Which of the following are generally good to eat because they have nutrients? Which should you avoid because they are toxic? Which don't really benefit or harm you?
Items are considered noxious if their chemical properties can actually harm humans.
Dangerous physical properties, like sharp edges, do not make an item noxious.
In human nutrition, nutrients include digestible carbs, fats, fiber, minerals, proteins and water.
Sawdust is not digestible by the human digestive system and is typically not considered a nutrient. What people call a nutrient is kind of random, though, but I maintain that something that cannot be digested cannot be a nutrient.