To start this off here's some fringe knowledge for the curious and especially for a chronic kidney disease (CKD) relation:
Don't cook your thiamin supplements (who would do that?) or thiamin-rich foods in acidic conditions or it will turn into oxythiamine. Especially not when having impairments in renal clearance.
Didn't we learn that keeping acidic cooking conditions would be great because that drastically avoids the synthesis of huge amounts of Advanced Glycation End products from sugars with fats and proteins? Bummer.
On the bright side, simply providing more supplementary thiamin counteracts the effects of oxythiamine from cooked foods.
On the sad side, foods naturally high in thiamin could actually have negative effects on crucial thiamin-dependent bodily enzymes if they've been cooked in acidic conditions.
And processed/cooked foods which are already borderline low in thiamin could not simply be "thiamin-neutral" but extra negative in their effects on thiamin-dependent enzyme functioning.
It's yet another reason to avoid processed foods but to do home cooking from original ingredients.
Although the rate and the necessary conditions for such conversion is not yet known in practical detail, the results of impeded enzyme functions and high levels of circulating oxythiamine however was shown. What they experimentally studied (no in-between values): 0.06% of thiamin converted to oxythiamin in acidic conditions over 1 hour. A 500-fold dose of thiamin freed the transkelotase from inhibitory oxythiamin. "Standard Dietary Recommendations" for thiamin seem grossly insufficient in CKD in light of theses findings and about 30mg thiamin daily are fine.
For the future, it would be good to know what the oxythiamine/thiamin ratios of such causative foods really are, i.e. how little dietary oxythiamin counteracts what amount of dietary thiamin!
And what usual renal clearance and serum levels can be expected for oxythiamine in people with healthy kidneys - is it an accumulation specific to chronic kidney diseases (who, along with diabetics, additionally show impaired thiamin transporters) or could it also occur in various other populations (e.g. in those who get served a lot of canned fruit: caring homes, hospitals)?
Also, poultry could be a general source for an anti-thiamin by itself if they've been fed with amprolium in their standard chick feed mixes against intestinal protozoa. But if that amprolium accumulates in chicken meat to an extent that is harmful to humans, imagine the corresponding metabolic quality of life (and quality of meat!) of those chickens. Analytics by the food industry would be great to find out about that.
@mostlylurking said in Ideas for getting more CO2 into your everyday routine:
@CrumblingCookie
You might find the article at this link of interest: https://portlandpress.com/bioscirep/article/38/1/BSR20171148/57181/Thiamine-and-selected-thiamine-antivitamins
My question is this: are these thiamine anti-vitamins created naturally in the body? Or are these strictly lab creations made for experimentation or for pharmaceutical purposes and do not occur in nature so can be patented?
@mostlylurking
They write about purely synthetic thiamin derivates which are being used in lab testing (to create functional thiamin deficiency) and for some medical uses.
However, there's one derivative which stands out:
"recent research of Zhang et al. [132] indicates that we can be exposed to trace amounts of thiamine antimetabolites like oxythiamine as a result of thiamine transformation through cooking under acidic con ditions at 100◦C. That kind of contamination may cause undesirable effects on our metabolism (e.g. transketolase inhibition in dialyzed patients with end-stage renal disease). Poultry fed with amprolium as a means of preventing coccidiosis as well as post-production impurities from poultry farms may be also potential sources of thiamine an timetabolites contamination. From this point of view, there is a need for intensive development of new methods for the measurements of thiamine antimetabolites in food, feedstocks, and environment in order to constant monitoring of the level of contamination and prediction of the possible effects of thiamine antimetabolits pollution for people health"
Zang et al. [132] is to be found here:
https://www.kidney-international.org/article/S0085-2538(16)30057-6/fulltext
"Decreased transketolase activity is an unexplained characteristic of patients with end-stage renal disease and is linked to impaired metabolic and immune function. Here we describe the discovery of a link to impaired functional activity of thiamine pyrophosphate cofactor through the presence, accumulation, and pyrophosphorylation of the thiamine antimetabolite oxythiamine in renal failure. Plasma oxythiamine was significantly increased by 4-fold in patients receiving continuous ambulatory peritoneal dialysis and 15-fold in patients receiving hemodialysis immediately before the dialysis session"
"Oxythiamine is likely of dietary origin through cooking of acidic thiamine-containing foods. Experimentally, trace levels of oxythiamine were not formed from thiamine degradation under physiologic conditions but rather under acidic conditions at 100°C. Thus, monitoring of the plasma oxythiamine concentration in renal failure and implementation of high-dose thiamine supplements to counter it may help improve the clinical outcome of patients with renal failure."
"A possible source of oxythiamine found clinically is formation by high-temperature processing of thiamine-containing foods under acidic conditions, similar to but not as severe as conditions of oxythiamine synthesis.15,17 To model this, we incubated 1 μM thiamine in water, pH 7.0, at 37°C and 100°C, and in 100 mM acetic acid, pH 2.9, at 37°C and 100°C for 1 hour. Oxythiamine was detected only in thiamine solution heated at 100°C and pH 2.9. The concentration of oxythiamine formed was 0.56 ± 0.06 nM or 0.06% of thiamine. Similar conversion of dietary thiamine in cooking or commercial food processing with limited clearance over 2 to 3 days could explain the accumulation of oxythiamine to low nanomolar levels in ESRD patients."
"Examples of thiamine-containing foodstuffs with natural low pH are fruits and fruit juices; canned fruits are heated during commercial processing. Foods may also be made acidic by vinegar, lemon juice, and other acidic culinary additives.19 The use of vinegar in cooking has been proposed as beneficial in the diet of ESRD patients to decrease the potassium and magnesium content of vegetables22 and to decrease the formation of advanced glycation end products in foods.23 This requires reappraisal in light of the current studies."
"Given the requirement for acidic, high-temperature processing for oxythiamine formation, high-dose thiamine administered as a pharmaceutical at ambient temperature does not lead to oxythiamine formation. Supporting evidence for this is experimental and from clinical studies of renal failure with high-dose thiamine or related derivatives where transketolase activity was increased."
"The recommendation for patients with stages 3 to 5 CKD to take a supplement of the daily reference intake of 1.1 to 1.3 mg thiamine may be insufficient given the increased concentration of OTPP in renal failure. The remedy to the antimetabolite effects of oxythiamine accumulation is pharmaceutical doses of thiamine to produce increased TPP for OTPP displacement from transketolase. Thiamine (30–45 mg/day equivalent) in HD patients was studied and found to alleviate transketolase deficiency."