Thiamine supplementation and salt intake in Cambodia
Perinatal food taboos in Cambodia
Responsive breastfeeding in Cambodia
Thiamine supplementation and salt intake in Cambodia
What do we know about thiamine?
We study thiamine (vitamin B1) status among lactating women and their predominately breastfed infants in rural Cambodia. Thiamine is an essential vitamin required for normal growth and development, and energy metabolism. It’s found in pork, whole grains, legumes, and in Canada, all prenatal supplements. Thiamine is very low in the typical Cambodian diet, which consists mostly of thiamine-poor white, polished rice.
Our previous work identified that thiamine deficiency remains an often-overlooked cause of infant mortality throughout Southeast Asia. Unlike many other micronutrients, maternal thiamine intake directly impacts human milk thiamine concentrations: mothers with low dietary thiamine intake produce thiamine-poor milk, putting their breastfed infants at risk of developing a potentially fatal deficiency disease called infantile beriberi.
Although we know that breastfed infants of well-nourished mothers in North America don’t develop beriberi, it is still unclear how much thiamine mothers need to consume to prevent the disease in their infants. In addition, we previously showed that fortification, or adding nutrients to commonly consumed foods, is an inexpensive, culturally-appropriate, and efficacious means of improving thiamine intake and status, but new evidence indicates that salt may be a better fortification vehicle than previously-investigated fish sauce.
What did we learn from this study?
We conducted a double-blind, four-parallel arm randomized controlled trial in 2018-2019 designed to determine the optimal thiamine dose, and also track maternal and household-level intakes of salt, to allow for future modelling of thiamine-fortified salt. We also explored the relationship between thiamine supplementation and infant cognitive and neurological development. Today, we continue to work closely with the Cambodian Ministry of Health and Ministry of Planning on a fortification ‘recipe’ produced from this dose response study which could inform future salt fortification research or programs in Cambodia and elsewhere in the region.
Optimal Thiamine Dose
We had 335 new mothers and their infants participate in our thiamine supplementation trial in rural Cambodia. Mothers were randomized to one of four daily thiamine doses (0, 1.2, 2.4, or 10 mg per day), and took their supplements from 2 weeks until 6 months postpartum. We collected blood and milk samples from mothers, and blood samples from their babies, to estimate the optimal thiamine dose to improve thiamine status.
Results
After nearly 6 months of supplementation, we found that women taking any of the thiamine-containing supplements had significantly higher thiamine content in their milk, than those in the placebo group. Importantly, the 1.2, 2.4, and 10 mg/day doses didn’t differ from one another. This means the low dose of 1.2 mg thiamine/day should be sufficient to improve thiamine status of breastfeeding mothers and their infants in rural Cambodia, and may reduce the risk of thiamine deficiency and beriberi.
You can learn more about our findings around optimal thiamine dose and thiamine biomarkers in our recent article “Low dose thiamine supplementation of lactating Cambodian mothers improves human milk thiamine concentrations: a randomized controlled trial” which is currently In Press with the American Journal of Clinical Nutrition.
Salt Intake
Food fortification is an effective way to increase vitamin intakes in a population, however it’s critical to have an accurate estimate of fortified food intake so that the vitamin can be added at the correct dose. Salt has been proposed as a “fortification vehicle” for thiamine in Cambodia to prevent beriberi in breastfed infants, therefore sought to discover how much salt breastfeeding moms normally consume.
We measured salt intake in three ways:
1) Household salt disappearance from 2- 22 weeks postpartum for all 331 participants.
2) Observed weighed intake of salt, soy sauce, fish sauce, and prahok (a fermented salt paste) for 104 participants.
3) 24-hr urinary sodium excretion for 104 participants.
Then we used the optimal dose of thiamine (1.2 mg/day) to model an ideal fortification dose for salt.
Results
We found that breastfeeding women ate approximately 9 g of salt/day, and we found that the main source of salt in the diet was discretionary table salt use during cooking. At the household level, families used about 11 g/salt/person/day, however we found that salt was often used for non-consumption purposes such as cleaning fish and vegetables.
Given the amount of salt consumed by breastfeeding mothers, we believe salt fortification is feasible. In a preliminary model, we found a fortification dose of 275 mg thiamine/kg salt was sufficient to meet the needs of this population.
The full results have been published in our recent article “Assessment of salt intake to consider salt as a fortification vehicle for thiamine in Cambodia” in the Annals of the New York Academy of Sciences. You can also read more about thiamine fortification, in general, here.
Looking ahead, our team is now doing further testing to assess the stability of thiamine-fortified salt, and investigating whether fortification has any effect on the colour of salt, which could affect acceptability. We also hope to do sensory/taste assessments in the future. All of this information vital to plan an effective thiamine-fortified salt program to support the healthy growth and development of babies.
Thiamine and Neurocognitive Development
The relationship between neurocognitive development and thiamine status is a fairly new area of research, with potentially far-reaching implications. In this trial, all infants were assessed using various neurological and cognitive domains throughout the study (to 6 months postnatal) and beyond, up to one year of age.
Results
We found that the infants of mothers taking the highest thiamine dose (10 mg/day) had significantly higher infant language development scores at 6 months than other groups, however these benefits were no longer seen at one year of age (6 months after mom stopped taking supplements). We also found that prenatal thiamine status was significantly associated with more advanced development between 12- 52 weeks.
These findings, and more to come, are helping us uncover the role of thiamine in neurocognitive development and we are very excited to see how this new line of research unfolds.
Stay tuned for upcoming publications from these findings!
This study is funded by the Bill & Melina Gates Foundation and the New York Academy of Sciences.
Perinatal food taboos in Cambodia
Rationale
Adequate nutrition during pregnancy and lactation is important for ensuring the health of both mother and infant. Food taboos, culturally driven food avoidances that go beyond personal taste or preference, may stand in the way of good nutrition during this important time. In Southeast Asia, there is substantial contemporary evidence that cultural food taboos are still followed. For instance, in Laos, up to 98% of women restrict intake of certain foods in their postpartum diet, including important nutrient-dense foods like meat, eggs, and fish. Although other traditional peripartum practices such as ‘ang pleung’ (mother roasting) are still practiced throughout Cambodia, little is known about food taboos. The purpose of this study was to identify the food taboos practiced by pregnant and lactating women in Cambodia, and identify predictors of following these taboos.
Methods
As part of the Trial of thiamine supplementation in Cambodia trial, we asked mothers whether they followed any taboos during pregnancy, or during three periods postpartum: from 0-2 weeks, 2-12 weeks, or 12-24 weeks.
What we learned
We found that most food taboos were practised early in the postpartum period, with women restricting a wide range of foods in their diets, including fish, beef, and chicken. More surprising given the trends of neighbouring countries, we found that the rationales provided for these dietary modifications differed woman to woman: there was a lack of cohesiveness in the predictors of dietary restrictions. In addition, rather than tradition or superstition, rural Cambodian women followed food taboos most commonly to support varying aspects of maternal and infant health. We believe the findings of this study can be used to influence policy and program guidance. It seems there is room for healthcare providers to deliver clear dietary messages during village meetings or antenatal care visits to help quash harmful taboos in favour of clearly sought after health-promoting dietary advice.
This study was funded by the Bill & Melina Gates Foundation and the New York Academy of Sciences.
Responsive breastfeeding in Cambodia
Rationale
While there is quite a bit of research exploring breastfeeding rates around the world, to date there have been no cultural comparisons of breastfeeding behaviours. For instance, breastfeeding is normal - and expected - in low-income countries such as Cambodia. On the flip side, it is not the cultural norm in many high-income countries like Canada, where substitutes like infant formula are more commonly fed to infants. Given the cultural, economic, and social differences between Canada and Cambodia, we saw a cross-cultural comparison of breastfeeding behaviours as a potential opportunity to explore responsive feeding, a feeding style that supports infant’s hunger and fullness cues and optimal growth.
Methods
We video-recorded breastfeeding sessions with 110 mother-infant pairs, 55 at each site (infants were age- and sex-matched). Videos were collected in the participant’s homes using three small cameras and were analyzed using the Nursing Child Assessment Feeding Scale (NCAFS).
What we learned
We found that Canadian pairs scored significantly higher overall, and higher on three of four NCAFS maternal subscales (Sensitivity to Cues, Social-Emotional Growth Fostering, and Cognitive Growth Fostering) and one of the two infant subscales (Responsiveness to Caregiver). Overall, this means that Cambodian pairs demonstrated significantly lower levels of responsiveness, though infants provided similarly clear cues. Canadian dyads likely scored higher due to ample information and available supports, such as resources on responsive feeding and recognizing infant cues; paid maternity leave, which allows for time dedicated to responsive feeding; and various physical breastfeeding supports which allow positioning that is optimal for interaction. With this, although breastfeeding is more common in Cambodia, there is room to improve breastfeeding practices to optimize responsive behaviours.
This study was funded by a Mount Saint Vincent University Internal Grant (165437)
