I am honored to introduce you all to our Legacy Leader Dr. Clint Gray. Just this week his research article, “Excess maternal salt or fructose intake programmes sex-specific, stress-and fructose-sensitive hypertension in the offspring“, was published in the British Journal of Nutrition. Dr. Clint Gray was one of the primary investigators on this 3 year study and he is here this week to offer a review of his most recently published research as well as answer some anticipated Frequently Asked Questions about this findings.
The developing embryo will experience more rounds of cellular replication during the first nine months of existence than any time during its entire life! Fetal development is a very precise and highly orchestrated process and it is now known that very small differences in growth, cellular mechanisms and altered gene expression can be influenced by maternal factors such as alcohol, smoking, obesity during pregnancy and nutritional factors such as; high intakes of salt and fructose. These nutritional ‘insults’ have been shown not only to have effects on placental development, fetal development and pregnancy outcome but are now recognised as being hugely important in moulding our future health as adults.
Known as Developmental Programming, Nutritional Programming, Fetal Origins of Disease and the Developmental Origins of Health and Disease. These are all terms that have been used to describe a hypothesis first proposed by Dr David Barker in 1995, ‘The Barker Hypothesis’. Dr Barker was one of the first researchers to describe “fetal undernutrition in middle to late gestation, can lead to altered fetal growth and ‘programmes’ later-life heart disease”. Put simply, this means that what you eat and drink during pregnancy can cause problems for your developing baby which can last throughout his or her entire life. Reduced or altered food supply caused by a reduction in supply of nutrients and blood flow from mother to fetus can interfere with the development of your baby, persisting through childhood and into adulthood, even into the next generation!
Over the years, I have researched many aspects of developmental programming with a particular focus on maternal salt and fructose intake and predisposition to cardiovascular disease in offspring. In our most recent research paper, we investigated the effects of fructose and salt intake during pregnancy, fetal development and later-life exposure to fructose and/or salt.
Our results showed two main outcomes.
- Maternal salt intake caused significant increases in resting blood pressure and larger blood pressure responses to stress in male, but not female offspring in later life.
- Maternal fructose caused a rapid increase in blood pressure when fructose was consumed by male and female offspring during later life. However, the increase in blood pressure was much greater in females.
Who did this study?
Our group of researchers at the University of Nottingham performed this study as part of a team. The study took nearly 3 years to complete and at great expense. The study team consisted of Dr. Clint Gray, Associate Professor David S. Gardner (Group leader), Professor Sheila Gardiner and Dr. Matthew Elmes along with support of other members of University staff.
Why fructose and why salt?
On average, we all eat too much salt and fructose in our day to day diets. Fructose and salt is ‘hidden’ in almost all packaged and processed foods. From an evolutionary perspective, 15000 years ago, we would eat very little fructose and of that, it would all come from fruit. Whereas, today’s diet may provide as much as 10-15% of our total daily calorie intake may be from fructose. Way back, when we were hunting and gathering we ate very little salt too. Our salt intake would be limited to salt found only in the plants and meats we would naturally eat. This would be around 250mg (about a quarter of a gram), considering that today’s average daily intake of salt can be as high as 9g in a woman and 11g in a man. We are simply not supposed, and not yet evolved to be consuming these levels of salt and fructose in our daily diets. Given that both salt and fructose can lead to health issues in the normal healthy adult. This led us to think about the effects on fetal development and what occurs during pregnancy when salt and fructose is consumed in excess. However, I would like to point out that the fructose we used and are discussing is ‘extrinsic’ fructose. This is fructose that is not natural fructose, but the manufactured fructose added to food products to enhance flavour. Not, ‘intrinsic’ fructose which is found naturally in fruit, within its cells and in much lower quantities which takes longer for your body to break down.
What does this study show?
This study provides strong evidence that consuming excessive fructose and salt during pregnancy can have a huge impact on your developing fetus and its ability to cope with further nutritional challenges and disease during adulthood. These can include higher resting blood pressure, increased response to stress and most interestingly, increased sensitivity to fructose. i.e. if your mother had a high fructose intake during pregnancy, you may have increased blood pressure following fructose intake when compared to someone whose mother had a ‘healthy’ diet during pregnancy. This may increase your risk of cardiovascular disease in later-life. The study shows that fructose and/or salt during pregnancy can potentially harm the health of our children before birth, which may last a lifetime and maternal fructose & salt contributes to the list of potential risk factors of cardiovascular disease in adult offspring.
Finally, the study does not prove that fructose and salt are the sole cause of cardiovascular problems during later-life; but it is clearly shows that maternal intake of salt and fructose are modifiable and preventable risk factors of future life disease risk. Based on these results and other studies we and other researchers have performed. It is essential that appropriate public education and policy change to improve pregnancy outcomes and give the developing baby a healthy start to life.
What implications can we derive from this study?
The implications of this research could be far reaching. With cardiovascular disease still being the world’s number one cause of death and high blood pressure being the underlying cause of most cardiovascular diseases. The reduction of maternal salt and fructose during pregnancy may reduce the overall incidence of cardiovascular disease in future generations. Furthermore, our research may, in part, explain some of the common metabolic and cardiovascular problems we observe in children today. Conditions such as; fatty liver disease, hypertension and obesity, usually not experienced in children, but which have all seen a massive increase in cases during recent decades.
When it comes to chronic disease, the quality of our food is very important. Restriction of fructose is an important in the prevention of diabetes, obesity, metabolic disease, fatty liver disease and cardiovascular problems. However, very little thought is given to the diet of pregnant woman or indeed the woman considering pregnancy. This study and research like it provides strong evidence that dietary advice and awareness to pregnant women is of huge importance.
Dr. Clint Gray BSc.(hons), PhD.
You can follow Dr. Gray on Twitter
If you have any questions regarding the use of rats during this study or others such as this just email me.