Bill Gates readily acknowledges he's always been "kind of a weirdo". That's what got the Microsoft cofounder into computers in the first place, he said.

But these days, Gates' odd streak is perhaps most apparent when it comes to his fascination with the human gut.

In November, Gates brought a jar of poop on stage with him at an event in Beijing, just to demonstrate that there could be trillions of virus particles, bacteria, and parasitic worm eggs inside.

Gates' interest in digestion goes beyond the disgusting and debilitating kinds of bacteria in our systems. The billionaire investor recently said he thinks we can revamp the inner workings of our guts by seeding the microbial colonies that live inside us.

"One thing that people are not expecting a breakthrough in that I'm quite optimistic we will get a breakthrough in is understanding nutrition," Gates said during a conversation last week at the 92nd Street Y in New York.

He thinks hacking the microbiome is the way to do it.

A robust, diverse microbiome sets us up for healthy development

Good nutrition is a growing problem in countries both rich and poor.

While 22.2 percent of kids under 5 worldwide, about 150 million, are stunted – meaning they aren't growing and developing in a healthy way because of poor nutrition and infections – another 5.6 percent, or 38 million, are overweight.

Part of the reason kids are not developing as they should is that their microbiomes aren't robust. A person's microbiome is the complex mix of bacteria, viruses, and fungi that live inside the gut; it has more than 2 million genes – more than the human genome.

Starting at birth, when a baby's sterile intestine is first exposed to a mother's microbes, 300 to 500 bacterial species begin to colonize this environment.

Normally, this is helped along by nutrient-rich breast milk, as well as all the other things babies happen to put in their mouths.

But if a baby's microbiome doesn't develop properly, it can have serious long-term consequences for the way they process food, leading to stunted growth on one end of the spectrum or obesity on the other.

After about a year, the baby's microbial colonies stabilise, meaning the first months of life are the essential time to develop a rich microbiome.

Our microbiome determines how much nutrition we can get from the food we eat

Take the case of Madagascar, where stunting (low height for a kid's age) is a problem forabout half of the country's children under 5.

Many kids there are not getting enough key nutrients that are crucial to healthy development, like iron, vitamin A, zinc, and iodine.

"They don't develop physically," Gates said. "They don't develop mentally."

Similarly, in Bangladesh, scientists have found that severely malnourished babies tend to have more immature microbiomes than other infants, suggesting that the first months of life are critical to how nourished we can be throughout our lives.

"Even if they're getting enough food, there's something about inflammation in their gut that their body isn't able to grow properly," Gates said.

That has long-term effects on the economy. The World Bank estimated that Madagascar misses out on US$720 million in gross domestic product every year because of vitamin and mineral deficiencies.

On the other end of the spectrum, rich nations like Germany, Australia, and the US are also missing out on billions of dollars because of poor nutrition.

One study that looked at the effects of obesity in three states – California, North Carolina, and Massachusetts – estimated that those economies lost a total of US$41 billion a year in indirect obesity costs like sick time, early death, and insurance payouts.

A microbiome treatment could help guts grow up strong

Gates said he thinks that one day a probiotic powder, food, or other kind of microbial therapy could address these nutritional problems by introducing some missing bacteria into our guts.

"We're actually trying to intervene with that, so that [children's] guts aren't complaining, so they're able to grow," Gates said.

The Bill and Melinda Gates Foundation is hoping that scientists can soon come up with a cheap microbiome treatment that's far more complex than just eating yogurt.

New probiotic therapies would include "a substantially larger number of difficult-to-grow commensal strains" of bacteria, the foundation said in its latest call for gut-therapy research.

Teams that receive phase-one funding for these projects will get US$100,000 from the Gates Foundation. If they're successful with that, researchers could get a second round of up to US$1 million in cash to develop their new gut therapies.

Already, the Gates Foundation has invested in a probiotic powder for babies called Evivo. The powder is mixed into breast milk to help babies repair and improve their gut microbiome.

It's designed to help malnourished babies boost their metabolism and develop a more robust immune system.

Trials of Evivo in severely malnourished kids under 6 months started in Bangladesh last year.

Another Gates Foundation-funded project at the Washington University School of Medicine is feeding special "microbiota-directed foods" to undernourished kids in Bangladesh too.

Ideally, the Gates Foundation says, these fixes will one day be sold around the world for less than US$0.10 per dose.

That could create long-term diet solutions, both in poor places where the Gates Foundation works and in rich countries facing obesity epidemics. Gut bacteria play a role in obesity too, since they send signals to the brain to tell us when we're full.

"Why is it that it's not easy to have some sort of broader approach that lets us control our appetite?" Gates said. "The microbiome looks like it will give us a solution there."

Nutritionists are increasingly recognising that there are no hard-and-fast rules that apply to everyone when it comes to diet, since each person's body (and microbiome) is different.

"We now know there is no diet or dietary intervention that is right for everyone, or even for an individual throughout their lifespan," a group of researchers wrote in an article published in The Lancet in January.

But Gates is convinced that if we can keep the microbes in our guts humming along happily, that will be a good start.

"Nutrition has always been a great mystery," Gates said. "A lot of myths – 'try this,' 'try that.' But in this decade I think that we can solve that."

This article was originally published by Business Insider.

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