Olestra vs Red Dye 3: which is worse?

What is Olestra?

Olestra (brand name Olean) is a synthetic fat substitute made from sucrose and fatty acids. Unlike regular fats, olestra is not absorbed by the digestive system — it passes through the body unchanged, providing zero calories while mimicking fat's texture and taste in food. It was developed by Procter & Gamble and FDA-approved in 1996.

What is Red Dye 3?

Red Dye 3 (erythrosine) is a synthetic cherry-pink fluorescent dye belonging to the xanthene class. It contains approximately 58% iodine by weight, distinguishing it from azo dyes. Its chemical formula is C20H6I4Na2O5. Approved since 1907, it is one of the oldest certified US food colorants and was notably the first synthetic food dye formally revoked by the FDA in decades.

Documented risks

Olestra: Olestra caused significant gastrointestinal side effects that were prominently noted on mandatory warning labels: 'This Product Contains Olestra. Olestra may cause abdominal cramping and loose stools. Olestra inhibits the absorption of some vitamins and other nutrients. Vitamins A, D, E, and K have been added.' Reported gastrointestinal effects included diarrhea, abdominal cramping, oily anal leakage ('anal leakage' or 'rectal leakage'), and fatty stools. These effects were often embarrassing and uncomfortable. Multiple consumer complaints documented GI distress from Olean chips. Beyond GI effects, olestra significantly inhibits the absorption of fat-soluble vitamins (A, D, E, K) and fat-soluble carotenoids (lycopene, lutein, beta-carotene). Since fat-soluble vitamins require fat for absorption, and olestra passes through without being absorbed, it 'captures' these vitamins and carries them out of the body. Studies found olestra consumption reduced serum carotenoid levels, prompting Frito-Lay to fortify olestra products with fat-soluble vitamins to compensate. The FDA removed the mandatory GI warning requirement in 2003 after Frito-Lay argued the warning was overstated, though olestra's use had already declined dramatically due to consumer avoidance.

Red Dye 3: The FDA revoked Red Dye 3 authorization in January 2025, marking the first synthetic food dye ban by the FDA since Red Dye 2 in 1976. The revocation was triggered by the Delaney Clause, which mandates revocation of any food additive found to cause cancer in animals regardless of dose. The carcinogenicity data stems from studies showing that high doses of erythrosine caused thyroid follicular cell tumors in male rats. The mechanism is indirect: erythrosine suppresses thyroid-stimulating hormone (TSH) feedback by elevating thyroxine (T4) levels, causing chronic TSH suppression that promotes thyroid cell proliferation and ultimately tumor formation. This is a rat-specific mechanism related to their thyroxine-binding protein system, which differs from human biology. EFSA's 2011 comprehensive safety assessment concluded erythrosine was unlikely to be genotoxic at typical food use levels and set an ADI of 0.1 mg/kg body weight — one of the lowest for any food color. EFSA restricted EU use to cocktail cherries only (max 200 mg/kg). The high iodine content (58% by weight) raises concerns for thyroid-sensitive individuals. Excessive erythrosine intake could theoretically contribute to iodine overload and thyroid disruption, particularly in individuals with hyperthyroidism or Hashimoto's disease. The FDA had been aware of the rat thyroid tumor data since 1990 but delayed action for 35 years. Advocacy groups including CSPI petitioned for a ban since 1983. The January 2025 revocation finally addressed this long-standing regulatory gap.