(NewsNation) — Nearly a third of U.S. adults take a daily multivitamin to support their overall well-being but new research indicates they may not improve longevity in healthy adults.

Researchers analyzed data from nearly 400,000 healthy U.S. adults followed for more than 20 years and found no association between regular multivitamin use and lower risk of death, in a study published in JAMA Network Open Wednesday.

Board-certified neurologist Dr. Tom Pitts joins NewsNation’s “Morning in America” to discuss the research, saying taking a daily vitamin pill not only doesn’t improve longevity but could worsen health.

“If you have a gallon of water and you fill it up with seven gallons, do you get more? No. You get one and you get a mess, right? You overflowed it,” Pitts said, saying if you are eating a normal diet, you don’t need vitamin supplements.

“If you cannot cook, you cannot be healthy, you just can’t, not to the extent you want,” Pitts said. “A supplement represents our habit in America of looking towards pills instead of changing lifestyle.”

According to Pitts, Vitamin E can lead to all-cause mortality, and Vitamin B6, found in excess in pre-workout drinks, can cause irreversible, painful neuropathy. The one exception he makes is Vitamin D, which is harder to come across in food.

“If you live in a first-world country and do not have a digestive issue of some sort, get it (vitamins) from your food. These supplements can reduce your lifespan,” Pitts noted.

“If you’re deficient and if you’re a postmenopausal woman, and you have a calcium deficiency, that’s different. Then it becomes a medical treatment.”