[sunnye (OP)]

Eating tuna and other fatty fish may help prevent memory loss in addition to reducing the risk of stroke, Finnish researchers said on Monday.
People who ate baked or broiled — but not fried — fish high in omega-3 fatty acids have been found to be less likely to have “silent” brain lesions that can cause memory loss and dementia and are linked to a higher risk of stroke, said Jyrki Virtanen of the University of Kuopio in Finland.

“Previous findings have shown that fish and fish oil can help prevent stroke, but this is one of the only studies that looks at fish’s effect on silent brain (lesions) in healthy, older people,,” Virtanen, who led the study, said in a statement.

Omega-3 fatty acids are also found in salmon, mackerel, herring, sardines, and in other foods such as walnuts. They have been shown to provide an anti-inflammatory effect and have been linked to a lower risk of heart disease.

The Finnish team studied 3,660 people aged 65 and older who underwent brains scans five years apart to detect the silent brain lesions, or infarcts, found in about 20 percent of otherwise healthy elderly people

The researchers found that men and women who ate omega-3-rich fish three times or more per week had a nearly 26 percent lower risk of having silent brain lesions.

Eating just one serving per week led to a 13 percent reduced risk, compared to people whose diets did not include this type of fish, the researchers reported in the journal Neurology.

Fried fish for some reason did not appear to have the same benefits, the researchers added.

“While eating tuna and other types of fish seems to help protect against memory loss and stroke, these results were not found in people who regularly ate fried fish,” Virtanen said.

[wannabe]

While consumption of cholesterol type fats and saturated oils promote the problems mentioned, consumption of beneficial lipids will interfere with such problem promotion.
It should be noted that a source of lipids from land-based animal foods, the class of lipids called CLA (conjugated linoleic acid) has similar protective effect. Meats from animals grazing on grass exclusively and not having been supplemented by high energy foods such as grains form that type of lipid vs the cholesterol type.
Further more, protection afforded by selecting one type of lipid consumption vs another begins to accumulate gradually over many years of exercising such choice and protection cannot be expected to accrue rapidly by consumption of, for example, fish oil capsules as a form of medicine that would undo a condition done by a lifelong habit of improper food choices.
The study does not mention the time frame over which fish consumption occurs but it is likely that the culture where such practices are normal have such food choices be lifelong habits vs other choices which promote problems.

[daveshorts]

Ben Goldacre (...sorry, you cannot view external links. To see them, please REGISTER or LOGIN) has a lot to say on this subject. And whilst there has been a lot of biased research done by this $1bn industry, it would appear that there is very little decent research which shows much of an effect.