As any expecting parent can attest, gestational health is of utmost importance during a pregnancy. One of the most common threats to this state of wellbeing, however, is Gestational Diabetes Mellitus (GDM). According to the American Diabetes Association, GDM is defined as any degree of glucose intolerance with onset or first recognition during pregnancy.1 Research demonstrates that individuals who develop GDM are more likely to develop Type II diabetes (T2D) later in life, and the prevalence of GDM has reportedly increased over 30% in the last two decades across the globe.2
With this in mind, during its March meeting ABC’s Nutrition Research Committee (NRC) issued a Request for Proposals (RFP) to experts across the globe to learn more about GDM and determine any role almonds may have in helping prevent this disease.
The relationship between diet and GDM?
Systematic reviews and meta-analyses provide what is considered the highest level of evidence and allow researchers to draw meaningful conclusions from a comprehensive body of research.3 One such study published in Nutrients concluded that diet plays an important role in helping to decrease GDM prevalence and incidence.4 This study investigated collective evidence from 40 individually published studies on a total of 30,871 pregnant women using criteria set by the American Dietetic Association. The study concluded that frequent consumption of high-carb or refined carb foods and processed meats was associated with an increased risk of GDM, while healthier dietary patterns were associated with a reduced risk of the disease.
In addition, the Mediterranean diet has been shown to reduce incidence of GDM and help improve several maternal and neonatal outcomes.5, 6
Results from a systematic review conducted by a research group in the UK demonstrated that women who adhered to a Mediterranean diet during pregnancy experienced favorable maternal and offspring health outcomes, especially mothers with GDM.5
Further, in a randomized clinical trial conducted by a research group in Spain, Hispanic women 12-14 weeks along in their pregnancies who were at high risk of GDM were randomly placed in one of two groups: the research group that received recommendations on what to eat as part of a Mediterranean diet (consuming olive oil and nuts) or a control group that consumed a regular diet (without olive oil and nuts).6 The women consumed their allocated diets throughout their pregnancy, and study results demonstrated that the GDM rate was lower among women who consumed the Mediterranean diet. These women also experienced lower rates of urinary tract infections, emergency caesarean-sections and perineal trauma.
The study concluded that consumption of a Mediterranean diet was instrumental in reducing GDM rate and several adverse maternal-fetal outcomes in Hispanic women. Looking ahead, the positive impacts of consuming a Mediterranean diet are believed to be reproducible despite the current COVID environment. 7
Where do almonds fit in the picture?
Nuts, being an integral part of a Mediterranean Diet, play an equally important role in reducing the prevalence of GDM.
A randomized, double-blind, placebo-controlled study published in 2018 demonstrated that co-administration of vitamin E and magnesium in women diagnosed with GDM resulted in significant lowering of plasma glucose and significant reduction in total cholesterol and serum triglycerides.8 Overall, the study demonstrated significant improvement in glycemic control and lipid profiles.
Almonds are a rich source of vitamin E (α-tocopherol) and magnesium.9 They also provide a good way to incorporate healthy unsaturated fats into one’s diet: one serving (an ounce or 28g) of almonds provides 9g of healthy monounsaturated fats.
Dietary fat intake has also been shown to play a crucial role in the risk of gestational diabetes. A prospective study, conducted to determine whether the total amount and type of dietary fats are related to GDM risk, reported that a higher amount of animal fat and higher cholesterol intake is associated with an increased risk of GDM, while no such associations were observed between dietary monounsaturated or polyunsaturated fats.10
Given GDM’s widespread impact across populations worldwide, the use of healthy foods to help reduce this disease should be further explored. With this foresight, NRC approved RFPs to investigate the role that almonds could play in improving maternal-fetal health outcomes for women with GDM. The call was disseminated to over 100 researchers across the globe with expertise in gestational diabetes. It generally takes six months from the time a call is disseminated to the selection of the winning proposals, and then takes another two-to-three years for the study to be conducted and for the study results to be published.
Although the process is long, the outcome of the process – study results that provide guidance to consumers and policy makers alike – is extremely rewarding. Stay tuned to learn which proposal is selected for funding and research!
1 American Diabetes Association. Gestational Diabetes Mellitus. Diabetes Care 2003;26(SI): S103-105.
2 Zhu et al. Prevalence of Gestational Diabetes and Risk of Progression to Type 2 Diabetes: A Global Perspective. Curr Diab Rep. 2016;16(I):7.
3 Haidich AB. Meta-analysis in medical research. Hippokratia 2010;14(Suppl 1):29-37
4 Mijatovic-Vukas et al. Associations of Diet and Physical Activity with Risk for Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis. Nutrients 2018; 10, 698
5 Amati et al. The Impact of Mediterranean Dietary patterns During Pregnancy on Maternal and Offspring Health. Nutrients 2019;11,1098.
6 Melero et al. Effect of a Mediterranean Diet-Based Nutritional Intervention on the Risk of Developing Gestational Diabetes Mellitus and Other Maternal-Fetal Adverse Events in Hispanic Women Residents in Spain. Nutrients 2020;12,3505.
7 Fedullo et al. Mediterranean Diet for the Prevention of Gestational Diabetes in the COVID-19 Era: Implications of IL-6 in Diabesity. Int. J. Mol. Sci. 2021;22, 1213.
8 Maktabi et al. The Effects of Magnesium and Vitamin E Co-Supplementation on Parameters of Glucose Homeostasis and Lipid Profiles in Patients with Gestational Diabetes. Lipids in Health and Disease 2018;17:163.
9 U.S. Department of Agriculture, Agricultural Research Service, USDA National Nutrient Database for Standard Reference, Release 28, 2015: http://www.ars.usda.gov/ba/bhnrc/ndl.
10 Bowers et al. A Prospective Study of Prepregnancy Dietary Fat Intake and Risk of Gestational Diabetes. Am J Clin Nutr 2012;95:446-53.
