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B vitamins are a group of nutrients that play many important roles in your body. Most people get the recommended amounts of these vitamins through their diet alone since they are found in a wide variety of foods. However factors like age, pregnancy, dietary choices, medical conditions, genetics, medications, and alcohol use increase the body's demand for B-vitamins. In these circumstances, supplementing B-vitamins may be necessary. 

What are B-Complex Vitamins?

B-complex supplements usually pack 6-8 vitamins into one pill. B-vitamins are water soluble which means your body does not store them. For this reason alone, your diet must supply them each day. B-vitamins have many essential functions and are vital for maintaining good health.

B-complex vitamins usually contain the following:

  • B1 (Thiamine): Thiamine plays an essential role in metabolism by helping convert nutrients into energy. The riches food sources include pork, sunflower seeds and wheat germ

  • B2 (Riboflavin): Riboflavin helps convert food into energy and also acts and an antioxidant. Foods highest in riboflavin include organ meats, beef and mushrooms

  • B3 (Niacin): Niacin plays a role in cellular signaling, metabolism and DNA production and repair. Food sources include chicken, tuna and lentils

  • B5 (Pantothenic Acid): Like other B-vitamins, Pantothenic Acid helps your body obtain energy from food and is also involved in hormone and cholesterol production. Liver, fish, yogurt and avocado are all good sources

  • B6 (Pyridoxine): Pyridoxine is involved in amino acid metabolism, red blood cell production and the creation of neurotransmitters. Foods highest in this vitamin include chickpeas, salmon and potatoes

  • B12 (Methylcobalamin): Perhaps the most well-known of all the B-vitamins, B12 is vital fo neurological function, DNA production and red blood cell development. B12 is found naturally in animal sources like meats, eggs, seafood and dairy

Although many have very similar characteristics, they all have unique functions and are needed in different amounts.

Who needs to take B-Complex?

Since B-vitamins are found in many foods, you are most likely not at risk of developing a deficiency as long as you follow a well-rounded diet. There are some circumstances that increase the need for B-vitamins, making supplementation necessary.

  • Pregnant or Nursing:

    • Pregnancy increases the demand for B-vitamins, particularly B12, which is needed to support fetal development

    • Nursing mothers, especially those following a strict vegetarian or vegan diet have a higher need for B-complex

    • B12 deficiency in pregnant or nursing women can lead to severe neurological damage or birth defects in the fetus or infant

  • Older Adults

    • Aging decreases our ability to absorb vitamin B12 and your appetite declines, making it difficult for some people to get enough B12 through diet alone​

    • Body's ability to release B12 from food for absorption depends on the production of adequate acid in the stomach; 10-30% of people over 50 do not produce enough stomach acid to properly absorb B12

    • Deficiency in B12 has been linked to increase rates of depression and mood disturbances in elderly people.

  • People with certain medical conditions

    • People with Crohn's disease, celiac disease, cancer, alcoholism, hypothyroidism, and anorexia are more susceptible to developing nutrient deficiencies including B-vitamins​

    • People that have gone through gastric bypass for weight loss are also more likely to be deficient in B-vitamins

    • In these circumstances, patients are often advised to supplement with a B-complex vitamin to correct or avoid deficiencies

  • Vegetarians or Vegans

    • Because B12 is naturally found in animal products like meat, dairy, eggs and seafood, vegans and strict vegetarians could be at risk of developing B12 definitely if they don't get enough B12 through fortified foods or supplements​

    • A daily B12 vitamin can help ensure that people who choose to follow strict diets that eliminate animal products are getting enough of the important nutrients 

  • People taking certain medications

    • Commonly prescribed medications can lead to a deficiency in B-Vitamins​ such as proton pump inhibitors that lower stomach acid. It can decrease the absorption of B12

    • Birth control pills can also deplete several B-vitamins including B12, and riboflavin 

Health benefits of taking B-Vitamins

While certain conditions make it necessary for some people to take B-Vitamin supplements, research has shown that taking these supplements may be helpful even for those people who do not have an increased need for these nutrients.

  • May reduce stress and boost mood​

    • studies suggest that B-vitamins can lift your spirits and improve your cognitive performance

    • another study in young adults showed that supplementing with multivitamins containing high levels of B-vitamins for 90 days reduced stress and mental fatigue

  • Reduction of Anxiety or Depression Symptoms

    • B-vitamins are not a cure for mental health issues but they may help improve symptoms of depression or anxiety​

    • enhanced treatment response when given in combination with antidepressant medications

    • one study found that supplementing patients with vitamins containing B12 led to a more enhanced and sustained antidepressant response over one year, compared to a placebo 

Potential side effects

Since B-vitamins are water soluble, it is unlikely that you will consume too much of these nutrients through your diet alone or by taking a supplement as directed. However, taking a supplement in excess could lead to serous side effects. High doses of B3 may lead to vomiting, high blood sugar levels, skin flushing and even liver damage. Furthermore, high doses of B6 can lead to nerve damage, light sensitivity and even painful skin lesions. Another side effect of B-Vitamins is that it can turn urine bright yellow. Although discoloring can be shocking, it is not dangerous but simply your body getting rid of excess vitamins that it can not use. If you need to take supplements, always choose reputable brands that volunteer to have their products independently tested by organizations like US Pharmacopeial Conventions (USP).


Pregnant women, older adults, vegans and those with certain medical conditions may benefit from taking a B-vitamin supplement. Taking these supplements may also improve mood, cognitive function and symptoms of depression. Side effects are unlikely if you follow the recommended dosage, which varies depending on age, nutrient demands, gender and health. If you are not sure if taking a B-vitamin supplement will benefit your health, speak with your doctor to help you determine if it is the right choice for you.


Written by Jillian Kubala, MS,RD, June 7, 2018,

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