How to reduce the risk of depression

This young bull fur seal did not like having his photograph taken.

In fact he raised his body up on his front flippers, barked loudly, and then chased the photographer down the beach.

There are several species of seals worldwide, with the New Zealand fur seal being distinguished by external ear flaps and hind flippers that rotate, allowing them to move quickly on land.

The New Zealand fur seal was brought close to extinction by commercial sealers during the 19th century but has recovered well under protection.

In some areas seal numbers are now a cause for concern among fishermen. Population increase is said to be around 2 per cent a year.

A fur seal’s body is covered by two layers of fur and in the past the pelts were used in the manufacture of fine clothing and footwear.

These days, fur seals can be found on most of our rocky coasts and large breeding rookeries are established in many rocky localities.

They feed on squid and fish that live in their environment and will hunt in deeper waters for conger eels, and larger fish. It’s reported that they can dive to depths of more than 200 metres and stay submerged for up to 10 minutes.

Seals can be observed after they have been well fed and come ashore to rest. They favour rocky ledges but as their numbers increase they are being found on grassy fields near the rocky shore and near human habitation.

Sea lions have similar characteristics to the fur seal but are much larger and prefer to rest on sandy or stony beaches. Also, sea lions have a rather blunt nose shape whereas the fur seal has a pointed nose and long pale whiskers.

This fine specimen is almost saying, ‘‘look at me, I’m quite handsome, but don’t come too close’’. There is growing evidence that the way we fuel our bodies affects not just our physical health but our psychological health too.

But, while plenty of diets purport to improve mood, a new Australian study has come back with a simple message: if you want to feel better, eat less junk.

The large study, published in the journal Psychosomatic Medicine yesterday, found a healthier diet can significantly improve symptoms of depression.

Researchers at Western Sydney University analysed dietary interventions in nearly 46,000 people participating in 16 different trials across the world. They found no one health diet worked better than another, rather, simply replacing junk food with whole foods alleviated low mood.

It was already known that poor diet can negatively impact mental health, but there was previously a lack of evidence about the impact of improving diet on ill mental health.

‘‘This is actually good news,’’ said lead author, Dr Joseph Firth of the NICM Health Research Institute at Western Sydney University.

‘‘The similar effects from any type of dietary improvement suggests that highly-specific or specialised diets are unnecessary ... just making simple changes is equally beneficial for mental health. In particular, eating more nutrient-dense meals that are high in fibre and vegetables, while cutting back on fast-foods and refined sugars, appears to be sufficient for avoiding the potentially negative psychological effects of a ‘junk food’ diet.’’

Foods high in sugar or fat activate the brain’s reward system, making us feel good, but the effect is temporary. ‘‘The ‘comfort’ afforded by indulging in junk food could potentially lead to a vicious cycle for those who become dependent on eating high fat/high sugar foods to temporarily boost their mood – but to their long-term detriment,’’ Dr Firth suggested, adding this hypothesis needed to be investigated.

The positive effects of swapping junk foods for nutrientdense foods were greatest among women, which Firth said may be because of biological differences, social factors, or could be driven by higher rates of depression among women.

‘‘Fruits and vegetables contain many important nutrients including fibre, vitamins and minerals, as well as phytochemicals like polyphenols, and a variety of these foods should be consumed daily for good health,’’ said Dr Carly Moore, an associate lecturer in Nutrition and Dietetics at Flinders University.

While the researchers said they need to do further research to understand the pathway underlying the effect, previous research has found that our microbiome (the community of bacteria in our guts) is ‘‘strongly associated’’ with mood-relating behaviours.