Saturday, January 21, 2006

Omega-3s are good for pregnant women

This week I wrote a story about how pregnant women may be able to make their children happier, healthier and smarter by eating more fish. This was picked up quite widely in the media.

The research was reported by an American NIH researcher Joseph Hibbeln, working with a British scientist Jean Golding. The results were important because pregnant women have been warned off fish by two federal agencies in the US. This advice has since been taken up in many other countries around the world. This research suggests that this is wrong. Yes fish has trace amounts of mercury, and mercury is bad for an unborn child, but omega-3s are so essential that avoiding fish is detrimental to the child’s health.

For the worried, it is possible to buy omega-3 supplements where mercury has been removed. But supplements from a vegetable source such as flax oil will only contain one type of omega-3 and I understand that pregnant women want to be consuming all three. So fish oil, or marine algae extract with the three types of omega-3, are the thing to consume.

This research comes hot on the heels of much research that says omega-3s are vital to adult health and can affect depression, cardiovascular disease and a whole bunch of other things. Perhaps the time has come for governments to consider setting an RDA for this nutrient? As our knowledge of nutrients grows, so does the list of things that we recognise to be essential. These days folic acid is added to our cornflakes because it is seen as essential, the same may, one day, happen with omega-3s.

Anyone worried about overfishing, but want to eat fresh fish should buy small fish that reproduce rapidly and are less likely to be overfished, sardines, herring, mackerel and skipjack tuna. Waitrose in the UK sells a wide range of fish that is certified from sustainable fisheries, and there is also the American Seafood Watch program to help consumers make more sustainable choices.

There is one final, interesting, twist to this tale. Another esential nutrient, omega-6s, taken in abundance, can strip the body of omega-3s. The main omega-6 molecule is linoleic acid, and comes from seed oils such as sunflower, soy and corn (or maize) oil. So another strategy for boosting omega-3s is to eat fewer omega-6s--of which there are rather a lot in the western diet. Fewer chips or fries. Fewer fryups unless its in olive oil, or.. lard!

It turns out that there is a strong relationship between the amount of linoleic acid consumed in a diet and homicide rates, both within and between countries. One idea about omega-3s that might help explain this relationship, is that omega-3s are essential for the correct wiring of the brain, and help us to contain our more violent impulses. I mean you never see a fish-loving Japanese guy dressing up in bling and engaging in a bit of a gang shootout.

I digress. So the arrival of linoleic acid in our diet is possibly the biggest single change in the human diet since the year dot. Americans get a whopping 10% of their calories from this single molecule.

The omega point
Jan 19th 2006
From The Economist print edition
Omega-3 fatty acids are a crucial component of a healthy diet—particularly, it seems, for pregnant women wanting bright, sociable children. (more...)

Food for thought
Jan 19th 2006
From The Economist print edition
In praise of omega-3s (more... sub req)