🩸 Vitamin B6 and anemia: when it helps, when it hurts

Perhaps unsurprisingly, I love looking into new “energy” and “hormone balance” supplements, especially being within two years postpartum. I'm always looking to get my energy levels up. It's a constant problem for me and, honestly, the reason I created this newsletter in the first place.

This B6 deep dive was particularly illuminating because it's one of the few vitamins that can actually cause harm if we aren't vigilant about the supplements we're taking and what they actually contain (particularly multivitamins and anything you take for PMS or to regulate hormones in general).

While I'm not really worried about myself because I'm so bad at taking supplements regularly, doing the research this week made me want to be more aware of the individual things in my multivitamins. When I do switch, I want to understand how my intake is changing.

Supplement stacking has become more and more common, and I think we tend to trust brands to know what they're doing. But we still have a responsibility to double-check that what we're taking is actually doing what we need, given our own status and biology.

This deep dive shouldn’t be taken as alarmist. It's one of those things that probably doesn’t affect you, but that's nice to know.

Short answer: Vitamin B6 does almost nothing for your iron function.

In fact, taking too much can actually hurt you.

B6 loads iron into hemoglobin. It’s essential.

But like many other things, supplementing only helps if it’s actually missing.

And it’s really missing only in a rare, inherited anemia — not for an ordinary low iron status.

Your red blood cells hold iron in a ring called heme. Building that ring takes several steps. B6 (in it’s active form called PLP) powers the very first one, an enzyme called ALAS2.

If ALAS2 isn’t working, there’s no heme. If there’s no heme, there’s nowhere for iron to actually sit in your red blood cell.

So B6 doesn’t add iron or help you absorb it, but it’s a critical piece of the assembly line to get things working as they should.

If this first step is stopped, iron gets shipped into the red blood cell…with nowhere to go.

Iron builds up in a ring around the cell’s nucleus, called a ring sideroblast.

Now the cell is stuffed with iron and still anemic. Iron stores look full, but the red blood cells come out small and pale. Iron is there, but the cell can’t use it.

This primarily happens due to a genetic fault: X-linked sideroblastic anemia. Only about 200 cases have ever been described worldwide. In these cases, give a big dose of vitamin B6 and the enzyme starts working again.

It does nothing more for low iron, and nothing more for deficiency that’s developed due to low iron.

Nutrients mentioned earlier in this series is, at worst, wasted money. B6 is different.

Too much causes nerve damage — tingling, burning, and numbness in the hands and feet. In one study, people on 200 mg a day had 2.8 times the risk of those on 150 mg within six weeks.

You need only about 1.3 mg a day, and your diet typically covers that amount.

Here are the safety limits:

This means that supplement stacking without understanding what’s in everything can be problematic.

🧮 Add up the B6 in everything you take: a B-complex, an "energy" or "stress" formula, a PMS supplement, your multivitamin. You need only about 1.3 mg a day.

🚫 Don't buy B6 for low iron or fatigue. It does nothing for ordinary iron. Put the money toward an actual iron panel instead.

🥚 Get your B6 from food. A cup of chickpeas nearly covers a whole day on its own (about 1.1 mg of the 1.3 mg you need). Tuna, salmon, chicken, potatoes and bananas can cover the rest.

Here’s what caught my eye this week:

📄 The hemoglobin level with the lowest death rate sits above the cutoff for “normal”: In 502,188 adults followed 13 years, the lowest death rate was those 1 to 3 g/dL above the anemia cutoff. Passing the test isn't the same as being in the best range, though the researchers say it's too early to move the threshold.

📄 Someone finally read the labels on 201 menopause supplements: Across 201 menopause products from nine UK retailers, most contained the same handful of ingredients. Herbs appeared in 80%, vitamins in 77%, and vitamin B6 alone in 69%, while doses varied wildly and prices ran from £1.50 to £95 a month. The products differ far more in dose and price than in what they actually contain.

📄 Brisk walking came out at least as well as lifting for bone density: Across 124 trials and 18,429 adults over 40, brisk walking and combined cardio-plus-resistance gave the biggest bone-density gains, at about two to three hours a week. More than that added nothing, and walking counted as much as lifting.

Just sharing here what's new this week. No affiliates, no sponsorships, no freebies. A mention here isn't a recommendation.