Prevention study of more than 11,000 people taking a purified form of omega-3 fatty acids as a supplement has shown a significant decrease in the occurrence of sudden cardiac death among the participants (Lee KW et al 2003; De Caterina R et al 2002; Richter WO 2003). The efficacy of this preparation was greater than that of pravastatin, a commonly prescribed statin drug. Remarkably, the reduction in fatalities was seen even in patients who were already taking preventive medications such as aspirin and statin drugs (Lee KW et al 2003; Richter WO 2003). Beneficial effects may be seen within 90 days of starting omega-3 therapy and may continue progressively with longer use, leading to their recommendation as a “promising additional measure for secondary prevention” (Richter WO 2003).

Both magnesium and potassium are intricately involved in the heart’s electrical stability (Cybulski J et al 2004); consequently, maintaining normal functional blood levels and ratios of each is important. Potassium is found in every cell of the body, and magnesium, the second-most-abundant intracellular mineral, is involved in many chemical processes (Swain R et al 1999). Magnesium deficiency may result in irregular heartbeats, muscle weakness, and irritability.

http://www.lef.org/protocols/heart_...hythmias_01.htm

http://www.lef.org/newsletter/2006/...6-1&key=archive