Tomato leaves – friend or foe?

From M., 12 December 2009, Tomato leaves: friend or foe?

Q: I have been tending to my burgeoning tomatoes, thanks to the warm Australian spring. I love the strong heady smell that you get from a tomato plant but unfortunatley it never comes across in the fruit. Do you know if it safe to cook/eat the leaves on a tomato plant – as I would love to capture that stong scent if I can.

A: You’re not the first person to notice that tomato leaves carry the essence of the tomato. Paul Bertolli, formerly executive chef at Chez Panisse, reportedly began using tomato leaves in tomato sauce to enhance the “tomatoey” quality back in 1987.

You ask whether the leaves are safe to eat. No doubt you ask because of the tomato plant’s membership in the Solanaceae, or nightshade, family, which includes potatoes, peppers (capsicums), and eggplant (aubergine), but also includes belladonna and tobacco. Often, the plants are poisonous – indeed, many parts of the potato plant except the edible tuber contain the poison solanine. Tobacco contains nicotine; belladonna contains atropine.

Many people believe, therefore, that tomato plants also must contain poisonous alkaloids. In On Food and Cooking, however, Harold McGee writes that tomatine, the principal alkaloid in tomato plants, appears to be relatively benign. He also notes that, following Paul Bertolli’s lead, he has experimented with some tomato leaf-cookery without ill effect.

After reading about McGee’s views on tomato leaves a few years ago, I did try the tomato leaf enhancement and found that it did add tomato flavor. I don’t use the leaves regularly but if you want to try them, add about 8 clean, unsprayed leaves per liter of sauce, about 10-15 minutes before the end of cooking, and do not eat the leaves as such. Remove them from the pot before serving. Be sure to use unsprayed leaves as you do not want to risk any toxins from pesticides etc.

4 thoughts on “Tomato leaves – friend or foe?

  1. Pingback: The bitter truth about tomato leaves. « The Upstart Kitchen

    • It’s hard to find reliable data on the alkaloid levels in tomato leaves. The most credible source I found (in Food and Chemical Toxicology, vol. 38, issue 7, July 2000, pp 549-553) found about 1g tomatine per kg leaves, so about 0.1% by weight. Green tomatoes had about half that amount, at 500 mg/kg. This was just tomatine, though- I don’t know if they evaluated levels of other alkaloids since the study specifically concerned the effects of tomatine on lowering serum cholesterol (LDL) in hamsters. Other alkaloids may be present in tomato leaves, but again, in small quantities.

  2. B says:

    I have seen reference to tomatine being a neurological toxin in animals that absorb it. It is apparently not absorbed in humans but removed cholesterol from the intestinal tract.
    I am curious about anabasine and anatabine content.

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