Polyphenols are a diverse group of naturally occurring compounds found in plants, widely recognized for their antioxidant properties. Scientific research has shown that polyphenols, such as resveratrol (from grapes), epigallocatechin gallate (EGCG, from green tea), and quercetin (from various fruits and vegetables), can exert beneficial effects on mitochondrial function. These compounds are believed to support mitochondrial health primarily through their ability to decrease oxidative stress, modulate mitochondrial biogenesis, and improve cellular energy metabolism.

Several in vitro and animal studies have demonstrated that polyphenols can activate signaling pathways (e.g., SIRT1, AMP-activated protein kinase) that enhance mitochondrial biogenesis and function. For example, resveratrol has been shown to increase mitochondrial number and improve mitochondrial efficiency in various tissues. EGCG has been reported to protect mitochondria from oxidative damage and improve mitochondrial respiration. However, the translation of these findings to humans remains limited, with most human studies being small, short-term, or focused on surrogate markers rather than direct assessments of mitochondrial function.

In summary, there is scientific rationale and some experimental evidence that polyphenols can support mitochondrial health, but human data are still emerging and not yet conclusive. Therefore, while polyphenols are scientifically investigated for mitochondrial support, the overall strength of evidence is moderate.