How Do B Vitamins Work?

How do they work?

B vitamins are required for a plethora of important functions inside the human body. These essential vitamins help to maintain good health, convert food from fatty acids, proteins, and carbohydrates into energy, and support optimal brain function. But they don't stop there.

The B vitamins are involved in many more functions and health benefits:

  • eye health
  • digestion
  • nerve function
  • formation of red blood cells
  • hormones
  • amino acid metabolism
  • energy production
  • immune function
  • synthesis and repair of DNA and RNA
  • cholesterol production
  • moving oxygen throughout the body
  • nervous system function
  • cardiovascular health
  • muscle tone

The B vitamins include:

  • Vitamin B1 (thiamine) 
  • Vitamin B2 (riboflavin) 
  • Vitamin B3 (niacin)
  • Vitamin B5 (pantothenic acid)
  • Vitamin B6 (pyridoxine)
  • Vitamin B7 (biotin)
  • Vitamin B9 (folic acid/folate)
  • Vitamin B12 (cobalamin)

Though similar, every B vitamin is unique and will provide different effects and benefits inside the body, thus they will be required in different amounts. This is why it's important to obtain a multitude of B vitamins through a variety of foods in the diet and supplement if necessary to avoid a vitamin deficiency. 

B vitamins can be obtained through a balanced diet, though a dietary supplement may be needed in certain circumstances. B-complex supplements may be particularly important for pregnant women, older populations, and those following a vegan or vegetarian diet.

A B-complex vitamin will contain all eight of the B vitamins and will help to bridge the gap between what you are obtaining through your diet and what your cells require.


Vitamin B12: What to Know

Vitamin B12 contains the mineral cobalt, which is why vitamin B12 compounds are called cobalamins. The 2 active forms of B12 include methylcobalamin and 5-deoxyadenosylcobalamin.

This nutrient is especially important for brain health and the nervous system but also a variety of functions in the body:

  • nerve tissue metabolism
  • DNA and RNA formation 
  • nervous system health
  • healthy red blood cell formation
  • cognitive function 
  • growth and appetite in children

 As an essential vitamin, an adequate intake is important to obtain through the diet or if necessary, supplementation, as the body cannot produce it on its own.

Vitamin B-12 Deficiency

Blood levels for vitamin B12 are typically routinely tested for as deficiency is common among the population, and more particularly among vegan diets, vegetarians, older adults, smokers, gastrointestinal surgeries and those with gastrointestinal disorders. Medications such as metformin and proton pump inhibitors can also create a greater risk for deficiency.

Low stomach acid can result in low vitamin B12 status as stomach acid is needed for the vitamin to be adequately absorbed. This is why working on your digestive health is important while supplementing if you are dealing with a deficiency.

Vitamin B-12 deficiency is one of the leading deficiencies in the world today. Without enough of this vitamin your energy, mental health, memory, digestion, and heart may be affected.

Symptoms of vitamin B12 deficiency may include:

  • chronic fatigue
  • muscle aches and weakness
  • joint pain
  • loss of appetite
  • difficulty breathing or shortness of breath
  • feeling dizzy
  • memory loss
  • tingling in the hands, legs, or feet
  • anemia 
  • poor concentration
  • anxiety
  • elevated homocysteine level
  • risk of depression
  • heart palpitations
  • poor dental health
  • cognitive impairment
  • digestive problems like nausea, diarrhea or cramping

 As B vitamins are water-soluble, the body does not store B vitamins for very long, and the need for them is increased by stress, smoking, use of alcohol and drugs, a vegan or vegetarian diet, unhealthy dietary patterns, shift work, illness, and demanding travel schedules.

As a water-soluble vitamin, it is less likely to reach toxicity levels as excess will be flushed out through the urine.

How Much to Get?

A vitamin B-12 supplement may be necessary depending on your situation.

The recommended dietary allowances for vitamin B12 are the following:

2.4 mcg a day for women

2.4 mcg a day for men

1.8 mcg a day for children (9-13 yo)

Keep in mind the dosage will differ according to your situation and how deficient you may be.

It's also important to be aware of the form of vitamin found in your supplement because it makes a difference!

Avoid the synthetic form, also known as cyanocobalamin, which is not found in nature and more poorly absorbed and assimilated by the body but instead look for the active vitamin form (1).

Cyanocobalamin needs to be converted into methylcobalamin or adenosylcobalamin by the body for it to be actually used. These are the two active forms of the vitamin and the forms we recommend looking for when reading the supplement ingredients.

Methylcobalamin is the naturally occurring form of vitamin B12 found in food sources such as dairy products, red meat, fish, eggs and chicken.

Vitamin B12 supplements can be taken in the form of a tablet, capsule, oral spray, or sublingual drops.

Vitamin B12 is rather poorly absorbed orally and digestive health plays a big role in how much you will absorb from your supplement. Sublingual drops or oral sprays may be the best choices for older populations and those with digestive issues for improved assimilation due to poor absorption in the stomach.

In the case of severe deficiencies or digestive issues, B12 injections may be necessary though this should be discussed with your doctor. 

Food Sources of Vitamin B12

The best food sources of vitamin B12 are animal products such as:

  • dairy
  • eggs
  • meat
  • fish
  • chicken
  • organ meats

Vitamin B12 is not found in significant amounts in plant foods unless they are fortified foods such as nutritional yeast, grain products and algae sources.

Daily intake of vitamin B12 rich foods will help you to ensure you are getting enough of this nutrient every day. The top food sources of B12 include beef liver, sardines, mackerel, lamb, wild salmon and nutritional yeast. As you can see animal-sourced foods are your best bet to get vitamin B12 from your food. If you are vegan or vegetarian it is likely you will need to supplement to avoid health issues down the road. 



About the Author

Laurence Annez

Laurence Annez is a Certified Nutritional Practitioner and Health Coach, specializing in PCOS and women's hormones. She also holds a degree in Creative Writing and has extensive experience writing on health and wellness topics. Laurence's mission is to inspire and motivate individuals to take control of their own health and reach their ultimate health goals. 

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