By the letter: Vitamins and what they do

By the letter: Vitamins and what they do

Vitamins from A to Z̶ K: Dietary sources and effect.

Vitamins. What are they good for? Absolutely n̶o̶t̶h̶i̶n̶g̶ everything. That’s why vitamins are considered essential nutrients. 

We’re about to offer a quick rundown of all the letter vitamins from A to Z... or more accurately, from A to K. But first, a little background.

The discovery and classification of the letter vitamins we know today happened in the years between 1913 and 1948. Each letter vitamin plays a specific role from keeping our bones strong to speeding wound healing to, well, name an important function of the body and there’s a vitamin for that.

Eating a healthy diet that prioritizes fresh fruits and vegetables is the best way to get the vitamins our bodies need. Supplementation — that is, vitamins and minerals typically in pill form — can help bridge the gap if we’re not getting enough of a given vitamin or nutrient in our diets.

Letter vitamins: A colourful mix of fruits and vegetables on a white background. Broccoli, peppers, radish, beans, tomatoes

Vitamins are essential to our body’s function. If food is fuel (and it is), vitamins are the fuel additives that keep things running smoothly. 

Vitamins C and all the B vitamins are water-soluble. That is, they dissolve in water. That also means anything the body hasn’t used is excreted from the body. 

The other letter vitamins (A, D, E and K) are fat soluble, meaning they dissolve in fat and can be stored in the body. For fat-soluble vitamins especially, it’s important to understand and stay within the recommended dose range. 

Speak to a pharmacist or other healthcare professional for advice before you start taking a new vitamin. Mednow pharmacists are available for free consultations any time. Use the Mednow app (Android | iOS | browser) to chat with a pharmacist or call 1-855-MEDNOW-1 

Vitamin A

The eyes h̶a̶v̶e̶ need it

Vitamin A is known as carotene and retinol, is important for maintaining healthy eyes and preventing age related macular degeneration. 

Food sources of vitamin A

Orange and yellow vegetables like squashes and carrots are great natural sources of vitamin A.

Letter vitamins: A bunch of carrots with tops still attached, sitting on a cutting board.

Vitamin B1

New cell, who ‘dis?

Vitamin B1, or thiamine, is essential for the growth of new cells and breaking down important nutrients for energy. Vitamin B1, AKA thiamine, has been linked to the prevention of heart disease.

Food sources of vitamin B1

Foods like whole grains, beans, and lentils will keep your heart beating strong.

Letter vitamins: Three reusable jars containing a variety of raw nuts sitting in a basket. One jar is open to reveal contents, the other two are sealed.


Vitamin B2

B2 or not B2?

Vitamin B2 is also called riboflavin, a key co-enzyme responsible for energy production and cellular function. Deficiencies in vitamin B2 can result in migraines and cardiovascular disease. 

Food sources of vitamin B2

Organ meats, milk, and eggs contain high levels of this essential vitamin.

Letter vitamins: A carton of 12 white eggs with one egg missing. In other words, 11 eggs in a carton.


Vitamin B3

In your DNA

Vitamin B3 is also known as niacin, a co-enzyme that helps to convert food to energy and is important in the repair and replication of DNA. Vitamin B3 is associated with heart and brain health. 

Food sources of vitamin B3

Vitamin B3 is found in nuts, seeds, and brown rice. 

Letter vitamins: Unmilled flax seeds in a white bowl on a rustic tabletop with wholegrain bread in the background


Vitamin B5

The pantheon

Vitamin B5 is also called pantothenic acid, important in making a co-enzyme responsible for metabolism and healthy fat retention. Adequate levels of vitamin B5 help to lower your cholesterol. 

Food sources of vitamin B5

Nuts, seeds and oats are a good source of vitamin B5 and help keep your blood pumping strong.


Vitamin B6

Immunity idol

Vitamin B6, or pyridoxine, has many responsibilities ranging from supporting the brain to helping keep up a strong immune system. This vitamin is linked to disease prevention. 

Food sources of vitamin B6

Fatty fishes like tuna and salmon contain high levels of vitamin B6.


Vitamin B7

Metabolize this

Vitamin B7, commonly known as biotin, plays an essential role as a cofactor for enzymes that are in charge of metabolic health. Vitamin B7 is also important for growing beautiful hair. 

Food sources of vitamin B7

Eating foods like beef liver, eggs, and salmon provide high levels of vitamin B7.

Letter vitamins: A salmon fillet on a BBQ grate with flame visible beneath


Vitamin B9

Be healthy, baby!

Vitamin B9 is also called folic acid, is particularly important during pregnancy. This vitamin has been shown to prevent neural tube defects during development. 

Food sources of vitamin B9

Fresh fruits and dark leafy green vegetables contain high levels of vitamin B9.

Letter vitamins: Close up of a white bowl containing a leafy green salad with beans and lentils sitting on a set table.


Vitamin B12

The nerve!

Vitamin B12, or cobalamin, is one of the most important vitamins that help to develop the central nervous system. It’s also important for DNA replication. Having a sufficient level of vitamin B12 prevents anemia. 

Food sources of vitamin B12

People who eat a vegan diet may have a deficiency in vitamin B12 as meat and seafood including tuna, salmon and certain shellfish are great sources of vitamin B12. Fortunately, nutritional yeast delivers B12.


Vitamin C

Juice it

Vitamin C, commonly known as ascorbic acid, is vital for collagen production and is important for developing bones and cartilage. It also plays a role in stimulating your white blood cells to support the immune system. This vitamin also helps to protect against anemia and scurvy. 

Food sources of vitamin C

Citrus fruits, broccoli, cabbage and cauliflower contain high amounts of vitamin C.

Letter vitamins: About a dozen ripe oranges fill the frame.


Vitamin D

The sunshine vitamin

Vitamin D is the only vitamin that is synthesized through the skin with enough sun exposure. This vitamin also helps your body absorb calcium to build strong bones and support a healthy immune system. 

Food sources of vitamin D

Eating fatty fishes like swordfish and salmon and getting plenty of daily sunlight is the best way to get the “sunshine vitamin.”

Letter vitamins: An overhead view of an iced drink focusing sunlight to a point in the tall shadow of the glass.


Vitamin E

Buy a vowel

Vitamin E is a known antioxidant that helps keep your immune system running strong. This powerful vitamin can help keep your immune system on point. 

Food sources of vitamin E

Plant based oils, pumpkins, and avocados contain high levels of vitamin E.

Letter vitamins: A whole avocado, a halved avocado with seed exposed plus some bread and leafy greens on a rustic tabletop.


Vitamin K

If you know you know

Vitamin K, also known as phylloquinone, is an essential co-enzyme important for clotting blood and maintaining bone health. People who take prescription blood thinners will especially want to keep an eye on their levels of vitamin K. 

Dark leafy green vegetables, soybean and canola oil are good sources of this important vitamin. 

Letter vitamins: A field of canola flowers filling half the frame with a blue sky behind.


The key vitamin take-away

Vitamins are key coenzymes, cofactors, and building blocks to maintain a healthy body. Each person is unique and may need to supplement with different vitamins depending on their diet and lifestyle.

Annual checkups including blood work by your primary care physician is a great opportunity to understand and track your vitamin needs and levels over time. 

Personalized supplementation can help you understand your unique needs and take appropriate steps to fill any gaps.

Mednow pharmacists are happy to help you get a deeper understanding of vitamins and your unique needs. Chat with a Mednow pharmacist in the Mednow app (Apple | Android | web browser) or by calling 1-855-MEDNOW-1 (1-855-633-6691).

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