Wow, I definitely held some of these misconceptions. A few examples:
- While the beta carotene in carrots can help improve night vision in those suffering from a deficiency of vitamin A, it does not enhance it beyond normal levels in those receiving an adequate amount.[365] The belief that it does originated from World War II British disinformation meant to explain the Royal Air Force‘s improved success in night battles, which was actually due to radar and the use of red lights on instrument panels.[366]
- Eating less than an hour before swimming does not increase the risk of experiencing muscle cramps or drowning. One study shows a correlation between alcohol consumption and drowning, but there is no evidence cited regarding stomach cramps or the consumption of food.[316]
- Poinsettias are not highly toxic to humans or cats. While it is true that they are mildly irritating to the skin or stomach,[277] and may sometimes cause diarrhea and vomiting if eaten,[278] an American Journal of Emergency Medicine study of 22,793 cases reported to the American Association of Poison Control Centers showed no fatalities and few cases requiring medical treatment.[279] According to the ASPCA, poinsettias may cause light to mid-range gastrointestinal discomfort in felines, with diarrhea and vomiting as the most severe consequences of ingestion.[280]
- European honey bees are often described as essential to human food production, leading to claims that without their pollination, humanity would starve or die out.[271][272] The quote “If bees disappeared off the face of the earth, man would only have four years left to live” has been misattributed to Albert Einstein.[273][274] In fact, many important crops need no insect pollination at all. The ten most important crops,[275] comprising 60% of all human food energy,[276] all fall into this category.
- Earthworms do not become two worms when cut in half. Only a limited number of earthworm species[256] are capable of anterior regeneration. When such earthworms are bisected, only the front half of the worm (where the mouth is located) can feed and survive, while the other half dies.[257] Some species of planarian flatworms, however, actually do become two new planarians when bisected or split down the middle.[258]