Omega-3 fatty acids

Omega-3 fatty acids are polyunsaturated fatty acids – and among the few fats your body absolutely has to get from food. They are building blocks of cell membranes, especially in the brain and the retina, and have an anti-inflammatory effect. The three most important are called ALA (alpha-linolenic acid), EPA and DHA.

ALA is the plant form: linseed oil is about half ALA, and rapeseed oil, walnuts, chia seeds and linseeds are also rich in it. The body can convert small amounts of ALA into EPA and DHA – but only at a rate of a few per cent. Oily sea fish such as salmon, herring, mackerel and sardines, as well as algae oil, provide EPA and DHA directly. The German Nutrition Society (DGE) recommends eating fish once or twice a week, including oily sea fish once, and, as an estimated value, getting 0.5% of your energy from ALA – that's about a tablespoon of rapeseed oil a day.

DHA is particularly important for children: the brain and eyes develop rapidly in the first years of life. Needs are higher during pregnancy and breastfeeding; vegetarians and vegans should also make a point of using ALA-rich oils and, where appropriate, algae oil.

Easy to put into practice: rapeseed oil as your standard cooking oil, one fish dish a week – pollock fish fingers count a little, but salmon or herring are better – and walnuts or crushed linseeds in your muesli. For healthy people who eat like this, fish oil capsules bring no proven additional benefit.