What Are the Benefits of Vitamin and Mineral Supplements?

What Facts Should I Know about Vitamins and Minerals?

Picture of vitamin C, a supplement that can help protect against COVID-19.
Picture of vitamin C, a supplement that can help protect against COVID-19.

What are vitamins and minerals?

  • Vitamins and minerals are essential nutrients required for healing and functioning of the body.
  • When we don't take in enough nutrients, vitamin and mineral deficiencies occur and diseases -- even death -- can result.
  • Vitamins are classified as either water-soluble or fat-soluble.
  • Minerals are classified as electrolytes or trace minerals.

What is the best way to get vitamins and minerals each day?

  • Vitamins and minerals come from healthy foods, but many people do not eat enough of the right foods to ensure they get the entire recommended daily intake.

What Do Vitamins and Minerals Do?

Vitamins and minerals function as cofactors in the body that enable many metabolic reactions to happen. Without vitamins and minerals, we couldn't make new cells, repair damaged tissue, or convert food to energy.

What Are Vitamins and Minerals?

Vitamins and minerals are essential nutrients. You don't need much, just milligrams to micrograms a day, but if you don't get enough or the right kinds of vitamins and minerals, essential functions in the body cannot happen. The difference between vitamins and minerals has to do with their chemical structure. Vitamins can be broken down, but minerals are inorganic and cannot be broken into smaller chemical units. Vitamins are essential, meaning we have to get them from our diet (or supplements). Some, but not all, minerals are essential. Vitamins can also be classified as fat-soluble or water-soluble. Water-soluble vitamins are only in the body for a short time before excesses are excreted in the urine and sweat. Fat-soluble vitamins can be stored in fat tissue, so they can accumulate over time. Minerals can be classified as macrominerals, which are also called electrolytes, or trace minerals.

What Are Symptoms and Signs of Vitamin and Mineral Deficiencies and Toxicities?

The signs and symptoms of deficiency depend on the specific vitamin or mineral. For example, if a person is deficient in the vitamins and minerals that are necessary to make and repair skin, connective tissue, and collagen, he or she will have signs and symptoms related to poor skin healing, excess skin wrinkling or dryness, lack of elasticity, dermatitis, or rashes. There are minimum requirements for the amount of vitamins and minerals we need. If we don't get enough, we become deficient and display the signs and symptoms of low nutrient intake. The signs and symptoms of deficiency are summarized in the chart below.

Symptoms and Signs of Vitamin and Mineral Deficiency and Toxicity
NutrientSigns and Symptoms of DeficiencySigns and Symptoms of Toxicity
Vitamin A (Retinol)Night blindness, xerosis, Bitot's spot, keratomalacia, perifollicular hyperkeratosis, anorexia, bone changesAnorexia, headache, blurred vision, dry skin, pruritus, painful extremities, hepatomegaly, splenomegaly
Vitamin DRickets/osteomalacia, bone pain, muscle weakness, fatigue, frequent infections, geriatric cognitive defects, pediatric asthmaHypercalcemia and tetany, anorexia, nausea, vomiting, constipation, polydipsia, polyuria, renal stones, hypertension
Vitamin ELoss of reflexes, gait disturbance (posterior tract-spinocerebellar symptoms), paresis of gaze, eczema, psoriasis, poor wound healing, broken capillariesFatigue, headache, delayed wound healing, increased bleeding, muscle weakness
Vitamin KBruising, bleeding gums, poor wound clottingHemolytic anemia, liver damage
Vitamin B1 (Thiamine)Beriberi, edema, peripheral neuropathies/hot feet, lactic acidosis with carbohydrateArrhythmias, anaphylactic shock with large intravenous doses
Vitamin B2 (Riboflavin)Reddened, greasy scaly, pruritic skin in the oculo-orogenital areas; dyssebacia (shark skin), stomatitis, angular cheilosis, magenta tongue, photosensitivity, corneal vascularizationNo cases reported
NiacinPellagra: photosensitive dermatitis; diarrhea; mucosal inflammation; dementia; beefy, red tongueRelease of histamine: severe flushing, pruritus, gastrointestinal disturbances, elevated serum uric acid and glucose, hepatic toxicity
Vitamin B5 (Pantothenic Acid)Burning feet syndrome, fatigue, enteritis, alopecia, dermatitisDiarrhea, water retention
Vitamin B6Seborrheic dermatitis, glossitis, cheilosis, angular stomatitis, peripheral neuropathy, irritability, convulsionsPeripheral sensory neuropathy, ataxia, perioral numbness
FolateMegaloblastic anemia, glossitis, hair loss, cognitive defects, pallor, persistent fatigue, tender tongue, absence of neurological symptomsMasks vitamin B12 deficiency
Vitamin B12 (Cobalamin)Megaloblastic anemia, glossitis & oral mucosal lesions, tachycardia, anorexia, sensory neuropathy/paresthesias, muscle weakness, memory loss, depression, constipation, fatigueNo clear toxicity reported
BiotinScaly dermatitis, alopeciaNone reported
Vitamin CScurvy, bleeding gums, anemia, fatigue, aching bones, joints, and muscles, perifollicular hemorrhages, poor wound healingNausea, abdominal cramps, diarrhea
CalciumTetany, depression, anxiety, irritability, bone pain, osteoporosis, rickets/ chondromalaciaConstipation, hypercalciuria, hypercalcemia
PhosphorusBone loss (rickets), weakness, anorexia, painTetany (infants), arrhythmias
PotassiumWeakness, anorexia, nausea, irrational behavior, arrhythmiasHyperkalemia cardiac toxicity
SodiumHypovolemia, muscle weaknessEdema, hypertension
ChlorideInfants: hypochloremic metabolic acidosisHypertension
MagnesiumNausea, weakness, cognitive impairment, arrhythmias, constipation, muscle crampsNausea, vomiting, diarrhea, hypotension
IronFatigue, anemia, glossitisAcute: vomiting, cyanosis, diarrhea, shock Chronic: hepatomegaly, slate-gray skin, cardiomyopathy, arthropathy
ZincAnorexia, growth retardation, hypogonadism, hypogeusia, poor wound healingChronic: hypocupremia (copper deficiency), microcytosis, impaired immune response, low HDL levels
IodineEndemic goiter, cretinismIodide goiter, myxedema (severe hypothyroidism)
SeleniumMuscle pain, cardiomyopathy, growth retardation, osteoarthritis (cartilage defects)Alopecia, fingernail changes, garlic odor, nausea, diarrhea, peripheral neuropathy
CopperHypochromic anemia, neutropenia, osteoporosis, growth retardationHyperactivity, depression, headaches, capillary fragility
ManganeseWeight loss, dementia, nausea/vomiting, changes in hair color, carb intoleranceNeurologic, cognitive, and behavioral changes
FluorideNot an essential nutrientMottled, pitted teeth; impaired bone health; kidney, nerve, and muscle dysfunction
ChromiumWeight loss, peripheral neuropathy, glucose intoleranceRenal impairment
MolybdenumIrritability, comaGout-like syndrome
N-Acetyl Cysteine, GlutathioneCataracts, macular degeneration, elevated gamma-glutamyl transpeptidaseNone reported

What Are the Benefits to Vitamin and Mineral Supplements?

The benefits of vitamins and minerals can be obtained by either eating more foods rich in vitamins and minerals (like vegetables, nuts, seeds, and whole grains) or by taking supplements. The benefits can include increased energy, healthier hair and skin, and prevention of heart disease, cancer, and other chronic diseases. For example, research shows that vitamins A, C, and E may play a role in the prevention of cancer. Minerals, such as iodine and selenium, are essential for normal thyroid function.

Can Vitamin and Mineral Supplements Be Harmful if Taken in Excess?

Like many good things, taking too much of a vitamin or mineral can be harmful. This is especially true of the fat-soluble vitamins, as excesses can't be excreted easily.

What Are the Recommended Daily Requirements for Vitamins and Minerals?

Daily requirements have been set by the USDA to help us understand the bare minimum of the nutrients we need to prevent major disease. There are different needs based on age, pregnancy status, and sex. The requirements are reevaluated periodically as scientific knowledge evolves. For example, the recommended daily value for adults for vitamin D is only 400 IU, but more recent research suggests that requirements may be 1,000 IU-4,000 IU per day. The chart below shows the minimum daily requirements for vitamin A, vitamin B1 or thiamin, vitamin B2 or riboflavin, vitamin B3 or niacin, vitamin B6, vitamin B12, vitamin C, ascorbic acid, vitamin D, vitamin E, folate, folic acid, vitamin K, calcium, chromium, copper, fluoride, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, and zinc.

Chart of Vitamin and Mineral Recommendations
NutrientRecommended Intake
Vitamin A5,000 International Units (IU)
Vitamin B1 (Thiamine)1.5 Milligrams (mg)
Vitamin B2 (Riboflavin)1.7 mg
Vitamin B3 (Niacin)20 mg
Vitamin B6 (Pyridoxine)2 mg
Vitamin B5 (Panthothenic Acid)10 mg
Vitamin B12 (Cobalamin)6 Micrograms (µg)
Vitamin C (Ascorbic Acid)60 mg
Vitamin D400 IU
Vitamin E30 IU
Folate (Folic Acid)400 µg
Vitamin K80 µg
Calcium1,000 mg
Chromium120 µg
Copper2 mg
Iodine150 µg
Iron18 mg
Magnesium400 mg
Manganese2 mg
Molybdenum75 µg
Phosphorus1,000 mg
Potassium3,500 mg
Selenium70 µg
Zinc15 mg

What Foods Are High in Which Vitamins and Minerals?

Healthy foods, such as fruits and vegetables, are high in necessary nutrients. Fruits and vegetables are good sources of vitamin C, vitamin K, potassium, and magnesium, as well as many other nutrients. Whole grains like brown rice and quinoa are also high in vitamins, especially B vitamins such as vitamin B1 or thiamin, vitamin B2 or riboflavin, vitamin B3 or niacin, vitamin B6, and folate. Beans and lentils are high in minerals such as iron, magnesium, and manganese, as are nuts. White foods (such as white bread, white rice, and sugar), which are highly processed, are low in vitamins and minerals.

Who Should Take Vitamin and Mineral Supplements?

Research studies have tried to answer the following question:

"Do people need to take vitamin supplements?"

The answer appears to be "it depends." Studies show that regular intake of a multivitamin is associated with a lower cancer rate and is especially beneficial to prevent a cancer recurrence (risk was reduced by 27%).


Older adults benefit from taking a multivitamin; it may help reduce cognitive decline, improve mood, physical strength, and well-being.

Pregnant Women

Pregnant women have a higher need for folate, which is necessary for normal brain development in the fetus, as well as higher needs for iron, calcium, and other minerals.

Menopausal Women

Women after menopause need more calcium and other bone-supporting nutrients like magnesium, vitamin D, boron, strontium, and vitamin K to reduce the risks of osteoporosis.

How Certain Medications Affect Nutrient Absorption

People who are taking medications that affect nutrients should also pay attention to ensure they get enough. For example, people taking statins need more CoQ10 than others. People taking acid-blocking medications are unable to absorb many nutrients and may benefit from a multivitamin or B12. Your health-care provider can help you decide whether taking a vitamin or mineral supplement is right for you.

What Should People Look for When Choosing Vitamin and Mineral Supplements?

When choosing a vitamin or mineral supplement, people must consider the quality, amount, and form of the nutrient. To find a good-quality vitamin or mineral supplement, look for a brand manufactured in the U.S., Europe, or Canada (where regulations are more strict) that carries an indication of third-party analysis. Several organizations do this and put their seal on the products: NSF International, U.S. Pharmacopeia, or Consumer Lab. Choosing a good-quality brand ensures that the supplement contains what the label says it contains. It is also important to get the right forms of the vitamins. For example, some people have genetic variation that affects processing of B vitamins and requires them to take methylfolate (instead of folic acid).

Where Can People Find Additional Information About Vitamins and Minerals?

People who have questions about whether they should take vitamins and minerals, or whether they would benefit from increased intake of specific nutrients, should talk to an expert in micronutrients. Naturopathic doctors, nutritionists, registered dieticians, and integrative medicine doctors are all good resources for people who want to understand their needs for vitamins and minerals. For people who want to study about vitamins and minerals themselves, be careful! There is a lot of misinformation on the Internet! Reputable institutes such as the Linus Pauling Institute and the NIH Office of Dietary Supplements are good resources for quality information.

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Medically reviewed by Kelly A. Truesdale, DO; Board Certification: Family Practice


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Linus Pauling Institute