While most B vitamins have a low potential for toxicity, some can lead to adverse effects if consumed in large quantities:
- Vitamin B3 (Niacin): High doses can cause flushing, itching, nausea, and liver toxicity. Niacin toxicity is more common when using supplements. - Vitamin B6 (Pyridoxine): Prolonged high intake can lead to severe nerve damage, causing symptoms like numbness and difficulty walking. - Vitamin B9 (Folate): Excessive folic acid intake may mask the symptoms of vitamin B12 deficiency, potentially leading to nerve damage. - Vitamin B12 (Cobalamin): Although rare, excessive intake can cause acne and rosacea in susceptible individuals.
