Eating spinach leaves is likely to produce the same effect on the human gut as taking a probiotic tablet, according to new research out today.
Research conducted by researchers in Melbourne and the UK found that spinach leaves contain significant amounts of a newly discovered enzyme, sugar sulfoquinovose (SQ), which feeds good gut bacteria.
Lead author of the study, Dr Ethan Goddard-Borger from the Walter and Eliza Hall Institute, explains that when we eat spinach, we also consume SQ sugars contained within the vegetable.
The SQ sugars make their way to our colon and once there, fuel good bacteria by encouraging them to take up ‘real estate’ in the gut to prevent bad bacteria from taking over.
“We call this the barrier effect,” says Dr Goddard-Borger.
“Just by the virtue of good gut bacteria being there taking up space, they create a [preventative] barrier to bad bacteria.”
Dr Goddard-Borger explains that although tests isolated store-bought spinach, the study’s findings hold true for all leafy greens available, including seaweed.
“We found leafy greens are not just good for you, but they are good for the good bugs in your colon, which is in turn good for you.
“So if you want to benefit from a probiotic, eat your green vegetables. The rule of thumb is that the greener it is, the better it is.”
Each year, leafy green vegetables – such as spinach – produce the SQ enzyme on an enormous scale globally, comparable to the world’s total annual iron ore production.
“All life on earth depends on sunlight for energy so there are many organisms that all produce SQ to aid them in photosynthesis.”
If you want to benefit from a probiotic, eat your green vegetables. The rule of thumb is that the greener it is, the better it is.
“And a lot of the good bugs we talk about as living in our gut are currently utilising this SQ sugar.”
The discovery of the SQ enzyme provides crucial insights into gut bacteria that could be exploited to develop an entirely new class of antibiotics.
“New antimicrobial strategies are desperately needed as more and more bacteria acquire resistance to existing classes of antibiotics,” Dr Goddard-Borger comments.
He believes it will soon be possible to use these SQ sugars to create antibiotics that target harmful forms of E. coli and other pathogens, such as Salmonella, responsible for food poisoning, but leave good gut bacteria untouched.
The research, published in the journal Nature Chemical Biology, also involved Professor Spencer Williams from the Bio21 Institute and University of Melbourne, and Professor Gideon Davies from the University of York, UK.
Prof Williams explains the research team also revealed how bacteria extracts sulphur-containing sugar from plants to fuel their growth.
“We discovered the enzyme YihQ, which is used by bacteria to absorb and metabolise these sulfur-containing sugars as food,” Prof Williams says.
“Sulfur is critical for building proteins, the essential components of all living organisms.
“SQ is the only sugar molecule which contains sulphur.
“The ‘digestion’ of the molecule [SQ] by bacteria releases sulfur into the environment. It then re-enters the global ‘sulfur cycle’ to be reused by other organisms.”
Prof Williams believes this work answers a 50-year mystery that has surrounded how sulfur – an element essential for life on Earth – was used and recycled by living organisms.
“What is remarkable is that the YihQ enzyme was hiding in plain sight and is produced by the humble bacterium E. coli, present in nearly every biologist’s laboratory.”
More research is yet to be conducted to identify how much SQ sugar is contained in each type leafy green and establish the quantity of SQ sugars required to produce a positive effect on the gut and overall health.