We don’t give much thought to our aging brains until we start forgetting things.
These findings were discovered in sedentary, older adults who had consumed a high-salt diet for a lifetime. Led by researchers at Baycrest in Toronto — in collaboration with colleagues at the Institut Universitaire de Gériatrie de Montréal, McGill University and the Université de Sherbrooke, this study was published in the online journal Neurobiology of Aging and uncovers new evidence in the search for increasing cognitive health in older adults.
“We have generated important evidence that sodium intake not only impacts heart health, but brain health as well,” said Dr. Alexandra Fiocco, a scientist with Baycrest’s Kunin-Lunenfeld Applied and Evaluative Research Unit (KLAERU) and the study’s lead investigator.
The study itself lasted three years and followed the diets of 1,262 healthy men and women aged between 67 and 84 in Quebec, Canada. These subjects were selected from a larger group of participants in the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge).
The participants were divided into three groups defined by their daily sodium intake:
- Low = a maximum of 2,263 mg per day
- Mid = a maximum of 3,091 mg per day
- High = in excess of 3,091 mg per day (this reached as high as 8,098 in some individuals)
In addition, participants were tested for cognitive function of the brain with markers at each yearly interval. Their fitness level was also measured using the Physical Activity Scale for the Elderly.
“The results of our study showed that a diet high in sodium, combined with little exercise, was especially detrimental to the cognitive performance of older adults,” said Dr. Fiocco.
“But the good news is that sedentary older adults showed no cognitive decline over the three years that we followed them if they had low sodium intake.”
“These data are especially relevant as we know that munching on high-salt processed snacks when engaged in sedentary activities, such as watching TV or playing in front of the computer, is a frequent pastime for many adults,” said Dr. Carol Greenwood, a senior author on the study and internationally-renowned scientist in the field of nutrition and cognitive function in late life.
“This study addresses an additional risk associated with lifestyles that are highly apparent in North American populations.”
This research is revolutionary as until now high sodium intake has only been associated with high blood pressure and heart disease.
Strategies to reduce salt intake have been put place in Canada and indeed many states in the US as well. Health Canada recommends a daily dose of no more than 2,300 mg of sodium for people aged 14 and older.
Baycrest Centre for Geriatric Care. “Older adults with too much salt in diet and too little exercise at greater risk of cognitive decline, study finds.” ScienceDaily, 22 Aug. 2011. Web. 22 Aug. 2011.