I'm so glad that I eat two Brazil nuts per day for selenium. The pandemic prompted me to make sure I get enough selenium, because a selenium deficiency promotes inflammation, weakens the immune system, and may even make it easier for viruses to mutate. I eat fish on a sporadic basis, and I take a daily fish oil supplement (for Omega 3 fatty acids). If mercury in fish is as problematic as some claim, at least I'm limiting my risk. If the mercury in fish really is overhyped, at least I'm not missing out on the nutritional benefits of eating fish.
