Brain food: Beat cognitive decline with daily serving of green veg

Researchers have found that eating just one serving of green leafy vegetables a day can slow down age-related cognitive decline, writes Margaret Jennings.

Although the profile of the modern-day nana may have changed from when granny said ‘eat up your greens’ back in the day, her advice, it seems, has a timeless wisdom about it, writes Margaret Jennings.

You could, in fact, say that she was using her grey matter — researchers at Rush University in Chicago who did a study of 81-year-olds found that just one serving of green leafy vegetables a day was linked to slowing down age-related cognitive decline.

The participants, who were all dementia free at the start of the study, underwent a battery of thinking and memory tests over almost five years while the research team focused on how much they consumed green leafy vegetables, specifically — spinach, kale, collards, and lettuce.

Although all of the 960 participants’ thinking and memory test scores (based on episodic memory, working memory, semantic memory, visuospatial ability, and perceptual speed) decreased over the years, the rate of cognitive decline among those who consumed the most leafy greens (a half cup serving or more a day), compared to those who ate the least veggies, was equivalent to being 11 years younger cognitively.

And the study did fully take into account lifestyle factors such as alcohol consumption, smoking, exercise patterns, high blood pressure, obesity, and education levels.

The researchers concluded that the nutrients which are plentiful in green leafy veg have a positive association with slowing cognitive decline.

Scientists don’t fully understand why green veg has this neuroprotective effect but it’s thought that specific nutrients found in them such as phylloquinone (vitamin K) lutein, and folate are beneficial for brain health, says consultant dietitian Paula Mee.

“Much of the earlier research focused on the role of individual nutrients and their effects on dementia. However, in the past few years, dietary patterns have increasingly been investigated in order to understand the link between diet and cognitive health.”

The scientific community is now scrutinising the MIND diet — a combination of the traditional Mediterranean diet which has long been hailed as a healthy ageing template to follow — and the DASH diet which was originally created to lower blood pressure without medication in research sponsored by the US National Institutes of Health.

“According to their research, the MIND diet seems to improve cognitive thinking, lower the risk of dementia, and slow the progression of Alzheimer disease,” says Mee.

Both dietary patterns are rich in leafy greens as well as a host of other well-identified ‘good’ foods — healthy for the brain as well as the body.

“The traditional Mediterranean dietary pattern includes mainly whole plant foods including wholegrains, legumes, vegetables, fruit, and nuts. It also contains smaller amounts of non-plant foods such as fish, milk, and dairy products, and a regular modest amount of alcohol. Red meat was only an occasional food,” says Mee.

“The DASH diet also emphasises vegetables, as well as fruits and moderate amounts of low-fat dairy products and includes whole grains, poultry, nuts and oily fish. It is also low in trans fats, red meat, sweets, and other refined sugary foods and drinks.”

Combining the two diets, the MIND diet emphasises natural, wholesome foods — with strong emphasis on those green leafy vegetables as well as berries — and limited intakes of animal-based and high saturated fat foods.

While scientists keep looking for the “magic pill” to stem age-related cognitive decline, especially as we are increasingly living longer than before, no one research study can offer a solution.

“Before we can really prescribe a brain diet we need to see more positive results from randomised controlled studies,” Mee tells Feelgood.

“While observational studies of the Mediterranean diet, for instance, suggest cognitive benefits, the first published review of randomised controlled trials — which featured recently in The American Journal of Clinical Nutrition — investigating Mediterranean diet effects on cognition or brain structure and function was disappointing.”

Granny from the 20th century might throw her eyes up to heaven at the constant search for ‘brain food’, citing as common sense (or a no-brainer) that we eat our greens and any other ‘real’ food that grows in nature.

And while diet is a huge factor in keeping our brain healthy, ageing experts advise that keeping cognitive decline at bay needs to be combined with a number of other healthy lifestyle factors as well.

In the meantime, taking a cupful of those nutrients in our leafy greens, as the Rush University research suggests, can only do us some good.

“To give you one example of how you can do this, a total of just 33 calories worth of kale provides 600% of daily vitamin K, 200% of vitamin A, and over 100% of vitamin C,” says Mee. “And if you really are lost for ideas on how to eat it, simply saute kale with a little garlic in healthy olive oil.”

And remember it’s still not too late to plant your own greens in the garden or a pot — and tending to them, will also help renew those neurons.