Young vegetables better for gut health than mature greens: study

By James Gamble via SWNS

Eating "microgreens" harvested before maturity is healthier than dining on fully-grown vegetables, according to a new study.

Scientists who experimented with mice on high-fat diets found that both mature and immature vegetables help to limit weight gain.

But they also found compounds beneficial to gut health - and some which may even ward off cancer - were significantly higher in young vegetables known as microgreens harvested before maturity.

Microgreens - which are older than sprouts but younger than baby greens - are akin to toddlers of the plant world and can be harvested after growing their first leaves within a few weeks of them being planted.

Researchers from the American Chemical Society (ACS) set about in a study to assess whether microgreens - which can be easily grown at home - are really the superfoods some claim them to be, and how they compare with more mature versions of vegetables.

The team performed experiments in mice and initially found that though both microgreens and more mature vegetables limited weight gain in mice, they differed in terms of other nutritional values.

The study, presented at the ACS Fall 2023 meeting in San Francisco, began with its focus on red cabbage.

Researchers found that whilst both young and fully-grown versions of the plant limited weight gain in mice on a high-fat diet, the vegetable's nutrient profile changed over time.

The microgreen version of the red cabbage was found to be significantly richer in substances like glucosinolates - nitrogen and sulfur-containing compounds which may afford protection from cancer.

The team, led by Dr. Thomas Wang, a scientist at the Agricultural Research Service of the U.S. Department of Agriculture (USDA), next turned their attention to kale.

"We wondered whether the bioactive components in microgreen kale were different from those in mature kale,” Wang explained.

"And we found that the nutritional composition is very different.

"The scientific literature suggests that cruciferous vegetables, like kale and broccoli, are good for you.

"But when we started this research, not a lot was known about the nutrient content or biological effects of microgreens, so we thought we should take a look at them."

The researchers found that the immature plant has around five times more glucosinolates than its older counterpart.

Other studies have also shown that nutrient levels in several other types of cruciferous vegetables - plants in the cabbage family - are higher in younger plants.

In this latest study, both microgreen and mature kale was found to limit weight gain in the high-fat diet mice, which Wang believes may be connected to the vegetable's impact on the animals' microbiome - the community of bacteria in the gut.

The researchers discovered that eating kale of any age increases the variety of gut bacteria - but the enhancement is more pronounced with microgreens.

Though future research focusing on the health effects on humans is needed, the study team notes the importance of these findings, due to the association of greater bacterial diversity with better health.

Wang said future research projects, with his collaborators at the USDA and the University of Maryland, will focus on other cruciferous plants and their individual health benefits.

These future projects could help guide diners who dislike some vegetables and are seeking alternatives with similar health benefits that they prefer.

“For instance," Wang said, "For people who don't like broccoli, can we find some other vegetable they like better that has similar health effects?"

It may also be possible to alter the flavor profiles of these vegetables to make them more palatable to those who do not like them.

Some of the health-promoting compounds in the vegetable responsible for their flavor - such as glucosinolates - are bitter.

But Wang speculates that these compounds may be present at higher levels than are necessary to reap the desired health benefits.

If that is the case, the vegetables could potentially be bred to reduce these levels and the associated bitterness in flavor that they produce.