Thanks sending me additional links including how to test for thiamine deficiency. With regards to your first link, I wasn't diagnosed with giardiasis and I didn't take antibiotic for it. I try to generally stay away from antibiotic unless absolutely necessary as it might affect gut health. For treating phimosis, the doctor didn't give me antibiotics. I need to have a circumcision surgery which I haven't got around to schedule it.

I'm not vegan, just vegetarian. I consume dairy but not egg. So I have started including some Vitamin D fortified milk as well as a multivitamin with 2000 IU daily. For Vitamin B12, like you said it's very difficult to get it from just vegetarian sources and have started consuming Vitamin B Complex daily. My PCP was worried when my Vitamin D result came out as It was 3.7 ng/ml last year. He said that being low for a lengthy time could have done some damage to the body over the years. Now, though Vitamin D level has improved after the supplements, I'm not sure if the neurological damage has already been done. I'll continue including the supplements and see if my symptoms improve. I'll also get tested for celiac to see if I need to be in gluten-free diet.

@ABP2025, Here's some studies and articles that will help you learn more about thiamin and all... I will write more later. It's possible that your antibiotic for giardiasis has caused thiamine deficiency.   https://hormonesmatter.com/metronidazole-toxicity-thiamine-deficiency-wernickes-encephalopathy/ And... https://hormonesmatter.com/thiamine-deficiency-testing-understanding-labs/ And... Thiamine and benfotiamine: Focus on their therapeutic potential https://pmc.ncbi.nlm.nih.gov/articles/PMC10682628/ and... Safety of High-Dose Vitamin D Supplementation: Secondary Analysis of a Randomized Controlled Trial https://pubmed.ncbi.nlm.nih.gov/31746327/      

Interesting you mention MCAS. I have come across mcas before but I wasn’t entirely sure if that’s what it was. When I eat certain food like dairy or soy my face gets so hot and I feel flush and my heart rate shoot’s up. And sometimes my bottom lip swells or I get hives somewhere. This started happening after I had a really bad case of Covid.  Before that I was able to eat all those things (minus gluten) I was diagnosed with celiac way before I had Covid.  Hmm, not sure really. I may look for a different allergist my current one told me to take Zyrtec and gave me an epi pen. 

This is all really useful information, thank you so much to you both.    I have a history of B12 and vit D deficiency which has always just been treated and then ignored until it’s now again.