Here are some of the great myths of our time: Humans walked with dinosaurs (nope, we were 65 million years apart), you need eight glasses of water a day (a fallacy, though you do need to be adequately hydrated) and Vitamin C cures a cold (uh, no…).
Oh, and here's another: too many eggs are bad for you.
Quite how this major misconception not only gained credibility but lasted for decades is a mystery, though renowned nutritionist Professor Elaine Rush puts it down to a "socially transmitted disease".
Rush, a scientific advisor to the New Zealand Nutrition Foundation and Professor of Nutrition at AUT, says recent science has given eggs a sparkling nutrition report card – undoing the mistaken impression that eggs were linked with bad cholesterol and heart disease.
"It really comes down to poor understanding of cholesterol," she says, adding that fallacious health and diet information does seem to have an unusually long shelf life.
Modern research has established there is little connection between dietary cholesterol (found in egg yolks) and blood cholesterol (made by the liver), the latter associated with heart disease. Eggs impact our good cholesterol (known as HDL), while bad cholesterol (LDL or low density lipoprotein) is not affected in most people.
But the link between eggs and heart disease endures. Research last year by Colmar Brunton showed only 41 per cent of adult Kiwis know we can eat eggs every day.
Yet the Heart Foundation, the Ministry of Health and the Nutrition Foundation have all given eggs a big tick for nutrition, protein and vitamins – while the Heart Foundation says even those at risk of heart disease can eat 6-7 eggs a week.
Rush equates it to other myths like not swimming for two hours after eating – something mothers drummed into many children for decades even though there is no scientific evidence or any recorded case of stomach cramps from eating giving a swimmer problems.
That's what she means by a "socially transmitted disease". Mothers are a powerful force of nature so what they strongly endorse tends to stick in our minds – even if it's wrong.
"What we hear, say and learn often determines what we eat," says Rush. "There are a lot of socially transmitted diseases like, for example: 'I can eat what I like, because I am young and I don't have to exercise now – I can do it in a decade.' Yet we know that attitude impacts a lot on us in later life.
"The poor understanding of cholesterol is part of what some people believe about eggs – when the reality is eggs are a little power pack of nutrients*, affordable and great in cooking.
"But you can still see on supermarket shelves, products which proclaim they are cholesterol-free. Plant-based products contain no cholesterol so of course they are cholesterol free; they are not supposed to say things like that, but plenty do."
So a product which contains no cholesterol can demonise those which do – even if it is good cholesterol, like eggs.
"It's like going to the fish and chip shop where some have signs up saying they are cooking their produce in cholesterol-free oil," says Rush. "There is no cholesterol in vegetable oil – but that does not mean what they are giving you is healthy, particularly if they have used the same oil for three weeks."
Part of the original misconception about eggs was largely caused by what they were eaten with - like bacon and eggs, steak and eggs and egg and chips – all high in animal fats which produced bad cholesterol.
Eggs, she says, should be part of a balanced diet of a combination of foods – "wholesome foods, not processed foods".
A diet consisting of fruit and vegetables plus eggs, proteins, carbohydrates "with fibre still in them" was good for health "and the health of the planet" and can be translated into many different combinations, she says.
"Eggs are such a brilliant solution to a lot of things," says Rush. "They are entirely affordable, even for people struggling to make their food budget stretch. They cost 34c each if you buy a tray of 30, which a lot of people do these days. Just adding an egg to a child's lunchbox is a great thing – research is now suggesting it helps add to their learning capacity at school.
"A simple rule of thumb is to remember that eggs contain all the nutrients for a chicken to create the miracle of life. That has to be good for you."
*Eggs contain the following essential vitamins, minerals and antioxidants:
• Selenium (protects our immune system)
• Folate (growth and maintenance of healthy cells)
• Vitamin B5 (releases energy from our food)
• Vitamin B12 (good for brain and nervous system functions)
• Vitamin A (for growth and eye health)
• Iodine (for our thyroid gland)
• Vitamin E an antioxidant to protect our bodies against disease
• Phosphorous (strong bones and teeth)
• Iron (for haemoglobin which carries oxygen around our bodies)
• Thiamine (turns carbohydrates into energy)
• Zinc (helps growth, wound healing, blood formation and maintenance of tissues)
• Vitamin D (for bone health)
• Calcium (strong bones and teeth)
• Biotin (helps cell metabolism and use of fats, proteins and carbohydrates)
• Lecithin (helps brain function)
• Choline (important in many metabolic processes, including in liver, heart and brain)
• Lutein (eye health)