Yes, I think there is some correlation between age and red meat but it could also be the damage done to your intestines after ?yrs of gluten/wheat and what applevenus said too about
the grain fed cattle. I would just do like you did with the gluten/wheat diet, start eliminating things until you are off All the meats, fish etc., then add them back in 1 at a time starting with the red meat and see what happens, hope this helps and keep us in the loop.