You need to be a bit careful with zinc. A doctor friend of mine compiled a load of data showing most zinc supplements are contaminated with cadmium, which is cumulative. I'm not sure if he's published yet.
Fyi in the consumerlabs review for zinc, all products passed testing for cadmium levels with the highest (Nature's Bounty) having 0.5mcg/g.
You basically need to be careful with any supplement since it's unregulated, and need to do a lot of careful diligence. It's a good sign if they are honest about their supplier and you trace back their supply chain. E.g. for many chelated supplements (zinc included), if you see a TRAACS trademark then the source is Balchem (Albion) which to my understanding is fairly well regarded.
ConsumerLabs tested one such TRAACS product and found it to be 0.1 mcg/g cadmium, so likely most products using TRAACS zinc bisglycinate formulation should be similar. I also found some EU food safety application [1] which confirms that across 3 different manufacturers of zinc bisglycinate (one of which is Albion), all samples were < 0.1mcg/g
Thanks! It is also critical to balance zinc with copper, and supplementing a lot of zinc without copper can effectively cause copper deficiency, which is very serious.
You basically need to be careful with any supplement since it's unregulated, and need to do a lot of careful diligence. It's a good sign if they are honest about their supplier and you trace back their supply chain. E.g. for many chelated supplements (zinc included), if you see a TRAACS trademark then the source is Balchem (Albion) which to my understanding is fairly well regarded.
ConsumerLabs tested one such TRAACS product and found it to be 0.1 mcg/g cadmium, so likely most products using TRAACS zinc bisglycinate formulation should be similar. I also found some EU food safety application [1] which confirms that across 3 different manufacturers of zinc bisglycinate (one of which is Albion), all samples were < 0.1mcg/g
[1] https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa....