B-Complex: The 12 Powerful Benefits Of The Vitamin Group

Reviewed By Merlin Annie Raj, MSc (Nutrition & Dietetics), RD
Written by Ravi Teja Tadimalla

B-complex is a group of eight essential water-soluble vitamins that serve different roles in the body. These are found in a wide variety of everyday foods. There is extensive research done on this vitamin group.

Studies show that these vitamins can promote brain health by stimulating the synthesis of various neurochemicals (1). The science behind the working of the B-complex vitamins is actually simple.

In this post, we will explore the various parts of research that tell us how this vitamin group can benefit your health.

What Is The Vitamin B-Complex?

This vitamin group consists of eight vitamins:

  • B1 (Thiamine)
  • B2 (Riboflavin)
  • B3 (Niacin)
  • B5 (Pantothenic acid)
  • B6 (Pyridoxine)
  • B7 (Biotin)
  • B9 (Folate/Folic acid)
  • B12 (Cobalamin)

These vitamins are most commonly found in everyday foods like seeds, meat, eggs, and vegetables (2). Each of these B vitamins has a specific benefit. In the following section, we will delve into the health benefits these nutrients offer.

What Are The Health Benefits Of B Vitamins?

B vitamins promote nerve health, thereby possibly improving brain function. They also boost heart health and immunity. Studies show that folate (vitamin B9) helps prevent birth defects during pregnancy.  

1. May Promote Brain Health


B vitamins have been found to impact the central nervous system. More specifically, vitamins B6, B12, and folate have been linked to better cognitive health in the elderly (3).

Individuals dealing with dementia were also found to have lower serum levels of B vitamins (especially folate and vitamin B12) (3).

In another study, higher concentrations of vitamin B6 were found to have better effects on an individual’s memory (4).

Folic acid and vitamin B12 may also aid depression treatment. Subjects with depressive tendencies were found to have lower levels of these two vitamins. Low serum folate levels are also found in patients with frequent mood disorders (5).

Interestingly, countries with a high folate intake (Hong Kong and Taiwan) were found to have lower rates of major depression among their populations (5).

B vitamins were also found to relieve anxiety and stress in certain workplace populations (6).

2. May Boost Nerve Function

Vitamin B12 has been linked to nerve regeneration. In rat studies, this vitamin was found to promote nerve regeneration in the event of peripheral nerve injury (7).

Vitamin B12 also scavenges the reactive oxygen species. It has an anti-apoptotic and anti-necrotic (preventing the early death of cells) effect on the brain’s neurons. It even increases the regeneration of axons (7).

Vitamin B12 is responsible for the improved function of nerve cells as well as their development (8).

A deficiency in vitamin B12 can also lead to neuropathy or nerve damage. The vitamin also preserves the myelin sheath, which is the protective covering around the body’s nerves (9).

3. May Improve Cardiovascular Health

B vitamins help replenish various energy stores in the body. A deficiency in these vitamins can lead to reduced energy stores, which have been linked to myocardial dysfunction in patients with heart failure (10).

Folic acid and vitamin B12 were found to have potential as heart disease treatments. While the former lowered homocysteine levels by 25 percent, the addition of the latter further lowered the levels by another 7 percent (11).

Homocysteine is an amino acid occurring in the body, high levels of which have been linked to heart disease (11).

Deficiency of vitamin B1 can lead to beriberi, a disease characterized by inflammation of the nerves and subsequent heart failure (12).

4. May Boost Immunity

The group of B vitamins has been identified as those that keep the immune system healthy (13).

Certain animal studies also show that a deficiency of vitamin B6 may lead to undesirable changes to immune responses (14). However, more research on humans is warranted in this regard.

Folate may also boost immunity, although we need more research at the moment. Folate plays a role in the process of production and repair of DNA and may have an impact on the immune system. Though folate deficiency was found to impair immunity in animals, similar effects are yet to be observed in humans (15).

5. May Help Treat Anemia

B vitamins are known to treat different forms of anemia. While folate and vitamin B12 can treat and prevent megaloblastic anemia (characterized by very large red blood cells and decrease in their number), vitamin B6 can treat sideroblastic anemia (characterized by the production of ringed blood cells instead of healthy red blood cells) (16).

Vitamin B12 is critical for making red blood cells, which, in turn, carry oxygen to all parts of the body. A deficiency of vitamin B12 can cause the most common form of anemia, called pernicious anemia (characterized by a lack of enough healthy red blood cells) (17).

6. May Promote Eyesight


A deficiency in B-complex vitamins was linked to a defective vision. In a study carried out on school children, supplementation with B-complex vitamins was noted to improve their visual acuity (18).

A deficiency of vitamin B12 may also lead to optic neuropathy. In a study involving an elderly male with decreased central vision (who was deficient in vitamin B12), supplementation of vitamin B12 was found to improve the condition (19).

In another study, a combination of vitamins B6, B12, and folate was found to reduce the development of age-related macular degeneration over a period of seven years (20).

7. May Aid Digestive Health

There is some research stating that dexpanthenol, a derivative of vitamin B5 (pantothenic acid), may ease constipation (21).

B vitamins have been found to have various benefits on the digestive system. Vitamin B12 deficiency was observed in several cases of liver diseases, including cirrhosis and hepatitis. It also may have a role to play in reducing the severity of stomach ulcers (and even canker sores) (22).

In patients with irritable bowel syndrome, supplementation with vitamin B1 over 20 days reduced most of the symptoms, including fatigue (23).

Vitamins B6, B9, and B12 were found to help prevent gastrointestinal cancer. In animal studies, vitamin B6 was found to prevent oxidative stress, thereby potentially combating colorectal cancer (24).

Dietary folate may also help prevent pancreatic cancer (25).

8. May Improve Hormonal Health

B-complex vitamins are involved in the metabolism and activity of estrogen (26). Vitamin B6 has been linked to the regulation of anterior pituitary hormones (27). However, research is limited here. More scientific evidence is warranted.

9. May Help Relieve Migraines

Vitamin B2 supplementation was found to relieve migraines in both adults and children. The nutrient may reduce the frequency and duration of migraine attacks with no adverse effects (28).

Other sources also quote vitamin B2 to be effective in treating migraine headaches (29). The mechanism behind how this vitamin works to treat migraines is still unclear, and more research is warranted.

10. Can Promote Healthy Pregnancy

Folate (vitamin B9) could be the most important B vitamin to be taken during pregnancy. The nutrient is known to prevent birth defects in infants (30).

As per the World Health Organization, vitamin B6 also plays a major role during pregnancy. It was found to prevent pre-eclampsia (a dangerous pregnancy complication accompanied by very high blood pressure) and preterm birth (31).

Maternal supplementation with vitamin B12 during pregnancy was found to cut the risk of B12 deficiency in the infant, in addition to further promoting its health (32).

11. May Promote Wound Healing

In studies conducted on diabetic mice, B vitamins were found to improve wound healing (33).

In another study, B vitamins (along with vitamin C) were found to influence human keratinocytes and fibroblasts positively. This way, the vitamins can promote the wound healing process (34).

12. May Help Relieve Symptoms Of Premenstrual Syndrome

High intake of vitamins B1 and B2 was found to reduce the risk of premenstrual syndrome, especially when the vitamins came from natural food sources (35).

In another study, intake of vitamin B6 (up to 100 mg per day) was found to treat premenstrual syndrome, including premenstrual depression (36).

These are the many benefits of the B-complex vitamins. As discussed, they have several roles to play in the human body system. Each of those B vitamins serves a specific purpose. Though B vitamin deficiency could be rare, it is important to understand which foods offer most of those vitamins.

What Are The Richest Sources Of B Vitamins?

Here we have collated the top 10 foods that contain most of the B-complex vitamins.



RDA = 1.2 mg



RDA = 1.3 mg



RDA = 16 mg


(Pantothenic Acid)

RDA = 5 mg



RDA = 1.4 mg



RDA = 300 mcg



RDA = 400 mcg



RDA = 2.4 mcg

Wild cooked salmon (1/2 fillet = 154 g)28%44%78%30%73%11%78%
Hulled, roasted sunflower seeds (1 cup = 128 g)9%19%45%90%51%76%
Cooked kidney beans (1 cup = 177 g)19%6%5%4%11%58%
Cooked spinach (1 cup = 180 g)11%25%4%3%22%1%66%
Ground beef (3 oz = 85 g)2%9%22%5%15%1%35%
Whole milk (1 cup = 244 g)7%26%1%9%4%3%18%
1 large, hard-boiled egg (50 g)2%15%7%3%3%5%9%
Cooked millet (1 cup = 174 g)12%8%12%3%9%8%
Cooked brown rice (1cup = 195 g)13%1%13%8%15%2%
Cooked barley

(1 cup = 157 g)


Source: United States Department of Agriculture, Food Composition Databases

*The values correspond to the daily value of a particular nutrient that the food source meets. 

Including these foods in your daily diet should take care of your B-vitamin needs. This way, you would rarely become deficient in B-complex vitamins. But, the question is, how would you know if you are deficient?

What Are The Symptoms Of A Deficiency Of B-Complex Vitamins?

Following are the symptoms of a B-vitamin deficiency. If you experience any of these, please visit your doctor:

  • Weakness
  • Extreme fatigue
  • Confusion
  • Tingling in the feet and hands
  • Nausea
  • Anemia
  • Skin rashes
  • Abdominal cramps

Your doctor may also recommend a supplement. Are supplements required?

A Note On B Vitamin Supplements

Whether these supplements are necessary or not depends on a number of factors. Most people should be able to meet the required amounts of B vitamins by following a balanced diet plan.

However, pregnant women, vegetarians, vegans, older adults, and those who have undergone gastric surgeries may need to take supplements. They may need to take vitamin B12, along with other B-complex vitamins. The combination depends on the person.

During pregnancy, there is a higher demand for B vitamins (especially folate and vitamin B12) (37).

Studies show that about 30% of older adults may not be able to properly absorb vitamin B12 as they do not produce enough stomach acid required for the absorption (38).

Vegetarians and vegans may also need to take supplements as their diet may not include all of the foods rich in B vitamins (39).

Even those with certain medical conditions might need to take B vitamin supplements. These include:

  • Those with celiac disease (40)
  • Those with inflammatory bowel disease (41)
  • Those with hypothyroidism (42)
  • Those undergoing cancer treatment (43)
  • Those diagnosed with chronic alcoholism (44)
  • Those who have undergone gastric bypass surgery (45)

What Are The Symptoms Of An Overdose Of B-Complex Vitamins?

B vitamins are water-soluble. The vitamins are not stored in your body but are excreted daily. Hence, it is highly unlikely you may overdose on B-complex vitamins.

However, it is important to know the symptoms of an overdose. These may include the following:

  • Blurry vision
  • Abdominal cramps
  • Nausea
  • Diarrhea
  • Increased urination
  • Excessive thirst


B-complex vitamins are essential. Start including the food sources in your diet today. If you still experience any symptoms of deficiency, consult your doctor.

How many of the foods rich in B vitamins do you consume regularly? Do let us know by leaving the list in the box below.  

Frequently Asked Questions

What is the best time to take a vitamin B-complex supplement?

Taking B vitamins after waking up could be the best time. Taking them on an empty stomach may improve their absorption. Check with your doctor, though.

Does vitamin B-complex make you gain weight?

No, taking vitamin B-complex supplements will not make you gain weight. Also, there is no information if these vitamins can help you lose weight. Most probably, they may not.

Do B-complex vitamins boost energy?

There is no research stating that taking B-complex vitamins can boost your energy levels. They definitely are not stimulants like caffeine.


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Ravi Teja Tadimalla is an editor and a published author. He graduated from SRM University, Chennai, and has been in the digital media field for over six years. He has a Professional Certificate in Food, Nutrition & Research from Wageningen University. He considers himself a sculptor born to chip away at content and reveal its dormant splendor. He started his career as a research writer, primarily focusing on health and wellness, and has over 250 articles to his credit. Ravi believes in the great possibilities of abundant health with natural foods and organic supplements. Reading and theater are his other interests.