Nutrition and Brain Growth in the Developing World

Gary Boas

The aging pickup truck bounces along a dirt road somewhere outside Bissora, one of the larger towns in the Oio region of the West African nation of Guinea-Bissau. The road, a major thoroughfare in the region, is pocked with holes. The rest of the year these would be deep and dusty. But it’s July now, monsoon season, and they are filled with water from the rains, and as often as not with pigs enjoying a warm summer bath. The driver dodges and weaves as he urges the truck forward.

In the back of the pickup is a piece of equipment, a tool unlike any seen before in the region: a portable, noninvasive brain monitoring device incorporating specialized lasers and other optical technologies. In the front, alongside the driver, are the two scientists who transported the device from their high-tech lab in Boston. The truck rumbles on toward the next village, where already a group of children and their parents are gathering to meet them.

Maria Angela Franceschini, PhD, a researcher with the MGH Martinos Center for Biomedical Imaging and an associate professor of radiology at Harvard Medical School, has traveled to Guinea-Bissau several times over the past year and a half to contribute to an ongoing research study there. On each of these trips, she was accompanied by Pei-Yei (Ivy) Lin, PhD, previously a postdoctoral fellow in the Center and now an assistant professor at Boston Children’s Hospital. The study has tested whether a particular food-based intervention can help treat malnutrition in children in resource-poor regions, and improve cognitive performance and brain growth. Franceschini’s role: to wield the sophisticated optical monitoring device to measure brain development in the children participating in the study.

Over the past 50 years, since the publication of a seminal study of young children in rural Guatemala, researchers have been developing ever-more refined understandings of the relationship between malnutrition and cognitive outcomes. They have been exploring the significant negative impacts poor diet and other symptoms of poverty can have later in life—in terms of achievement in school and even with respect to mortality—and trying to find ways to prevent these.

A number of studies have directly targeted children’s diets, seeking to improve cognitive outcomes by providing the children with nutrition supplements. But these have been shown to have little or no impact unless they are combined with other interventions—medical treatments or social enrichment, for example—leading some to abandon the idea that the supplements alone can help.

Susan B. Roberts, PhD, thought otherwise. Roberts, a senior scientist and professor of nutrition at the USDA Human Nutrition Research Center on Aging at Tufts University, felt the lack of success in the earlier studies might not have been because food-based interventions don’t work, but rather because the studies didn’t use the most optimal nutrition supplements. Current recommendations for those supplements, she noted, do not include particular nutrients that have been shown to be important for cognitive health. With support from local businessman Bill Schawbel and the Boston Foundation, she formulated a new food supplement that incorporated those nutrients and launched the study in Guinea-Bissau to determine its effect on cognitive performance and growth.

The new and improved nutrition supplement wasn’t the only novel aspect of the study, though. Most previous investigations relied on tests given to the subjects to determine cognitive performance and how it has changed over time. Roberts wanted a more objective measure of what was happening in the brain, of how the new supplement was actually impacting its development. And for this, she turned to an emerging noninvasive and portable brain monitoring technology.

The study included villages throughout the Oio region of Guinea-Bissau.

The scientists set up a makeshift lab in the one-room schoolhouse in the heart of the village. As children and their parents file in the lab comes alive with spirited chatter. The assembled are decked out in patterned dresses, bright dashikis, and T-shirts emblazoned with an array of American characters and brands—donated clothes from across an ocean bought in second-hand market stalls in Guinea-Bissau. A young girl appears wearing an irrepressible smile and a Minnie Mouse top.

It feels almost festive. When the scientists arrived in the village, earlier today, many of the children and their parents came out to greet them, laughing and smiling and embracing them. Even now, the area around the schoolhouse is abuzz with conversation. A few of the kids are playing with inflatable balls the scientists brought with them.

Each of the scans takes only a few moments. With the noninvasive technology they are using—near-infrared spectroscopy / diffuse correlation spectroscopy—measurements involve little more than briefly, gently pressing a probe against the head; this system was designed so parents themselves can hold the probe in place, helping to keep the children calm and comfortable during the measurements. Over the course of the next eight days, the scientists will scan 485 children in six different villages.

Introduced some 20 years ago, near-infrared spectroscopy (NIRS) can determine the amount of oxygen in the blood, non-invasively, by transmitting laser light into the body and detecting the light as it emerges. A more recent development, diffuse correlation spectroscopy (DCS) adds measures of blood flow to the optical monitoring toolbox. Together, the two techniques have made it possible to calculate the cerebral metabolic rate of oxygen (CMRO2)—an established marker of brain maturation—relatively easily with a small piece of hardware and a laptop computer.

Franceschini has taken full advantage of this opportunity. Over the past decade, she has worked on the cutting edge of developing and applying combined NIRS-DCS for the study of brain development in newborns and infants. Her work has yielded a number of new insights, and these in turn have pointed to possible interventions in the care of infants. Today, she is also collaborating with clinicians at MGH and elsewhere, seeking to establish NIRS-DCS as a tool to guide and optimize individual care.

The technique works for global health applications for the same reasons it works for bedside monitoring in the clinical environment: It is a noninvasive and portable technology, user friendly while also robust. The Guinea-Bissau measurements, performed over the course of the three visits, demonstrated the feasibility of using the technology in remote, resource-poor regions, where portable generators provide the only electricity and the average temperatures hover in the 100 degree range. For all its advantages elsewhere, MRI wouldn’t work here. Nor would most other brain imaging techniques. NIRS-DCS is, simply, the right tool to get the job done.

In addition to validating the technology for this and other, similar global health applications, the pilot study in Guinea-Bissau yielded some important early findings—showing that children who perform poorly on cognitive testing also have lower-than-average measures of cerebral blood flow. Ultimately, the neuroimaging tool could allow the researchers to compare brain maturation before and after the nutrition intervention, to help determine the impact of the intervention on cognitive and neurodevelopmental outcomes.