Peanut butter contains phosphatidylcholine, which restores mitochondrial respiration.
From Ray Peat’s article “Fats, functions, and malfunctions”:
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The crucial mitochondrial respiratory enzyme, cytochrome c oxidase, declines with aging (Paradies, et al., 1997). Some lipids, such as a phosphatidylcholine containing two myristic acid groups, can support the enzyme’s activity (Hoch, 1992). Supplementing old animals with hydrogenated peanut oil restores mitochondrial respiration to about 80% of normal (Bronnikov, et al., 2010).
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http://raypeat.com/articles/articles/fats-functions-malfunctions.shtml