TRENTON, N.J. ? The wisdom mothers have been dispensing for ages — wash your hands, eat your vegetables, go to bed earlier — turns out to be great advice for avoiding the flu.

Doctors and nutritionists say careful hygiene, a balanced diet and plenty of rest and fluids can go a long way toward keeping people healthy during the influenza season, especially considering this year’s vaccine shortage.

“Taking care of yourself from a health standpoint is probably the best thing you can do,” said Dr. R. Michael Gallagher, a family physician and dean of the University of Medicine and Dentistry of New Jersey’s School of Osteopathic Medicine.

“People who are run down, they’re overworked, not getting proper rest or proper nutrition, these people increase their risk” of illness, he said.

Besides getting enough sleep — at least seven hours a night for adults and more for youngsters — managing stress is important, Gallagher said, because too much can weaken one’s immune system.

Frequent hand-washing, using soap and hot water and rubbing vigorously for about half a minute, also is crucial.

“What you want to do it is try to interrupt transmission of disease with the kinds of things our mothers taught us,” said Dr. Mitchell Cohen of the federal Centers for Disease Control and Prevention.

Avoid touching your eyes, nose or mouth, because germs on your hand could infect you, he said. And, if you do get the flu, stay home from work or school so you don’t infect others.

The United States will get only half its expected supply of flu vaccine this year because British health officials suspended the license of vaccine producer Chiron Corp. at the company’s Liverpool, England, factory because of contamination.

Cohen said the CDC was planning public education campaigns to teach people how to protect themselves through hygiene and “cough etiquette.”

The old advice was to cough or sneeze into your hands, then wash them, but children and many adults don’t wash up immediately. That means they can spread the flu virus via a handshake or touching a doorknob. Now doctors are urging that, if a tissue isn’t at hand, people — especially children — should sneeze into their sleeve.

Another new piece of advice is to stop refilling the bottles of water so many of us carry.

The bottles accumulate germs and shouldn’t be reused or shared, doctors say.