About half of all adult Americans take a daily multivitamin, according to industry data, but are these supplements really necessary?
ABC News contacted 25 primary care physicians and asked them which vitamins -- if any -- they recommend to their patients.
Most doctors said they do not recommend daily vitamins to their healthy patients, and even among pro-vitamin doctors, some said they viewed one-a-days as a kind of insurance policy on nutrition, but were not wholly convinced they were necessary.
"There is no compelling indication for adults who eat a well-balanced diet to routinely take a multivitamin," says Dr. Erin Michos, assistant professor of cardiology at Johns Hopkins School of Medicine.
Dr. Jeff Susman, chair of family medicine at the University of Cincinnati agrees, saying that "for the vast majority of healthy individuals, vitamins are unnecessary."
He adds, "In the end, our obsession with quick fixes is likely to only cause expensive urine (as these vitamins are passed) and not positively influence health; save up this money and enroll at a gym!"
There is also little to no support for a standard multivitamin recommendation among health organizations.
Recent studies from the National Institute of Health and the Department of Health and Human Services both concluded that there is insufficient evidence to justify recommending daily vitamins for the average, healthy individual.
Similarly, neither the American Academy of Pediatrics nor the American Dietetic Association recommends a multivitamin for kids.
Of course, your standard one-a-day vitamin doesn't hurt either, doctors admit.
As they don't appear to be harmful -- except, maybe, to your wallet -- Susman comments, "If a person wishes to use them, fine," and Michos points out that they certainly couldn't hurt for those of us who are skimpy with the fruits and vegetables.
Overwhelmingly, however, for kids and adults, doctors say that unless you have an underlying reason for a vitamin deficiency, nutrients should come from eating a variety of healthy foods -- not from a gel capsule or a cartoon-shaped chewable.
The Council for Responsible Nutrition told ABC News in a statement that "There is a wide body of scientific research that demonstrates the benefits of dietary supplement products. Dietary supplements should be used as supplements to, not substitutes for, other healthy lifestyle choices."
Click here to read the full statement.
"Patients should get most of their vitamins and minerals via a balanced diet …because foods contain other substances, such as phytochemicals, in addition to nutrients, that are beneficial to health," says Cheryl Williams, a dietician at the Emory Heart and Vascular Center.
Supplementations can be a sort of "insurance on nutrition" says Julie Schwartz, a dietician at Emory Healthcare, "but I'm still going to coach patients...that supplements do not take the place of food (or physical activity, for that matter)."
It's when patients are unable to eat all the food groups or when other health conditions make deficiencies unavoidable that doctors, Schwartz included, say that vitamins should come into the picture.
While healthy eating is the holy grail of good nutrition -- some nutrients are also just plain hard to get from food (at least in sufficient amounts), doctors say.
Omega-3 fats are a heart healthy nutrient that doctors noted is difficult to get through diet alone but easy to supplement by taking fish or flax seed oil. Especially for those with an elevated risk of heart disease, doctors recommended adding this supplement to patients' diets.
B vitamin supplements are a good option for vegetarians and vegans since they avoid eating fish and meat, the best source for vitamin B. Several doctors contacted noted that they suggest supplementing to their patients who have these kinds of diet restrictions.
Dr. Richard Besser, ABC News' senior health and medical editor, said the only way to get vitamin B12 is from meat. Non-meat eaters should therefore take a multivitamin or vitamin B12, he added.
Another way to get vitamin B12 is to eat a fortified cereal that includes it, he added.
Vitamin D and calcium were repeatedly noted as problematic nutrients to keep up with using diet alone -- especially if a patient doesn't get enough exposure to sunlight or can't or chooses not to eat dairy.
Michos says that "unlike the other vitamins, vitamin D is hard to get sufficient quantities from food alone. Fortified milk, orange juice, and cereal have vitamin D, but in low amounts," so "vitamin D supplementation is widely used to treat and prevent osteoporosis and fractures."
Most doctors also mentioned that during certain phases of a patient's life, extra calcium and Vitamin D are needed, such as during pregnancy or menopause, and during the first decade or so of life, and these times, a supplement might be needed.
Vitamin D, especially, has become a hot topic among pediatricians after several studies suggest widespread deficiency in American children. A 2009 study from the America Academy of Pediatrics showed that over 60 percent of kids in the U.S. are lacking in this vitamin, especially among minority populations.
Anecdotally, doctors also mention seeing patients with low Vitamin D. Schwartz recommends routinely checking patients for a deficiency and notes this issue is becoming more common.
Dr. Andrew Racine, director of the section of general pediatrics at Montefiore Medical Center, notes that mother's milk or cow milk-based formulas do not provide the recommended daily amount of Vitamin D that infants need. He and several other doctors suggest using Vitamin D drops or pre-made vitamin mixtures to supplement an infant's diet.
Besser agrees that most people do not need to take a multivitamin if they are healthy, eat a balanced diet and get enough exposure to the sun for vitamin D.
"If you have a very balanced diet … you probably don't need a multi-vitamin," Besser said, but added that "there are many people for whom I recommend them."
Besser also said he recommends vitamins for some children.
Because children are developing rapidly and tend to be picky eaters, there may be times when they will benefit from a multivitamin in chewable or liquid form.
"Children are growing, they're developing and their taste buds are developing as well," he explained. Besser's own son went through a phase where he didn't want to eat vegetables.
"My son was in the beige phase," he said. "During that period I put him on a multi-vitamin."
Children can take chewable vitamins and vitamin drops are available for newborns, he said, adding that pregnant women should take a prenatal vitamin.
Women who are breastfeeding also should take prenatal vitamins, and breast-fed babies should be given vitamin D drops, Besser said. Vitamin D is important for bone health, and that's critical for growing children.
"Breast milk is the perfect food, except for one thing," Besser said. "It doesn't contain vitamin D. Women who are breastfeeding need to give their kids Vitamin D drops."
So, the bottom line on vitamins, according to doctors, is that they certainly don't hurt, but unless you are actually vitamin-deficient or fall into a specific category, they probably won't help, either.
"There are so many misconceptions out there," says Dr. Lee Green, a professor in family medicine at the University of Michigan. "Many people believe that vitamins will give them energy [or other benefits]...I spend a lot of time explaining to people that vitamins are not a substitute for a healthy diet and regular exercise!"
When it comes down to it, Green says, you have to eat nutritious food to get the nutrients you need. In other words, "You have to eat the vegetables...because it's not the vitamins that make you healthy -- it's the vegetables!"