A new study released by Lund University has revealed that people who suffer from lactose intolerance are at lower risk of suffering from lung, breast and ovarian cancers. A western style diet has been thought to contribute to higher incidences of breast and ovarian cancer in different countries. North America, Western Europe and Nordic countries have higher rates of cancer than their East Asian and Central African countries.
“We found that people with lactose intolerance, who typically consume low amounts of milk and other dairy products, have a reduced risk of lung, breast and ovarian cancers,” said Jianguang Ji, Associate Professor at Lund University and researcher at the Center for Primary Care Research in Malmö.
“The risk of cancer was not reduced in relatives of people with lactose intolerance, which indicates that protection against these cancers is related to diet. However, it would be wrong to conclude that milk is a risk factor for these cancers,” said Jianguang Ji.
The scientists examined 22,788 individuals with lactose intolerance and examined their risk of suffering from lung, breast and ovarian cancer. It was determined that the risk of lung cancer (standardised incidence ratio [SIR] = 0.55), breast cancer (SIR = 0.79) and ovarian cancer (SIR = 0.55) was significantly lower in people with lactose intolerance compared to people without lactose intolerance, irrespective of country of birth and gender.
“In order to investigate this unanswered question we adopted a novel approach,” said Jianguang Ji. “We investigated whether low consumption of milk and other dairy products protects lactose-intolerant people against breast and ovarian cancers. Since epidemiological and animal studies show that milk consumption and lung cancer risk are both associated with the protein IGF-1 (insulin like growth factor 1), we also investigated lung cancer.”
The researchers caution about attributing a definitive causation between lactose intolerance and cancer but specify that factors such as lower calorie intake because of low milk consumption and protective factors in plant-based milk drinks may contribute to the observed negative association between lactose intolerance and the studied cancers.
J Ji, J Sundquist, K Sundquist. Lactose intolerance and risk of lung, breast and ovarian cancers: aetiological clues from a population-based study in Sweden. British Journal of Cancer, 2014; DOI: 10.1038/bjc.2014.544