Clearly, germs are bouncing off school walls. Keeping kids healthy in the classroom also requires keeping their immune systems strong, says pediatrician Jim Sears, co-host of The Doctors talk show. "That's one of the things I preach. People think it's cliché but it makes a difference," he says. "Every time you eat a fruit or veggie or a piece of fish, you're helping your immune system fight things better," and any time you eat junk food or drink soda, you're weakening your immune system, he adds. The white blood cells that gobble up bacteria typically slow down for about six hours after a heavy dose of sugar, Sears says. "I always ask my kids, 'Is this a good time to be suppressing your immune system?' And the answer is always no."
And if your kid is sick, don't send him to school. Otherwise, he could inadvertently infect his classmates. Kids should stay home if they have a fever of 100 degrees or higher; if they're vomiting or have diarrhea; and if they're coughing up mucus. "Sometimes as a parent you feel stuck," Sears says. "And you think, 'He's alive, so he should be well enough to go to school.' But it's really not fair to send kids in when they're contagious, because then he'll infect 10 of the other kids, and a few days later those parents are going through the same thing."