In startling new research outlined in Nature Neuroscience, scientists have discovered a link between high salt intake and dementia. "We discovered that mice fed a high-salt diet developed dementia even when blood pressure did not rise," said senior author Dr. Costantino Iadecola. Iadecola goes on to explain that the results were surprising to the team, given that the effects of salt on the human brain were previously put down to hypertension (high blood pressure).
However these new findings discovered that a high-salt diet actively reduces blood flow to the brain. Scientists analysed the effect of a 16 per cent increase in dietary salt for mice, making the diet comparable to a high-salt human diet. After only an 8 week period, cognitive decline was evident in the mice, with noticeable blood flow reductions to the brain areas responsible for memory and learning.
Blood flow function to the brain can be restored however, with the scientists able to return the mice to correct levels through salt reduction. Despite their physiological function returning to normal, cognitive brain functions remained affected, with the high-salt eating mice developing dementia.
The mice that were fed more salt returned poor results when tested on object recognition, maze completion, and normal mouse behavioural activities, such as building a nest.
The findings are even more worrying given the current rates of salt consumption in Australia. The National Health and Medical Research Council has detailed an ‘adequate’ intake of salt corresponding to 1.15–2.3 grams per day. According to the council, most Australian adults have a daily salt intake of about 10 grams, more than five times the recommended amount.