The role of parental influence in acquiring diabetes
Diabetes is a chronic disease that costs Australia approximately $14.6 billion per year. It is estimated that up to 3 million Australians over the age of 25 years will have diabetes by the year 2025. The increasing number of people with obesity is likely part of the reason for this upward trend, as well as a combination of genetics and environmental factors. How do we lower the impact of this insidious disease with no cure? A disease that takes a substantial toll not only on individuals, but also the community, the economy and the health system. Prevention is our best chance against this silent pandemic. Understanding what influences the onset of diabetes – looking at both environmental and genetic factors - and advising on suitable interventions to prevent the onset is one-way researchers are tackling the problem. In a bid to understand if parental exposure contributes to the onset of diabetes in their offspring, Dr Amita Bansal from the Australian National University (ANU) Medical School and colleagues have delved deep into the influence of genetics and environmental factors in acquiring diabetes. Specifically, how diet and environmental chemicals play a role. Dr Bansal investigated the effects of maternal undernourishment during the pre-conception and early pregnancy period on offspring. “We’re very aware that maternal health and nutrition during pregnancy is an important factor in the longer-term health of baby. There is evidence that if a mother is undernourished during pregnancy it increases the offspring’s chance of developing diabetes, obesity and heart disease in adulthood.” Dr Bansal explains. “Using a sheep experimental model, we asked whether maternal undernourishment during pregnancy as well as prior to pregnancy (pre-conception) has long-term detrimental effects on offspring’s metabolic health? Our findings suggest that the periconception window (61 days before to 30 days after conception) is particularly important.” “We found that female sheep that were undernourished during the periconception period gave birth to lambs that were impaired glucose tolerant at 10 months of age.” Impaired glucose tolerance is the inability to process glucose and results in high blood glucose levels. Individuals with impaired glucose tolerance are at a greater risk of developing diabetes than those with normal glucose tolerance. “We extended our sheep study to 36 months of age and recorded persistent impaired glucose tolerance and reduced insulin secretion in these sheep indicating a lasting impact of maternal undernourishment on the offspring.” Thirty-six (36) months of age in experimental sheep is comparable to adulthood in humans. The results from this sheep model suggest that chances for developing diabetes in later life is increased, if the mother is undernourished during the periconception period. Mothers do play a significant role in influencing offspring’s future health. In a previous study, Dr Bansal and colleagues have demonstrated the impact of maternal exposure to a common environmental chemical, Bisphenol A (BPA). BPA is a chemical that has been used since the 1960s to make plastic products. Exposure to BPA constantly occurs as it is present in everyday products such as food containers, water bottles, lining of aluminium food and drink cans, and in thermal paper receipts (e.g. cash registers, ATM machines). Its potentially damaging effects have led for calls to remove its use in plastic wares, and for manufacturers to declare their products ‘BPA free’. Worryingly, if mothers are exposed to BPA, the effect of BPA exposure is multigenerational. Dr Bansal and colleagues have reported that not only the first generation (child), but the second-generation (grandchild) also has an increased risk of developing diabetes when mothers are exposed to BPA. By the third-generation (great grandchild) there is some effects, but far less than the second-generation. This shows that the burden of diabetes can be transmitted from one generation to next when it comes to BPA exposure. It’s not only mothers that need to be vigilant about keeping healthy. Fathers also have a role to play in their offspring’s ability to remain diabetes free. In another recently published paper by Dr Bansal and colleagues, the impact of paternal exposure to BPA on development of diabetes in offspring was explored. Dr Bansal said, “Very little is known about how a father’s exposure to BPA affects offspring. To assess potential impact, we compared dietary exposure effects at two stages of life - male mice that were exposed to BPA during early development (i.e. preconception through lactation exposure during which the mother was fed food containing BPA), and male mice that were fed BPA containing food post-puberty until adulthood. For both scenarios, exposed male mice were mated with unexposed virgin females.” “We observed that female offspring, born to fathers developmentally exposed to BPA, exhibited impaired glucose tolerance, meaning they were at a higher risk of developing diabetes than female offspring of unexposed fathers. Interestingly, we did not observe this characteristic in male offspring of exposed fathers.” These findings suggest that female children of developmentally exposed fathers are at a greater risk than male children. “Surprisingly, we did not observe impaired glucose in female or male offspring of fathers that were exposed to BPA post-puberty.” Together, this study suggests that early life exposure to BPA in developing males can be more harmful than if BPA exposure occurs post-puberty in males. Thanks to the work of researchers such as Dr Bansal and colleagues, we have increasing awareness of the factors that contribute to acquiring diabetes. The ongoing research aims to discover biological mechanism by which these factors offset our developmental trajectory and lead to diabetes. This will help in designing targeted interventions to prevent the development of diabetes at its origin. While Dr Bansal and others continue to find a solution, here are few key health tips that she follows: eat fresh fruits and vegetables, always wash fruits and vegetables thoroughly prior to consumption, avoid plastic as much as possible, and do not heat food in plastic containers. When in doubt, Dr Bansal recommends referring to the EWG consumer guides and healthy living tips.