The Internet is loaded with ridiculous health claims about how to live longer and feel your best—but what’s real science and what’s straight-up silliness? Separate fact from fiction with the following five health misconceptions.

1 myth Antiperspirant causes breast cancer.

truth Antiperspirants—which reduce underarm sweat—and deodorants—which cover up odors—do not cause breast cancer, says Dan Herron, MD, director of Women’s Imaging at Mercy Imaging Center. “This myth may persist [since] we ask women not to use either prior to a mammogram, [as] the particles they contain can falsely look like calcium deposits on the mammogram and raise a false alarm of cancer,” he explains. “The Journal of the National Cancer Institute in 2002 reported on a study that showed no increased breast cancer risk in women who used antiperspirants or deodorants. Additionally, the National Cancer Institute and the U.S. Food and Drug Administration reports no evidence that aluminum—the active ingredient in antiperspirants—nor the infrequently added paraben preservatives cause breast cancer.”

 2 myth Eating fish during pregnancy is bad.

truth “Fish is important for the brain development of a baby. However, high-mercury fish like swordfish and shark should be avoided,” says Katherine Gillogley, MD, division head of OB/GYN at Mercy Medical Group, a service of Dignity Health Medical Foundation. “A British study published in 2007 showed that children of women who ate no or less fish during their pregnancy had a greater chance of poor developmental outcome (IQ, social behavior, fine motor coordination and communication) than those whose mothers ate more fish. Bottom line: Eat eight to 12 ounces of small- to medium-sized fish (low mercury) per week while pregnant.”

 3 mythYou can get the flu from the flu vaccine.

truth Ashley Sens, MD, and Department of Pediatrics chair at Dignity Health Medical Foundation’s Davis clinic, clarifies what it really means when you say “the flu.” According to Sens, “influenza is a respiratory illness caused specifically by the influenza virus [that] causes high fever and a severe cough and can cause pneumonia.” That said, you won’t get the flu after getting the flu vaccine. “In a randomized double-blind study, volunteers were either given a flu vaccine injection or a salt-water injection. The only difference in reaction between the two groups was the group who received the vaccine had more soreness and redness at the injection site,” she says. “There was no difference between the groups in terms of fever, muscle aches and pains, cough or illness of any kind.” With few exceptions, everyone six months of age and older should get a flu vaccine every season, she says.

 4 myth Vaccinations cause autism.

truth There are many myths around this issue, says Michael Chez, MD, director of pediatric neurology research and epilepsy surgery director at Sutter Neuroscience Institute. “Almost every claim of vaccines causing autism has been debunked,” he says. Yet autism rates continued to rise. “The issue is not vaccinations, but more commonly numerous factors—including prenatal risks, maturity when born, genetics and environmental issues,” he says. “Because vaccines occur when children are also developing—at two months, four months and six months—this often coincides with parents becoming aware something may be wrong, [which is] why parents often confuse what they see as cause and effect, instead of separate risk factors and issues that cause the observed changes.”

 5 myth Sugar makes kids hyper.

truth Parents, don’t fret. That candy bar will not have a significant effect on your kids’ behavior. “There have been numerous studies looking at food additives, dyes and sugar content, which have been worrying parents as a cause of hyperactivity in children,” Chez says. “These have all come to produce no evidence that sugar content—or majority of dyes or additives—causes changes in baseline behaviors.”