Mega B

Most people reach for a B complex because they're tired, and the honest conversation is about which of the eight you might actually be short of. These are the questions our naturopaths ask in store.

A good fit if

• You eat little or no animal food and want B12 covered along with the rest of the group
• Your diet is genuinely limited by illness, appetite, allergy or circumstance
• You're choosing a product close to the recommended intakes rather than a high-strength one, and you understand why that matters for B6
• You want the whole group rather than a single B vitamin, and no blood test has pointed to one in particular
• You already take one and want to understand the number on the front of the pack

Check with us first if

• You're looking at a B50 or B100. These give you 50 mg or 100 mg of vitamin B6, at or above the recommended upper limit, so they're worth a proper chat rather than a default choice.
• You've noticed any tingling, burning or numbness in your hands or feet while taking a product with B vitamins.
• You take a statin and the product contains nicotinic acid rather than nicotinamide. Higher death rates from all causes have been reported with that combination.
• You take metformin, a proton pump inhibitor or an H2 blocker, all of which reduce how much vitamin B12 you absorb.
• You're pregnant, planning to be, or breastfeeding. Your needs rise for every B vitamin, and a general B complex isn't a pregnancy formula.
• You already take a multivitamin, a fortified drink or a separate B12. The amounts add up, and folate has a combined limit.
• You have reduced kidney function, or you're choosing something for a child.

• RDI-level B complex. Best known for: Everyday cover at or near recommended daily amounts. Absorption: Usually below the 10 mg vitamin B6 level, so no required warning applies. Typical use: The closest an Australian product can come to the doses used in the homocysteine trial.
• B50. Best known for: The mid-strength option sold for stress and busy times. Absorption: 50 mg of vitamin B6 sits right at the NHMRC upper limit and needs the required warning. Typical use: No trial we hold states a milligram dose, so a B50 can't be matched to an amount that's been studied.
• B100. Best known for: The high-strength end of the shelf. Absorption: 100 mg of vitamin B6 is the Australian legal maximum for an adult, and double the upper limit. Typical use: No trial we hold supports 100 mg of B6 for any benefit; at that level, the evidence points to harm.
• Activated or methylated B complex. Best known for: P5P instead of pyridoxine, methylfolate instead of folic acid, methylcobalamin instead of cyanocobalamin. Absorption: No head-to-head evidence we hold shows any activated form works better than the standard one. Typical use: Australia applies the same B6 cap and warning to P5P, and the same 500 µg folate cap to methylfolate.
• B complex with added herbs or minerals. Best known for: B vitamins combined with things like passionflower, valerian, magnesium or iron. Absorption: Not tested separately; the added ingredients bring their own caps and warnings. Typical use: Check the full label. A combination product can double up on amounts you're already getting elsewhere.

Reference values. Adult Recommended Dietary Intakes are small: thiamin 1.2 mg for men and 1.1 mg for women, riboflavin 1.3 and 1.1 mg, niacin 16 and 14 mg niacin equivalents, B6 1.3 mg for both, folate 400 µg dietary folate equivalents, and B12 2.4 µg. Pantothenic acid and biotin have an Adequate Intake rather than an RDI: 6.0 and 4.0 mg, and 30 and 25 µg. Every one of these rises in pregnancy, folate most sharply, from 400 to 600 µg.

Typical supplemental range. Products are usually labelled B50 or B100, meaning roughly 50 mg or 100 mg of each of the B vitamins measured in milligrams. Compared with an adult B6 requirement of 1.3 mg, a B100 is about seventy-seven times the reference value. For thiamin, riboflavin, B5, biotin and B12, that kind of multiple has no known risk, because no upper limit could be set. For B6 it does, which is why it's worth reading the number rather than the strength name.

Upper level. Only three of the eight have an NHMRC upper limit: vitamin B6 at 50 mg a day, folate at 1,000 µg of folic acid from fortified foods or supplements only, and niacin with two separate figures (35 mg as nicotinic acid from supplements and fortified foods, and 900 mg as nicotinamide from all sources). No upper limit could be set for thiamin, riboflavin, pantothenic acid, biotin or B12. That means there wasn't enough evidence, not that any dose is safe.

Worth knowing. The Australian legal limit and the NHMRC upper limit are different numbers with different jobs, and for vitamin B6 they disagree: Australia's permitted ingredients list (Schedule 1) allows up to 100 mg in an adult listed medicine, while the upper limit is 50 mg. What you need depends on your age, diet and health, so talk to one of our naturopaths.

If any of these sound like you, talk to one of our naturopaths or your doctor before you start.

• You take more than 10 mg/day of vitamin B6. Australian labels must warn about this; high intake over a long time causes nerve damage, mostly affecting feeling in the hands and feet.
• You're looking at B50 or B100 products. 50 mg sits right at, and 100 mg at double, the NHMRC upper limit of 50 mg/day.
• It's for a child. Schedule 1 sets lower B6 caps for each age group (15/20/30/40 mg), so adult products aren't suitable.
• You take nicotinic acid with a statin. Higher death rates from all causes have been reported.
• You take nicotinic acid at all. The NHMRC upper limit is 35 mg/day from supplements and fortified foods, compared with 900 mg/day for nicotinamide.
• You're pregnant or breastfeeding. Your needs rise for all eight, and a general B complex usually can't make the folic acid pregnancy claim.
• You take high folate and might have an undiagnosed B12 deficiency. This is a possible concern still being researched, not an established clinical finding.
• You take metformin, proton pump inhibitors or H2 blockers. All of these reduce vitamin B12 absorption.
• You've had bariatric (weight-loss) surgery. B1, B12 and folate deficiency are common and need medical care, not self-treatment.
• You already take a multivitamin or eat fortified foods with the same vitamins. Don't double up with a B complex.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before you start.