Table 2.

Assessment subquestions

	Subquestion	Method
sQ1	What is the ADME of the B6 vitamers in humans? Are there differences related to age or other individual factors, e.g. genetic polymorphisms of vitamin B6 metabolism?	Narrative review
sQ2	How does blood PLP, PN, PL, 4‐PA concentration and urinary excretion of 4‐PA and total vitamin B6 reflect ‘high’* vitamin B6 exposure? Is there a biomarker or a combination of biomarkers which is particularly representative for ‘high’ vitamin B6 exposure?	Narrative review
sQ3	What is the dose–response relationship between vitamin B6 intake and the development of peripheral neuropathy in humans? What is the relationship between biomarkers of B6 exposure and the development of peripheral neuropathy in humans? Could a dose‐response be characterised? What are the potential mechanisms/mode(s) of action underlying the relationships between vitamin B6 intake and peripheral neuropathy in humans? What is the dose–response relationship between vitamin B6 intake and the development of peripheral neuropathy in animals?	Systematic review Narrative review
sQ4	Is there a positive and causal relationship between vitamin B6 intake and developmental toxicity (including congenital defects) in humans and animals?	Systematic review
sQ5	What other adverse effects have been reported to be associated with high intake of vitamin B6?	Narrative review
sQ6	What are the levels of vitamin B6 in foods, beverages and food supplements in the EU? What is the distribution of daily vitamin B6 intake from all dietary sources in EU populations and subgroups thereof?	Collection of data based on existing EFSA intake estimates and complementary searches in relevant databases and inquiries to competent authorities of European countries

4‐PA, 4‐pyridoxic acid; ADME, absorption, distribution, metabolism and excretion; PL, pyridoxal; PLP, pyridoxal 5′‐phosphate; PN, pyridoxine; sQ, subquestion.

^*Intakes above the population reference intake.