We all know that the human body functions best with an adequate supply of vitamins and minerals. However, knowing if we’re getting enough nutrients from food and whether we should be taking a supplement can be more complicated.¹ On one hand, without enough nutrient availability, biochemical pathways become inefficient, which can cause cellular damage.²

On the other hand, excessive nutrient availability (especially in nutrients such as iron and copper) is not optimal either and can degrade the health of our cells.³ And to make matters more confusing, biological and environmental factors–such as medications, genetics, and exposure to toxins—can affect nutrient absorption, and thus whether supplementation is needed.  

Ultimately, whether to take a multivitamin is a question best answered during a conversation with a health professional. But according to recent research, it’s a conversation many Americans should be having.

Dietary guidelines indicate most Americans fail to meet daily vitamin and mineral requirements

The 2015-2020 Dietary Guidelines for Americans indicate that about 90 percent of the US population fails to meet the daily requirement for vitamin D, vitamin E, potassium and choline.^4,5 Only about 50 percent of the population achieves the daily requirement for magnesium; which is responsible for helping over 300 enzymes in the human body regulate blood pressure, blood sugar levels, nerve function, protein synthesis, and muscle function.⁶

About 65 percent of the population falls short of the daily requirement for vitamin K. Vitamin K is found abundantly in plant-based diets and supports healthy bones, proper blood clotting, and may provide cardioprotective effects.^7,8 Forty percent of the US population fails to achieve the daily requirement for vitamin A, vitamin C, and calcium. Vitamin A is critical for optimal vision, immune function, lung function, kidney function, and reproduction.⁹

Vitamin C helps to protect our cells from damage caused by free radicals when exposed to sunlight, pollution, and many other compounds that are toxic to cells. Calcium is a critical nutrient not only for healthy bones but for muscle and nerve function, blood vessel mobility, proper hormone release, and to support the enzymes involved in nearly all body functions.¹⁰

Even overweight people can be malnourished, a state referred to as ‘hidden hunger’

Although it may seem counterintuitive, overweight (and even obese) individuals can be malnourished. This is because, regardless of the amount of food consumed, many people do not achieve a sufficient intake of vitamins and minerals. Indeed, hidden hunger is a term used to indicate a state of micronutrient malnutrition characterized by vitamin and mineral deficiencies.¹¹

While hidden hunger can occur in any lifecycle, it is most commonly seen in older adults, who often have difficulty obtaining adequate nutrients. This is because the aging process can result in a decrease of smell and taste, reduced appetite, mobility issues, and mechanical chewing problems; all of which can be risk factors for malnourishment.^12–14

For individuals with hidden hunger (or those unwilling or unable to receive adequate nutrition from foods alone), supplementation support is often the only option. 

Examples of people who are more likely to need multivitamins:

• Bariatric surgery patients
• Those with various medical conditions
• Those with disordered eating
• Those practicing a restrictive diet (such as a vegan diet)
• Those who are attempting to lose weight  
• Those with food allergies
• Pregnant women or those who plan to become pregnant
• Adolescent girls 

Multivitamin users have a lower prevalence of nutritional inadequacy

Some evidence suggests that multivitamin users are far less likely to have insufficient intakes of vitamins and minerals^15,16 In a recent study, researchers evaluated the impact that multivitamin supplementation had on nutrient intake and vitamin deficiencies.¹⁶ Dietary intake of 17 vitamin and minerals were assessed in those who consumed food only, versus those who also took multivitamin supplements. 

This analysis showed that compared to diet alone, multivitamin users had a much lower prevalence of nutritional inadequacy. Multivitamin use effectively eliminated inadequacy in 15 of the 17 micronutrients evaluated, including seven of the under-consumed nutrients noted in the 2015-2020 Dietary Guidelines for Americans.

Four Factors that may make it more likely to have a nutritional deficiency

1. Prescription medications

Many prescription medications are known to deplete vitamins and minerals.^17,18 According to the CDC, about 50 percent of the US population use at least one prescription drug and roughly 23 percent use three or more medications.¹⁹ To give an example of drug-induced nutrient depletion, millions of Americans take metformin, which has been associated with depletions in vitamin B12.²⁰

Other examples include antacid medications, which have been shown to cause depletions in calcium, iron, magnesium, B12, and vitamin C.²¹ Needless to say, those taking more than one prescription medication are at an increased risk of experiencing depletions in several vitamins and minerals. 

2. Genetics

Individual differences in genetic makeup may alter the requirements for vitamins and minerals.²² Some studies have shown that certain genetic alterations affect the body’s ability to absorb, transport and metabolize a wide variety of nutrients such as vitamin B12, B6, folate, vitamin C and vitamin D.^23,25 Future genetic research that helps determine individualized requirements for vitamins and minerals are greatly anticipated. 

3. Pollution

Exposure to a wide variety of toxins is a part of modern living, and emerging research shows that vitamin and mineral losses can be a result. Microplastics in the water supply is a growing concern, and most water filters are not yet capable of removing them.²⁶

Bisphenol A (BPA) is an example of a microplastic that can become waterborne, and BPA exposure has been linked to lower vitamin D levels.^27,28 Exposure to air pollution may lower levels of specific vitamins such as vitamin C and D.^29,30 Even noise pollution has been shown to cause higher excretion rates of magnesium, which may lower magnesium levels.³¹

4. Herbal Supplement Interactions

Many people are taking herbal supplements such as curcumin and green tea extracts. Some of these herbal preparations may cause decreases in certain vitamins and minerals. 

Animal and human studies suggest that turmeric or curcumin supplementation could lower iron levels.^32,33 Green tea contains catechins and caffeine, both of which have been shown to deplete folate levels.^34,35 It is currently unknown whether combinations of select herbal supplements in certain people may increase the risk for vitamin or mineral depletion. 

Consult with your health professional about whether a multivitamin might be right for you

According to the statistics, most Americans do not consume enough vitamins and minerals from their diet alone.^4,5 Even for those who do eat an adequate supply of nutrients, there are many potential reasons why additional support from a multivitamin supplement might be necessary. 

Although multivitamins are not necessary for everyone, given the number of factors that can influence nutrient absorption and depletion, speaking with a health professional about whether multivitamins are a good idea for you—especially if any of the factors discussed in this article apply to you—is something everyone should consider.