In the Heian times there was a custom of night visits, when gentlemen came to visit their ladies at night and stayed with them until dawn. It might be very romantic, but the body that cannot get sufficient rest tends to excrete vitamin B1 in greater quantities which only aggravates the condition. Heian ladies eventually got themselves heart attacks, staying up all night waiting for their lovers and dying of jealousy.
We can find plenty of examples of such misfortunate deaths in The Story of Prince Genji, Lady Yugao and Lady Aoinoue among them. They suffered from what we call now heart beriberi, a heart attack from the lack of vitamin B.
?Vitamin B is sometimes called the heart vitamin, because its lack in the body multiplies the amount of lactic acid in the heart muscles, leading to spasms. That can cause various heart diseases, such as cardiac infarctions, angina pectoris, heart failures, etc.
Sudden deaths caused by malnutrition were not exceptional in the Heian period, and we should not forget how vital it is to consume meat in proper, sufficient quantities.
