Why does throat itches after eating patrode ( taro leaves ) ?

 Today my mother prepared "patrode ( ಪತ್ರೊಡೆ )" from taro leaves. ( ಕೆಸುವಿನ ಎಲೆ ) . It is usually prepared during rainy season .

My mother prefers tiny and young taro leaves when preparing patrode . I asked her the reason . She said grown leaves when eating makes our throat itchy .

Even I had experienced itchy throat once when eating patrode . I was curious to know why it is ?

Taro leaves are low calorie leafy greens which are high in fiber , potassium , folate and vitamins . 

But there is one major precaution to be aware of when eating taro leaves ,  their toxicity level .

Taro leaves have a high oxalate content which is a naturally occurring compound  found in many plants . Many vegetables such as spinach , beans and others also contain this oxalates but in very less amount that we won't experience any poisonous effects .

Older taro leaves contain more amount of oxalates than the younger ones . But both are poisonous when consumed raw .

To deactivate the poisonous oxalate content of taro leaves , they must be cooked properly till the leaves become soften .

That's why my mother steam cooks the patrode .