Microgreens and mature vegetables may limit weight gain, experts suggest

15 Aug 2023 --- US-based researchers found both young and mature types of kale are effective in limiting weight gain in mice fed a high-fat diet. However, the nutritional profiles of both types of produce notably differ, as do their effects on gut bacteria.

The scientific literature supports the beneficial properties of cruciferous vegetables, such as kale and broccoli. Claimed to be superfoods, microgreen versions – young vegetables – of these vegetables are particularly touted for having higher levels of certain nutrients than mature crops. They are typically harvested a few weeks after they start growing. 

“When we started this research, little was known about the nutrient content or biological effects of microgreens, so we thought we should look at them,” says the project’s lead researcher Thomas Wang, a scientist at the USDA Agricultural Research Service. 

“We wondered whether the bioactive components in microgreen kale were different from those in mature kale,” he continues. “And we found that the nutritional composition is very different.” 

For example, the immature plant has about five times more glucosinolates, which research has linked to regulatory functions in inflammation, stress response, metabolism, antioxidant activities and antimicrobial properties. 

The researchers will present their results today at the fall meeting of the American Chemical Society.

Gut microbiome effects 
During eight weeks, the researchers fed mice either a low-fat diet (10% of fat) or a high-fat diet (45%), supplementing several with kale microgreen or mature kale, while the control group did not consume kale. 

Wang suggests the weight effects in mice may, in part, be related to the vegetable’s impact on the animals’ gut microbiome. 

Consumption of both types of kale reduced weight gain in mice consuming a high-fat diet and increased the diversity of bacteria in the gut microbiome. However, this effect was more pronounced with microgreens. 

The weight effects may be related to microgreens’ impact on the gut microbiome note the researchers.Further analysis identified a potential biomarker that correlates with mature and microgreen kale consumption in both types of diets. 

Though microgreens are often viewed as high-value gourmet ingredients, earlier research suggests that plants could unlock nutrition challenges. 

At the time, the study’s lead author Francesco Di Gioia said: “Our study shows that depending on the species or botanical family, microgreens can provide vitamins A, C, E and K, polyphenols, glucosinolates and omega 3 fatty acids, especially alpha-linolenic acid. This is besides being a good source of fibers and minerals.”

Studying red cabbage
In earlier research, the scientists found that both young and fully grown red cabbage limited weight gain in mice fed a high-fat diet. The plant’s nutrient profile changed over time, with the microgreen version being substantially higher in compounds such as glucosinolates. 

Wang notes that the bitter taste of some of the health-promoting constituents in cruciferous vegetables, such as glucosinolates, is responsible for the products’ characteristic flavor. 

The team aims to continue its research on the impact of other cruciferous plants on health, to help consumers find better-tasting alternatives with similar health effects or to determine whether the flavor profiles could be altered to make them more palatable. 

Eat your greens
Although microgreens can easily be grown in people’s homes, environmental conditions can affect the nutrient content of broccoli and kale microgreens. The researchers noted the plants’ growth environment could also impact their flavor and health benefits. 

Literature on kale and other leafy greens consumption indicates several health benefits. For example, US-based researchers suggest adding dark leafy greens, such as kale and yellow or orange vegetables, to athletes’ diets to improve their visual range. 

In a different study, scientists linked the MIND diet – prioritizing green leafy vegetables and other vegetables – and the Mediterranean diet to reducing Alzheimer’s disease-related biomarkers. 

Edited by Jolanda van Hal