How many servings of fish do you eat on average per month? A serving is about the size of a tennis ball, or half a cup (125ml).
Possible responses:→ None / rarely / don't know
→ Three to four
→ Five or more
More salmon for consumption are now raised in captivity than caught in the wild. These fish are fed corn meal, soy and canola oil. When the fish are fed these foods, the concentration of their fats turns far away from the ideal beneficial 3:1 omega-6 to omega-3 ratio and turns closer to the 20:1 found in commercially-raised beef. This means that salmon raised in salt water pens contain substantially less omega-3 oil than wild salmon, and can no longer be considered a good source of omega-3 essential fatty acids unless clearly identified as 'wild caught'. Also, pigments are added to the artificially-raised salmon to ensure a pink color. [Seattle Times, September 02, 2001]
Although mercury occurs naturally in the environment, of bigger concern is the mercury that is released into the air through industrial pollution. When mercury falls from the air into water, it is converted into "methylmercury" by bacteria in the water. Methylmercury accumulates in streams and oceans where it is absorbed by fish as they feed in these waters. Mercury levels are highest in older, larger predatory fish. Larger predatory fish accumulate high levels of mercury by eating smaller fish (that contain mercury) who have eaten even smaller fish (that contain mercury).
Nearly all fish and shellfish contain trace amounts, but some fish contain much more, depending on how big they are, how long they live, what they eat, and where they were caught. According to an FDA survey, the fish with the highest average levels of mercury are, in order:
(Highest levels of mercury – at least 1 part per million): tilefish (golden bass or golden snapper), shark, swordfish, king mackerel; ("Mid-levels" of mercury – around 1/2 part per million): grouper, orange roughy, marlin, Spanish mackerel, tuna.
Researchers from the University of Pittsburgh announced in August, 2012 that eating fish regularly appears to boost the size and health of the brain's neurons, and that people who eat grilled or baked fish (but not fried or dried fish) at least once a week are up to five times less likely to develop Alzheimer's Disease than those who do not consume fish.
However, the most effective ways to reduce risk of developing dementia are eating a healthy diet including fruit and vegetables, taking regular exercise, and giving up smoking.