Maitake extract reliably boosts the immune system to fight cancer
MisleadingThe Claim
Maitake (especially its 'D-fraction' beta-glucan extract) is marketed to cancer patients as an immune booster that strengthens the body's defenses against tumors.
Origin
The claim stems from preclinical studies in which maitake beta-glucans stimulated immune cells and slowed tumor growth in animals.
What Science Says
Human trials are small and measure lab immune markers rather than cancer outcomes. In a phase I/II trial in 34 breast cancer survivors, oral maitake extract both stimulated and suppressed different immune measures, with non-monotonic dose effects, prompting the authors to warn it may depress as well as enhance immunity. A phase II study in 18 evaluable patients with myelodysplastic syndromes found improved neutrophil and monocyte function in vitro, but no trial has shown improved tumor control or survival.
Verdict
Misleading