Litchis are safe. But you’re in trouble if you eat unripened litchis (the small, green ones) on an empty stomach.
Unripe litchi fruit contains the toxins hypoglycin A and methylenecyclopropyl-glycine (MCPG) that may cause vomiting if had excessively. It may cause fever and seizures serious enough to need hospitalisation in severely malnourished children.
Eating unripe lychees on an empty stomach has been linked with outbreaks of high fever followed by seizures and death in young children from poor socio-economic backgrounds in rural Muzaffarpur in Bihar and other litchi-growing regions in India during the harvest season in May and June.
In 2014, fever and convulsions killed 122 and hospitalised 390 children within three weeks (between May 26 and July 17) in Muzaffarpur. All the sick children had eaten litchis and gone to bed without eating an evening meal and developed high fever, seizures and convulsions followed by coma before daybreak.
On admission to hospital, close to two in three (62%) had low blood glucose levels of less than 70 mg/dL, and traces of the toxins hypoglycin A and methylenecyclopropyl-glycine (MCPG) found in unripened litchis in urine specimens.
Hypoglycin A is a naturally-occurring amino acid found in the unripened litchi that causes severe vomiting (Jamaican vomiting sickness), while MCPG is a poisonous compound found in litchi seeds that cause a sudden drop in blood sugar, vomiting, altered mental status with lethargy, unconsciousness, coma and death.
Giving children sugar to normalize their rapidly plummeting blood glucose levels helps them recover from illness, recommends a study in The Lancet Global Health.
The take away? Eat ripened lychees but avoid the fruit when you’re fasting.