Scientists from the Baycrest Centre for Geriatric Care, McGill University, the Institut Universitaire de Geriatrie de Montreal, and the Universite de Sherbrooke found that a high-salt diet combined with inadequate physical activity can undermine cognitive health in seniors.
The authors say that their findings may have considerable health implications, stressing the need to address lifestyle factors that can affect brain health.
Dr. Alexandra Fiocco and team tracked the salt consumption and levels of physical activity of 1,262 healthy male and female adults aged between 67 and 84 years in Quebec over a three-year period. They were recruited from a pool of individuals from the Quebec Longitudinal Study on NuAge (Nutrition and Successful Aging).
The researchers explained that previous studies had shown a link between low salt consumption and lower blood pressure and risk of heart disease, they believe theirs is the first study to link salt intake to brain health in older individuals.
Dr. Alexandra Fiocco, a scientist with Baycrest's Kunin-Lunenfeld Applied and Evaluative Research Unit (KLAERU), said:
"We have generated important evidence that sodium intake not only impacts heart health, but brain health as well."
According to Health Canada, individuals aged 14 years or more should limit their sodium intake to a maximum of 2,300 mg per day.
The researchers classed the senior participants as:
- Low sodium intake - no more than 2,263 mg/day
- Mid sodium intake - no more than 3,090 mg/day
- High sodium intake - minimum of 3,090 mg/day
The researchers assessed the mental state of the participants four times - once at baseline (at the start of the study), and then every year for three years. They used a modified Mini-Mental State Examination to gauge cognitive function. The participants' levels of physical activity were measured with the Physical Activity Scale for the Elderly.
Dr. Fiocco said:
"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.
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. "
Senior author, Dr. Carol Greenwood said:
"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. This study addresses an additional risk associated with lifestyles that are highly apparent in North American populations."
As the country's large boomer population ages, brain failure rates are expected ro increase considerably. Seniors need to learn about the benefits of lifestyle changes to prevent or delay cognitive decline, the authors stressed.