Speaking at the 9th International Conference on Alzheimer's Disease and Related Disorders held this week in Philadelphia, US researchers from Harvard Medical School reported that women who ate green leafy or cruciferous vegetables in middle age preserved more of their cognitive abilities as they entered their 70s.
In their large study, carried out over eleven years on more than 13,000 women, they found that although increased consumption of fruits and vegetables did not affect the overall decline in cognitive scores, whether due to ageing or any forms of dementia, women with the highest consumption of green leafy vegetables and cruciferous vegetables - both high in folate and antioxidants such as carotenoids and vitamin C - declined less than women who ate little of these vegetables.
"This difference can be approximated as being one to two years younger in terms of cognitive ageing," said study author Jae Hee Kang. "Although this difference may be modest, if confirmed by other studies it may have a large impact in reducing the public health burden of dementia."
Kang and colleagues evaluated participants in the Nurses Health Study that has been following the diets and health status of more than 13,000 women since 1972.
There are currently nearly 18 million people with dementia in the world, and the most common cause of this dementia is Alzheimer's disease. According to the US Alzheimer's Association in the US alone an estimated 4.5 million people have the disease, a figure that has more than doubled since 1980. By 2050 the number of individuals with Alzheimer's could range from 11.3 million to 16 million.
National governments are footing the bill. Direct and indirect costs of caring for individuals in the US with Alzheimer's disease are at least $100 billion, according to estimates used by the Alzheimer's Association and the National Institute on Aging. And in light of the expense, food solutions are increasingly the target of new research, such as the Harvard-Kang study reported this week at the Alzheimer's conference. Also at the event, researchers from the Karolinska Institute in Stockholm, together with collaborators in Sweden and Finland, presented their findings that suggest cardiovascular disease risk factors such as midlife obesity, high cholesterol, and high blood pressure could have a very significant impact on the speed of cognitive decline later in life.
Reporting on data from a group of nearly 1,500 elderly subjects, followed for an average of 21 years, the researchers found that study participants who were obese in middle age - for example, weighing more than 197 pounds at a height of 5 feet, 8 inches - were twice as likely to develop dementia later in life. For those subjects who also had high cholesterol and hypertension in middle age, the risk of dementia was multiplied by as much as six times.
"More and more research is pointing to common causes for cardiovascular disease and dementia," Marilyn Albert, chair of the Alzheimer Association's Medical and Scientific Advisory Council, said at the conference this week.
"This study should make physicians and policy makers take notice that they can make significant contributions to healthy ageing in several areas by encouraging people to eat healthful foods and exercise more."