Maternal protein intake in pregnancy associated with higher offspring blood pressure 20 years later
In a new article published in the Journal of American Heart Association, Danish Diabetes Academy Postdoc Ekaterina Maslova worked with colleagues at University of Iceland and Aarhus University to examine the association of maternal protein intake during pregnancy with offspring blood pressure at age 19-21 years. The study, led by PhD student Laufey Hrolfsdottir, showed that substituting carbohydrates for protein during pregnancy was related to higher blood pressure in the adult offspring.
EARLY LIFE ORIGINS OF CARDIOVASCULAR DISEASE
High blood pressure is an important risk factor for cardiovascular disease. Some of this risk may be determined already during fetal life when relevant organ and tissue development (e.g. kidneys) may be compromised by external factors, including maternal diet.
LIMITED EVIDENCE ON MATERNAL HIGH-PROTEIN DIETS IN PREGNANCY AND OFFSPRING CARDIOMETABOLIC HEALTH
Past work on protein intake in pregnancy has been focused on low-protein diets (6-12% of daily energy intake) in animal models. These studies tried to understand mechanisms that could explain observational findings from human famine studies where severe maternal caloric deficiency was associated with a number of adverse cardiometabolic outcomes in the offspring. Less attention has been given to high-protein diet, despite recent popularity of these diets to aid weight loss. Two studies from the 1940s-50s in Scottish populations suggested that protein, especially from animal sources, may lead to higher blood pressure in the offspring many decades later. As lifestyle habits as well as obstetric care has changed since the 1950s, this study aimed to replicate these past finding in a more recent cohort.
MATERNAL PROTEIN INTAKE AT THE EXPENSE OF CARBOHYDRATES ASSOCIATED WITH MODEST INCREASES IN OFFSPRING BLOOD PRESSURE
This study examined 434 offspring born in Aarhus, Denmark, in 1988-89 whose mothers had provided information on dietary, anthropometric, lifestyle, and sociodemographic factors and at a visit in late pregnancy. In 2008-2009 the offspring was invited to fill out questionnaires on their health and lifestyle, and participate in a clinical examination.
After adjusting for potential confounders, higher maternal protein intake at the expense of carbohydrates was associated with a 2.4 mm Hg (95% CI 0.4–4.4) increase in offspring diastolic blood pressure, comparing the highest to lowest quintile of protein intake. Similar differences, although not significant, were found for systolic blood pressure. The authors used substitution of calories rather than an absolute increase because most free-living individuals tend to exchange calories rather than increase their caloric intake. Additionally, macronutrient composition may be more informative and relevant for dietary recommendations.
IMPLICATIONS FOR POPULATION HEALTH
Even a minor decrease in a population’s average blood pressure levels may substantially reduce the burden of blood pressure-related diseases. For example, a 2 mm Hg reduction in the population mean of diastolic blood pressure could decrease the prevalence of hypertension by as much as 17% and coronary disease by 6%. Along with the results of this study, this suggests that even modest dietary changes in pregnancy could potentially have considerable effects on population health. These dietary changes need to be weighed against other health risk (e.g. high carbohydrate intake and risk of gestational diabetes) and take into consideration both the quality and quantity of nutrients.
AUTHORS AND AFFILIATIONS
Laufey Hrolfsdottir1, Thorhallur I. Halldorsson1,2, Dorte Rytter3, Bodil Hammer Bech3, Bryndis E. Birgisdottir1, Ingibjorg Gunnarsdottir1, Charlotta Granström2, Tine Brink Henriksen4, Sjurdur F. Olsen2,5, Ekaterina Maslova2,6,7
1Unit for Nutrition Research, Landspitali University Hospital and Faculty of Food Science and Nutrition, University of Iceland, Reykjavik, Iceland
2Centre for Fetal Programming, Department of Epidemiology Research, Statens Serum Institute, Copenhagen, Denmark.
3Department of Public Health, Section for Epidemiology, Aarhus University, Denmark
4Perinatal Epidemiology Research Unit, Pediatric Department, Aarhus University Hospital, Skejby, Denmark
5Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA 6Department of Primary Care and Public Health, Imperial College, London, UK
7Danish Diabetes Academy, Odense, Denmark