13 replies to this topic

[dunbar]

I was thinking about getting a high dosed B complex.
But on the Linus Pauling site I read this here:

When high doses of vitamin B₁₂ are given orally, only a small percentage can be absorbed, which may explain the low toxicity.

Does this mean that taking let's say 400mcg of B12 makes no sense cause you only absorb let's say 5mcg at best so that it really doesnt
make any difference if you take 5mcg B12 in a pill or 100mcg or 400mcg? This would mean that everything which is above 5mcg would be wasted.

I'm just wondering cause most B complex supplements also contain B12 in huge amounts. But if only a small amount can be absorbed in the stomach
then this wouldn't make any sense.

Does this mean it would be best to take a high dosed B complex for all B vitamins except B12 and then add B12 spray to bypass the absorption issue?

[blood]

"High" doses of B12 taken orally are OK, even necessary, to overcome B12 deficiencies.

For example, someone mildly deficient in B12 might have to take 500-1000 mcg B12/ day for several months to overcome the deficiency.

In this study, a range of B12 doses (100, 250, 500, 1000 mcg) was given to people with mild B12 deficiency; only the higher doses were associated with normalisation of a biomarker of B12 deficiency:

http://www.ncbi.nlm....e finding trial

Arch Intern Med. 2005 May 23;165(10):1167-72.

Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial.

Eussen SJ, de Groot LC, Clarke R, Schneede J, Ueland PM, Hoefnagels WH, van Staveren WA.

Abstract

BACKGROUND:

Supplementation with high doses of oral cobalamin is as effective as cobalamin administered by intramuscular injection to correct plasma markers of vitamin B(12) deficiency, but the effects of lower oral doses of cobalamin on such markers are uncertain.

METHODS:

We conducted a randomized, parallel-group, double-blind, dose-finding trial to determine the lowest oral dose of cyanocobalaminrequired to normalize biochemical markers of vitamin B(12)deficiency in older people with mild vitamin B(12) deficiency, defined as a serum vitaminB(12) level of 100 to 300 pmol/L (135-406 pg/mL) and a methylmalonic acid level of 0.26 mumol/L or greater. We assessed the effects of daily oraldoses of 2.5, 100, 250, 500, and 1000 mug of cyanocobalamin administered for 16 weeks on biochemical markers of vitamin B(12) deficiency in 120people. The main outcome measure was the dose of oral cyanocobalamin that produced 80% to 90% of the estimated maximal reduction in the plasma methylmalonic acid concentration.

RESULTS:

Supplementation with cyanocobalamin in daily oral doses of 2.5, 100, 250, 500, and 1000 mug was associated with mean reductions in plasma methylmalonic acid concentrations of 16%, 16%, 23%, 33%, and 33%, respectively. Daily doses of 647 to 1032 mug of cyanocobalamin were associated with 80% to 90% of the estimated maximum reduction in the plasma methylmalonic acid concentration.

CONCLUSION:

The lowest dose of oral cyanocobalamin required to normalize mild vitamin B(12) deficiency is more than 200 times greater than the recommended dietary allowance, which is approximately 3 mug daily.

PMID: 15911731 [PubMed - indexed for MEDLINE]

I quite like this B complex from Swanson (it has folate as methyl-folate, and a decent amount of B12):
http://www.swansonvi...ity-60-veg-caps

Another good one (higher potency):
http://www.swansonvi...ity-60-veg-caps

Edited by blood, 17 February 2014 - 03:59 PM.

[Darryl]

I'm wary of high doses of riboflavin, as high transient levels of this potent photosensitizer may be genotoxic.

Fenech, Michael, et al. "Low intake of calcium, folate, nicotinic acid, vitamin E, retinol, β-carotene and high intake of pantothenic acid, biotin and riboflavin are significantly associated with increased genome instability—results from a dietary intake and micronucleus index survey in South Australia."Carcinogenesis 26.5 (2005): 991-999.

Edwards, Anam. "Light-induced flavin toxicity." Comprehensive Series in Photochemistry and Photobiology (2006): 115.

Gisson, A., and J. Morgenthaler. "Riboflavin: The Dose Makes the Poison."Townsend Letter for Doctors and Patients (2003): 135-135.

[username]

I'm not worried about high-dose B2 at all. The body does a good job at getting rid of excess riboflavin.
High-dose riboflavin works for migraine prophylaxis and there have been studies performed for many months with 400mg/day B2 without side effects.
Tbh, I believe it's the least problematic B Vitamin.

Link 1: Too many confounders. low folate, calcium, Vit E etc. -> very bad
(edit: Okay, I'm too lazy to read through that all. Was each single vitamin intake analyzed by itself? But even if that was the case:
Maybe riboflavin is mostly found in foods that are not nutritious and had B2 added to them. Maybe - by conincidence - those foods that have more B2 don't have many other vitamins and minerals? These studies are observatory and do not prove a causation. There are like a trillion confounders. Their use in determining positive and negative effects of vitamins on health is very limited)

Link 2: Any human trials? Which dosages?
Link 3: Intravenous B2 connot be compared to taking it orally.
e.g. while high-dose vitamin C causes stomach cramps and diarrhea, intravenous sodium ascorbate can cause hypoglycemia and possibly be deadly if one is not careful enough.

I prefer looking at human studies and observations compared to what happens in rats or when you give it humans intravenously. You cannot conclude that riboflavin is in any way dangerous. Or am I missing something?

Furthermore, there is no upper limit. Why is that if it's that dangerous?

Edited by longschi, 17 February 2014 - 08:03 PM.

[Darryl]

Transient levels of riboflavin after oral dosing are significantly higher than the amounts retained in flavoproteins. This is my concern with B2.



From:

Zempleni, Janos, John R. Galloway, and Donald B. McCormick. "Pharmacokinetics of orally and intravenously administered riboflavin in healthy humans." The American journal of clinical nutrition 63.1 (1996): 54-66.

It's also worth noting that the U.S. DRIs for B vitamins are at least 16 years old, and even there are hints of issues that may occur with long term supplemental dosing:

No adverse effects were reported in humans after single oral doses of up to 60 mg of supplemental riboflavin and 11.6 mg of riboflavin given intravenously as a single bolus dose (Zempleni et al., 1996). This study is of limited use in setting a Tolerable Upper Intake Level (UL) because it was not designed to assess adverse effects. It is possible that chronic administration of these doses would pose some risk.

...

The only evidence of adverse effects associated with riboflavin comes from in vitro studies showing the formation of active oxygen species on intense exposure to visible or ultraviolet light (Ali et al., 1991; Floersheim, 1994; Spector et al., 1995). However, because there are no demonstrated functional or structural adverse effects in humans or animals after excess riboflavin intake, the relevance of this evidence to human health effects in vivo is highly questionable. Nevertheless, it is theoretically plausible that riboflavin increases photosensitivity to ultraviolet irradiation. Additionally, there is a theoretical risk that excess riboflavin will increase the photosensitized oxidations of cellular compounds, such as amino acids and proteins (McCormick, 1977).

Most research on essential micronutrients have looked at minimal requirements, with rather little research interest in supplement level dosing, and still less on long term effects. It's rather plausible given the basic chemistry that high-dose B-complex supplements could accelerate retina and skin aging, largely due to riboflavin photoreactivity, but this simply has never been addressed in long-term human cohort studies, nor is it likely to. The population of high-dose B-complex supplement users is rather small, and not of great scientific interest.

The long-term risk/benefit ratio for supplements is left to the consumer: I personally think the risks of high-dose oral riboflavin outweigh the benefits. As with most B vitamins, the best sources are whole foods like mushrooms, nuts, and greens. There's no particular advantage to pharmacological doses for most, with the likely exception of methylfolate, which is both highly absorbed and a potent peroxynitrite quencher.

Edited by Darryl, 17 February 2014 - 08:53 PM.

[timar]

There are not only the US DRIs but also many other much more recent evaluations from governmental and non-governmental institutions. The EFSA evaluated the satefy of riboflavin as a food additive just last year. They didn't establish an ADI but concluded that...

...despite the uncertainties in the database, that riboflavin (E 101(i)) and riboflavin-5′-phosphate sodium (E 101(ii)) are unlikely to be of safety concern at the currently authorised uses and use levels as food additives.

Moreover, the LPI's monograph on riboflavin has been updated last year and doesn't discuss any recent toxicity concerns.

Probably the best evidence of safety are the millions of people worldwide taking B-complex supplements for at least 20 years, generally containing 50 mg of riboflavin. If photosensitivity would be a significant concern at such a dose, it must have become dramatically apparent by now.

With regard to the OP's question: yes, I think it makes sense, as I have explained here, but it can be part of a multivitamin.

Edited by timar, 17 February 2014 - 10:00 PM.

[Dorian Grey]

Lower doses taken twice per day instead of one thumping big dose per day (or megadosing twice/day) seems logical to me.

Looking at Darryl's riboflavin chart above, it appears blood levels return to baseline in about 12 hours. Twice daily dosing, (perhaps cutting pill in half if they are tablets) would keep blood level more stable. Lower spikes and more consistent availability.

[timar]

Huh!? Obviously, the base of the spike is ~8 hours. Taking it twice a day would simply cause twice as many spikes...

Not that I'm convinced that those blood levels do any harm, though. You could draw similar pharmacokinetic curves for a whole host of other, totally benign substances, including most dietary polyphenols.

Edited by timar, 18 February 2014 - 07:42 AM.

[dunbar]

Hello,

I don't understand a few things about oral B12. If for example a person takes 500mcg B12 in a multi vitamin then
how much of the B12 will be absorbed because of the intrinsic factor stuff? If for example the body can only absorb
let's say 10mcg B12 at most then taking really high doses of B12 in pills would make absolutely no sense.

I don't know what's better: To take let's say 500mcg B12 as a spray or a lozenges or in a multi as a pill.

And how do we know what a safe daily amount of the other B vitamins is?
For example I have a prescription drug at home which contains 50mg B1 and B6 and it says that one shouldn't take it
for a longer period of time cause it can cause nerve damages.

But most high dosed B complex supplements contain these amounts (50mg). Isn't this dangerous?
I mean what if you take a high dosed B complex and then develop nerve issues after a few months?

[kurdishfella]

Drinking water with B vitamins can increase absorption since they are water-soluble. Likewise with eating fatty food with fat-soluble vitamins can increase their absorption as well.

[ironfistx]

No clue.  But I know when I take B vitamins I feel worse than when I don't.  They make my OCD worse.  This happens for sure with methyl versions and feasibly with regular versions.  When I take b12 separately, methy version makes me feel worse.  Cyanocobalamin makes me feel good.

[kurdishfella]

overdosing on vitamins like b12 can be counterproductive and the excess be used by viruses to multiply with and via metabolism activation. And if you take high dose b vitamin some would think you would need high dose of other vitamins like magnesium and with viruses depended on all the vitamins to activate metabolism but no as long as there is magnesium even if deficient it will be pathways activated just less perhaps.

Edited by kurdishfella, 03 April 2021 - 06:58 AM.

[kurdishfella]

When you are severely deficient in b vitamins, toxins like mercury build up to activate those pathways but very badly, but it takes the place for b vitamins until deficiency is corrected. But it can happen that if you are deficient too long then your folate levels will drop to zero and your body won't make correct dna so when you supplement with b vitamins they wont do anything because the DNA has changed to use the toxins as badly as it does to activate. so you would need to block it out but that wouldnt work? so youd need to repair the dna , and thats not possible. currently.

Edited by kurdishfella, 09 June 2021 - 01:27 PM.

[ironfistx]

Link to source?