Between 2011 and 2015, the proportion of Australian adults who said they had the condition rose from 2.8% to 4.0%, Roy Morgan Research has found.
The proportion of men—1.7%—has stayed relatively stable over the last few years, growing by just 3,000 each year. In contrast, 6.2% of women now say they are lactose intolerant, compared to 3.8% from 2011—up from 337,000 to 576,000.
Women aged between 25 and 34 have the nation’s highest incidence of lactose intolerance, followed by those from the 35-49 age bracket. These female groups are up to four times more likely to suffer from the condition than the corresponding age groups among men.
Lactose intolerance occurs when a person’s body doesn’t produce enough of the lactase enzyme to break down the lactose found in dairy and some foods.
“Although medical and health research does not tend to identify women as being more susceptible to the condition than men, our data shows that it is considerably more prevalent among Australian women,” said Roy Morgan’s Michele Levine.
“One could speculate that the lower prevalence among men may simply be due to a lack of diagnosis, but it is worth noting that our findings also show that almost identical proportions of men [27.3%] and women [27.5%] visit their doctor in any given four weeks.”
Compared with the average Australian, those who are lactose intolerant are one-and-a-half times more likely to experience nausea, twice as likely to be vitamin deficient and over four times more likely to suffer from digestive problems. They are also 72% more likely to suffer from osteoporosis.
“To minimise its symptoms, people who are lactose intolerant need to avoid certain dairy products and our data bears this out: 58.6% of them avoid dairy foods whenever possible [compared with the national average of 13.4%],” said Levine.
“Curiously, given their heightened risk of osteoporosis, lactose intolerant people are slightly less likely than average to try to get enough calcium in their diet.”