B Vitamins (B-Complex) – General Overview

B vitamins are the behind-the-scenes “helpers” your body uses every day to turn food into energy and support systems like your nervous system, skin, eyes, hair, liver, mouth, and muscles.  In supplement aisles, you’ll often see “B-complex,” which usually means a blend that includes (at minimum) B1, B2, B3, B5, B6, B7, B9, and B12.  

B1 (Thiamine)

You’ll often hear about thiamine when people talk about energy and nerve support.  B1 is reported to support heart function and circulation, help with blood formation, improve carbohydrate metabolism and digestion, and maintain cognitive and liver function.  

Food sources (common):

• Whole grains (brown rice, whole wheat/wheat germ), oatmeal
• Meat & seafood (pork, poultry, fish; organ meats such as liver)
• Egg yolks and legumes (beans/peas)
• Nuts and seeds (including sunflower seeds)
• Vegetables (broccoli, Brussels sprouts, asparagus)
• Fruit & other (plums/prunes/raisins, brewer’s yeast)

B1 – thiamine – absorption may be inhibited by antibiotics, advanced age, phenytoin (an anti-seizure medication), sulfa drugs, oral contraceptives, and heavy alcohol/caffeine use.

Normal dosing is 100–600 mg/day under medical guidance.  Spray or sublingual forms may be easier to absorb for some people (for example, older adults or people with malabsorption).

Some supplement options you may see include:

• Thiamine HCl
• Benfotiamine
• Thiamine tetrahydrofurfuryl disulfide (TTFD)

B2 (Riboflavin)

Riboflavin (B2) is one of those quiet “workhorse” vitamins—supporting red blood cell formation, antibody production, musculoskeletal growth, vision health, nutrient metabolism, a healthy digestive tract, improved iron absorption, and healthy skin and nails.

Possible signs of deficiency include dermatitis, hair loss, dizziness, insomnia, light sensitivity, poor digestion, reduced mental capacity, and reduced physical performance.

Food sources include

• Dairy (milk, yogurt, cheese)
• Meat, poultry, and fish
• Eggs
• Legumes and whole grains
• Vegetables (spinach, asparagus, broccoli, Brussels sprouts)
• Nuts and mushrooms

Vigorous exercise and oral contraceptive use may increase the need for B2.  Taking more than 50 mg/day for long periods may lead to vision issues such as cataracts or retinal disease.

Some supplement options may include:

• Riboflavin
• Riboflavin-5-phosphate (R-5-P)
• B-complex (as a source of B2)

B3 (Niacin: Nicotinic acid / Niacinamide)

B3 is one of the more talked-about B vitamins.  B3 is reported to support many bodily functions including – maintaining skin integrity, boosting energy levels, supporting circulation and nervous system function, improving cognition, and increasing nutrient metabolism.

Low levels of B3 may result in canker sores, depression, dementia, diarrhea, dizziness, fatigue, halitosis, headache, indigestion, insomnia, extremity pain, poor appetite, low blood sugar, muscular weakness, skin eruptions, and inflammation.

Food sources (common):

• Meat and fish (including organ meats like liver)
• Poultry and eggs
• Dairy
• Whole grains (whole wheat products, wheat germ)
• Vegetables (potatoes, tomatoes, carrots, broccoli)
• Nuts and brewer’s yeast

High doses of vitamin B3 (more than 500 mg/day) can cause liver damage.  People with diabetes, glaucoma, gout, liver disease, and/or peptic ulcers should consult a healthcare provider before using vitamin B supplements.

Some supplement options you may see include:

• Nicotinic acid (niacin)
• Niacinamide (nicotinamide)
• Inositol hexanicotinate (“no-flush niacin”)

B5 (Pantothenic Acid)

B5 – pantothenic acid – supports the production of adrenal hormones, antibody formation, vitamin metabolism, and helps convert dietary nutrients into energy.  It has been mentioned to help support normal red blood cell formation, and address possible mental health conditions.

Food sources (common):

• Meats & seafood – especially beef, pork, lobster, saltwater fish, organ meats
• Dairy and eggs
• Legumes, nuts, and mushrooms
• Vegetables (broccoli and other fresh vegetables)
• Sweet potatoes
• Whole grains (whole wheat, whole rye flour)

A deficiency in B5 may be evidenced by fatigue, headache, nausea, and peripheral neuropathy (numbness and/or tingling in the extremities).

Some supplement options you may see include:

• Pantothenic acid (often as calcium pantothenate)
• Pantethine
• B-complex (as a source of B5)

B6 (Pyridoxine)

B6 – pyridoxine is involved in over 100 functions in the body, including hormone regulation, red and white blood cell formation, brain function, immune support, and RNA/DNA-related processes.

Key functions mentioned in the source include:

• Facilitating the production of hydrochloric acid necessary for the absorption of fats and proteins
• Essential in maintaining sodium/potassium balance
• Promotes red and white blood cell formation
• Supports normal brain function
• Integral in the synthesis of RNA and DNA (the genetic blueprint for the reproduction of all cells)
• Activates specific enzymes necessary for the absorption of Vitamin B12
• Supports normal immune function 
• Necessary in the production of dopamine and serotonin
• Supports cardiovascular health

Food sources (common):

• Meat, poultry, and fish
• Eggs
• Legumes (beans, peas, soybeans)
• Nuts and seeds (sunflower seeds, walnuts)
• Whole grains (brown rice, wheat germ)
• Vegetables (spinach, broccoli, cabbage, potatoes, carrots)
• Fruit (avocados, bananas, cantaloupe)

B6 deficiencies can contribute to a wide range of neurological and skin-related symptoms.  

Estrogen replacement therapy, diuretics, and cortisone-based medications may increase the need for B6.  Prolonged intake of high doses (over 1,000 mg/day) can be toxic and may cause nerve damage and/or loss of coordination.

Some supplement options you may see include:

• Pyridoxine HCl
• Pyridoxal-5-phosphate (P-5-P)
• B-complex (as a source of B6)

B7 (Biotin)

Biotin is commonly included in B-complex and “hair/skin/nails” formulas.

Some supplement options you may see include:

• Biotin
• B-complex (as a source of biotin)
• Hair/skin/nails formulas (often include biotin as one ingredient)

B9 (Folate / Folic Acid)  

Folate is a core B vitamin that shows up in many multivitamins and B-complex blends.

Some supplement options you may see include:

• Folic acid
• L-methylfolate (5-MTHF)
• Folinic acid (calcium folinate)

B12 (Cobalamin)

B12 is one of the most important B vitamins.  B12 (Cobalamin) supports nerve cells and fibers, helping form RNA and DNA, supporting cognitive function, and contributing to cardiovascular and eye health.  Here is a list of some other functions

• Protection of the nervous system, especially against deterioration due to aging.
• Supports normal neurological function.
• Supports normal red blood cell formation.  
• Aids in the proper metabolism of carbohydrates and fats.
• Has been studied for its role in sleep-wake regulation.

Food sources (common):

• Meat including organ meats such as liver and kidneys
• Poultry
• Seafood especially clams, herring, mackerel
• Eggs
• Dairy products

Malabsorption of B12 is common in older adults and people with digestive disorders.  This can result in symptoms including abnormal gait, bone demineralization, fatigue, depression, digestive disorders, dizziness, enlarged liver, vision impairments, headaches, memory loss, moodiness, nervousness, palpitations, pernicious anemia, tinnitus, and spinal cord deterioration.

Anti-gout medications, anticoagulants, and potassium supplements may block B12 absorption.  It also notes that sublingual tablets, injections (prescription only), and sprays may be options for people with malabsorption issues, and mentions the Schilling test as a way to assess B12 absorption.

Some supplement options you may see include:

• Cyanocobalamin
• Methylcobalamin
• Adenosylcobalamin (dibencozide)

If you’re feeling overwhelmed by all the different forms and dosages, you’re not alone—please consult your healthcare professional before beginning any dietary supplement.  Your safety is always the most important concern.