A combination of fish oil and visits to the gym can help ageing muscles stay strong, research suggests.
Women pensioners following the advice in a pilot trial doubled the rate at which exercise improved their muscles.
The results were so encouraging that a bigger study involving both men and women is now under way.
Experts believe the anti-inflammatory properties of omega-3 fatty acids in fish oil counteract the natural effects of ageing that weaken the body later in life.
Age-related loss of muscle mass, known as sarcopenia, starts in middle age. It seriously affects around 20% of the population aged 50 to 70 and half of everyone aged 80.
The condition saps strength leading to problems performing every day tasks, such as shopping, dressing and rising from a chair.
Although exercise helps, ageing muscles do not respond to training as well as young ones.
"We're trying to make older muscle adapt like younger muscle, and that's where we think fish oil can come in," said lead scientist Dr Stuart Gray from the University of Aberdeen's Musculoskeletal Research Programme.
He launched the new research today at the British Science Festival, taking place at the university.
Fourteen women aged 65 and over took part in last year's pilot study. Half took four grams of fish oil a day for a month, while the remainder received olive oil.
All the women attended two gym sessions a week during which they were given lower limb resistance training which involved leg flexing, pushing, and pointing ankles.
"In the placebo group, muscle growth improved by 11% in response to exercise training, but the fish oil group improved their strength by 20%, almost doubling their response," Dr Gray said.
The new study will be run on similar lines but recruit 60 older men and women and involve a longer 18 week period of gym training.
It will include a battery of tests to monitor changes in muscle mass and volume, the fat content of muscles, insulin sensitivity, inflammation, protein synthesis and molecular signalling.
"Volunteers in the study will also be timed carrying out physical activities such as standing up and down, walking for four metres, and balancing in three different positions, to establish if those participants taking fish oil perform these activities more efficiently," Dr Gray added.
Other research already suggests omega-3 fatty acids can improve heart health, lower blood pressure, combat chronic inflammatory conditions, and boost mental performance. They may also have anti-cancer effects.
An average portion of oily fish contains about three grams of omega-3. Other sources include green algae, hemp and flaxseed.
Dr Gray said it was too early to make any recommendations about taking fish oil to maintain muscles, but added: "We hope that providing new mechanistic insights into the benefits of fish oil on muscles could lead to the development of new pharmacological treatments to prevent against the loss of muscle with age."