One Minute Insight
Professor Nick Wareham talks about nutrition, diet and lifestyle research and how different saturated fats can affect people with diabetes.
Reducing calories to improve pregnancy outcomes in gestational diabetes
Women with gestational diabetes are being recruited to receive home-delivered food boxes to investigate if a normal or reduced calorie diet reduces the mother’s weight change during pregnancy and improves the baby’s birthweight.
Diabetes which first develops in pregnancy (gestational diabetes) affects around 5% of pregnant women in the UK. Gestational diabetes causes short term issues in pregnancy, such as increased fetal growth and increased birth-weight, but it is also associated with an increased long-term risk of type 2 diabetes for both mother and child. Current guidelines advise women diagnosed with gestational diabetes to change towards a healthier diet during pregnancy and to increase exercise levels. Such changes can often help control blood glucose (sugar) levels without medication. However, there is not a lot of evidence about the best diet for women with gestational diabetes.
Researchers from Cambridge are recruiting 500 women diagnosed with gestational diabetes for a dietary intervention study led by Dr Claire Meek, Senior Clinical Research Fellow at the Wellcome-MRC Institute of Metabolic Science. Participants will receive weekly home-delivered food boxes that contain all meals and snacks from 28 weeks pregnancy to when the baby is born. Women will be randomly allocated to receive either a standard calorie or a reduced calorie diet box.
The researchers are investigating the impact of the diet on the mother’s weight change in this period of pregnancy and on the baby’s birthweight. They are also making detailed measurements to investigate the impact of the diet on body fat changes. The mother’s usual diet will be measured before and after the diet box intervention using an online diet tool to record what they are eating and drinking (Intake24).
This innovative study, which is funded by Diabetes UK, will help to improve care for women with gestational diabetes and their babies in future.
Kusinski LC, Murphy HR, De Lucia Rolfe E, Rennie KL, Oude Griep LM, Hughes D, Taylor R, Meek CL. Dietary intervention in pregnant women with gestational diabetes: protocol for the DiGest Randomised Controlled Trial. Nutrients 2020, 12(4), 1165;
Understanding the link between vitamin D and risk of type 2 diabetes
It is well known that having enough Vitamin D is essential to maintain healthy bones but there has been a growing interest in whether vitamin D also has a role in other conditions, such as type 2 diabetes. Cambridge researchers have undertaken new research in multiple countries to investigate this link.
The number of people globally with type 2 diabetes continues to increase. There is an urgent need to find ways of preventing this serious condition.
Cambridge researchers established a collaboration with colleagues in 8 European countries to study the link between blood vitamin D markers (which show how much vitamin D a person has in their blood) and developing type 2 diabetes. They also forged a collaboration with a laboratory with technical expertise in the measurement of a number of different forms of blood vitamin D in the blood.
They found that higher levels of total vitamin D were related to having lower risk of type 2 diabetes but that some types of vitamin D can be associated with a risk of developing type 2 diabetes.
Their findings help to expand prior scientific knowledge as previous studies looked at the total amount of vitamin D diabetes patients had.
This research also helped researchers to understand whether people from northern and southern European countries had different levels (on average) of vitamin D, and the dietary sources that contribute to vitamin D levels in the blood.
This research provides the first evidence for differences in risk of type 2 diabetes depending on the specific type of blood vitamin D. It raises the importance of the need for further understanding of the biology of vitamin D when it is metabolised (processed) into different forms in the body. Further research will be needed to test if the links observed in this research point to cause and effect.
This case study relates to the publication by Zheng J et al. J Clin Endocrinol Metab 2019 Apr 1;104(4):1293-1303.
Working with researchers in Leicester, they recruited 1,368 people – including more than 300 of south Asian ethnicity – to take part in the NIHR-funded PROPELS study.
Study participants all had blood glucose (sugar) levels that were higher than normal, and this put them at risk of developing T2D.
Participants were allocated to one of three groups. The first group received detailed advice on how to reduce their risk of T2D. The second group received the same information, a pedometer (step counter), encouragement to walk 2,000-3,000 steps more each day and an annual 4-hour education programme about diet and physical activity. The final group received all this plus follow-on support through personalised text-messaging and telephone calls to encourage behaviour change and monitoring of physical activity by a pedometer.
After 12 months and then again at 4 years, participants provided blood samples and their physical activity was measured. The data is being analysed and the results should provide new evidence for the long-term effectiveness of a tailored programme to reduce T2D risk in high-risk groups.
Using nutritional biomarkers to show that not all fats are the same
Poor diet is a leading cause of obesity and ill health in the UK and globally, putting health systems under strain. Accurately measuring people’s diet can be difficult, as it has traditionally relied on questionnaires in which people report what they eat and drink, which is prone to error.
One way of adding objective information to this picture is to use ‘nutritional biomarkers’ – molecules found in the body that reflect the foods we eat. These can be measured in body tissues such as blood or urine, and can provide helpful additional information.
To improve their understanding of the link between dietary saturated fat consumption and the risk of developing type 2 diabetes, researchers in Cambridge studied saturated fatty acid blood biomarkers as a way to help distinguish between different types of saturated fat.
They developed a sophisticated method of high-speed blood analysis to study biomarkers from thousands of people across eight European countries. They found that saturated fatty acids can be associated with both an increased and decreased risk of developing type 2 diabetes, depending on the type of fatty acids present in the blood.
These findings provide evidence that individual saturated fatty acids are not all the same. And they could partially explain recent other evidence that suggests some foods high in saturated fats, such as dairy products, could actually lower the risk of type 2 diabetes, while other high fat foods, such as red and processed meat, raise its risk.
Work remains to understand more about the precise relationship between what people eat and the chemicals found in their blood. However, in time, these types of findings could be used to help refine dietary guidance for everyone, and even as part of identifying groups of patients who could benefit from personalised lifestyle recommendations.