The fourth-century recipe never heated the water.
What this line claims
Analogy, not evidence. Ge Hong's text (about 340 CE) says to soak qinghao in water, wring out the juice and drink it, where most recipes boiled. Tu Youyou later asked whether heat had destroyed the active ingredient and switched to low-temperature extraction (Chemistry World). That is artemisinin, a different plant and compound. It says nothing about whether cannabis, or any one plant, is a dietary requirement.
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