The final session of the workshop provided an opportunity to summarize and reflect on the presentations and discussions that took place over the course of the 2 days. The session began with an invited speaker who offered her thoughts and then expanded to include audience reflections. The workshop ended with Anna Maria Siega-Riz of the University of Massachusetts Amherst providing brief closing remarks.
Characterizing the workshop as “broad, deep, nuanced, and highly informative,” Patsy Brannon, visiting professor (and until her retirement in 2018, professor) in the Division of Nutritional Sciences at Cornell University, provided her observations on the new information that has emerged. She began by noting that the health and characteristics of women becoming pregnant has changed since the early 1990s. Mothers are older, with fewer adolescent pregnancies. Fewer women smoke, but there is a greater prevalence of overweight, obesity, and diabetes. There have also been shifts in the dietary patterns in the population, with diets (e.g., intermittent fasting, paleo, low-carbohydrate), organic, and sustainability becoming more popular. From the presentations, Brannon found it clear that evidence has emerged over the past 30 years on a number of topics, including macronutrients, energy (particularly related to obesity), one-carbon metabolism micronutrients, obesity, gestational diabetes, Developmental Origins of Health and Disease (DOHaD), and community engagement to optimize nutrition during pregnancy and lactation. She went on to identify cross-
cutting themes, discuss implications for the expanded Dietary Reference Intake (DRI) model, and note advancements and remaining issues.
Brannon identified topic areas that cut across several of the presentations. These crosscutting themes included biomarkers, supplementation, DOHaD, the reproductive continuum, and disparate outcomes, status, and intake for at-risk populations.
Concerns and limitations related to biomarkers during pregnancy and to a lesser extent lactation were raised for several nutrients, including omega-3 fatty acids, iron, vitamin D, folate (especially high status), choline, vitamin B12, antioxidants, and iodine. For some nutrients, no biomarkers currently exist, while for others the appropriate cutoffs, adjustments, or interpretations during pregnancy are unknown.
Regarding supplementation, dose, form, and bioavailability emerged as common concepts. Several of the speakers addressed whether requirements for certain nutrients could be met with diet alone or likely necessitated supplementation. The role of an individual’s baseline status was also mentioned for such nutrients as omega-3 fatty acids, folate, and iodine, where those who are replete may not see added benefits from additional supplementation. “It is no wonder that we sometimes get negative results, because we averaged those with low status, those with adequate status, and those with high status,” remarked Brannon.
DOHaD was also discussed throughout the workshop, particularly related to human milk oligosaccharides and the placenta. New evidence has emerged suggesting a mother’s diet can affect the microbiome, which in turn, can influence the growth, body composition, and brain development of her child. Acknowledging the potential for interventions, Brannon underscored the importance of first understanding the specific effects and then possible synergies. She also thought that identifying developmentally validated surrogate endpoints would be crucial to advancing the field, as waiting decades for a chronic disease to develop is not practical. There is a complex relationship between the placenta and DOHaD. The evidence presented underscores the importance of the interactions between maternal nutrition, obesity, gestational diabetes, oxidative stress, and other stress factors for long-term health. Presentations and discussions also touched on placental and fetal sexually dimorphic responses to maternal nutrition, gestational diabetes, and maternal obesity. Brannon indicated that consideration may need to be given to the mother–father–fetus triad, as opposed to just the infant–mother dyad in terms of DOHaD as emerging evidence in animal models suggest fathers contribute to epigenetic changes in their offspring.
Several speakers stated that preconception, pregnancy, postpartum, and lactation are part of a reproductive continuum, rather than being discrete phases. With the exception of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), health care systems and interventions often put these stages in siloes, said Brannon.
Disparities and inequities affect the outcomes, status, and dietary intake of pregnant and lactating women, particularly in at-risk populations. Presenters noted that some of these groups include lower-income women, women pregnant with multiples, women who are overweight or have obesity, non-Hispanic blacks, unplanned pregnancies, adolescents, and those following restrictive diets (e.g., vegans, gluten free). These disparities are driven and exacerbated by social injustice, stress, obesity, gestational diabetes, poverty, and food insecurity. Systems approaches, informed by implementation science, can be used to help address these issues, noted Brannon.
Implications for the Expanded DRI Model
One topic that was not raised by workshop speakers that Brannon wanted to highlight was the consideration of chronic disease endpoints in the context of the recently expanded DRI model. The addition of a new category of values, called Chronic Disease Risk Reduction Intake (CDRR), has important implications for the underlying body of evidence. Brannon suggested that the research community should be aware that there needs to be at least moderate strength of evidence for both a causal and a dose–response relationship for a chronic disease outcome in order for a CDRR to be established. For several nutrients, including vitamin D, antioxidants, and omega-3 fatty acids, there are inconsistent findings or discordant results between observational studies and randomized controlled trials, leading to “challenges in synthesizing the evidence and inconsistency of results that arise from variability in study design, in dosage, in timing, in baseline status considerations, and in biomarkers,” noted Brannon.
Using chronic disease outcomes in a separate DRI category can also affect the determination of reference values for adequacy. “If we lack biomarkers that we can interpret and set cutoffs to tell us whether a nutrient status is adequate or not, what kind of adequacy outcomes are we going to use for those nutrients?” asked Brannon. She also noted that chronic disease outcomes are no longer intended to be used for establishing Tolerable Upper Intake Levels.
Advancements and Remaining Issues
The new evidence related to macronutrients requirements during pregnancy and lactation revealed where innovations have taken place and where
limitations remain. For omega-3 fatty acids, maternal supplementation appears to decrease risk of preterm birth but may also prolong gestation. Evidence on relationships between omega-3 fatty acids and other outcomes are conflicting or of limited clinical significance. A new analytic approach to assessing protein adequacy suggests requirements during pregnancy may be higher and more dynamic than the existing DRI values. There remains a need to consider protein quality and to educate those who are potentially at risk (e.g., vegans). Similarly, carbohydrate quality appears to be of importance. Evidence of a relationship between the glycemic index and chronic disease outcomes, however, is limited.
The understanding of nutrients involved in one-carbon metabolism has also evolved, but several challenges persist. Although folic acid fortification has helped to reduce neural tube defects, preconception compliance with folic acid supplementation is low. The long-term effects of folic acid supplementation are not well characterized and warrant consideration of low vitamin B12 status. The importance of choline has also been raised, despite limited availability in prenatal supplements and issues in meeting adequacy requirements through dietary intake alone.
Iron and vitamin D also emerged as two nutrients of critical importance but with limited outcome data. “The best we can prove with iron supplementation is maternal hematological indices improve and anemia is reduced,” said Brannon. Similarly for vitamin D, supplementation can increase maternal and newborn circulating 25-hydroxy-D concentrations, but relationships with other outcomes are limited.
The evidence on relationships between antioxidants and pregnancy outcomes is discordant, noted Brannon. She also suggested that the relationship between vitamin E and congenital heart defects merits further investigation.
Low maternal iodine status is associated with developmental deficits in offspring, particularly related to cognition and verbal skills. Iodized salt was also raised as a model for food fortification. Brannon questioned whether women receive mixed messages, given that sodium reduction is generally recommended for the population, and she wondered if there were other fortification vehicles to deliver iodine.
The presentations highlighted that dietary supplements can help pregnant and lactating women meet needs for certain nutrients. However, the discussions revealed that there are issues in standardization, bioavailability, and characteristics across different formulations.
There have been advancements in the state of the science on human milk and lactation. With respect to human milk content, there are some vitamins and minerals that are affected by maternal intake. Brannon cautioned, however, that the effects might not always be desirable. There is new evidence on the potential benefits of human milk oligosaccharides,
but more research is needed to elucidate those relationships fully. Maternal obesity and gestational diabetes can affect lactation performance and alter human milk composition, including factors that affect infant appetite regulation and body composition. Longitudinal data have shown that lactation reduces maternal risk of type 2 diabetes later in life.
Finally, Brannon highlighted that inequities exist related to social injustice and that frameworks are needed to better address the contributing factors affecting a woman’s nutritional status, such as poverty, food insecurity, and stress. She underscored the importance of a systems approach informed by implementation science to consider these factors across different systems. WIC serves as one model that has integrated concepts of health equity.
After providing her reflections on the workshop, Brannon encouraged others to offer their thoughts on what they heard over the course of the 2 days.
Audience member Liliane Mavridara, a mind–body health and lifestyle medicine professional, began by touching on several topics addressed by speakers. She agreed with the sentiment that the reproductive cycle should be viewed as a continuum, and she thought there should be support beginning in the preconception period all the way through postpartum. Mavridara suggested that women have a tendency to not seek out support, when in fact pregnancy and postpartum should be bolstered by the community. She appreciated the presentations that discussed stress, as emotional and mental health are intertwined with nutrition and overall well-being, and she thought environmental pollution should also be considered. Mavridara summarized her reflection by saying that a holistic approach is needed: “We have to think more at that level of change and improvement for the health of babies and then for the health of the community.”
Related to the concept of care throughout the reproductive cycle, Ann Yaktine of the National Academies of Sciences, Engineering, and Medicine suggested that WIC serves as one model that breaks the siloes of clinical care by providing supplemental food packages, nutrition education, nutritional assessment, and referrals to other health services. Brannon agreed, noting that WIC is anchored in the community. She went on to acknowledge that while the focus is typically on the mother–infant dyad, fathers also play a critical role, and she wondered if future expansion of the WIC program could accommodate both parents. The audience further explored the concept of different models that could be leveraged, including
- Maternity homes—A webcast audience member thought that Cuba serves as one example of community-oriented, integrated maternity
- care. Siega-Riz, who was familiar with this approach, explained that doctors have a limited number of patients and live within the communities they serve. There are also maternity homes that give women with high-risk pregnancies (e.g., adolescents, women with gestational diabetes) medical care, nutritional care, nutrition education, and foods, and require their families to visit. Siega-Riz noted that maternity homes are also used in Africa, as women often do not reside near a hospital.
- Midwifery—Rafael Pérez-Escamilla of the Yale School of Public Health indicated that midwifery is much more prevalent in European countries as compared to the United States.
- Doulas—Siega-Riz said that there is a movement in certain communities toward using a doula—a woman who has helped throughout the pregnancy—to continue to provide support, care, and assistance to the mother in the postpartum period. She indicated that women are matched so there is peer support that allows for cultural acceptance.
- Kenya’s Baby-Friendly Community Initiative—Audience member Justine Kavle of Kavle Consulting, LLC, offered Kenya’s Baby-Friendly Community Initiative, an offshoot of the Baby-Friendly Initiative, as another example to consider. To improve breastfeeding, maternal nutrition, and complementary feeding, community support groups were formed. The groups include family members, community members, and others, and decide on the issues they would like to discuss. There are also support groups specifically for mothers. Kavle suggested such a model could be used in conjunction with the continuum of clinical care and community services.
- Adding nutrition to other models—Barbara Laraia of the University of California, Berkeley, suggested that there are other models to which nutrition education could be added or enhanced and tailored to specific populations. She noted that prenatal groups are quickly being adopted (e.g., Expect with Me). Participants report high satisfaction, although the evidence for outcomes is mixed. Another model Laraia suggested was Food is Medicine, a program where health care providers provide vouchers for food to their patients.
- Pregnancy-centered models—Siega-Riz mentioned that there has been some work on pregnancy-centered care and qualified health centers, but noted that pregnancy-centered models have not been brought to scale.
Pérez-Escamilla offered his experience in implementing a new initiative that leveraged the community. In his previous role directing the Center
for Eliminating Health Disparities among Latinos at the University of Connecticut, Pérez-Escamilla worked on a 2-year community-based participatory research project in collaboration with the Hispanic Health Council in Hartford. His team involved stakeholders, community families, and others to decide on and develop an intervention to improve the food system. The result was a mobile produce market that would travel to WIC offices, clinics, and other locations that women with young children would frequent. He explained that in the beginning of the project, his team had no concept of how to run a mobile produce market, but it was ultimately bolstered by the support of the community who started to operate the unit. Pérez-Escamilla suggested that connecting community members through social networks and citizen science can facilitate the development of effective community networks, fostering peer-to-peer learning and empowering communities to work together for a common cause.
Adding to the conversation, Angela Odoms-Young of the University of Illinois at Chicago noted that grassroots groups can operate in the same space and may not be aware of each other. Offering her experience, Odoms-Young explained that her group was recently working on a breastfeeding inequity project and met several women of color who had been advocating for breastfeeding support for years. She wondered how frontline and grassroots efforts could learn about the advancements in the state of the science discussed at the workshop. From the audience, Nikki Plaskett, a grassroots activist and breastfeeding advocate, described her experience with models she has encountered through her work. With respect to access, she noted there are WIC locations that are coupled with hospitals and health facilities in Washington, DC. Plaskett also described the Elizabeth House, a rapid housing program in Washington, DC, for teen mothers facing housing and food insecurity. The Elizabeth House, which provides continuing education, allows teens to stay from pregnancy until their children are school aged.
Shifting the conversation, Plaskett thought that science does not always translate to policy. In her experience, she has encountered WIC clients who do not report that they breastfeed their infant, because they would receive a different food package from the program. Participants can also receive emergency formula, which some women then share with friends or family members outside of their households who were not successful or interested in breastfeeding. “I think the program definitely can benefit from a greater community presence in terms of meeting the needs of the people in the community and translating their needs into policy,” Plaskett offered.
Kavle raised the issue of the quality of nutrition counseling. She thought that physicians are not well versed in nutrition and suggested medical schools should include curriculum to better equip physicians to actively counsel women. Kavle thought that women are often left to figure out guidance for themselves.
In closing, Siega-Riz said she thought the workshop accomplished its objective of exploring evidence that has emerged over the past 30 years on topics related to nutrition during pregnancy and lactation. The presentations and discussion offered different ideas and possibilities for future work. Siega-Riz hoped the workshop would generate interest from a variety of stakeholders to consider how to move forward capturing the current state of the science on nutrition during these important life stages.