Writing in the journal Neurology the researchers highlight the role of these nutrients, which also include α-tocopherol and kaempferol, and their importance in neuroprotective mechanisms.
These include maintenance of serum carotenoid levels, decreased oxidative stress, mitochondrial dysfunction, neuroinflammation inhibit protein levels that underlie Alzheimer disease progression.
According to the team the rate of cognitive decline is “linearly associated with higher food intakes of folate, phylloquinone, and lutein”.
“This appeared to account for the protective relation of green leafy vegetables to cognitive change,” said the researchers based at Chicago’s Rush University.
Population projections have thrust healthy aging as well as brain health into the limelight creating a demand for neuro-nutrition solutions designed to maintain or enhance physical and mental function.
Consumption of green leafy vegetables have long been identified as being one of the most effective and simplest method for protecting against cognitive decline.
Other compounds thought to boost the brain include ginkgo biloba, ginseng, turmeric and omega-3 fatty acids.
News filtered through last November of a nutritional drink that contained essential fatty acids, vitamins and other nutrients that could aid everyday cognitive performance.
Nutricia’s ‘Souvenaid’ drink also included choline, uridine monophosphate, phospholipids and antioxidants contained in a once daily 125ml medical nutrition drink, classed as a Food for Special Medical Purpose (FSMP).
Extracts of Ginkgo biloba leaves were the subject of a recent Polish trial that identified a host of mental and physical benefits for young, active men.
Swedish ingredients supplier AAK recently made available its senior nutrition product Akovita - a blend of plant sterols, egg phospholipids and essential omega-3 fatty acids specifically designed to target brain health in this growing demographic.
The prospective study, led by Dr Martha Clare Morris, professor of epidemiology, at Rush University Medical Center took 960 participants from the Memory and Aging Project.
The individuals were aged 58–99 years, who completed a food frequency questionnaire and had more than two cognitive assessments over a mean 4.7 years.
In a model adjusted for age, education, participation in cognitive activities and physical activities, consumption of green leafy vegetables was associated with slower cognitive decline.
The rate of decline among those who consumed 1–2 servings per day was the equivalent of being 11 years younger compared with those who rarely or never consumed green leafy vegetables.
“Consumption of green leafy vegetables may help to slow decline in cognitive abilities with older age, perhaps due to the neuroprotective actions of lutein, folate, β-carotene, and phylloquinone.
“The addition of a daily serving of green leafy vegetables to one’s diet may be a simple way to contribute to brain health,” the study suggested.
Veg link to healthy brain
Dr James Pickett, head of research at Alzheimer’s Society added that while it was no secret that eating vegetables were good for your health, eating spinach, kale, asparagus and Brussels sprouts - foods rich in vitamin K appeared to slow cognitive decline as people age.
“The researchers did not directly look at dementia, so we cannot say that it would delay or prevent the onset of the condition. However, older people who ate one or two servings of vitamin K rich food per day performed better on memory tests than those who didn’t. In fact, their scores were similar to those of people 11 years younger, irrespective of other factors such as obesity, high blood pressure and education level.
“What’s good for the heart is good for the head. A healthy diet rich in essential nutrients, combined with regular exercise and avoiding smoking, can help to reduce your risk of developing dementia.”
Dr Sara Imarisio, head of research at Alzheimer’s Research UK said the research would “add to evidence of a link between a diet rich in vegetables and a healthy brain”.
“Future studies will need to explore how leafy, green vegetables might contribute to brain function or if there is any link to whether people develop dementia.”
Published online ahead of print, doi: 10.1212/WNL.0000000000004815
“Nutrients and bioactives in green leafy vegetables and cognitive decline.”
Authors: Martha Clare Morris, Yamin Wang, Lisa Barnes, David Bennett, Bess Dawson-Hughes and Sarah Booth