Dubbed 'brain food', many of us munch on the ocean treat to help maintain a healthy diet and lifestyle. And now research has further proved how beneficial fish really is, as well as other animal proteins, with results suggesting a diet rich in these can help older people reduce the chance of mental or physical illness by 39 per cent.

Researchers from the National Institute of Health and Nutrition in Japan questioned over 1,000 men and women to assess their mental and physical fitness. Questions such as how easy they found public transport to use, how they found paying bills and how often they visited friends were posed to the study group.

They were also quizzed about their daily diets. Results found that those who ate the most animal protein had a 39 per cent less chance of failing either mentally or physically in the seven years that followed.

Protein is essential for building muscle and many people training hard add extra to their meals and drinks. When we get older protein is necessary for protecting against falls and slips, which can lead to fractures and breaks.

But as our body ages, it's thought that we find it harder to absorb and process the nutrients. So we need even more protein to keep our body ticking over.

Fish is not only packed with protein, but also contains high levels of omega-3 fatty acids. These have been praised for their health benefits including helping ease arthritis pain and even delaying the onset of dementia.

Researchers of this latest study claim the results are important and the decline of physical and mental impairment will have "an enormous effect" on hospitals and care homes.

"Keeping a higher protein intake could contribute to maintaining elderly functional capacity," researchers wrote in the Journal of the American Geriatrics Society, reports the MailOnline.