Why Do We Need Vitamins: Why Every Vitamin Counts When It Comes to Our Health

Jan 27, 2023 Lifestyle Tips 15 MIN

Why Do We Need Vitamins: Why Every Vitamin Counts When It Comes to Our Health

Our bodies run on vitamins. Every day these essential nutrients help build and sustain everything from our skin to our bones to our muscles. Despite relying on these essential nutrients, our bodies (for the most part) don’t make vitamins. We must get them from our diet. It’s up to us to choose the correct foods with the right amounts of these nutrients, every single day.

Yet 9 out of 10 Americans don’t consume adequate amounts of nutrients from food alone. The National Health and Nutrition Examination Survey (NHANES) found that most Americans don’t meet their recommended intakes for vitamins A, C, D, and E. The gap was so large, in fact, the 2020–2025 Dietary Guidelines for Americans (DGA) identified vitamin D as a “nutrient of public health concern.”1  Because it helps support our bones, muscles, and immune system vitamin D deficiency, which is almost 30% of the population, can have implications for our well-being.21

Healthy diet aside, the data shows many of us are still missing out on the vitamins we need and may benefit from a dietary supplement.3 Take our quiz and find out which vitamins and supplements best support your lifestyle and nutrition needs.

So, why are vitamins important? It’s worth taking a quick look at exactly what these little guys are doing inside our bodies and what we could be doing to better support them.

The Vital Role Vitamins Play in Our Health

The term “vitamin” conjures up images of capsules and bottles, but these organic compounds were sustaining life long before the supplement aisle existed. Vitamins make up almost half of all the micronutrients we need to live, with minerals making up the rest of them. But don’t let the name deceive you, there’s nothing small about them.

In the most technical sense of the term, vitamins are organic compounds required in small amounts by the body to sustain life. Vitamins are the nutrients with which we build and maintain almost everything in our bodies. Without vitamins, our body systems would shut down entirely (and so would we).

The best way to get our vitamins is through healthy food and a balanced diet, but personalized vitamins can help out as well to fill the gap. When it comes to the right vitamins and supplements for you, it all depends on your lifestyle, habits, and needs. Beyond meeting the recommended dietary intakes, there is no one-size-fits-all approach. Plus, our dietary needs evolve over the course of our lives. Age, gender, environment, lifestyle, diets, and location can all affect the kinds of nutrients we consume in our foods. This is why personalized nutrition is so important. We have to know our bodies better to give them the fuel they need to thrive.

While we may know a lot about the crucial role vitamins play in human health, we’ve still got a lot more to learn. The term “vitamin” itself is even a misnomer. Vitamins were originally thought to be compounds derived from amino acids, and therefore given the suffix “amines.” But the first half of the word is derived from the term “vital” and that part is right on the money. We need vitamins to live and the data shows we’ve got a long way to go.3

See our blog on multivitamin benefits to learn about the power of a mighty multi.

The Fluid Nature of a Water-Soluble Vitamin

There’s a reason why vitamins are often sorted into “water-soluble” and “fat-soluble.” How and where each nutrient is absorbed into our body affects the role it plays and the amounts we’ll require during various stages of our lives.

Each of the eight B vitamins is water soluble, as well as the famous vitamin C. These vitamins are carried throughout our body’s tissues but are not generally stored in the body. There is no backup plan for water-soluble vitamins. They’re consumed and then they’re used. Which makes it even more important to pay attention to whether or not we’re regularly addressing these needs.

You may know about these vitamins already, but we love nerding out over biology. After all, knowledge is power—so here’s a little extra knowledge about each of the vitamins.


Vitamin B1 in the body

Thiamin (vitamin B1) plays a key role in supporting cellular energy production. It assists in carbohydrate and amino acid metabolism and helps support nervous system function. The bacteria in your gut can synthesize small amounts of thiamin, but it’s not enough to support your daily needs, which is why it’s essential to get it from your diet.  

Vitamin B1 in your diet  

Thiamin can be found in whole grains and enriched/fortified cereal, bread, pasta, and rice. It can also be found in certain seafood like trout and mussels, as well as pork. Thiamin is in many legumes such as soybeans and black beans. Seeds, nuts, and acorn squash also contain it.

Vitamin B1 as a nutrient gap

While a B1 shortfall is uncommon, certain medications and lifestyle choices may inhibit thiamin absorption and therefore leads to gaps in nutrition and even deficiencies. 3 Almost one third of older adults may have a deficiency due to medications and/or diet. Over three fourths of people who frequently drink alcohol suffer from a thiamin deficiency.


Vitamin B2 in the body

Vitamin B2 (riboflavin) helps convert carbohydrates into cellular energy. Fun fact, riboflavin is so efficient in energy flow, scientists have developed a solar battery called the “energy flow battery” by tweaking a riboflavin molecule.6  Also, it’s the B vitamin that turns your pee bright yellow (yep, all by itself).

Vitamin B2 in your diet

Riboflavin can be found in fortified breakfast cereals and breads, oatmeal, yogurt and milk, mushrooms, almonds, and organ meats. 

Vitamin B2 as a nutrient gap

Most people in the United States consume enough B2, however, those who do not consume meat or dairy products, such as vegetarians or vegans, may not meet B2 needs. 3 Frequent alcohol intake may affect the absorption and metabolism of vitamin B2.


Vitamin B3 in the body

Vitamin B3 (niacin) keeps busy by supporting over 400 metabolic pathways in the body (more than any other B vitamin). This includes everything from supporting cellular energy production support to helping support nervous system function. Vitamin B3 may even have extraterrestrial origins; it was first discovered in meteorites over billions of years old, which means niacin may be tied to the origin of life.8

Vitamin B3 in your diet

Niacin is found in meat, poultry, and fish that the body can readily use. Plant-based foods such as legumes, grains, and nuts contain a natural form of niacin that our bodies cannot easily use. Food manufacturers often fortify foods with a form of niacin that the body can also easily use. 

Vitamin B3 as a nutrient gap

Most people in the United States meet the recommended intake for niacin.3 That said, our medications or lifestyle choices may affect how easily this essential vitamin is absorbed and metabolized. Frequent alcohol intake affects this nutrient’s effectiveness as well. Malabsorption and GI conditions may also affect how the body absorbs niacin. Immunosuppressive drugs may affect niacin metabolism as well. That is why it is always important to talk to your healthcare practitioner to determine if this vitamin is right for you.


Vitamin B5 in the body

Vitamin B5 (pantothenic acid) is essential to cellular energy production like all B vitamins. But it also helps make and break down fats and supports the body's natural stress response. Basically, it’s always hard at work. Think of it like that trainer at the gym that doesn’t let anybody have a “light” day.

Vitamin B5 in your diet

Vitamin B5 can be found in beef liver, shiitake mushrooms, sunflower seeds, chicken, tuna, avocados, and fortified breakfast cereals. 

Vitamin B5 as a nutrient gap

Thankfully, vitamin B5 deficiencies and shortfalls are very rare.3 It’s one of the few vitamins for which no risk groups have been identified. 


Vitamin B6 in the body

Vitamin B6 (pyridoxine) is a versatile helper that’s essential for over 100 different reactions in protein processes in the body. It also helps support normal red blood cell formation, which plays a key role in transporting oxygen throughout the body. Like many other B vitamins, B6 plays a role in supporting the nervous system.

Vitamin B6 in your diet

Vitamin B6 can be found in organ meats, and in more common animal-based foods like tuna, salmon, and poultry. Plant-based sources include chickpeas, potatoes, and fortified cereal . 

Vitamin B6 as a common nutrient gap

Vitamin B6 is one of the most prevalent deficiencies of the B vitamins in the United States.11 Approximately 11% of population aged 1 year and older have a vitamin B6 deficiency.11 Children, women, and adults over 40 are susceptible to lower B6 levels most likely due to either increased needs or lower intake.12 Frequent alcohol intake also affects vitamin B6 absorption . As far as medications go, oral contraceptives, and long-term non-steroidal anti-inflammatory drugs (NSAIDs) usage may affect how well our body metabolizes and absorbs this nutrient.


Vitamin B7 in the body

Vitamin B7 (biotin) is involved in over 40 cellular reactions, primarily those involved with turning the carbohydrates, proteins, and fats we eat into cellular energy. This energy supports many of your body’s necessary functions.

Vitamin B7 in your diet

Like many other B vitamins, biotin is found in organ meats. It is also found in eggs, salmon, pork, beef, and sunflower seeds.

Vitamin B7 as a nutrient gap

Most of us get enough biotin in our diets. Frequent alcohol intake may inhibit biotin absorption and therefore, increase the risk of a biotin vitamin deficiency or shortfall. People suffering from a rare genetic condition known as “biotinidase deficiency” are also at risk.


Vitamin B9 in the body

Vitamin B9 (folate and folic acid) is a critical nutrient for making the building blocks of life we call DNA. While folate is essential for brain development and function at all ages, it’s best known for its critical role in the proper development of fetal nervous systems and may help reduce the risk of  neural tube defects in utero.

Vitamin B9 in your diet

Folate is naturally found in dark green leafy vegetables, avocado, papaya, orange juice, eggs, beans, and nuts. Folic acid (the fortified form of B9) is found in fortified cereal, pasta, and bread.

Vitamin B9 as a nutrient gap

The data shows many Americans get enough folate in their diets.3 Most doctors recommend a folic acid supplement for pregnant and soon-to-be pregnant women to support healthy brain and spinal development in their babies. Anyone who is unable to properly absorb nutrients because of gastrointestinal conditions or frequent alcohol intake may also fall short of this critical nutrient.


Vitamin B12 in the body

Vitamin B12 (cobalamin) plays a critical role in the biological pathways that release cellular energy, as well normal red blood cell formation, which plays a key role in transporting oxygen throughout the body. B12 is also required for proper nerve function. Unlike other water-soluble vitamins, B12 can be stored in the liver for 3–5 years!

Vitamin B12 in your diet

Vitamin B12 is found in animal products such as clams, salmon, beef, milk, and yogurt as well as some fortified foods. 

Vitamin B12 as a nutrient gap

While most people in the United States meet the recommended intake for B12, some of us may find ourselves at risk of a nutrient shortfall anyways due to medications, or dietary and lifestyle choices. 3 Medications that reduce gastric acid in the stomach may inhibit our body’s ability to absorb B12 from foods. GI conditions also affect vitamin B12 absorption.

Natural aging may lead to a nutrient shortfall as well, due to producing less of a specific stomach acid required for B12 absorption. If you’re vegan or vegetarian, you’re probably already aware that B12 supplementation can help fill this nutrient gap, which often arises from a lack of eating meat and animal byproducts. Read more about vitamin B benefits in our blog.


Vitamin C in the body

Known for its immune health support, vitamin C is an antioxidant which helps neutralize free radicals in the body. It also plays an integral part in the synthesis of collagen, which is a key component of healthy skin.

Vitamin C in your diet

Vitamin C is found in citrus fruits like oranges, lemons, grapefruit, and limes. It’s also found in tomatoes and strawberries.

Vitamin C as a common nutrient gap

Up to 46% of people in the United States do not get enough vitamin C in their diet.3 This may include anyone who gets less than five servings of fruits and vegetables per day, smokers, or anyone encountering a great deal of air pollution. Smoking and air pollution create oxidative stress on the body, which then speeds up how quickly our bodies use vitamin C.

Let those water-soluble vitamins flow

Nutrient shortfalls for water-soluble vitamins vary depending on our age, lifestyle, and personal needs. For example, pregnancy can increase our body’s demands for certain vitamins whereas certain diseases or medications can affect our body’s ability to absorb the vitamins we do consume. These variations and dependencies are why it’s so important to remain in constant communication with our bodies (and our health care practitioners) to ensure we’re always getting the amount of micronutrients we need.

Why fat-soluble vitamins tend to stick around

Vitamins A, D, E, and K require fat all the way through—from our diets to our bodies—to do their jobs. Because these vitamins need, use, and are stored in fat—they’re referred to as “fat-soluble.”

Yet despite their integral roles in our health, vitamins A, D, and E are under consumed” because a significant percentage of Americans don’t get enough of them.3 These nutrient shortfalls can have meaningful long-term effects on our health, so it’s worth taking a closer look at them as well.


Vitamin A in the body

Vitamin A comes in two forms, retinol and carotenoids (like beta-carotene). Vitamin A is best known for its essential role in healthy eye function, but it also supports a healthy immune system. It’s directly involved in photochemical reactions in the retina, which is responsible for our ability to see the world.

Vitamin A in your diet

Retinol sources of vitamin A include animal foods such as liver, fish, milk, and eggs, as well as fortified breakfast cereal. Carotenoids are found in leafy green vegetables, such as spinach, kale, collards, as well as orange and yellow vegetables such as carrots, sweet potatoes, and squash.

Vitamin A as a common nutrient gap

Approximately 45% of the U.S. population doesn’t meet the recommended intake of vitamin.3 Also, GI conditions can affect the body’s ability to absorb fat-soluble vitamins like vitamin A.


Vitamin D in the body

Vitamin D is probably best known as the sunshine vitamin, but not a lot of people are aware of what exactly it does. Believe it or not, there are vitamin D receptors throughout our entire body. Vitamin D is critical in bone health and helps the body absorb calcium. Muscles need it to move and function. Many equate vitamin C with immune health, but vitamin D is a major player in supporting immune health as well.

Vitamin D in your diet

Vitamin D comes in two forms: D2 (plant sources, ergocalciferol) and D3 (animal sources, cholecalciferol). Both forms are found in fortified foods and dietary supplements. Vitamin D2 can be found in mushrooms, while vitamin D3 is found in fatty fish—such as salmon, tuna, and mackerel—as well as fish liver oils. Fortified breakfast cereal, juices, and dairy can contain D3 as well. Both forms are effective, but vitamin D3 is better at raising and maintaining adequate levels of circulating vitamin D in the body.

Vitamin D as a common nutrient gap

Vitamin D is the one nutrient that we can get from a source outside of our diet. Sunlight is the main source of vitamin D; however, most of us don’t get adequate sun exposure to make enough of it. Compound that with the fact that vitamin D is only naturally found in a few foods, and it makes sense why many people may be at a risk of vitamin D deficiency. In the United States alone, 90% of us don’t get enough vitamin D from our diets.3 As such the DGA deemed it a nutrient of public health concern for all Americans.1

Apart from diet, limited sun exposure is the best-known cause of low vitamin D. Wearing sunscreen can reduce our ability to get enough vitamin D from the sun as well (by more than 90%). Anyone who spends a lot of time indoors, lives in parts of the United States with a lot of cloud coverage, or in areas with high air pollution is also at risk of a vitamin D nutrient gap.

Other factors include skin pigment because a higher melanin concentration can reduce the skin’s ability to make vitamin D from sunlight. Older adults are less efficient at both making and processing vitamin D. GI conditions play a role here, as do other conditions that affect the body’s ability to absorb dietary fats (including fat-soluble vitamins like D).


Vitamin E in the body

Vitamin E is a powerful antioxidant that’s an essential nutrient for many cells, including heart muscle cells. It helps neutralize free radicals in the areas of the body that have fatty or lipid structures, like every cell membrane. Vitamin E also works together with vitamin C to battle the daily bombardment of free radicals. Together, vitamins E and C are the two leaders of dietary antioxidants—and Americans aren’t getting enough of either nutrient.

Vitamin E in your diet

Vitamin E is naturally found in nuts and vegetable oils. It’s also found in avocado, spinach, seeds, and whole grains.

Vitamin E as a common nutrient gap

Nearly 84% of Americans do not meet their dietary vitamin E needs.,3 This can be due to a diet lacking in nuts, seeds, and green leafy vegetables. GI conditions which affect dietary fat absorption may also inhibit the body’s ability to absorb vitamin E.


Vitamin K in the body

Vitamin K comes in two natural forms: K1 and K2. They are important for many roles such as supporting healthy vascular function.

Vitamin K in your diet

Vitamin K1 is derived from plants and is primarily found in green leafy vegetables such as spinach, kale, and broccoli. Vitamin K2, on the other hand, is found in small amounts of animal-based foods such as liver, certain cheeses, and other fermented foods including natto (made from soybeans). Vitamin K2 can also be made by intestinal bacteria.

Vitamin K as a nutrient gap

Only 45% of Americans have an adequate intake of vitamin K in their diets.3 Those more at risk include people on a restrictive diet due to blood-thinning medications and people suffering from malabsorption.

Adapting to our micronutrient needs

Vitamins are for everybody, but every body needs different things. Our needs evolve as we age and experience all life has to offer, like moving to a new state or starting a family. It’s important to regularly check in with your diet and exercise, and to see if you’re providing your body with everything it needs to thrive.


This information is only for educational purposes and is not medical advice or intended as a recommendation of any specific products. Consult your health care provider for more information.


  1. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020. Available at DietaryGuidelines.gov.
  2. Oregon State University. “Thiamin.” 2013. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/thiamin
  3. Reider, CA, et al. Inadequacy of Immune Health Nutrients: Intakes in US Adults, the 2005–2016 NHANES. Nutrients 2020, 12, 1735. https://www.mdpi.com/2072-6643/12/6/1735
  4. National Institutes of Health. “Riboflavin Fact Sheet for Health Professionals.” 2019. NIH Office of Dietary Supplements. Accessed on: October 9, 2019. https://ods.od.nih.gov/factsheets/Riboflavin-HealthProfessional
  5. Oregon State University. “Riboflavin.” 2013. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/riboflavin
  6. Burrow, Leah. “A battery inspired by vitamins: Research opens a ‘new universe’ of organic molecules that can store energy in flow batteries.” 2016. Harvard John A. Paulson School of Engineering and Applied Sciences. Accessed on: October 9, 2019. https://www.seas.harvard.edu/news/2016/07/battery-inspired-vitamins
  7. Oregon State University. “Niacin.” 2017. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019 https://lpi.oregonstate.edu/mic/vitamins/niacin
  8. Steigerwald, Bill. “Vitamin B3 NASA's Might Have Been Made in Space, Delivered to Earth by Meteorites.” 2014. NASA’s Goddard Space Flight Center. Accessed on: October 9, 2019. https://www.nasa.gov/content/goddard/vitamin-b3-might-have-been-made-in-space-delivered-to-earth-by-meteorites
  9. Oregon State University. “Pantothenic Acid.” 2015. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/pantothenic-acid
  10. Oregon State University. “Vitamin B6.” Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-B6
  11. Pfeiffer, CM et al. The CDC's Second National Report on Biochemical Indicators of Diet and Nutrition in the U.S. Population is a valuable tool for researchers and policy makers. J Nutr. 2013;143(6):938S–47S. https://www.ncbi.nlm.nih.gov/pubmed/23596164
  12. Morris, MS et al. Plasma pyridoxal 5'-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003-2004. Am J Clin Nutr. 2008 May;87(5):1446-54. https://www.ncbi.nlm.nih.gov/pubmed/18469270
  13. Oregon State University. “Biotin.” 2015. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/biotin
  14. Oregon State University. “Folate.” Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/folate
  15. Oregon State University. “Vitamin B12.” 2014. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-B12
  16. Oregon State University. “Vitamin C.” 2018. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-C
  17. Oregon State University. “Vitamin A.” 2015. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-A
  18. Oregon State University. “Vitamin D.” 2017. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-D
  19. Oregon State University. “Vitamin E.” 2015. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-E
  20. Oregon State University. “Vitamin K.” 2014. Linus Pauling Institute, Micronutrient Information Center. Accessed on: October 9, 2019. https://lpi.oregonstate.edu/mic/vitamins/vitamin-K
  21. Liu, X. et al. Vitamin D deficiency and insufficiency among US adults: Prevalence, predictors and clinical implications. Br. J. Nutr. 2018, 119, 928–936. https://pubmed.ncbi.nlm.nih.gov/29644951/


Carroll Reider, MS

Scientist, Principal Science & Technology

Carroll is a nutrition scientist and communicator with over 25 years of experience as a clinician, researcher, and educator at major universities, medical centers, and nutrition industry settings. She is a passionate advocate of nutritional health and established the nutrition education and science platforms at Pharmavite. Carroll is an expert in personalized nutrition and has published several scientific papers on vitamin and mineral inadequacies and the impact on health and wellbeing. Prior to joining Pharmavite, Carroll taught nutrition at UCLA Medical School and Santa Monica College and was a chief clinical dietitian and researcher.

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