Prof Tim Noakes is not a registered doctor. He is better known for sports and exercise science. He does not give medical advice because he is not allowed to do so. On that basis, I don’t think you can rely on his word as gospel. Or even sensible.
Putting your trust in him seems a little misplaced. Or misguided.
The toxicity of Berberine is explained in terms you might understand in the Wikipedia article on the substance. It’s doing bugger all to help with diabetes, for sure, it’s action in the body is not involved with glucose metabolism in any respect. It’s just a yellow dye for wool and leather. And all your body does with it is to break it down serially as it would with any other alkaloid poison. Might give your liver some entertainment destroying it, but that’s about the limit.
Thanks MikeyB I will look at Wikipedia. No need to be offensive about my capacity to read and understand if pointed to a source. Wikipedia, whilst aways a valuable tool, is not a primary resource. Research papers are.
Whilst Noakes may not currently be a registered doctor he is a scientist of renown, an emeritus professor, and holder of International Cannes Grand Prix Award for Research in Medicine and Water. So he is not an idiot and he has Type 2 diabetes. He was a registered doctor, until voluntarily de-registering at the age of 70, declining to continue registration following an unreasonably pursued allegation of mispractice for having given medical advice to a mother on weaning a child on to real food. It was established that, by replying to a question on social media, a) the questionner was not a patient b)he was not in a doctor patient relationship c) that the general information he had given was consistent with his country's dietary advice.
He continues to work as a scientist at The Noakes Foundation which " aims "to fix the future outlook of human health, by changing the way people eat and the food policies to enable this". There he is supported and works with a team of other scientists amongst whom are several medical doctors. It seems odd that they would let the old boy swallow berberine if it is genuinely toxic and has no effect on blood sugar.
I assumed your response was based on more recently published research papers than I have read and hoped to have the opportunity to read them.There are numerous research articles in such publications as the Endocrine Journal, Biomedicine and Pharmecotherapy, the American Journal of Physiology etc between 2008 and 2021which support the role of Berberine and I have not yet found one which remarks on its toxicity, save in combination of certain drugs. (Wiki I see notes statins). I will look harder.
PubChem says "In published trials, berberine has appeared to be well tolerated with only minor and few adverse effects which have been similar in frequency among persons receiving placebo. Despite wide scale use as an herbal supplement, berberine has not been linked to published instances of clinically apparent liver injury. The frequency of hypersensitivity reactions to berberine is also not known.Likelihood score: E (unlikely cause of clinically apparent liver injury)." It has an "unspecified potency on GYP2D6 enzyme" (on which more later).
There appear to be numerous trials recruiting not least in regard to its potential as a remedy useful in the treatment of Covid 19 but also in regard to its use in diabetes. Doubtless their outcomes will be interesting.
MedlinePlus.gov indicates that it is possily effective for reducing blood sugar in diabetes; lowering cholesterol and high blood pressure. However it notes it is unsafe to give to jaundiced newborns as it inhibits removal of bilirubin, and urges caution and suggests there may be moderate interaction with a range of drugs, including potentially decreasing or increasing the effectiveness of Losartan, and some blood thinners and pain killers. The site seems quite unsure about which way it might go which is unhelpful to say the least.
Nonetheless since I take losartan and rivaroxaban and have raised bilirubin (although very long past babyhood) I mean to do some more research. I am obliged to you for bring to my attention a new area requiring investigation.