A recent study found that older adults in Asia and were less likely to develop dementia if they regularly consumed fish. The study examined 15,000 people 65 and older in , , It found that those who ate fish nearly every day were almost 20 percent less likely to develop dementia than those who ate fish just a few days a week. Adults who ate fish a few days a week were almost 20 percent less likely to develop dementia than those who ate no fish at all.
An earlier study reported in 2006 found that people with the highest blood levels of an omega-3 fatty acid called docosahexaenoic acid, or DHA, were about half as likely to develop dementia as those with lower levels. The bad news is that ninety-nine people developed dementia over the course of the study, including 71 cases of Alzheimer's disease. The average level of DHA among all the participants was 3.6 percent of all fatty acids, and the top 25 percent of the population had values above 4.2 percent. The good news is that people in this top one-quarter in DHA levels had a 47 percent reduced risk of developing dementia, even after controlling for body mass index, diabetes, hypertension, smoking status and other known or suspected risks. Importantly, risk reduction was found only at that top level of DHA - those in the bottom three-quarters in DHA level showed no detectable difference in risk. People who ate two or more servings of fish a week reduced their risk for dementia by 39 percent, but there was no effect on the risk for dementia among those who ate less than that.
In 2003 another study found similar results. People older than 65 who eat fish at least once a week reduced their risk of Alzheimer's disease. In fact, they had a 60 percent lower risk of Alzheimer's than those who never or rarely ate fish.
These studies show some lack of agreement on exactly how much fish consumption produces the desired large reduction in falling victim to dementia. So the safe route is to either eat a lot of fish consistently or take one or two quality fish oil capsules every day.
And remember that fish oil has also been found to offer heart benefits as well. Here is what the American Heart Association has to say. "Omega-3 fatty acids benefit the heart of healthy people, and those at high risk of-or who have-cardiovascular disease. We recommend eating fish (particularly fatty fish) at least two times a week . Fish is a good source of protein and doesn't have the high saturated fat that fatty meat products do. Fatty fish like mackerel, lake trout, herring, sardines, albacore tuna and salmon are high in two kinds of omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid(DHA) ."
The AHA also recommends eating tofu and other forms of soybeans, canola, walnut and flaxseed, and their oils. These contain alpha-linolenic acid (LNA), which can become omega-3 fatty acid in the body.
The basis for these views is that research has shown that omega-3 fatty acids decrease risk of arrhythmias, which can lead to sudden cardiac death; decrease triglyceride levels; decrease growth rate of atherosclerotic plaque; and lower blood pressure (slightly). According to the AHA, randomized clinical trials have shown that omega-3 fatty acid supplements can reduce cardiovascular events (death, non-fatal heart attacks, and non-fatal strokes). They can also slow the progression of atherosclerosis in coronary patients.
A note of caution is necessary. The AHA notes that people taking more than 3 grams of omega-3 fatty acids from capsules should do so only under a physician's care. High intakes could cause excessive bleeding in some people. This is especially pertinent for people with heart disease taking blood thinners such as aspirin and medicines like Plavix.