I read this after making my post above: "Is Psoriasis A Prediabetes Last Line Of Defence".

After reading I wondered. If this works and if the theory I had come to had any merit, then a web search on black cumin might reveal it lowers blood sugar. This is what I found:

"
Studies have indicated that black seed oil has the potential to substitute the use of insulin in the treatment of diabetes. This is because the substances in black cumin have shown to lower blood sugar levels. The acids present in the seeds help the body produce hormones that speed up the metabolism of blood sugar. "




Apparently King Tut had some in his tomb . This is interesting because Egypt was a post hunter gatherer society that would have been higher carb than earlier peoples and getting blood sugar right would have been important for these bread eaters.