"Memory is one of the most important functions of our brains for numerous everyday activities such as working, driving, shopping, studying, playing sports, etc," says Welma, an associate professor at the university's Institute of Food, Nutrition and Human Health. "Maintaining brain health and getting your brain to perform at its optimal capacity is just as vital as maintaining physical health and wellbeing."
Omega-3s can be found in plants such as flax seeds, walnuts and soybean oil that produce alpha-linolenic acid (ALA). This can convert to marine omega-3s but, unfortunately, our bodies don't create enough.
"In the human diet this is a very ineffective process. That is why we need to consume the DHA directly for our diet," Welma explains. But don't expect results overnight. "It takes six months for the tissue to get saturated with omega-3s. So you can't just eat fatty fish or take a supplement and think it's going to have immediate effects."
One of the leading authorities on long-chain omega-3s, the Omega-3 Centre, has analysed more than 12,500 studies on their health benefits. The Australian-based centre's executive director is Kevin Krail. He takes three 1000mg fish oil capsules a day, and eats at least two fatty fish meals a month. Kevin says studies have shown omega-3s are important in pregnancy to help develop healthy brains. Increasing evidence demonstrates they have a therapeutic effect on mental health disorders.
"When these indications are present of depression and mood disorders, researchers also find that these individuals are omega-3 deficient," Kevin says.
The American Psychiatric Association recommends all adults eat two or more oily fish meals a week and patients with mood impulse control, or psychiatric disorders consume at least one gram of DHA and EPA a day - that's 1000mg of fish oil.
The New Zealand Ministry of Health's latest adult nutrition survey shows a third of adults do not regularly eat fish. But Welma explains that we only need a small portion of fatty fish to obtain a good dose of DHA, salmon being the best.
"You can eat a 150g portion of salmon per week to give you your daily-recommended amount for a week," says Welma.
Although salmon is not native to New Zealand, we farm some of the best in the world. The country's biggest producer, New Zealand King Salmon, invests a lot in research on the benefits of omega-3s.
Its product development technologist, Cindy Steele, warns consumers that "not all salmon are created equal".
"King salmon [which is farmed in New Zealand] differs substantially from the Atlantic salmon commonly farmed in the Northern Hemisphere and Australia. In particular, Regal King salmon contains around double the levels of long-chain omega-3s," she says.
"Most would prefer a tasty meal over supplements to get their omega-3 intake but affordability might be thought of as an issue, but people don't realise how affordable salmon actually is."
The average salmon fillet is 170g, which will set you back about $6 at the supermarket - not bad for a nutritious meal and a better functioning brain.
Further info
Fatty fish containing the best source of DHA include:
Salmon
Sardines
Tuna
Mackerel
Anchovies
White fish has low levels of DHA. The recommended dietary intake of long-chain omega-3s is 610mg per day for males and 430mg for females, 14 years and older. To contact the Omega-3 Centre click here.
