Eating an antioxidant-rich diet may help protect cognitive skills from deterioration during old age, according to new research presented at a meeting of neuroscientists in the US this weekend.
The study, conducted at the University of Toronto, Canada, showed that old dogs that were on an antioxidant-fortified diet performed better on a variety of cognitive tests than dogs that were not on the diet. In fact, the old dogs eating the antioxidant foods performed as well as young animals.
Dogs, like humans, develop a range of cognitive impairments as they age, including loss of some of their ability to learn new information and more difficulty retaining information in both short-term and long-term memory. The results of the study suggest that antioxidants could also help buffer the effects of aging in people.
Antioxidants, such as vitamin E, vitamin C, and beta-carotene, have been shown to help reduce oxidation, a process that can cause damage to cells and may contribute to ageing, including the reduced cognitive decline that typically develops with age. Studies also suggest that antioxidants may protect against certain cancers, heart disease and other non-neurological age-related diseases, although evidence is so far inconclusive.
"Although we found that not all cognitive functions respond to antioxidant treatment, our data suggests that antioxidants play an important role in preventing or slowing age-related cognitive impairments," said Dr Dwight Tapp, now at the University of California Irvine, speaking at the Society for Neuroscience annual meeting, running from 8-12 November in New Orleans, US.
Tapp and his colleagues used 39 beagles in the current study, part of a three-year trial examining the effects of age, cognitive stimulation and antioxidant treatment on cognitive decline in the dogs.
Previous reports from this study revealed improvements in simple cognitive functions. The present study examined the effects of antioxidants on more complex cognitive processes, measured by a size-concept task, which engages more cognitive faculties (such as stimulus generalisation, transposition, memory and concept learning), according to the researchers.
The dogs were divided into four groups based on age, cognitive ability and diet. There were 11 aged dogs on the control diet, 12 on the antioxidant diet, seven young controls and nine young antioxidant-fed dogs. The dogs were on the diets for 1.5 years and all were in the cognitively enriched group.
Antioxidant treatment led to significantly improved test performance in aged dogs but did not affect the young dogs suggesting a selective improvement of factors related to the aging process rather than general cognitive enhancement, reported the researchers.
Tapp said that the diet is most effective in animals that already have some degree of cognitive impairment. The study is currently ongoing in the younger dogs to determine if the diet has a protective effect on age-related cognitive decline in general.
"The role of diet in cognitive function is one of the vastly understudied areas in the neurosciences," commented Carl W. Cotman, of the University of California-Irvine, at this week's meeting. But as this and other new research shows, significant new findings highlight the importance of research into diet and cognition for future generations.