What are B vitamins, and what exactly do they do?
B vitamins are a group of eight water-soluble vitamins that work together in the body. They share a common purpose: to convert food (carbohydrates, fats, and proteins) into energy that cells can use, and to maintain proper nervous system function. Each has its own specific role, but it is their collective action that makes the difference—which is why B-complex supplements combining several B vitamins are often more effective than taking each vitamin separately. B-vitamin formulas are available in the store.
- B1 (thiamine): converts carbohydrates into energy—essential for the nervous system—a deficiency causes beriberi and Wernicke’s syndrome in alcoholics
- B2 (riboflavin): plays a role in the energy production chain in the mitochondria and protects cells from oxidative stress—deficiency is often asymptomatic but may sometimes manifest as chapped lips or sensitivity to light in the eyes
- B3 (niacin/niacinamide): a coenzyme essential for more than 400 enzymatic reactions—including energy production, DNA repair, and immune cell function—a deficiency causes pellagra (affecting the skin, digestion, and nervous system)
- B5 (pantothenic acid): a component of coenzyme A—necessary for the synthesis of steroid hormones and cholesterol, and for fat metabolism—found in almost all foods (its name comes from the Greek word for “everywhere”)
- B6 (pyridoxine): cofactor for more than 100 enzymes—synthesis of neurotransmitters (serotonin, dopamine, GABA)—formation of red blood cells—regulation of homocysteine—increased requirements when taking oral contraceptives
- B7/B8 (biotin): fat and sugar metabolism—healthy hair, skin, and nails—essential during pregnancy for fetal development
- B9 (folic acid/folate): DNA synthesis and cell division — critical before and during pregnancy (prevention of neural tube defects) — regulation of homocysteine levels alongside B6 and B12
- B12 (cobalamin): nerve myelination — red blood cell formation — the only B vitamin absent from plants — severe deficiency that often goes unnoticed for years in vegans
Why are B vitamins so often deficient?
- Modern diets destroy them: B vitamins are heat-sensitive and water-soluble — prolonged cooking in water eliminates 30 to 70% of the B vitamins in foods — refining grains (white flour, white rice) removes 70 to 90% of their B1, B3, and B6 content — ultra-processed foods are practically devoid of them
- Stress depletes them significantly: vitamins B6, B5, and B1 are directly involved in the stress response—chronic stress increases the body’s needs and accelerates their depletion—it’s a vicious cycle: stress depletes B vitamins, and a lack of B vitamins amplifies sensitivity to stress
- Certain medications block or deplete them: oral contraceptives (B6, B9, B12 ↓)—metformin (B12 ↓—up to 30% of diabetics on metformin develop a deficiency) — PPIs (B12 ↓) — certain antiepileptic drugs (B6, B9 ↓) — chronic alcohol use (B1, B2, B3, B6, B9, B12 — all affected)
- Vegans and vegetarians are particularly at risk: B12 is absent from plant foods — systematic supplementation is essential — B2 and B3 are also less abundant in strict plant-based diets
- Older adults absorb B12 less efficiently: B12 absorption requires the “intrinsic factor” produced by the stomach — as people age, gastric secretion decreases — furthermore, PPIs, which are common among seniors, exacerbate this deficiency—regular blood testing for B12 is recommended after age 60
What signs indicate a B-vitamin deficiency?
- Persistent fatigue for no apparent reason: B vitamins are essential for ATP production (cellular energy)—without them, cells function at a reduced rate even if you sleep well and eat a balanced diet—fatigue is often the first sign of a subclinical deficiency
- Nervous and cognitive disorders: tingling in the hands and feet (B12 neuropathy)—difficulty concentrating and with memory—irritability—mild depression—vitamins B6, B9, and B12 regulate homocysteine, an amino acid that, in excess, is toxic to neurons and increases the risk of cognitive decline and neurodegenerative diseases
- Anemia: B12 and folate (B9) are essential for the normal formation of red blood cells—a deficiency results in abnormally large red blood cells that function poorly (megaloblastic anemia)—symptoms: pale complexion, shortness of breath, palpitations, severe fatigue
- Skin, Hair, and Nails: Cracks at the corners of the mouth (B2, B3) — scaly or oily skin (B2, B6) — excessive hair loss (biotin B7) — ridged and brittle nails (B7) — topically applied B3 (niacinamide) is, in fact, one of the most widely used active ingredients in skincare — see our page dedicated to niacinamide
- Pregnancy: A deficiency in B9 (folate) during the first weeks of pregnancy significantly increases the risk of spina bifida and other neural tube defects — supplementation with folic acid (400 µg/day) should begin at least one month before conception — Vitamin B12 is also essential for the fetus’s neurological development
How can you ensure you’re getting enough B vitamins?
- The best dietary sources: brewer’s yeast (all B vitamins except B12—the most complete source)—chicken liver (B1, B2, B3, B5, B6, B9, B12—exceptionally rich)—eggs (B2, B7, B12)—lean meats and fatty fish (B1, B3, B6, B12) — legumes (B1, B6, B9) — dark green vegetables (B9, B2) — whole grains (B1, B2, B3, B6)
- Vegans: Vitamin B12 is non-negotiable —no plant contains it in significant quantities—algae and fermented products contain inactive analogs that do not meet dietary needs—supplementation is mandatory: sublingual methylcobalamin 1,000 µg 2–3 times a week or 250 µg daily — get a blood test every 6 to 12 months
- B-complex or isolated B vitamins?: B vitamins work together as a network—taking only B12 or B6 without the others can create imbalances—a complete B-complex (B1+B2+B3+B5+B6+B7+B9+B12) is preferable for fatigue, stress, and overall nervous system health—isolated B vitamins in high doses are useful for specific purposes (B9 for pregnancy, B12 for vegans, thiamine for alcoholism)
- Combine with magnesium: magnesium and B vitamins share the same targets—together they regulate neurotransmitters, energy production, and the stress response—the magnesium + B-complex combination is the foundation of anti-stress and anti-fatigue supplements
- Precautions to be aware of: High doses of B6 (>50 mg/day for several months) can cause peripheral neuropathy — High doses of B3 (niacin > 500 mg) cause hot flashes and may affect the liver — High doses of B9 may mask a B12 deficiency — Always follow the recommended doses listed on the labels of B-vitamin supplements
