The Sugar Nobody Eats

Soren's baby sister had been home for four days, and she did exactly three things. She slept. She cried. And she ate.

"She eats all the time," Maya said. She was lying upside down on the couch with her feet up the wall, which was how she thought best. "That can't all be food."

"It's milk," said Soren. "Milk is food."

"I know it's food." Maya flipped right side up. "I mean is it only food."

This was the kind of thing Maya said that other people ignored. Soren wrote it in his notebook instead. Is milk only food. He underlined only.

They were supposed to be doing a project on nutrition. Soren's mom, who was a chemist before she was anyone's mom, had handed them a printout from a science journal and gone to lie down because the baby had been awake since five.

The printout said human milk contained over one thousand different things. Not one thousand of one thing. One thousand different kinds of thing. Proteins. Hormones. Things called oligosaccharides, which Soren practiced saying until it came out smooth.

"Oligosaccharides," he said. "They're sugars."

"Okay. Sugar is food." Maya leaned over the page. Then she stopped. "Wait. Read that part again."

Soren read it again. He read it a third time because it didn't make sense the second time either.

"It says the baby can't digest them," he said slowly. "The sugars. Her body can't break them down. They go all the way through."

Maya sat very still, which she only did when something had snagged.

"Then why are they in there," she said.

It wasn't really a question yet. It was the shape of one.

"Maybe it's a mistake," Soren said. "Like leftover stuff the body didn't filter out."

"A thousand different things and one whole group of them is a mistake?" Maya shook her head. "It's too much. You don't make that much of something by accident. Somebody's getting fed."

Soren looked up from the notebook. "What do you mean somebody."

"If the baby can't eat it," Maya said, "then it's not for the baby."

That sat in the room for a second. From down the hall, the baby made a small wet sound and went quiet again.

Soren started flipping pages on the printout, fast now. He had a rule with himself. When Maya leapt somewhere, he didn't argue. He checked. He looked for the thing that wasn't working in her idea, and when he couldn't find it, that was how he knew.

"Here," he said. "It does keep going." He read it out loud, careful with the long words. The sugars the baby couldn't digest traveled down into her gut. And in her gut there were bacteria.

"Bacteria," Maya said. "In the baby."

"In everybody. We're full of them." Soren kept reading. "And one kind especially. It eats the sugar. The exact sugar. It's like the sugar was built to match it."

Maya was off the couch now, standing over the page with him.

"So the milk isn't only feeding her," she said.

"It's feeding them," said Soren.

They looked at each other.

"It's feeding the bacteria first," Maya said, and her voice did the thing it did when she was running ahead of what she could prove. "On purpose. Her body is making food for something that isn't even her."

Soren read the rest with his finger under the line so he wouldn't lose it. The bacteria, fed by the sugar nobody could digest, grew and crowded in and lined the baby's gut. And once they were there, the bad germs, the ones that caused infection, couldn't get a foothold. There wasn't room. The good ones held the door.

It got stranger. The same bacteria sent signals out into the baby. Signals that helped her immune system learn. Helped it figure out what to fight and what to leave alone.

"Wait," Soren said. He put the paper down. He needed his hands free to think. "So the baby's body teaches itself how to fight off sickness. But it can't do it alone. It needs the bacteria to teach it."

"And the bacteria can't be there," Maya said, "unless something feeds them."

"And the thing that feeds them is the sugar."

"The sugar the baby can't even eat."

They stopped. The whole loop was sitting in the air in front of them and it was complete and it was a little bit dizzying.

Maya put it together first, the way she always did, out loud, half to herself.

"It's three things at once," she said. "The mom makes the food. The food grows the bacteria. The bacteria teach the baby. And none of them are the same body. It's three separate living things working like one machine and nobody's in charge of it."

Soren felt the back of his neck go cool the way it did at the aurora, the time he tested the same thing six times because he couldn't believe it. He looked toward the hallway where his sister was sleeping.

"She's not one thing," he said quietly. "She's a whole crowd. From the first day. There's more of them in her than there's her in her."

"That's everybody," Maya said. "That's you. You're a crowd too. You just got fed into being one a long time ago and forgot."

Soren tried to picture it. Every person he had ever stood next to in a line, every grumpy bus driver, every teacher, all of them carrying around a population, all of them gardens that somebody had planted with milk before they could remember anything at all.

"Nobody ever told me that," he said.

"Nobody tells anybody anything," Maya said. "You have to catch it."

Down the hall the baby woke up and started to cry, that thin new cry that meant she was hungry again. Soren's mom shuffled past the doorway, half asleep, hair everywhere.

"She's eating again," Soren said.

His mom yawned. "Always eating."

"She's not the only one," Maya said.

His mom didn't catch it. She went into the other room and the crying softened and stopped.

Maya and Soren stood in the quiet living room with the printout between them, and Soren reached down and turned the baby monitor up, just a little, so they could hear the small busy sounds of the most crowded person in the house getting fed.