Findings of a recent trial show that women aged over 65 who received omega-3 fatty acids gained almost twice as much muscle strength following exercise than those taking olive oil.
Researchers said a larger trial is planned to confirm these findings and to determine why muscle condition improves, the 'BBC News' reported.
Some studies have linked diets high in omega-3 - commonly found in oily fish to potential health benefits, such as a lower risk of coronary heart disease.
During healthy ageing, muscle size is reduced by 0.5-2 per cent per year.
This process - known as sarcopenia - can result in frailty and immobility in old people.
Little is known about the prevalence of sarcopenia in the UK, but data from the US shows that 25 per cent of people aged 50-70 have sarcopenia and this increases to more than half of those aged over 80 years.
According to Dr Stuart Gray from the University of Aberdeen, the cost of sarcopenia is immense; either in direct nursing and care costs or in hospital admissions through falls.
"Around one-and-a-half percent of the total US healthcare budget is spent on sarcopenia-related issues", he said.
The findings are being presented at the British Science Festival in Aberdeen.