For children’s nutrition, the biggest new thing may be the smallest. And strictly speaking, it’s not really new.
“And, it’s more than one thing, really,” laughs PATH’s Peiman Milani.* “It’s trillions of beneficial, healthy microbes.”
As scientific evidence on the value of beneficial microbes, including bacteria and yeasts, grows, Peiman and his team of global health and nutrition experts at PATH are digging deeper. In particular, they’re exploring new ways to harness these tiny allies to help more children—in more places—grow up strong.
But let’s back up. Because this particular story really starts in Senegal, in a simple wooden bowl.
A tiny ally
On a mild morning in northern Senegal, the team sat in the home of a local woman, chatting through a translator in French and Fulani, a local language. Then, with her blessing, they clustered—testing kits in hand—around her wooden cooking bowl, and the film of healthy bacteria living inside.
A new paradigm
The team’s mission, and their interest in that not-so-empty bowl, began with new trends in health and science.
“You might not think of it,” explains Megan Parker, a senior nutrition research officer with the team. “But that thin film of bacteria is a powerful ally for children’s health.”
This new understanding is part of a paradigm shift in health and nutrition, explains Peiman. “Before, we thought we were at war with bacteria and other microbes. I always think of soaps sold with promises to kill ‘99.9 percent of bacteria’.”
Today he says, research suggests that humans actually evolved together with microbes in a primarily cooperative relationship, and that many types of bacteria are good for us. In fact, they may even be us: more than 99 percent of the genetic material in our bodies isn’t human, but microbial.
Among other shifts, these findings are giving us a better understanding of our digestive systems (which scientists also call our gut). Every gut is an ecosystem, made up of many kinds of bacteria and other microbes. In a healthy gut, this microbiome stays in equilibrium, regulated by the immune system. “Good” microbes support our digestive processes, contribute to the synthesis of some micronutrients and the absorption of others, prevent damaging bacteria from settling in, promote a healthy immune system and, in children, support healthy development. Of course, notes Peiman, things aren’t always so rosy. The wrong gut balance can trigger otherwise neutral microbes to become dangerous, block other bacteria, or even launch an attack against their host.
Overall, scientists still have a lot to learn, including which parts of this we can and can’t control. But we do know that the foods we eat can help us shape a healthier and more balanced microbiome.
That caught the team’s attention. “Worldwide,” says Megan, “diarrhea remains a top threat to children. Millions suffer from poor nutrition. And both threats work together to create a cycle of poor health. So the new findings got us thinking. What if we could harness healthy bacteria to improve children’s gut heath, and with it, their lives?”
The problem with probiotics
In wealthy countries, consumers are already seeing an explosion of “probiotic” yogurts, pills, and other products. “Many probably work,” says Peiman, “but most aren’t viable in the resource-strapped settings where children need them most.”
For one thing, they’re expensive. Access is also an issue: imagine providing cold yogurt or daily pills in places where it’s hard to get, let alone refrigerate, even desperately needed medicines.
Seeking a simpler, more sustainable way to introduce beneficial microorganisms into children’s diets, the team thought about traditional fermented foods. Inexpensive, full of healthy bacteria, and eaten worldwide, they stood out more and more.
And that takes us back to where we started: that small home in Senegal.
Senegal: a question of culture
In Senegal, Megan, Peiman, and the team worked with local communities to study people’s diets and their beliefs about nutrition. They also watched women make a fermented drink called lait caillé or “curdled milk” for their families.
“Lait caillé is popular throughout Senegal,” says Megan. “Some people drink factory-made products, while others still ferment it at home. That homemade process is what we were interested in.”
The team found that most people simply heat the milk and let it sit to curdle. But something seemed to be missing. “Typically, you’d need a starter culture; a sample of the bacteria to populate the fresh milk,” explains Megan. “But people told us they did not use any culture. So where were the bacteria coming from?”
By now, you’ve guessed it: The secret is in the bowl.
“People usually use and reuse specific wooden bowls to hold milk for fermentation,” explains Megan. “So when we looked inside, we found a bacterial film left on the inner wall: the starter.”
In fact, when the team tested samples from the lait caillé made in homes, from mom-and-pop shops, and from chain stores, they found the richest bacterial diversity in the homemade milk.
Today, the team is working with global partners and local communities to apply these and other findings to improve child health. “For example,” says Peiman, “what if we created a spread containing bacterial strains we know help children resist diarrheal disease and get better nutrition, and added it to the bowl to populate new batches of milk? Will that make the milk taste different? Will it significantly alter the microbial community?”
To learn more, they’re partnering with a team of microbiologists in the Netherlands; local communities; and other health and nutrition experts to test their ideas. There is still a lot to learn—and tremendous potential for child health worldwide.
* Editor’s Note: Since publication, Peiman Milani left PATH to join Sight and Life where he continues to work to improve nutrition outcomes globally.