Do you like to eat a lot of dairy? I've noticed that for most people, especially as we get older, they develop an inability to process/digest dairy products completely and this can lead to inflammatory responses including increased mucous production. I might try eliminating dairy for a couple of weeks and see if this helps.
Also, just as a general comment, I'm not a huge fan of supplements. I think isolating a single compound thought to be beneficial and ingesting it in quantities not generally found in whole foods is not the way our bodies have evolved to absorb compounds.
Over the years I've tried to balance my diet with whole food items (fruits/veggies/nuts/seeds/animal protein) as much as possible with a heavy emphasis on plant based nutrition over animal, something like 85%/15% plant/animal ratio.
For supplements I've narrowed things down to a few that I feel I can't get enough of from whole foods whether because I don't consume enough of the food in question or I just don't like the taste.
Curcumin - (about 1g daily in powdered form) for general anti-inflammatory/joint health benefits. I just don't eat enough Indian food lol.
Ubiquinol - (about 100mg daily in liquid capsule) Normally you would get this from organ meats (liver, kidney, heart etc.) but I just don't eat enough naturally.
Vitamin D - I supplement about 2000 I.U. daily during winter months where exposed skin just can't produce enough. Difficult to get enough from food only.
I can't stress enough how much concentrating on eating whole (real) foods has improved my health. I try to avoid anything with a nutrition label if I can help it. A nutrition label means it was processed in some fashion and you just can't beat the real thing in most instances. Just my
