New University of Otago research has found exposure to female odours and pheromones can cause mice to lose weight and live longer, and the discovery may have implications for humans.
Lead researcher Dr Michael Garratt said it was already known that sensory cues in humans and animals influenced the release of sex hormones, but this study showed these cues could have more wide-spread physiological effects on metabolism and ageing.
"Our studies show that female odours slow the sexual development of female mice, but consequently extends their lifespan.
"And we also show that the smell of females can increase male mouse energy expenditure, which subsequently influences their body weight and body fat levels."
In the research, newborn mice were exposed to odours from adult females until they were 60 days old.
Those females exposed to the odours reached sexual maturity later and lived an average of 8% longer than those not exposed, Dr Garratt said.
Male odours had no effect on female mouse lifespan, and odours from either sex had no effect on the lifespan of males.
"As far as we know, this is the first observation that lifespan can be increased in a mammal by olfactory signals, or indeed secreted factors found in soiled bedding and urine," he said.
"More generally, the work hints that sensory cues from our social environment can cause changes to our physiology and development, which may have long-term effects that extend to influence how we age."
Although male mice did not directly benefit in terms of longevity from female odours during development, their weight and metabolism was "substantially affected" when they were exposed to female odours as adults.
"We have found that exposing male mice to female odours increases their energy expenditure for several hours after exposure.
"These effects are sufficient to induce weight loss and protect against males getting very fat when they are fed a diet that has an excess of energy."
Dr Garratt said the results would not necessarily translate directly to humans, but it confirmed how sensory cues — smells, taste and even things we see — set off reactions in our bodies that affects things like metabolism, health and ageing.
He said it was already known that smells could release sex hormones in humans and mammals, but this research took it further.
"We would now like to understand how information received by the olfactory system is capable of inducing widespread effects."
