NEW YORK (CBSNewYork) — Some people are refusing to get a flu shot and instead using other methods to prevent getting sick, according to a new study.

But the only proven way to ward off the flu is to get a flu shot, said Dr. Aaron Glatt, chairman of South Nassau Communities Hospital’s Department of Medicine.

He said all the vitamins, powders, soft chews and other supplements that claim they boost your immune system and prevent illnesses are false.

“The way you boost your immune system is by doing difficult things like eating correctly, by exercising, by getting enough sleep,” Glatt said. “But there is no supplement available, none that has any benefit to improve your immune system.” 

Nearly half, 46 percent, of Metro-Area residents polled said they take dietary supplements. Of those taking supplements, 40 percent said they took them hoping to ward off colds and flu.

“There is absolutely no professional medical organization that recommends routine usage of supplements,” said Glatt. “They are not proven to work.”

Thirty-nine percent of people surveyed by the hospital said they take supplements instead of getting the flu shot, spending up to $100 per month on the items in the hopes it prevents them from getting sick.

“The one proven thing to prevent the flu, which is flu vaccination, they’re not willing to take that,” Glatt said. “It’s absolutely amazing that there are people out there who understand the importance of not getting the flu and are actively taking products that are absolutely not proven to work, that have no regulation, potentially have drug interactions or serious side effects.” 

Glatt said about 15 percent of those surveyed said they took supplements because of advertising.

The most common supplement taken by those surveyed was some form of Vitamin C, followed by Zinc.

As CBS2’s Dr. Max reported, the trouble is the multi-billion dollar supplement industry is unregulated. The FDA is prohibited by law from enforcing the same standards of safety and efficacy it requires of drugs.

Because more than two thirds of supplement takers do not do it with their doctor’s knowledge, there’s also a medical risk beyond not working.

“They can create a side effect profile with your medication that can be dangerous to you or it can make your medication ineffective,” Dr. Adhi Sharma, of South Nassau Communities Hospital, said.

The poll was conducted via both landlines and cell phones from January 2-5 with 600 adults in New York City and on Long Island.