High-Protein Diet Reduces Alzheimer's Disease Risk in Older Adults, Study Finds

Go on, add some more fish to your diet. Justin Sullivan/Getty Images

High-protein diets rich in fish, meat and nuts may help to stave off Alzheimer's disease later in life, new research from Australia suggests.

The study found a link between high protein intake and lower levels of dangerous protein in the brain, but more research is needed to better understand what is behind this relationship.

For the study, published online in the Journal of Alzheimer's Disease, scientists from Edith Cowan University in Australia looked at the diets of 541 "normal older" volunteers who had not experienced any apparent memory decline. Researchers also measured levels of the amyloid beta in the volunteers' brains via biomarkers in their blood.

The volunteers were split into three groups, those with the highest, lowest and most average amount of protein intake. Results revealed that individuals with the highest protein consumption, which was around 118 grams a day, were 12 times less likely to have high levels of amyloid beta.

Amyloid beta is a protein found naturally in the body, but sometimes it can clump together in the brain and form plaques. These plaques surround nerve cells and can disrupt brain cell communication. The plaques may also trigger an autoimmune reaction, causing the body's immune system to get rid of disabled brain cells, the Alzheimer's Association reports. High levels of amyloid beta are considered to be a precursor to Alzheimer's disease.

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This study is the first to show a relationship between protein consumption and amyloid beta proteins.

"The research clearly demonstrates that the more protein eaten the lower the chances someone has of having a high Aβ burden on the brain, which corresponds to a lower risk of developing Alzheimer's in the future," said lead study researcher Binosha Fernando, a post-doctoral research fellow in neuroscience at Edith Cowan University, in a statement.

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At the moment, it is not clear why eating more protein can lower an individual's risk of developing Alzheimer's disease. Fernando suggested that it may be due to protein's effect on blood pressure. For example, past research has shown that high-protein diets can lower blood pressure. In addition, it's been shown that high blood pressure is a risk factor for Alzheimer's disease. This may be the link between high-protein diets and brain health, but according to Fernando in her statement, more research will need to be done to confirm this.

In the meantime, there are many other health benefits to adding more protein to your diet, beyond Alzheimer's protection. For example, a 2006 study published in Cell Metabolism found that protein was able to help curb hunger and regulate body weight. In addition, another study from that same year found that protein helped the body recover faster after injury.

Fernando explained that she plans to further investigate protein's effect on Alzheimer's risk, and in forthcoming research will explore how factors such as gender and genetics play a role in this relationship.