I think everyone understands that plenty of things in nature are poisonous or dangerous in other ways.

But it's also reasonable to trust our intuition that food is generally better - i.e., more easily digested and more nutritionally complete - the closer it is to its natural form.

In the linked article, the supplement in question was was far from natural; it was highly refined and concentrated.

So the cause of the damage in this case was not from consuming a natural product, but from taking a highly _unnatural_ product.

If he'd just had ordinary green tea (i.e., dried tea leaves steeped in water) once or twice a day, as millions of people have done for many generations, this would not have happened.