Maybe because of Vitamin A and selenium which speed up thyroid.
Interesting. I was diagnosed too hypothyroid, but when I included food with real Vitamin A in it, not carotene, my thyroid diagnostics made improvement. My thyroid was not slow years ago when I ate wheatgerm, sunflower seed sprouts and other mineralful foods like that.
Selenium is a trace mineral that is essential to good health but required only in small amounts. It helps synthesize antibodies; helps synthesize co-enzyme Q10and helps transport ions across cell membranes. The best sources of selenium are Brazil nuts, wheat germ, molasses, sunflower seeds
I was hyPERthyroid at that time though, it seems, and euphoric maybe too. I like the feeling and energy without those two foods though, and with RAF.