Multivitamin: Why do we need vitamins & what role do they play?

The most popular nutrition and health supplement in the world are multivitamin. People take multivitamins to improve their health. Some even believe a multivitamin can substitute for a healthy diet, or at least compensate for not eating a healthy diet. 

Multivitamins certainly have their benefits. It can be difficult to get all the minimum daily requirements of all the vitamins and minerals we need to stay healthy. A good multivitamin can supplement what is missing. 

But we need to understand what we get with multivitamins. The truth is, there is no substitute for a healthy diet, and multivitamins will not keep us healthy if we are not doing the right things for ourselves. 

But there are also legitimate benefits of multivitamins. Like anything else, the key is to strike a balance between eating right and supplementing when we are coming up short on certain nutrients. To strike this balance, we need to understand what a multivitamin is. 

What are multivitamins? What are the benefits of multivitamins? And when should we take a multivitamin? This guide will give you basic information on multivitamins and how to use them correctly.   

What is a multivitamin?

A multivitamin is a supplement that contains many different vitamins and minerals. Some multivitamins contain other things besides vitamins and minerals. No standard determines what is in a multivitamin, so you should always read the label to see what it contains. 

Multivitamins can come in tablets, capsules, chewable, powders, and liquids. Some multivitamins are designed to help specific types of people. For example, there are multivitamins specifically formulated for children. These contain doses of certain vitamins at levels that are meant for developing bodies. 

Some multivitamins may contain things like herbal extracts. Multivitamins may contain things like green tea extract, for example, to provide added antioxidants along with vitamins and minerals. 

Multivitamins are available almost anywhere. You can buy them in drugstores or online. Perhaps the most important thing to think about when considering a multivitamin is the exact ingredients in any one multivitamin. These ingredients and the concentrations of various vitamins and minerals can vary greatly from one brand to the next. Always carefully read the product label on any multivitamin. 

Why do we need vitamins?

Vitamins are natural organic compounds necessary to support life. As organic compounds, vitamins occur in nature and are found in dietary sources. Some vitamins are derived from other compounds which are found in dietary sources. 

There are 13 basic vitamins each of which is essential to certain physiological functions. All vitamins support multiple functions, but each works toward a specific area. 

  • Vitamin A: Supports eye health. 
  • Vitamin B1: It is essential for producing various enzymes that help break down blood sugar.
  • Vitamin B2: Essential for the growth and development of body cells and helps metabolize food.
  • Vitamin B3: The body needs niacin for the cells to grow and work correctly.
  • Vitamin B5: Necessary for producing energy and hormones.
  • Vitamin B6: Vital for the formation of red blood cells.
  • Vitamin B7: Enables the body to metabolize proteins, fats, and carbohydrates. It also contributes to keratin, a structural protein in the skin, hair, and nails.
  • Vitamin B9: Essential for making DNA and RNA.
  • Vitamin B12: Essential for a healthy nervous system.
  • Vitamin C: Contributes to collagen production, wound healing, and bone formation. It also strengthens blood vessels, supports the immune system, helps the body absorb iron, and acts as an antioxidant.
  • Vitamin D: Necessary for the healthy mineralization of bone.
  • Vitamin E: Antioxidant activity helps prevent oxidative stress, an issue that increases the risk of widespread inflammation and various diseases.
  • Vitamin K:  Necessary for blood clotting.

Any multivitamin will contain some or all of these vitamins at various concentrations. Some multivitamins are specially formulated for things like bone health, for example, and will contain added vitamin D. 

In any case, one can see that each of the thirteen vitamins is essential to our health, and we need to make certain we consume a minimum amount of each vitamin on any given day. When we do not get enough of a specific vitamin, we run the risk of a vitamin deficiency. Vitamin deficiencies can lead to serious health problems. 

On the other hand, some vitamins can accumulate in the body. Too many certain vitamins can be dangerous. Vitamin A, for example, can become toxic and even fatal if we take too much. This is one reason we need to pay close attention to the ingredients of a multivitamin. 

Benefits of taking a multivitamin

Multivitamins have the potential to generally increase wellness in several ways. Here are some benefits taking a multivitamin has:


Calcium is known to improve bone health, particularly in older adults.

Vitamin D

Vitamin D also improves bone health, particularly in older adults. Vitamin D also helps colon health and may reduce the risk of colon cancer. 

Folic acid 

Folic acid is often prescribed by doctors for women or are pregnant or are trying to become pregnant. It vastly reduces the risk of birth defects and reduces the risk of heart disease. Folic acid may also prevent certain types of cancer. 

B Vitamins

All the B vitamins are essential. B vitamins increase energy levels and help with neurological function. B vitamins are also helpful in decreasing the onset of neurodegeneration in older adults. 


Magnesium helps the body relax, both mentally and physically. It is also a well-established antioxidant. 

Vitamin C

Vitamin C is also a powerful antioxidant and may prevent certain types of cancer. 

Approximately 75 percent of the population of the United States does not get enough vitamins and minerals from diet alone. For this reason, many healthcare professionals recommend multivitamins. A multivitamin that contains fiber and things like omega-3 fatty acids also vastly improves overall health. 

How to take multivitamins

Water-soluble vitamins must be taken every day since the body does not store them. These include vitamin C and all the B vitamins. Take all of these with or without food with one exception. Vitamin B12 is absorbed best with food so this with a meal. 

Vitamins A, D, E, and k are all fat-soluble. These need to be taken with food to help the body absorb them properly. You do not need to go heavy on the fat in your diet, but it is safe to take in plenty of good fats like avocado and nuts. 

Iron is absorbed most efficiently on an empty stomach. Take with water. To increase the absorption of iron, take it with citrus fruit juices. Iron and vitamin C tend to work together and can make some people a little nauseated. You can save these for a meal to help with that issue. 

Do not take calcium with high-calcium foods. This is especially true for me and post-menopausal women. Both should skip supplements with calcium if they are eating a calcium-rich diet. 

Large doses of minerals can compete with each other for absorption in the body. Do not use calcium, zinc, and magnesium supplements at the same time. All of these minerals will also be easier on your stomach if you take them with food. 

Avoid taking any single vitamin supplement while taking a multivitamin. This is especially true of multivitamins that contain added antioxidants, beta-carotene, or lycopene. 

Be careful with vitamin A supplements. High levels of vitamin A and beta-carotene (another form of vitamin A) can become toxic. Doses higher than 10,000 IU can lead to birth defects. Also, avoid vitamin A if you are a smoker as it can increase your risk of lung cancer. This is also true of ex-smokers. 

Folic acid and iron in prenatal vitamins are important for the health of your baby. Some people may want to take folic acid even before they become pregnant. Some prenatal vitamins can cause nausea. You can help fight this by taking prenatal multivitamins with a light snack. You should always talk to your doctor about the best prenatal multivitamin for you. 

Even essential nutrients can interfere with certain medications. For example, if you take blood thinners such as warfarin, even a small amount of vitamin K in a multivitamin can reduce its effectiveness. Taking more than 1000 mg of vitamin E per day can increase your risk of bleeding. Calcium, magnesium, and iron can decrease the strength of some thyroid medications. 

RDA (recommended daily allowance) is the daily amount of a nutrient you should get, based on sex and age. DV (daily value) is the percentage of a nutrient that a supplement or food serving adds to the average daily diet for all ages. UL (upper limit) is the most of a nutrient you should get in a day. Side effects from big doses range from tiredness or diarrhea to kidney stones or organ damage.

Multivitamins are not standardized by the FDA. Some have more of one nutrient than others. The RDA of any given nutrient in a multivitamin can vary drastically from one brand to another. Make sure you carefully read the product label on any multivitamin to determine if it is good for you and safe for you. 

When to take multivitamins

Generally, you can take your multivitamin any time you like. Just remember that some things are best taken with food and others are more effective on an empty stomach. Some people find that multivitamins cause an upset stomach. You can alleviate this problem by taking your multivitamin with a snack. 

You can time your multivitamin according to your schedule. If you are not a breakfast person, plan on having your multivitamin with you at lunchtime. Some people prefer to take their multivitamins before bed with a light snack since this tends to reduce the likelihood of some of the side effects. 

You can always keep a log of your vitamins and multivitamins to keep track of when you take them and how much you take. This is a good idea if you are taking multiple supplements for various reasons and if you are taking prescription medicines that can be impacted by multivitamins. 

Multivitamins side effects

The most common side effects of multivitamins include: 

  • Constipation
  • Diarrhea
  • Upset stomach
  • Nausea

These are often temporary and will abate as you become used to taking the multivitamin. If your doctor has recommended a multivitamin and these symptoms persist, be sure to let your doctor know. 

Other side effects that are rare include:

  • headaches
  • nosebleeds
  • insomnia
  • gout

Keep in mind that individual nutrients in any given multivitamin may cause specific side effects. Be sure to pay close attention to what is in your multivitamin to guard against dangerous problems such as those that can come with taking too much vitamin A. 

Any side effects in children and infants should be immediately reported to a doctor. For older adults, some side effects may be more pronounced. 


There is an entire industry of multivitamins these days. Check out any vitamin and supplement section in a drug store and you will see entire shelves of multivitamins. The challenge is figuring out which multivitamin is best for you. 

The popularity of multivitamins can be attributed to several factors. Most Americans do not get all the vitamins and nutrients they need in their diets. Whether from lack of attention or from lack of time, we simply are not getting all the essential nutrients we need to be healthy from our diets. A multivitamin can help. Also, some people simply require extra help with certain vitamins, minerals, and other nutrients. Again, a multivitamin can be the answer.

Given that multivitamins also often contain things like added antioxidants and anti-inflammatory supplements, a multivitamin may be about more than just nutrition. Sometimes a multivitamin is taken for reasons beyond basic health.

The key to multivitamins is to be aware of what is in your multivitamin and your own specific needs. Be mindful of any medications you are taking, and also be mindful of simple things like your age and gender. These things can determine the type of multivitamin you take. 

There are plenty of benefits to taking multivitamins. From basic health to reducing the risk of cancer, a multivitamin can easily be a welcome part of your supplements and healthcare plans. 


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