A study at the University of Colorado at Boulder has found that older adults may beable to combat oxidative stress in their cells by increasing vitamin C intake.
Although virtually all living things on Earth need oxygen to exist, oxygencan combine with other molecules to form toxic oxygen "free radicals," saidChristopher Bell of the university's kinesiology andapplied physiology department. "When oxygen mixes with the wrong crowd, itcan also be our enemy."
Destructive molecules have been to shown to "buddy-up" with oxygen in thehuman body, resulting in oxidative stress, said Bell. As we grow older, theeffects of oxidative stress become greater, and some scientists believe that bydestroying tissue, increased oxidative stress may contribute to manyage-related ailments of older people.
A team of CU-Boulder researchers now believes oxidative stress may haveplayed a part in previous observations of reduced resting metabolism inolder adults.
In 1998 and 2001, a group led by Assistant Research Professor Pamela ParkerJones of the kinesiology and applied physiology department published papersshowing that older adults burn fewer calories at rest than their youngercounterparts. Bell claims that this finding demonstrated thatmore calories are available to turn into fat in older adults.
In 2001, Professor Jones' group also published a follow-up study showing that thelower metabolic rate in older adults is due in part to a decreased abilityof the nervous system to support resting metabolism. Professor Jones' group believesthis decline in neural support of resting metabolism with age may be relatedto increased oxidative stress.
In a new study, Bell is aiming to remove the influence of oxidative stressin older adults to find out if resting metabolism will be increased.
"We can combat the effects of oxygen free radicals by giving older adultssubstances known as antioxidants," said Bell. "The body produces anabundance of antioxidants when we are young, but as we age, the productiongoes down. This increases the importance of healthy eating for older adultsbecause foods such as fruit and vegetables are rich in antioxidants."
In preliminary experiments, Bell has measured resting metabolism before andafter an infusion of vitamin C directly into the veins of older adultsbetween 60 and 74 years old. The results show that following vitamin Cinfusion, resting metabolism increases on average by almost 100 calories perday.
"It is possible that the removal of oxidative stress using vitamin C couldlead to a significant increase in resting metabolism in these older adults,"said Professor Jones. "This has important implications for reducing age-associatedweight gain."
In addition, higher resting metabolic rates have been linked with areduction in risks for cardiovascular and metabolic diseases such asdiabetes due to the favourable influence on body weight and body fat, shesaid.
Professor Jones said it was too soon to draw definitive conclusions from the studies.But the vitamin C studies suggest older adults might be able to avoidincreased body fat and some of the associated diseases by removing theunfavorable effects of free radicals and increasing resting metabolism.
Professor Jones is currently looking for volunteers to participate inthe research, which is funded by the National Institutes of Health.