The Benefits of B Complex Vitamins

Healthy B vitamin rich foods
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A B complex vitamin is a dietary supplement that delivers all eight of the B vitamins: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6, B7 (biotin), B9 (folate), B12. Also found naturally in a number foods, B complex vitamins play an important role in health, such as helping the body to produce energy and form red blood cells.

Why Do People Take B Complex Vitamins?

People at risk for multiple vitamin B deficiencies include older adults, vegetarians or vegans, and those with alcoholism, heart failure, or recent obesity surgery.

B vitamin deficiencies may be linked to depression, psychiatric disorders, memory function, cognitive impairment, and dementia. 

Proponents claim that B complex vitamins can help with a variety of health conditions, including acne, anxiety, depression, fatigue, heart disease, premenstrual syndrome, and skin problems.

In addition, many people take a B complex vitamin to increase energy, support brain health, enhance mood, improve memory, ease stress, stimulate the immune system, and boost hair and skin health.

The Benefits of B Complex Vitamins

Proponents suggest that taking a B complex vitamin may help treat or prevent certain health problems. Often touted as natural immune boosters and mood-lifters, B complex supplements are also said to enhance heart health, alleviate anxiety, and soothe skin disorders.

Each B vitamin is essential to certain bodily functions:

  • B1 and B2 are important for healthy functioning of the muscles, nerves, and heart. B1 helps the body make new cells and B2 is important for red blood cell production and fighting free radicals.
  • B3 helps regulate the nervous and digestive systems and helps convert food into energy
  • B5 breaks down fats and carbohydrates for energy and is responsible for the production of hormones. B5 and B12 are required for normal growth and development
  • B6 supports the immune system, helps the body produce hormones, and aids the body in breaking down protein
  • B7 is involved in the production of hormones
  • B9 helps cells make and maintain DNA and promotes the growth of red blood cells
  • B12 helps regulate the nervous system and plays a role in red blood cell formation
  • B6, B9, and B12 help to regulate levels of the amino acid homocysteine (an amino acid thought to contribute to heart disease when it occurs at elevated levels)

Studies suggest that taking supplements containing certain B vitamins may benefit your health. For instance:

  • B1 may help prevent kidney disease in people with type 2 diabetes and reduce the risk of cataracts
  • B2 may prevent migraines; B3 may boost HDL cholesterol and lower cholesterol levels
  • B6 may protect against heart disease, relieve PMS symptoms, and alleviate pregnancy-related nausea
  • B7 is associated with healthy skin, hair, and nails
  • B9 may help prevent breast cancer, colorectal cancer, and pancreatic cancer, as well as decrease risk of birth defects when taken by pregnant women
  • B12 may prevent confusion in older adults and reduce levels of homocysteine

Although few studies have tested the effects of taking a B complex supplement, in recent years, several studies have shown that B vitamins can help with a host of health conditions.


Although the function of the eight B vitamins are closely related, much of the research as focused on vitamins B6, B9, and B12, vitamins that play a key role in the metabolism of homocysteine. 

B vitamin supplementation (folic acid and vitamins B6 and B12) may help protect against cognitive decline. For example, in a 2014 study in Nutrition Journal suggests that B vitamin intake is associated with cognitive function in cognitively impaired older adults with Alzheimer's disease or mild cognitive impairment. 

In a study published in the American Journal of Clinical Nutrition in 2015, researchers found that supplementation slowed brain atrophy, but only in those with high levels of omega-3 fatty acids (as measured by MRI).

However, other research indicates that taking B complex supplements may not protect against certain conditions. A 2015 study in the British Journal of Psychiatry found that long-term supplementation with vitamins B6 and B12 and folic acid didn't reduce overall depression risk in midlife and older women.

Food Sources of B Complex Vitamins

To boost your intake of B vitamins, look for the following foods:

  • B1 (thiamine): Whole grains and breakfast cereals
  • B2 (riboflavin): Almonds, Brussels sprouts, cereals, chicken, fish, green leafy vegetables, kidney beans, eggs, soybeans, spinach, turkey, yogurt, wild rice
  • B3 (niacin): Chicken, eggs, fish, nuts, red meat, whole grains, yeast
  • B5 (pantothenic acid): Avocados, eggs, legumes, meat (vitamin B5 is found in almost all foods)
  • B6 (pyridoxine): Bananas, beans, beef, brown rice, chicken, chickpeas, carrots, cheese, lentils, papayas, potatoes, salmon, spinach, sunflower seeds, tuna, turkey, whole grain cereals
  • B7 (biotin): Bananas, barley, chicken, cauliflower, egg yolks, fish, mushrooms, milk, nuts, oats, pork, potatoes, Swiss chard, liver, yeast
  • B9 (folate): Asparagus, beans, beets, broccoli, bulgur wheat, chicken, citrus fruits, nuts, dark leafy greens, salmon, whole grains
  • B12 (cobalamin): Eggs, cheese, beef, fish, milk, shellfish

Possible Side Effects

Although B complex supplements are water-soluble (making the risk of overdose low), they may cause certain side effects, such as skin problems and an increase in blood sugar levels, or interact with medications. 

The Bottom Line

To stay healthy, most people can get what they need by eating a well-balanced diet filled with a combination of B vitamins. If you're not getting enough B vitamins from your diet, taking B complex vitamins may be beneficial for some people. Deficiency in B vitamins can cause a number of symptoms, including tiredness, anemia, loss of appetite, depression, abdominal pain, muscle cramps, hair loss, and eczema. Consult your health care provider to find out whether a B complex supplement is right for you.


Clarke R, Bennett D, Parish S, et al. Effects of homocysteine lowering with B vitamins on cognitive aging: meta-analysis of 11 trials with cognitive data on 22,000 individuals. Am J Clin Nutr. 2014 Aug;100(2):657-66. 

Dong H, Pi F, Ding Z, Chen W, Pang S, Dong W, Zhang Q. Efficacy of Supplementation with B Vitamins for Stroke Prevention: A Network Meta-Analysis of Randomized Controlled Trials. PLoS One. 2015 Sep 10;10(9):e0137533.

Jernerén F, Elshorbagy AK, Oulhaj A, Smith SM, Refsum H, Smith AD. Brain atrophy in cognitively impaired elderly: the importance of long-chain ω-3 fatty acids and B vitamin status in a randomized controlled trial. Am J Clin Nutr. 2015 Jul;102(1):215-21. 

Kim H, Kim G, Jang W, Kim SY, Chang N. Association between intake of B vitamins and cognitive function in elderly Koreans with cognitive impairment. Nutr J. 2014 Dec 17;13(1):118. 

Okereke OI, Cook NR, Albert CM, Van Denburgh M, Buring JE, Manson JE. Effect of long-term supplementation with folic acid and B vitamins on risk of depression in older women. Br J Psychiatry. 2015 Apr;206(4):324-31. 

Disclaimer: The information contained on this site is intended for educational purposes only and is not a substitute for advice, diagnosis or treatment by a licensed physician. It is not meant to cover all possible precautions, drug interactions, circumstances or adverse effects. You should seek prompt medical care for any health issues and consult your doctor before using alternative medicine or making a change to your regimen.

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