Health Risks from Native Fruit and Vegetables

I wish to add to the interesting review article by Wendt et al. (1) that native unripe fruit or indigenous vegetables can also constitute a health risk (2, 3).

The potato (a plant in the genus solanum) contains solanin (an alkaloid) in its peel, which serves to protect the potato from pests. Solanin can lead to light-headedness and cause headache and gastrointestinal problems. Not least it is hepatotoxic.

Boiled green beans are not dangerous and even healthy, but the raw pods can contain a high proportion of phasins. These protein compounds can cause gastrointestinal problems and also trigger the agglutination of erythrocytes, which can be fatal in the extreme case scenario. Only high cooking temperatures of 90–100°C (for at least 15 minutes) can destroy phasins. Beans should therefore never have too much bite/be too al dente and should always be thoroughly boiled.

The stalks, skins, and especially the leaves of rhubarb contain oxalic acid, at least 500 mg/100 g of plant. This can harm not only teeth and cause renal calculi but in larger quantities it can trigger headaches and vomiting. The later in the year rhubarb is harvested, the more oxalic acid it will contain. It is therefore safest to enjoy rhubarb in the spring.

Beetroot (a type of turnip/beet)—just like rhubarb—contains a lot of oxalic acid and should therefore always be thoroughly peeled and is best boiled—but not re-heated. Beetroot also contains nitrates, which can consequently turn into potential carcinogenic nitrosamines.

Hobby farmers and allotment gardeners can also be at risk. Especially for pumpkin or courgettes, accidental crossbreeds/recultivated strains, occasional fatal toxins (cucurbitacin) can develop that had previously been bred out.