Eating just one cup of leafy green vegetables like spinach each day may help maintain muscle strength and mobility into old age, research shows.
Edith Cowan University (ECU) researchers tracked the diets of 1,420 West Australian women aged over 70 and found that those who ate more nitrate-rich vegetables like spinach, rocket and lettuce had significantly better muscle strength and physical function.
Muscle strength was assessed by measuring grip strength. Physical function was measured by using the timed up-and-go (TUG) test which looks at how long it takes to rise from a chair, walk three metres and return to the chair to sit down.
ECU lead researcher Dr Marc Sim said a decline in muscle strength and physical function were associated with greater risk of disability and even premature death.
Previous research in older people had shown that a 1 kg decline over 12 months in grip strength was linked to a 33% increased mortality risk. Every one second slower TUG time increased mortality risk by 8% over three years.
“Poor strength and function are also associated with other adverse outcomes such as falls and fractures, which substantially compromise an individual’s independence.
“In our study we found that eating one cup of spinach, rocket or lettuce a day may increase grip strength by up to 2 kg and improve TUG time by up to 1.6 seconds.”
While it was unclear exactly how nitrate positively influenced muscle function, one reason could be improved vascular function and blood flow, Dr Sim said.
“We know from previous research that nitric oxide is a vasodilator, which means that it widens your blood vessels, potentially allowing greater blood flow for your muscles. It could be that higher daily nitrate intake consistently increase muscle blood flow, thereby facilitating musculoskeletal health.”
The next step would be to conduct an intervention study to test precisely how eating nitrate-rich vegetables influenced muscle function, Dr Sim said.
The study “Higher dietary nitrate intake is associated with better muscle function in older women” was published in the Journal of Cachexia, Sarcopenia and Muscle.