Here is a graph (source) of the omega-3 and omega-6 content of common foods. Although walnuts are relatively high in omega-3, they are much higher in omega-6. This may be why eating them reduced the performance of my lab assistants on a brain test.
When I’m in China, I eat 60 g/day of ground flaxseed. According to this graph, this provides 1.2 g/day omega-3, far more than I would get from any ordinary diet. For example, eating lots of fish would provide much less. I chose this amount based on balance and brain speed results. Flaxseed is hard to get in Beijing. Surely I am the biggest consumer in the China. I am pretty sure I am the only person ever to have optimized my intake. The best amount turned out to be surprisingly high. “We recommend one to two tablespoons [per day],” says a website that sells flaxseed. High consumption of omega-3 should protect me against bad effects of omega-6. For example, when I eat peanuts (high in omega-6), my brain test scores don’t change.
Experts say flaxseed is a poor source of omega-3 because it provides short-chain omega-3 whereas the brain needs long-chain omega-3. My results — plenty of brain benefit from flaxseed — suggest this is wrong. The experiments that measured short-chain-to-long-chain conversion did not take account of the effect of experience on enzyme production. If you eat more of a certain food, your body will produce more of the enzymes that digest it. The subjects in the conversion experiments may have had little experience. If your long-chain omega-3 supply is limited by what enzymes can produce, you will get a steadier supply of long-chain omega-3 from enzymatic production than you will from eating the same amount all at once. For this reason dietary short-chain omega-3 could easily be a better source of long-chain omega-3 than dietary long-chain omega-3 itself.