The European food safety authority (EFSA) last evaluated vitamins and minerals for safety in 2006 and set a so-called Tolerable Upper Intake Level (UL) for each micronutrient, provided sufficient data were available. This UL reflects the maximum safe level of a micronutrient that will not cause adverse effects when taken daily from all sources for a lifetime.
| The maximum safe daily intake for vitamin B6 is 25 mg. The maximum safe daily intake for vitamin B6 is approximately 18 times the EU recommended daily intake (Nutrient Reference Value, NRV). |
This value applies to adult men and women, as well as pregnant and lactating women. No undesirable side effects have been observed to date due to high intakes of dietary vitamin B6. The data from the NVS II (National Nutrition Survey II, 2008) on the daily intake of vitamin B6 from all sources (conventional diet and dietary supplements) indicate that the safe maximum daily intake of 25 mg is not reached in the German population. Numerous studies have found no negative effects after the intake of large amounts of vitamin B6 over long periods of time. In one study, no undesirable side effects occurred over a period of 8 months to 6 years with daily intakes of 250 to 500 mg of vitamin B6. Similarly, in a study of elderly subjects, no adverse effects were observed with a daily intake of 225 mg of vitamin B6 for one year. Other studies with daily intakes of 150 to 300 mg of vitamin B6 over several months also found no negative effects. In contrast, however, many studies observed adverse effects even at lower doses over longer periods. In addition to the level of vitamin B6 intake, the duration of intake of higher doses is also important for the occurrence of adverse effects. Adverse effects of high vitamin B6 intake develop very slowly over a long period of time. Adverse effects of permanently excessive vitamin B6 intake have been observed primarily in disorders of the nervous system and increased photosensitivity (increased sensitivity to light). Disorders of the nervous system in the form of peripheral neuropathy (disease of the peripheral nervous system) and ataxia (gait disorders) occurred in a study in women with isolated and high-dose administration of 500 to 5,000 mg of vitamin B6 daily over a period of one to three years. Other studies also showed nervous system disturbances with long-term intake of 500 mg daily and with intake of 2,000 mg daily for one year. Daily intakes of 500 to 2,000 mg of vitamin B6 over a period of at least one year are usually necessary to cause adverse effects on the nervous system. In rare cases, mild neurological disorders have been observed with sustained intakes of as little as 50 mg of vitamin B6 per day. Increased photosensitivity (increased sensitivity to light) was noted with daily intakes of up to 2,500 mg of vitamin B6 (35 mg/kg body weight) over a four-year period. In an individual case report, increased photosensitivity also occurred with a daily amount of 200 mg of vitamin B6 as a component of a multivitamin preparation. In summary, it can be stated that significant negative effects are to be expected from a quantity of 500 mg of vitamin B6 per day. Amounts of 200 mg per day, taken over two years, are associated with a low frequency for side effects. At lower amounts around 100 mg of vitamin B6 per day, adverse effects cannot be completely ruled out when taken continuously (over three years). Such amounts are far removed from conceivable intakes via the conventional diet and properly dosed vital substance preparations. A NOAEL (No Observed Adverse Effect Level)-the highest dose of a substance that has no detectable and measurable adverse effects even with continued intake-could not be established because of this inconsistency of data.
