Fish is regularly promoted as an important part of a healthy diet. With benefits ranging from reduced cardiovascular risk to the prevention of dementia, it’s little wonder health authorities are talking up the value of eating fish. We’re now also learning the importance of fish and omega-3 fats from fish for children’s development, with reports showing these poly-unsaturated fats are important in preventing learning difficulties and minimising ADHD, dyslexia and more.

More recently, though, concerns have been expressed over the levels of mercury in fish and mothers-to-be have been advised to limit their fish intake. Worried about the health of their unborn babies and not wanting to expose them to this toxic metal, many pregnant women have elected to remove fish completely from their diet.

However, given the health benefits to be had from eating omega-3s, is totally removing fish from your diet the best strategy? Let’s examine the links between fish, mercury and health in general, as well as the situation with mothers-to-be. By not eating fish, are you missing out?

The benefits of eating fish

Fish is a great source of low-saturated fat protein. It’s also high in the minerals zinc and iodine, along with vitamin B12. But, more significantly, fish is one of our primary sources of two types of omega-3 polyunsaturated fats: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). It’s these omega-3s that have excited nutritionists and health bodies, as there is evidence they will reduce your risk of cardiovascular disease and of having a heart attack.

Omega-3s are also good for your brain. They are important in the brain’s structure, with estimates that they make up 8 per cent of your brain. These fats are used in the myelin sheath, a fatty layer surrounding neurons that enables the speedy transmission of messages to and from your brain. Low levels of omega-3s are thought to interfere with neurotransmitter production, which may be why a 2002 New Zealand study of more than 4500 adults found people who ate fish had better mental health. Omega-3s are now often used in the treatment of depression and fish consumption has also been shown to slow cognitive decline and reduce the risk of both dementia and Alzheimers.

Ongoing research into the health benefits of omega-3s is suggesting they can benefit and prevent a wide range of conditions including arthritis, inflammatory bowel disease and autoimmune conditions. Omega-3s are also a current subject of research in the area of children’s learning and development. In 2005, 100 children with learning and motor coordination problems were given fish oil supplements for six months. They showed improvements in behaviour, reading, spelling and short-term memory. An Australian study, also of more than 100 children, found omega-3s improved ADHD-related problems, including inattention, hyperactivity and impulsivity. This kind of result is why an adequate intake of omega-3s is recommended for children’s learning and mental development.

Beyond omega-3

Not only does fish contain omega-3 polyunsaturated fats but it’s also one of the best dietary sources of the mineral iodine. Iodine deficiency is common in Australia and New Zealand. Soils in both countries are low in iodine, meaning it’s not part of the collection of minerals taken up by plants and very little iodine enters our food chain. However, iodine is necessary for the proper functioning of the thyroid gland, which produces hormones necessary for physical growth and development. A low iodine intake will also inhibit a child’s mental development and ability to learn. If your kids are not eating fish, they are possibly not getting enough omega-3 fats or iodine.

Fish is also important in pregnancy. As well as providing important omega-3 for development of the unborn baby’s central nervous system, fish is a good source of protein. Recent research is suggesting that eating fish while pregnant may protect your baby from developing asthma and other allergic conditions such as eczema and hayfever.

In recent years, though, concern about mercury levels has tarnished fish’s healthy reputation. Many people, particularly mothers and pregnant women, have stopped eating fish in an attempt to reduce their mercury exposure and avoid toxicity. Despite cutting out fish, few people have supplemented their diets with alternate sources of either omega-3s or iodine. Given the health benefits from both, this is problematic.