It’s simpler than you think, or may have read in marketing material.

The source of water used in mushroom farming (or any farming enterprise) is directly linked to human health i.e. via what you are ingesting.

Scientific research links Vitamin D deficiency (that is, not absorbing/consuming enough per day), to seventeen varieties of different cancer

One of their most well-known health benefits is the positive influence eating shiitake has on aging.