The trial, carried out in New Zealand at Massey University, gave 176 adults between the ages of 18 and 45 either an omega 3 fish oil supplement providing 1.16 grams of DHA or a placebo for six months. They selected non-smokers, who didn’t take fish oil supplements and consumed less than 200mg of DHA+EPA a week – in other words, didn’t eat fish often.
They measured various aspects of cognitive function including tests for memory, reaction time at the beginning and end of six months. Those of the omega 3 DHA supplements had a highly significant improvement in two tests for memory (episodic and working memory) and a significant but small improvement in reaction time. This is the first study to show that normal adults can benefit from a higher intake of DHA. Another study gave can otherwise healthy older adults with the first stages of memory decline a similar amount of DHA (900mg) for 24 weeks and again reported improvement in learning and memory. However, a study giving DHA to those with dementia/Alzheimer’s disease didn’t show improvement perhaps indicating that it is too late in the disease process. DHA is one of the main essential fats in fish oil, the other being EPA.
While EPA is a more effective anti-inflammatory - good for heart disease, arthritis and also mood - DHA is part of the brain’s structure and used to build new brain cells. The amount given in this study is quite high and equates to eating the equivalent of a serving of oily fish almost every day. While this might not appear practical, having three servings of oily fish a week, a serving of cod roe or taramasalata and supplementing 250mg of DHA a day would give you about 1,000mg a day. The richest food source by along way is caviar, giving 3,000mg per 100g – but it’s also the most expensive. A 100g serving of mackerel gives you close to 1,000mg. Every day I take two Essential Omega capsules which provides 350mg of EPA, 224mg of DHA and 42mg of DPA, which can convert into DHA as needed. So that’s the equivalent of about 260mg of DHA. Whether lower doses would produce the same effect will not be known until more studies are carried out.