Selects: How Peanut Butter Works

What It Covers

Josh and Chuck trace peanut butter from 7,600-year-old Peruvian archaeological evidence through its Canadian patent in 1884, the rise of Jif, Skippy, and Peter Pan, FDA regulation establishing the 90% peanut standard in 1971, hydrogenation's health tradeoffs, aflatoxin risks, and the contested history of peanut allergy prevalence.

Key Questions Answered

• •Peanut butter composition standard: Since 1971, the FDA legally requires peanut butter to contain at least 90% peanuts. Products falling below this threshold cannot be labeled as peanut butter. The standard also defines texture grades: smooth must have zero graininess, medium allows particles under one-sixteenth of an inch, and chunky has no upper size limit.
• •Hydrogenation tradeoff: Partial hydrogenation, patented by Joseph Rosefield in the 1920s, converts heart-healthy monounsaturated liquid oils into saturated fats by bonding hydrogen atoms to lipid chains using a powdered nickel catalyst. This extends shelf life and improves spreadability but creates arterial plaque risk. Hydrogenated varieties now represent roughly 80% of the current peanut butter market.
• •Natural peanut butter health profile: Per 100 grams, non-hydrogenated peanut butter delivers 45% RDA of vitamin E, 67% of vitamin B3, 73% of manganese, and 39% of magnesium. The monounsaturated fats support healthy cholesterol levels rather than raising them. The primary drawback is caloric density at approximately 600 calories per 100 grams, not nutritional deficiency.
• •Aflatoxin contamination risk: The mold aspergillus, which grows on peanuts underground, produces toxins called aflatoxins. Processing removes roughly 89% of aflatoxins, leaving an unquantified residual amount. Long-term human exposure has been linked in studies to certain cancers, birth defects, and cognitive disabilities, though short-term effects on humans appear minimal.
• •Peanut allergy perception vs. diagnosis gap: A national survey of 5,300 households found self-reported peanut allergies tripled from 0.4% to 1.4% between 1997 and 2008. However, separate studies tracking physician-diagnosed peanut allergies show rates holding steady over the same period, suggesting a significant gap between perceived and clinically confirmed allergies during that timeframe.