Fatty acids containing double bonds are called unsaturated fatty acids. When more than one double bond is present in a fatty acid, such an acid is called a polyunsaturated fatty acid. Each fatty acid has two ends- an end ending with a methyl group and an end ending with a carboxyl group. The methyl end is also known as the omega (ω) end.
CH3 ——————————————————————— COOH
The omega-3-fattyacids are fatty acids contain a double bond after the third carbon as counted from the omega end. These fatty acids are essential fatty acids because they cannot be synthesized in the body. They are also essential for maintaining normal health. The most important omega-3-fatty acids are α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). When ALA is supplied in the diet, it can be partly converted into EPA and DHA in the body. Fatty fishes are the best sources of EPA and DHA. Plants are good sources of ALA. Flaxseed and canola oils are good sources. ALA is also present soybeans, walnuts and tofu. Omega-3- fatty acids offer several health benefits.
Protecting the Heart
The most important benefit is cardioprotection. Omega-3-fatty acids are anti inflammatory. Inflammatory reactions are the main contributors towards plaque formation in the arteries. Thus, omega-3 fatty acids can prevent coronary vascular disease. These fatty acids also counter the onset of hypertension and bring about a decrease in the circulating levels of triglycerides. These two factors are partly responsible for increasing the risk for heart disease.
ω-6- fatty acids
The modern diets contain mainly omega-6-fatty acids and very little omega-3-fatty acids. Thus, this ratio is lopsided and is heavily in favor of omega-6-fatty acids. It is believed that the onset of many of the diseases including coronary heart disease is due to the predominance of omega-6-fatty acids. Hence, there is need to shift the ratio in favor of omega-3-fatty acids.
Slowing Down of Ageing of Heart
Telomeres are short nucleotide sequences that act as chromosomal caps. The role of the telomeres is to prevent the chromosome from being damaged and thus, the chromosomal integrity is maintained. Ageing is an irreversible process and as one ages, the telomere lengths get shortened. Thus, the extent of shortening of the telomeres is an index of ageing. Recent studies have indicated that the inclusion of omega fatty acids in the diet leads to decreased reduction in the lengths of the telomeres. Thus, these fatty acids exhibit the ability to slow down the ageing of the heart.
Preventing Homocysteine Formation
Homocysteine is an amino acid and the increase in the circulating levels of this amino acid has been closely linked to increased risk for coronary artery disease. Omega fatty acids have the ability to decrease the blood levels of homocysteine. These fatty acids deactivate an enzyme involved in the formation of homocysteine.
Altering LDL/HDL ratio
LDL has been considered as carrying ‘bad’ cholesterol and HDL has been shown to transport ‘good’ cholesterol. The health of the heart is determined by the LDL/HDL ratio in the circulation. This ratio is decreased by the omega-3-fatty acids and this benefits the heart.
Thus, it is clear that including more of omega-3-fattyacids in the diet can protect the heart in several ways.