Fish oil may be the true elixir of youth, according to new evidence of itseffect on biological ageing. Omega-3 fattyacids from fish oil preserve the genetic "fuse" that determines thelifespan of cells, say scientists.
The discovery, made in heart disease patients, may explain many of theclaimed health benefits of omega-3.
Taking fish oil supplements is said to protect against heart disease,improve survival rates after a heart attack, reduce mental decline in old ageand help to prevent age-related changes in the eye that can lead to blindness.Research has also shown that rodents live one-third longer when given a dietenriched with fish-derived omega-3.
Although omega-3 fatty acids have powerful anti-inflammatory propertiesand lower levels of some blood fats, the mechanisms behind these effects arepoorly understood. The new research suggests that omega-3 has a direct effecton biological ageing by slowing down the rate at which protective caps on theends of chromosomes shorten.
The caps, called telomeres, are made from copied strands of DNA and have asimilar function to bookends or the plastic ends of shoelaces. They prevent theends of chromosomes – the "packages" of DNA in the cell nucleus –becoming damaged and keep the DNA organised and contained.
Each time a cell divides, its telomeres get shorter until a critical pointis reached. DNA then becomes damaged and the cell stops dividing, and may die.In this way, the telomere acts like a biological fuse.
The rate at which the fuse "burns" can vary both betweenindividual people and individual cells. This is believed to have an impact onage-related diseases.
US scientists conducting the research looked at the effect of omega-3fatty acids on telomere shortening in 608 hospital out-patients with heartdisease. At the start of the study, measurements were taken of the length ofchromosomal telomeres in the patients' white blood cells. Blood levels of thetwo fish-derived omega-3 fatty acids docosahexaenoic acid (DHA) andeicosapentaenoic acid (EPA) were also measured.
The tests were carried out again after five years, and showed a clearcorrelation with omega-3 intake. Patients consuming the least omega-3 had thefastest rate of telomere shortening, while those in the top 25% of consumptionlevels had the slowest rate.
The scientists, led by Dr Ramin Farzaneh-Far of the University ofCalifornia at San Francisco, wrote in theJournal of the American Medical Association: "The present findingsidentify deceleration of telomere attrition as a potentially novel pathway forthe anti-ageing effects of marine omega-3 fatty acids.
"In summary, among patients with stable coronary artery disease,there was an inverse relationship between baseline blood levels of marineomega-3 fatty acids and the rate of telomere shortening over five years ...These findings raise the possibility that omega-3 fatty acids may protectagainst cellular ageing in patients with coronary heart disease. "
2010-01-31 22:28 编辑：kuaileyingyu