Multivitamins are some of the generally used dietary supplements in the US — round one-third of adults at the moment take them (1).
Individuals who take multivitamins typically accomplish that to enhance or preserve their well being, defend themselves in opposition to nutrient deficiencies, or just make up for the odd nutrient hole of their food plan (1).
You should buy multivitamins with out a prescription, and most of the people view them as secure, which could clarify their recognition. Regardless of this, multivitamins are usually not risk-free.
This text discusses whether or not you ought to be involved about taking multivitamins. It opinions the potential negative effects of multivitamins and which elements could trigger them.
Potential negative effects of multivitamins
Your physique must eat at the very least 13 nutritional vitamins and 16 minerals often to operate correctly.
A well-balanced food plan is one of the best ways to acquire these vitamins. That mentioned, multivitamins present an excellent different supply for individuals who are unable to fulfill their nutrient necessities via food plan alone.
Multivitamins that present as much as 100% of the every day Dietary Reference Intakes (DRIs) are typically thought-about secure and sometimes freed from negative effects, so long as you’re taking them as directed.
Nonetheless, some folks should expertise a couple of negative effects when taking multivitamins. Some negative effects are extra frequent than others (2, 3).
Frequent negative effects
Sure negative effects usually tend to happen than others while you’re taking multivitamins. These embody (2, 3):
These gut-related negative effects are typically minor and sometimes momentary. They have an inclination to vanish as your physique will get used to taking the multivitamin.
However, contact your healthcare supplier for additional help in case your signs persist.
Uncommon negative effects
Rarer negative effects of multivitamins embody (2, 3):
These sometimes happen very sometimes, particularly if the dosage of vitamins in your multivitamin doesn’t exceed the every day secure higher restrict (UL).
Nevertheless, individuals who mix multivitamins with different dietary supplements or eat vital quantities of fortified meals could exceed the UL for sure vitamins. This may increasingly enhance their danger of negative effects (4).
Meals firms typically add vitamins to meals through the manufacturing course of. These are fortified meals.
Some folks might also expertise extreme allergic reactions to sure multivitamins, though that is very uncommon.
For those who discover hives, problem respiratory, or swelling of the face, tongue, lips, or throat after taking a multivitamin, search emergency medical assist instantly.
Negative effects in infants and youngsters
Negative effects in kids are related to people who adults could expertise. Nevertheless, kids are prone to expertise them at a lot decrease doses than adults.
In different phrases, kids who take multivitamins could have the next danger of consuming extraordinarily excessive ranges of vitamins, which may result in nutrient overdoses and even demise in extreme circumstances.
Firms market many multivitamins particularly for infants and youngsters. Nevertheless, a latest research means that as much as 65% of them comprise nutrient ranges above the secure higher limits (UL) for kids (5).
This may increasingly clarify why specialists report that kids who eat multivitamins have a excessive danger of exceeding the UL, significantly for vitamin A, folic acid, and zinc (4).
Giving your little one an iron-containing multivitamin after they don’t want it might additionally trigger them to overdose on iron. Scientists take into account this to be a lead reason behind poisoning in kids 6 years outdated and underneath (4).
To cut back the danger of negative effects or poisonous overdoses, make certain to seek the advice of your healthcare supplier earlier than giving your little one a multivitamin.
Dosage
The Nationwide Institutes of Well being asserts that multivitamins offering nutrient ranges that fall near their DRI shouldn’t trigger severe negative effects. Nevertheless, it’s necessary to notice that the federal government doesn’t regulate multivitamins in the identical approach because it does drugs (4).
This implies there’s a danger {that a} multivitamin might comprise increased ranges of vitamins than its label states. Nutrient ranges in some multivitamins could typically even attain or exceed the every day UL.
Others supply megadoses of sure vitamins that purposefully exceed the UL suggestions, capitalizing on some folks’s perception that the extra vitamins you ingest, the higher the well being results.
Megadoses of some vitamins will not be significantly dangerous, however extraordinarily excessive doses of sure vitamins can significantly hurt your well being (4).
Vitamins to be careful for
Multivitamins typically comprise three classes of vitamins:
A few of these trigger extra negative effects at increased dosages than others. The sections beneath spotlight the vitamins from every class which may be significantly dangerous when you take them at excessive doses.
Water-soluble nutritional vitamins
Extra intakes of water-soluble nutritional vitamins don’t sometimes trigger extreme negative effects, even when intakes are near the UL.
It’s because your physique tends to flush out extra intakes of those nutritional vitamins via your urine. Nonetheless, intakes which might be a number of instances over the UL could lead to a wide range of points.
For example, vitamin C intakes which might be thrice bigger than the UL could trigger cramps, diarrhea, nausea, vomiting, or migraines (6, 7).
Extra vitamin B3, often known as niacin, ranging from intakes thrice above the present UL could lead to abdomen ache, hypertension, imaginative and prescient issues, and liver injury (8).
Equally, taking vitamin B6 at 10 instances above the UL over the long run has been linked to pores and skin lesions, gentle sensitivity, heartburn, and neurological issues (9).
Lastly, extra intakes of vitamin B9, often known as folic acid, could weaken the immune system, trigger neurological issues, and masks a extreme vitamin B12 deficiency (10).
Fats-soluble nutritional vitamins
Multivitamins that supply giant quantities of fat-soluble nutritional vitamins might be dangerous, as extra ranges of those nutritional vitamins can construct up within the physique.
For example, extra intakes of vitamin A could trigger complications, liver injury, weaker bones, and start defects (11).
People who smoke and former people who smoke could particularly profit from avoiding multivitamins containing excessive quantities of vitamin A or beta carotene, which the physique can convert into vitamin A. Getting an excessive amount of of those vitamins could enhance the danger of lung most cancers (1, 4, 11).
Equally, taking an excessive amount of vitamin D, both on account of manufacturing errors or taking an inappropriately excessive dosage, could lead to nausea, vomiting, muscle weak spot, cognitive issues, coronary heart issues, kidney failure, and even demise in extreme circumstances (12).
Furthermore, extra quantities of vitamin E could lead to bleeding, diarrhea, weak spot, blurred imaginative and prescient, and fertility issues (1, 13).
As for vitamin Okay, analysis has not discovered extreme intakes to trigger too many issues. Nevertheless, this vitamin can work together with varied drugs, together with antibiotics and blood thinners.
Individuals at the moment taking drugs ought to let their healthcare supplier know in the event that they’re taking a multivitamin containing vitamin Okay (14).
Minerals
Like fat-soluble nutritional vitamins, minerals can accumulate within the physique when you take them in extra, probably inflicting dangerous results.
For example, overly excessive intakes of sure minerals, corresponding to iron, copper, magnesium, and zinc, could cause abdomen upset, constipation, diarrhea, nausea, vomiting, abdomen ache, and complications (4, 15, 16, 17, 18).
Extra iron consumption is especially dangerous as a result of it might additionally trigger liver issues.
Because of this, authorities advise grownup males and postmenopausal ladies to keep away from taking multivitamins that comprise 18 mg of iron or extra except their healthcare supplier advises them to take action (19).
Multivitamins containing excessive ranges of iron, copper, and zinc might also forestall the physique from absorbing different vitamins you eat (15, 16, 17).
Multivitamins containing an excessive amount of iodine could cause thyroid issues. Alternatively, these with an excessive amount of selenium could trigger garlic-like breath, hair loss, brittle nails, or a metallic style within the mouth (20, 21).
Selenium intakes above the UL might also trigger extreme neurological signs, kidney failure, and coronary heart points (21).
DRIs and ULs for every nutrient of concern
Many of the negative effects talked about on this article happen after an individual consumes nutrient quantities that exceed the present higher ranges (ULs).
Each nutrient has a UL at which scientists consider it turns into poisonous. Exceeding a nutrient’s UL can result in an overdose and extreme negative effects, corresponding to liver injury and even demise.
The next chart outlines each the DRI and UL for every nutrient of concern for adults.
Particular suggestions for infants and youngsters differ extensively based mostly on their age. You will discover extra data in these exhaustive nutrient tables (22).
*Applies solely to artificial types from dietary supplements, fortified meals, or acombination of the 2.
It’s necessary to notice that there’s no DRI obtainable for folic acid, the artificial type of vitamin B9 that you will discover in multivitamins.
The type of vitamin B9 within the desk above is named folate, and you may get it from pure sources — not multivitamins.
Nevertheless, research have discovered that dosages of the artificial folic acid of greater than 1,000 mcg per day could also be related to a variety of damaging well being penalties in a number of populations (23, 24, 25).
At present, researchers don’t totally perceive the consequences and security of long-term intakes of vitamin or mineral dosages that fall between the DRI and UL. Due to this fact, scientists have to do extra analysis on this subject.
Till extra is thought, it’s probably most secure to keep away from dietary supplements that supply nutrient ranges that exceed their DRIs.
Different elements that will trigger multivitamin negative effects
Multivitamins might also turn into contaminated with dangerous compounds, corresponding to arsenic or lead (26, 27).
Once you ingest these dangerous compounds in giant quantities or over an extended time frame, they might trigger a wide range of well being points, together with bodily, muscular, and neurological issues, in addition to start defects (26, 28).
It’s inconceivable to establish whether or not a multivitamin accommodates these dangerous compounds by taking a look at its label alone.
Nevertheless, some producers decide to get their dietary supplements verified by third-party labs, which may affirm whether or not they’re freed from contaminants and that they honestly comprise what the label states.
Some examples of impartial complement testing firms embody ConsumerLab, NSF Worldwide, and U.S. Pharmacopeia.
Brief- versus long-term negative effects
Relying on the nutrient and its dosage, some negative effects could happen in a short time, whereas others could take an extended time to develop (11).
For example, taking a really excessive dose of 1 or a number of vitamins could trigger intestine signs that typically develop shortly after taking the complement (15, 16, 17).
Nevertheless, extra extreme negative effects could develop over time as extra quantities of vitamins or undesirable contaminants regularly accumulate within the physique. These longer-term negative effects could embody start defects and liver, coronary heart, and cognitive points (11, 20, 21, 27, 28).
For those who suppose you’re experiencing any negative effects, make certain to carry them up along with your healthcare supplier as promptly as attainable.
The underside line – “multivitamins headache”
Multivitamins might be useful for individuals who are unable to achieve their every day nutrient wants via food plan alone.
Nevertheless, multivitamins can not substitute a balanced food plan, and taking them in excessive quantities could lead to negative effects starting from gentle abdomen upset to extreme liver and coronary heart issues.
Like many dietary supplements, multivitamins are usually not strictly regulated and will comprise a lot increased ranges of vitamins than the label states. Relying on the nutrient, this may affect the pace and severity at which you’ll expertise negative effects.
You may reduce your danger by solely taking multivitamins while you really want them. Go for ones that comprise nutrient ranges near the present DRIs and have been examined by a third-party lab.