Consuming fermented soymilk products may help protect against ultraviolet radiation damage by increasing the number of isoflavone compounds in the body.
Researchers from the Yakult Central Institute in Japan tested female hairless mice, feeding groups of six soymilk (SM) or fermented soymilk (FSM), with additional untreated and control groups. They found mice fed on FSM showed less skin reddening and skin thickening compared to those fed on regular soymilk.
The researchers found that isoflavone concentrations in the blood and UV-exposed skin were significantly higher in the FSM group compared to SM mice.
They had previously found isoflavone absorption is higher for subjects fed aglycone-enriched FSM compared to glucoside-enriched SM.
The mice had their ovaries removed prior to being tested, as a preliminary experiment showed ovariectomised mice were more susceptible to UV skin damage. The researchers speculated that isoflavones were exerting “oestrogen-like activity” in the mice in the main experiments.
These findings support the observation that oestrogen insufficiency decreases defences to oxidatives stress.