Multivitamins are commonly and appropriately referred to as a "nutritional insurance policy." Unlike a stand-alone vitamin, they contain a broad spectrum of key vitamins and minerals. This ensures you that your bases are covered by providing you with adequate amounts of nutrients that you may be overlooking, or simply having a hard time obtaining through your diet.
Multivitamins are used to guarantee that you're receiving a regular influx of required nutrients. Keeping your nutrition optimal 100-percent of the time is not easy. Calculating macronutrients (carbs, fats, proteins) is be challenging enough, but keeping track of micronutrients (vitamins and minerals) is a completely different chore and can quickly overwhelm. A properly formulated multivitamin will fill in some of the gaps in your nutrition that would otherwise be easily overlooked.
Vitamins can be divided into two categories based on their absorption: fat soluble and water soluble. Water soluble vitamins need to be replinished in the body regular because they are easily absorbed in water, therefore they are more rapidly excreted. Fat soluble vitamins, on the other hand, adhere to fat, making them more difficult to excrete. You can go longer without taking certain fat-soluble vitamins because they stay in the body longer. Multivitamins will include both water and fat soluble vitamins. When choosing a product, look for a formula that includes adequate amounts of the following key components:
Vitamin A is a group of compounds that are fat soluble. Vitamin A is intricately involved in immune function, vision, cellular communication, and reproduction.[1, 2]
Also known as ascorbic acid, this water soluble vitamin plays an important role in immune function. It also provides profound antioxidant benefits.
Vitamin D is a group of two fat soluble compounds, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol), that have multiple functions in the body. Most notably it is recognized for it's crucial role in bone health.[5, 6, 7, 8]
Vitamin E is a collective name for a group of eight fat-soluble compounds that share distinct antioxidant qualities. These compounds ward off free radical damage.
Vitamin B complex
There are eight B vitamins known as vitamin B complex, or simply B complex. All of these compounds are water soluble.
Vitamin B1 (thiamine)
Similar to other B vitamins, thiamine is often referred to as an "anti-stress" vitamin because of it's important role in the immune system, nervous system, and brain health. Your body needs thiamine to perform a number a metabolic actions. It's also needed to form adenosine triphosphate (ATP), the source of fuel for every cell in the body.
Vitamin B2 (riboflavin)
Riboflavin helps the body produce energy, provides antioxidant benefits, and helps utilize vitamin B6 and vitamin B9 more efficiently.
Vitamin B3 (niacin)
In addition to improving circulation, niacin helps the body form multiple stress and sex-related hormones.
Vitamin B5 (pantothenic acid)
Pantothenic acid assists in the breakdown of fats and carbohydrates for energy. It is also needed to form sex and stress hormones, synthesize cholesterol, manufacture red blood cells, and maintain a healthy digestive tract. Furthermore, it helps the body utilize vitamin B2 more effectively.
Vitamin B6 (pyridoxine)
Vitamin B6 aids the body in forming neurotransmitters. It's essential for healthy brain development and functionality. Additionally, vitamin B6 helps the body build serotonin and norepinephrine — two hormones that influence mood — and melatonin, a powerful hormone that helps regulate your biological clock. Pyridoxine is needed for the absorption of vitamin B12.
Vitamin B7 (biotin)
Commonly referred to as vitamin H, biotin is used to metabolize carbohydrates, fats, and protein. It's needed for a healthy liver and helps the immune system function properly. It's also beneficial to the skin, hair, and eyes.
Vitamin B9 (folic acid)
Folic acid is critical for proper brain function and essential to mental health. Furthermore, it assists in the production of DNA and RNA. Vitamin B9 also works synergistically with B12 in assisting the body to properly utilize iron and generate red blood cells.
Vitamin B12 (cobalamin)
Cobalamin is a particularly important nutrient in regards to maintaining healthy nerve cells. It also helps with the production of the body's genetic material, DNA and RNA. Vitamin B12 works hand in hand with folic acid to help the body properly utilize iron and form red blood cells.
In order to achieve a more well-rounded product, many companies choose to pair their multivitamin formula with a mineral complex. These are the most common minerals used in such products:
Calcium is the most abundant mineral in the human body. Among all of its functions, it's most noted for its role in bone health.
Phosphorous is another mineral that's critical for bone health.
This mineral has multiple roles in the body, but is most recognized for its key functions in thyroid health.
It's one of the most abundant minerals on earth, but in the human body, iron is a key component involved in oxygen transportation. It is also essential for the regulating cell growth.
This is a diverse mineral that helps regulate a multitude of biochemical reactions, including blood glucose control, protein synthesis, blood pressure regulation, muscle and nerve function.
Zinc plays a key role in immune function, protein synthesis, DNA synthesis, and cell division. This essential element has also been shown to support normal growth and development during pregnancy, childhood, and adolescence.[24, 25, 26, 27, 28]
Selenium plays a critical role in thyroid hormone metabolism, reproduction, DNA synthesis, and protection from oxidative damage and infection.
This trace mineral enhances the action of insulin. In turn, the body more effectively metabolizes fats, carbohydrates, and proteins.
Potassium is required to ensure the proper functioning of all organs, tissues, and cells. It's particularly crucial for proper heart function and plays a key role in both smooth and skeletal muscle contraction, making it important for healthy muscular and digestive function.
Manganese is necessary for healthy nerve and brain function. It's also essential in helping to form bones, connective tissue, and sex hormones. Additionally it's an important factor in fat and carbohydrate metabolism, calcium absorption, and blood sugar regulation.
Copper assists in iron absorption, energy production, generation of red blood cells, and keeping the immune system and nerve cells healthy. It's also essential in the formation of collagen, making it crucial for healthy bones and connective tissue. The mineral has also been shown to exhibit antioxidant properties, helping to rid the body of free radicals that would otherwise damage cells and DNA.
Not all brands include essential fatty acids (EFA) in their multivitamin formula. If your product of choice doesn't include EFA's, fish oil is an excellent source and will be useful in helping you meet your daily nutritional requirements.
While many companies include a mineral complex of some sort in their multivitamin formula, it is wise to check the label. If yours doesn't, you should consider stacking with a multimineral.
Stacking multivitamins with digestive enzymes helps promote proper digestion and optimal nutrient absorption.
If your multivitamin is lacking a joint support complex, you should consider stacking it with a product that promotes healthy joint function.
Most of the studies proving the benefits of multivitamins are based on their role in disease cure and prevention. While interesting, these studies are highly controversial and constantly disputed. It is true however, that one of the biggest benefits multivitamins provide is the ability to correct vitamin deficiencies and prevent further deficiencies from occurring. They are also particularly beneficial while dieting in a caloric deficit, as you likely won't be getting adequate amounts of micronutrients from whole food sources.
Most of the controversy surrounding multivitamins is based on claims regarding their effects on major diseases and illness. There are dozens of conflicting studies that seem to disprove each other.[42, 43] Taking this into consideration, we can only advise supplementation with multivitamins on the basis of ensuring certain daily micronutrient requirements are met.Recommended dosageDifferent formulations contain a multitude of nutrients at varying dosages. Because of this, you should expect dosages to vary from product to product. As a general recommendation, we suggest that you consume an appropriate amount of vitamins to meet your corresponding recommended daily intake (RDI). We always suggest that you follow the directions on the product, and always speak with your healthcare practitioner before starting a new multivitamin regimen.
Take a multivitamin to guarantee that you're receiving a regular influx of required nutrients.
Multivitamins are available in many forms. Some of the most common are chewable tablets, powders, pills, liquids, and gummies. There are also more exotic forms available, such as transdermal patches, suppositories, and oral sprays. It is worth noting that many companies use vitamin packs (e.g. Animal Pak), in which case one serving will consist of multiple pills, sometimes upwards of ten. Choosing the right formulaMany specialized formulas are available for specific needs and age groups. When choosing a specialized formula you should look for the following basic characteristics:
Children's formulas should have little to no iron. It's also important to choose a product designed specifically for kids, as the nutrient dosages will be adjusted accordingly. Most children's vitamins come in the form of flavored chewables. Products that include calcium and vitamin D are suggested for proper bone health and development.
Parents of teens should look for a formula that includes skin and immune system support. There are also product that include vitamins and/or minerals known for stress management and mood balancing characteristics . — a common concern for man pubescents. To help meet their recommended intake, teens should look for a brand with ample amounts of the B vitamins. Additionally, it is wise to take into consideration that kids between the ages of TK and TK rarely eat a sufficient amount of vegetables. With this in mind, it's smart to choose a product that contains a greens or veggie blend.
Females should choose a product that includes bone, breast, and reproductive support. Pregnant women should consider using prenatal vitamins, but always need to consult with their doctor before using any supplements. It is important for women to make sure their multivitamin includes iron, as they are more prone to become deficient in this mineral.
A proper men's formula will focus on prostate health, including sufficient amounts of selenium and vitamin A for their reproductive health benefits. It is common to see inclusion of additional herbal ingredients because of their alleged benefits regarding prostate health. It is most important for men to choose a multivitamin containing little to no iron since they're more likely to reach iron toxicity.
Athletes tend to burn through nutrients at increased rates. Therefore, it is suggested that they look for a product containing higher doses of nutrients close to or at the upper tolerable limit (UL). Athletes need to choose a very well rounded product that includes sufficient amounts of B vitamins for energy production.
Seniors should look for a formula that includes vitamin A for vision, potassium for heart health, and B vitamins for immune function, energy, circulation, and brain function. There also needs to be great care taken in choosing a product that does not contain ingredients that could interfere with medications they might currently be taking.
While it is essentially impossible for a company to create a "one size fits all" type of formula, many brands have successfully created unique products that can be useful tools in aiding you to meet your own specific needs and concerns.
Side effects from multivitamins will generally occur if you're reaching toxic levels of certain vitamins or minerals.To reduce the chances of toxicity, the Institute of Medicine (IOM) has established recommended daily allowances for vitamins and minerals.
- Vitamin A toxicity can cause reduced bone mineral density, dizziness, nausea, headaches, skin irritation, painful joints and bones, coma, and in extreme cases, even death.
- Vitamin C is considered very safe, with only a small risk for toxicity. It's believed that there are no serious adverse effects at high doses. However, some reports of mild side effects, such as diarrhea, abdominal cramps, nausea, and other gastrointestinal disturbances, do exist.
- Vitamin D toxicity can cause an array of symptoms, like anorexia, weight loss, polyuria, and a heart arrhythmia. It can also raise blood levels of calcium, which can lead to more serious side effects, such as vascular and tissue calcification.
- Studies have shown that increased dosages of vitamin E raises the risk of excessive bleeding because it interrupts the process of blood coagulation.[36, 37]
- Thiamine, also known as vitamin B1, is considered safe and has no established UL. However, there have been reports of upset stomach at high doses.
- Even in large doses, vitamin B2, or riboflavin, is considered safe. There is no established UL. While no serious side effects have been confirmed in association with B2 supplementation, high doses may cause itching, burning, numbness, sensitivity to light, and fluorescent yellow or orange urine.
- High doses of niacin (vitamin B3) have been proven to cause side effects. The most common are burning-tingling sensations in the face and chest, which is often accompanied by reddened skin. This is commonly referred to as the "niacin flush." Very high doses of B3 have been linked to liver damage and stomach ulcers.
- Vitamin B5 (pantothenic acid) is generally considered safe, but at very large doses it has been shown to cause diarrhea. Also, it is noteworthy to mention that numerous companies and publications have stated that pantothenic acid may increase the risk of bleeding. However, it is unclear how to interpret this warning with such inconclusive evidence to back up the claim.
- Vitamin B6, also known as pyridoxine, in extremely high doses can cause temporary neurological problems, such as imbalance and loss of feeling in your legs. Minor side effects can include loss of appetite, sensitivity to sunlight, nausea, and abdominal pain.
- Vitamin B7 (biotin) is non-toxic, even in large doses. No UL has been established.
- Vitamin B9, also known as folic acid, in very high doses has been shown to cause sleep and digestive problems, skin reactions, and seizures.
- The IOM states that vitamin B12 (cobalamin), even in excess, is safe to use and, for the most part, causes no adverse effects. For that reason, there is no established UL for B12. Excessive levels of calcium have been linked to poor kidney function, soft tissue and vascular calcification, constipation, and hypercalciuria (heightened levels of calcium in the urine), which can lead to kidney stones. Some evidence suggests that high calcium intake may also interfere with the absorption of zinc and iron, however this side effect is not well established. Excessive calcium supplementation can increase the risk of cardiovascular disease.
- In excess amounts, phosphorus can cause calcification of organs and soft tissue. It has also been linked to diarrhea and can interfere with the body's ability to use iron, magnesium, calcium, and zinc.
- Taking too much iodine can cause similar side effects to iodine deficiency, possibly leading to the formation of goiters, elevated TSH levels, and hypothyroidism.
- Magnesium supplementation at high dosages can often result in diarrhea, nausea, and abdominal cramping. Toxic levels of magnesium can result in ileus (a painful obstruction in part of the intestine), hypotension, vomiting, facial flushing, difficulty urinating, depression, and lethargy. Without intervention, symptoms can progress, causing extreme hypotension, muscle weakness, irregular heartbeat, difficulty breathing, and cardiac arrest.
- Zinc toxicity can result in digestive abnormalities, such as nausea, vomiting, loss of appetite, abdominal cramps, and diarrhea. Excessive amounts of the mineral have also been linked to headaches. These effects can be both chronic and/or acute.
- Too much selenium can result in brittle hair and nails, hair and nail loss, skin lesions or rashes, nausea, diarrhea, fatigue, irritability, and nervous system abnormalities. It has also been reported that high levels of selenium can cause your breath to have a garlic-like odor or a metallic taste in your mouth.
- High levels of copper can cause digestive problems, such as nausea, vomiting, stomach pain, and diarrhea. Excess copper intake has also been shown to cause dizziness, headaches, weakness, and a metallic taste in the mouth. At toxic levels it can cause jaundice, heart problems, coma, and even fatality.
- Excess manganese poses a potential threat for nervous system damage. At toxic levels, symptoms may include, hallucinations, irritability, violent outbursts, loss of appetite, headaches, leg cramps, muscle tension, tremors, and convulsions.
- High doses of chromium have not been linked to adverse side effects. As a result, the IOM has not established a UL.
- Potassium, taken at high doses, can result in diarrhea, stomach irritation, and nausea. At toxic doses it can cause muscle weakness, slowed heart rate, and abnormal heart rhythm. This mineral is minimally excreted from the body, causing receptor sites to fill quickly. Excess iron is stored in multiple body tissues and organs, which can be fatally toxic.
It's possible to accidentally over-supplement vitamins and minerals. In some instances, accumulating too much can result in toxicity. While these occurrences are rare, you should be aware it can happen, especially if you're already meeting many of your daily nutritional requirements through a healthy diet.
Vitamins and minerals can be obtained naturally through a diet rich in a variety of foods. You should always strive to eat a well balanced diet. Supplementation is meant solely to optimize nutrition, it's not a substitute for a healthy meal plan.
Supplements containing iron should be used with caution and kept out of the reach of children at all times. Pregnant women, seniors, and individuals with pre-existing medical conditions should always consult with a doctor regarding possible contraindications before using a multivitamin.
This article is not intended to provide medical advice. It's a compilation of research and opinions. We recommend that you always consult with a healthcare professional before starting any new supplementation.
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- Institute of Medicine. Food and Nutrition Board; National Academy Press;Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc; 2001.
- Office of Dietary Supplements; "Vitamin A"
Strohle A., Hahn A.; Med Monatsschr Pharm; "Vitamin C and immune function;" February 2009
- Jacob RA, Sotoudeh G.; Nutrition in Clinical Care; "Vitamin C function and status in chronic disease;" March-April 2002
- Frei B, et al.; Procedings of the National Academy of Sciences; "Ascorbate is an outstanding antioxidant in human blood plasma;" August 1989
- Institute of Medicine; "Dietary Reference Intakes for Calcium and Vitamin D;" November 2010
- Cranney A., et. al.; Evidence Report; "Effectiveness and safety of vitamin D in relation to bone health;" August 2007
- Bischoff-Ferrari HA, et. al.; JAMA; "Fracture prevention with vitamin D supplementation: a meta-analysis of randomized controlled trials;" May 2005
- Bischoff-Ferrari HA, et. al.; BMJ; "Fall prevention with supplemental and active forms of vitamin D: a meta-analysis of randomised controlled trials;" October 2009
- Sen CK., et. al.; Life Sciences; "Tocotrienols: Vitamin E beyond tocopherols;" March 2006
- University of Maryland Medical Center; "Vitamin B1 (Thiamine);" Reviewed June 2011
- University of Maryland Medical Center; "Vitamin B2 (Riboflavin);" Reviewed June 2011
- University of Maryland Medical Center; "Vitamin B3 (Niacin);" Reviewd August 2011
- University of Maryland Medical Center; "Vitamin B5 (Pantothenic acid);" Reviewed June 2011
- University of Maryland Medical Center; "Vitamin B6 (Pyridoxine);" Reviewed June 2022
- University of Maryland Medical Center; "Vitamin H (Biotin);" Reviewed June 2011
- University of Marlyand Medical Center; "Vitamin B9 (Folic acid);" Reviewed June 2011
- University of Maryland Medical Center; "Vitamin B12 (Cobalamin);" Reviewed June 2011
- Office of Dietary Supplements; "Calcium;" Reviewed November 2013
- Straub DA.; Nutrition in Clinical Practice; "Calcium supplementation in clinical practice: a review of forms, doses, and indications;" June 2007
- Heaney RP.; Mayo Clinic Proceedings; "Phosphorus nutrition and the treatment of osteoporosis;" January 2004
- Hess SY.; Clinical Endocrinology and Metabolism; "The impact of common micronutrient deficiencies on iodine and thyroid metabolism: the evidence from human studies;" February 2010
- Office of Dietary Supplements; "Iron;" Reviewed August 2007
- Office of Dietary Supplements; "Magnesium;" Reviewed November 2013
- Solomons NW.; Nutrition Reviews;"Mild human zinc deficiency produces an imbalance between cell-mediated and humoral immunity;" January 1998
- Prasad AS.; Nutrition; "Zinc: an overview;" Jan-Feb 1995
- Simmer K. Thomas RP.; Acta paediatrica Scandinavica; "Zinc in the fetus and newborn;" 1995
- Fabris N, Mocchegiani E.; Aging; "Zinc, human diseases and aging;" April 1995
- Rink L, Gabriel P.; The Procedings of the Nutrition Society; "Zinc and the immune system;" November 2000
- Office of Dietary Supplements; "Selenium;" Reviewed July 2013
- Office of Dietary Supplements; "Chromium;" Reviewed November 2013
- University of Maryland Medical Center; "Potassium;" Reviewed July 2011
- University of Maryland Medical Center; "Manganese;" Reviewed July 2011
- University of Maryland Medical Center; "Copper;" Reviewed March 2011
- Office of Dietary Supplements; "Vitamin C;" Reviewed June 2013
- Office of Dietary Supplements; "Vitamin D;" Reviewed June 2011
- University of Maryland Medical Center; "Vitamin E;" Reviewed January 2012
- Office of Dietary Supplements; "Vitamin E;" Reviewed June 2013
- Office of Dietary Supplements; "Vitamin B12;" Reviewed June 2011
- University of Maryland Medical Center; "Phosphorus;" Reviewed June 2011
- Office of Dietary Supplements; "Iodine;" Reviewed June 2011
- Office of Dietary Supplements; "Zinc;" Reviewed June 2013
- Hennekens CH, et. al.; JAMA; Lack of effect of long-term supplementation with beta carotene on the incidence of malignant neoplasms and cardiovascular disease; May 1996
- Huang HY, et. al.; Evidence Report; Multivitamin/mineral supplements and prevention of chronic disease;" May 2006