The Spanish Explorer Ponce De Leon spent countless years looking for the fountain of youth. The answer wasn't the water but what was swimming in it. Yet another study shows that fish oil may be a key to longer life.

Omega-3 fatty acids from fish oil may slow the ageing process by slowing the rate that telomeres shorten. Telomeres are the structures at the end of a chromosome that affect cell stability and replication. A growing body of research shows that the longer the telomeres, the longer the life of cells, which ultimately means slower ageing.

"Telomere length is an emerging marker for determining biological age, and many scientists are interested in understanding the impact of influences such as age, exercise, oxidative stress, diseases like diabetes and heart disease, and how interventions like dietary supplements, statins and omega-3 fatty acids impact length," said the study, which was lead by Dr. Ramin Farzaneh-Far, assistant professor of medicine at the University of California, San Francisco. "We are excited to identify omega-3 fatty acids as a potentially protective factor that may slow down telomere shortening," he said.

Previous research indicates that heart patients with a higher intake of Omega-3s have higher survival rates. Now researchers may know why. The new telomere Omega-3 research validates this and other studies on the importance of Omega-3 with regards to life expectancy. A study published in the April 2009 edition of PLoS Medicine, an online journal, showed that Omega-3 deficiencies may contribute to as many as 97,000 deaths annually.

"We know that daily doses of Omega-3 EPA/DHA can help with many conditions, such as cardiovascular disease, and we're committed to increasing consumer awareness about the drastic Omega-3 EPA/DHA deficiency in the Western diet. However, these recent studies validate that Omega-3 EPA/DHA is more than just part of a healthy diet … it's a matter of life and death," said Lori Colvert, Ocean Nutrition Canada's Vice President of Marketing and Communications.

For the telomere study, published in the Journal of the American Medical Association, researchersevaluated 608 patients with stable heart disease (from the Heart and Soul Study from September 2000 and December 2002) and followed up on their status for a median period of six years.

Researchers evaluated participants for Omega-3 fatty acid levels at the start and throughout the study. They also isolated DNA from the blood and evaluated the length of the telomere of the leukocyte, a type of blood cell. Telomeres in patients with the lowest Omega-3 levels shortened 2.6 times faster than patients with the highest levels of Omega-3s. The study only looked at blood levels of Omega-3s, not dosage.

Cardiologists note that this study was the first to look at telomere length over time. The question remains whether the study results apply to healthy people because the researchers only looked at patients with heart disease. Though according to Farzaneh-Far, telomeres shorten in everyone, so Omega-3s could indeed benefit most people.

For more on telomeres, see Nobel Prize News.