Unborn baby's predictions of the future may hold key to disease prevention

A new theory, which explores the link between biological evolution and the risk of disease, looks set to have world-wide implications for future health strategies to combat the continued increase of so-called 'lifestyle' diseases such as obesity, diabetes, cardiovascular disease and osteoporosis.

The phenomenon of 'predictive adaptive responses' (PARs) is set out by Professor Peter Gluckman of the Liggins Institute in Auckland, New Zealand and Professor Mark Hanson of the University of Southampton in a paper published in Science today (17 September).

The co-authors of the paper contend that a growing foetus in the womb takes cues or messages from its mother to predict the environment it is likely to live in after birth. It then adapts its physiological development to ensure it has the best chance of survival in that expected future environment.

If those predictions are correct and its physiology is appropriate for its environment, all is well. However, inaccurate predictions lead to an increased risk of certain diseases. The size of that risk depends on the size of the mismatch between the predicted and actual environment. For example, if individuals receive poor nutrition in the womb and grow up eating high calorie, high fat diets, they will be at a higher risk of certain diseases.

The authors believe that their theory may explain why there has been an increase in the incidence of type 2 diabetes in the developing world, where diets are becoming richer even though foetal development is still constrained.

Gluckman and Hanson's idea challenges the accepted view of evolution that genetic changes are long-term and happen slowly over many generations. Predictive adaptive response mechanisms make possible rapid and short-term changes which can take place within a generation as a result of individuals 'matching' the way their genes are controlled to the prevailing environment almost from the moment of fertilisation.

A similar predictive adaptive response can also be seen in animals, including in locusts, which have different body colours and wings, behaviour and food preferences depending on the messages they receive about population density while they are larvae.

This idea presents a compelling case for improving the health of expectant mothers in order to prevent disease in the next generation.

Professor Hanson commented: "If our appetite, food preferences, ability to lay down fat and inclination to exercise are all predetermined in the womb at a very early stage of foetal development, then changing one's lifestyle later in life in to reduce the risk of disease may be too late to have any real effect. For maximum effect, public health programmes need to target expectant mothers to ensure optimal nutrition rather than at-risk adults."