Manuka Honey - Methylglyoxal - Toxic?

[Ben Stone]

Methylglyoxal - the sought after active component of Manuka, is cited quite broadly as being toxic - thoughts on safety profile and whether this should be something we pursue in our honey?

 

[LucH]

Hi,
Chronic intake of methylglyoxal, at levels that could be attained in food, is toxic by depletion of blood GSH and could have adverse effect on some GSH dependent functions in vivo.
=> Dose dependant. Needs for selenium are higher (or NAC to make Glutathion) for optimizing GSH-S-Tranferase. Capacity of red blood cells to refract oxidative stress is lowered too.
Toxicity of low levels of methylglyoxal: depletion of blood glutathione and adverse effect on glucose tolerance in mice - ScienceDirect

 

[Ben Stone]

Thanks. I gleaned similar findings. It's just very hard to square with the reported efficacy of manuka as a therapeutic honey! Any thoughts on that, it is well studied.

 

[LucH]

Yes, manuka is very useful on infected open wounds (bandage).

 

[Ben Stone]

Yes, manuka is very useful on infected open wounds (bandage).

Heh. That makes sense. I wonder how the cancer patients who take this report benefits if internal use seems like it should deplete their immune system.

 

[S-VV]

@Travis pls come

 

[LucH]

I wonder how the cancer patients who take this report benefits if internal use seems like it should deplete their immune system.

I won't say it like this. We need more selenium to counteract side effects.

 

[Ben Stone]

I won't say it like this. We need more selenium to counteract side effects.

Are you implying Manuka taken orally would be net beneficial if taken along with a rich source of selenium in the diet?

 

[LucH]

Are you implying Manuka taken orally would be net beneficial if taken along with a rich source of selenium in the diet?

Yes and No.
Yes for the short term (like a cure). No for side effects and depressed metabolism (supposition). Nothing scientific but I remember RP saying it won't be a good idea to take manuka. Not quite sure.

 

[Ben Stone]

Yes and No.
Yes for the short term (like a cure). No for side effects and depressed metabolism (supposition). Nothing scientific but I remember RP saying it won't be a good idea to take manuka. Not quite sure.

Thanks for your input my friend.

 

[LucH]

Find this back:
Methylgyoxals (MG) is a toxic metabolite known to accumulate in various cell types.
Methylglyoxal (MG) is a widely occurring ketoaldehyde that is accumulated under physiological conditions with uncontrolled carbohydrate metabolism (1, 11, 20). MG synthesis is mediated by enzymes, including methylglyoxal synthase, cytochrome P450, and amine oxidase, which are involved in glycolytic bypass, acetone metabolism, and amino acid breakdown, respectively (8, 18).
Conversion of Methylglyoxal to Acetol by Escherichia coli Aldo-Keto Reductases
=> MG can come from 2 sources: glucose or ketones (ketosis). MG has 2 carbonyl groups: aldehyde and ketone. Carbonyls are 2000 times more reactive than glucose, says Chris Masterjohn, Ph. Dr.
http://blog.cholesterol-and-health.com/2016/05/the-daily-lipid-podcast-episode-6-why.html

MG is a highly toxic electrophile and reacts with cellular macromolecules, including DNA and proteins (16, 18).
=> We call this reaction “glycation”. Glycation may happen with glucose, fats or protein. Which one is the most reactive and prejudicial? Not exactly the one we are told: too much refined sugar is bad, of course, but free fatty acids are many more times reactive!
From glucose when there is glycolysis, from fatty acids when ketones are formed during ketosis (diet). MG is not necessarily bad but it has to be neutralised by Coenzyme A enzyme and other reductase enzymes. Chris Masterjohn says insulin stimulates Coenzyme A and helps so minimizing MG. He is not saying to overeat carbohydrates since insulin pike is bad if it happens too often (excess weight and diabetes II). Remember too that insulin prevents catabolism of fats (free fatty acids): When you eat carbs, free fatty acids are not catabolised into blood circulation.
Control of MG is essential for preventing aging but is not necessarily bad if not in excess. MG are useful in the burning of glucose (glycolysis => pyruvates).
So, remember: Restricting carbohydrate is more likely to increase glycation rather than decrease it. So suppressing all carbs from your diet is not a good idea! Glycation is not a good argument against consuming carbohydrate.
For more related writings (which contain the relevant references), see "Start Here for Glycation and AGEs."
Where Do Most AGEs Come From? O Glycation, How Thy Name Hast Deceived Me!

 

[LucH]

Summary:
Methylgyoxals (MG) are toxic metabolites that accumulate in cells. Especially during the metabolism of sugars and ketones.
This process is often called "glycation". Glycation can occur with sugars, fats or proteins.
We often accuse sugars. An excess of sugar, especially refined, is obviously harmful (weight, blood sugar) but the free fatty acids are 2000 times more reactive. Two thousand times!
We have enzymes and antioxidants to neutralize these MGs. No worry about if not in excess ...

 

[Ben Stone]

Summary:
Methylgyoxals (MG) are toxic metabolites that accumulate in cells. Especially during the metabolism of sugars and ketones.
This process is often called "glycation". Glycation can occur with sugars, fats or proteins.
We often accuse sugars. An excess of sugar, especially refined, is obviously harmful (weight, blood sugar) but the free fatty acids are 2000 times more reactive. Two thousand times!
We have enzymes and antioxidants to neutralize these MGs. No worry about if not in excess ...

Much appreciated again my friend. I suppose we just need to wrestle with what is "not in excess". I would like to be able to enjoy a tablespoon a day without crashing my glutathione!

 

[reality]

Am I doing myself a disservice eating a lot of manuka honey? I use a good quality raw product with the honeycomb crushed in aswell, and I have around 40g a day in my greek yogurt. It’s absolutely delicious.

 

[LucH]

Am I doing myself a disservice eating a lot of manuka honey?

No if you manage well so, if you metabolize well. Glyoxals are a bit like polyphenols.
I used to say to vary and not to exceed 500 mg polyphenols per day. With pause. I wouldn't push the accelerator pedal too much.

Methyl glyoxals has both an aldehyde and a ketone functional group.
Metabolism
DOI: 10.1002/iub.1324
Extract:
The deleterious nature of the compound is due to its ability to glycate and crosslink macromolecules like protein and DNA, respectively.
(...)
Several studies on methylglyoxal biology revolve around the manifestations of its inhibitory effects and toxicity in microbial growth and diabetic complications, respectively.