Studies of the Pescatarian diet and possible benefits to prevent Alzheimer’s have been mixed for good reason. The vast majority of fish /Alzheimer studies are from populations that eat fish once or twice a week. The Pescatarian eats fish daily.

Below is the general smattering of present research in this area:  

People who eat more fish have a lower risk of developing Alzheimer’s disease and dementia. This may be due to the omega-3 fatty acids in fish, which may help reduce inflammation and improve brain function.

Fish consumption and Alzheimer’s
In one study, people who ate fish at least once a week had a 60% lower risk of developing Alzheimer’s. Another study found that people who ate the most fish had a lower risk of cognitive impairment, dementia, and Alzheimer’s.

Omega-3 fatty acids
Fish oil supplements contain omega-3 fatty acids, which may help reduce inflammation and improve brain function. Although there are conflicting studies saying fish oil supplement has little or no benefit.

Mediterranean diet
Studies of people who eat a Mediterranean diet rich in fish, fruits, and vegetables have shown that the diet may have brain-protective effects.

Fish as a substitute
Eating fish may also help people reduce their intake of less healthy foods, like red meat high in saturated fat.

Mercury
Some studies have noted that high fish consumption may also increase the risk of mercury and lead poisoning. This has also been found so far to not be a significant factor with Pescatarians. 

In cross-sectional analyses, moderate seafood consumption was correlated with lesser Alzheimer’s disease neuropathology. Although seafood consumption was also correlated with higher brain levels of mercury, these levels were not correlated with brain neuropathology.

As physicians and scientists; we must always caution patients and the general population to allow the science to unfold slowly. With the Pescatarian diet followed properly there have been numerous studies that confirm benefits to prevent Alzheimer’s disease as well as Dementia. Large populations of fish eaters whose primary protein source is plant-based and seafood-based have much lower incidences of Alzheimer’s and Dementia. They also enjoy longer healthy life expectancy. 

Studies links eating fish with healthier brains, regardless of mercury

Even more importantly, all studies regardless of their design have shown that eating fish appears to prevent dementia as well as slow its progress. The question boils down to the quantity of consumption. The fish diet has been shown particularly effective with intermittent dementia. 

Conclusions are always difficult to draw when the variables are so widely varied. There are groups that oppose the fish diet based on the sketchy notion that fish can cause mercury toxicity. To a great extent, this is a myth. Below is a discussion by Dr. Ken Drouillard, that covers the scientific data. The discussion is from Helen Rennie’s renowned Cooking School. Helen Rennie presents the Mediterranean diet which delivers many of the benefits of the Pescatarian diet. It is best to think of the Pescatarian diet as a Vegetarian Diet that includes fish.

With so much at stake with Alzheimer’s Disease and Dementia, so far the only diet that has acted to prevent Dementia and Alzheimer’s is a fish diet. Prevention is especially important with Alzheimer’s since the disease may have progressed far before symptoms arise. It is best to start eating fish before brain damage occurs.