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U.S. Department of Health and Human Services

FDA Poisonous Plant Database

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AUTHOR(S): Crocco, S.
TITLE: Potato sprouts and greening potatoes: Potential toxic reaction.
YEAR: 1981 CITATION: JAMA, 245(6), 625 [English]
FDA #: F06925
ABSTRACT: Complete article: Question: Some of my patients have asked about reports in the lay press that eating potato sprouts or the green discolored flesh just below the potato skin may have toxic effects. Is there any scientific basis to these reports? If so, what are the chemical agents involved? Answer: Parts of the potato may contain the glycoalkaloid solanine as well as other related glycoalkaloid compounds. Solanine has a low rate of absorption into the bloodstream, is hydrolyzed intestinally to a less toxic and poorly absorbed product, and has a rapid fecal and urinary excretion rate. Potatoes also contain oxalic acid, arsenic, tannins, and nitrate.(1) Medical and toxicological studies have dealt mainly with solanine, and, thus, little is known about the potential toxicity of other glycoalkaloids; this lack of information has contributed to some doubts about solanine toxicity.(2) Since the glycoalkaloid content of potatoes can vary, existing and newly developed varieties are monitored vor their alkaloid content. The maximum acceptable content has been set at 20 to 25 mg/100 g of fresh potato weight. An oral dose of 225 to 1,000 mg/kg is necessary to produce pathological effects in animals.(2) The general symptoms of ingestion of large amounts of solanine are reported as moderate to severe gastrointestinal inflammation, nausea, diarrhea, and vomiting. Headache and throat irritaion have also been reported. In isolated and sporadic cases (as in "greening"), the solanine concentration has been reported as 80 to 100 mg/100 g of fresh potato weight. Since solanine is water insoluble, heat stable, and concentrated in the potato skin, the green discolored flesh just below the skin could contain the greatest amount of solanine and should be discarded. Among solanceous plants, the potato tuber has the unique capacity to trigger postharvest glycoalkaloid synthesis in response to light induction. However, harvested potatoes routinely are treated to inhibit sprouting. Potato growers, packers, and commercial usese have built safeguards into their procedures to prevent problems that might occur. The potential concern about potato sprouts and greening potatoes is probably known to many home gardeners as well. (1) Coon JM: Toxicity of natural food chemicals: A perspective. in Toxicants Occurring Naturally in Foods, Committee on Food Protection, National Research council. Washington, DC, national Academy of Sciences, 1973, p 575. (2) Zitnak A: Steroids and capsaicinoids of solanaceous food plants in Childers NF, Russo GM (eds): Nightshade and Health. Somerville, NJ, Somerset Press, 1977, pp 70-72.
GRIN #: 103137 Exit Disclaimer
STANDARD PLANT NAMESolanum tuberosum L.