From beer bellies to birthmarks - myths and old wives' tales debunked

These prominent stomachs which prevent some people seeing parts of their body without the help of a mirror are simply due to an unhealthy diet and lifestyle, he says. "People who accumulate abdominal fat aren't eating a healthy enough diet. Of course, it's possible that they do drink beer, but there are others who don't and they also have a stomach like this," he points out. "This is android or visceral obesity which accumulates in the belly and waist and poses a high risk, much more so than if the fat is deposited in the buttocks or thighs, because being in the belly, close to the viscera, it increases cardiovascular risk, especially in women. And the likelihood of diabetes," he explains.

This one really makes Dr Russolillo laugh: "It's completely false, there is absolutely nothing to back it up, under any circumstances. It's just funny," he says. And obviously, the same goes for peanuts.

Eating a lot of chocolate can release a series of neurotransmitters at cerebral level that make us feel better: "It's possible that when you eat a food like this, it helps the synthesis and secretion of serotonin, maybe. In general, these are sweet foods or foods that remind us a lot of our childhood, and they may help cheer us up, although not because the food itself has that capacity, but because it releases a series of neurotransmitters," explains this nutritionist.

Dr Russolillo says this can happen with any food which is very high in fat. "If you eat a diet with a lot of fat, especially those of animal origin, as well as putting on weight there can be reactions such as the appearance of acne," he says.

That's a well-known saying in Spain, but this expert confirms that there is no evidence to support the idea that the time of day makes melon any better or worse for you. "I do believe in listening to your body, though: if you realise that every time you eat a certain product you get acne or don't feel well, then find something else or try it at a different time of day. This one is a myth because there is no evidence for it, but if something makes a person feel ill and it carries on over time they should consult a nutritionist because it's not a good thing to cut foods out of your diet," he advises.

Gynaecologist Francisco Carmona responded humorously to some of the things people say about sexual relations, conception, pregnancy and birth, fertile ground for old wives' tales.

This is something you often hear, even from highly-educated people. Dr Carmona says he has a couple of friends who are doctors and are convinced it works, "but it has nothing to do with it". "What is essential is that the spermatozoa have the capacity for spontaneous movement, that they are able to move linearly, not in circles. And orgasm is important for women because these contractions act as a Hoover for the sperm," he says. He also points out that the ovary that is ovulating releases substances that cause the male cells to move towards it more than towards the other ovary.

This is one of the most common myths, people who think that the shape of a pregnant woman's stomach - pointed, higher, lower - indicates whether she is having a boy or a girl. "Definitely not. I did an internship with a gynaecologist who had a reputation for always guessing the sex of the baby to come from the shape of the bump. He would say to the pregnant woman: 'You're going to have a boy,' but in his papers he would write that it was going to be a girl. So if he was right about what he had said, great, and if he was wrong and they came to ask for an explanation, then he would take out his papers and it would be very clear that he had predicted a girl! You have a 50% chance of getting it right, it's easy!"

Dr Carmona jokes that pregnant women are very keen to keep this myth going because it means they can insist on being indulged. "There's nothing more to be said about it," he says.

So they will love asparagus... or maybe not. It's like when people say pregnant women shouldn't drink cow's milk because otherwise the baby will develop an intolerance to it. Everything a mother-to-be eats or drinks decomposes into other components and it is those that are passed to the baby via the umbilical cord. So, no.

There are plenty of studies to confirm that there are no more births than usual during a full moon, although this is a widely held belief. "Otherwise the hospitals would be overwhelmed, and that doesn't happen. I don't know where this belief has come from, I suppose it has to do with the tides being caused by the moon, but oceans are vast expanses of water, while the water that a pregnant woman carries is very small indeed," says Dr Carmona.

We asked Lucía Galán, who is a pediatrician and the director of Centro Creciendo, to clear up some misconceptions.

"Well, I know there is a saying about 'licking your wounds' but we really don't recommend that anybody does that, says Galán. She explains that human saliva contains a large variety of bacteria which are inoffensive in our mouths but can cause serious infection in open wounds elsewhere on the body. "In fact, human bites, when they break the skin, become infected more easily and are more serious than those caused by animals," she says. The best way to treat a wound is to clean it with water and soap and disinfect it with antiseptic.

Not necessarily so. Sometimes a wound can itch as part of the scarring process, but Dr Galán says it can also be because it is becoming infected. "The itching doesn't always mean it is healing, so be careful," she says.

"The common cold isn't caused by cold weather but by a virus. In other words, if there is no virus there will be no common cold, even if it's freezing outside. And viruses are transmitted by close contact between people when one of them is carrying it; people understand that more now, because of the coronavirus," says Dr Galán.

So what happens in winter, in that case? Respiratory viruses particularly like the cold to reproduce and stay active, and that's why there are more of them in the winter than in the summer. "Also, in winter we tend to be indoors more, so there is more contagion and the low humidity inside also helps the viruses to replicate. That dryness in the atmosphere means our mucous membranes are not sufficiently hydrated and our virus-cleaning systems don't work fully," she says, referring for example to the little hairs in our noses that help to trap and clean out germs. So during the winter, spending more time with other people in heated rooms which dry out the atmosphere is "the perfect storm for becoming unwell". She does point out as well, though, that prolonged exposure to cold "can cause hypothermia and weakens the immune system, but not if you're just popping out to take the rubbish to the bin without a jacket on".

Quite the contrary, actually, because if you tilt your head back it can mean all the blood goes to the throat "and that could make you cough, choke or vomit," says Dr Galán. What we should do is sit the person down and lean them forward slightly so any blood that reaches the throat can be expelled through the mouth. "We tell them to breathe through their mouth and press our fingers on their nostrils for a few minutes until the bleeing stops. Normally, it will have stopped in about ten minutes," she says. It is best not to blow the nose or put paper or cotton wool in the nostrils, because removing it could make the bleeding start again.

"Well, cutting an onion into quarters and leaving it by the bed won't cause you any problems, but apart from the smell, which will linger for weeks, it won't help the cough. The cough might get better, but it won't be because of the onion, or at least there is no scientific evidence to say it is, I'm sorry," says Dr Galán. "And saying 'it works for me' is no substitute for scientific research. That's like saying I always drive through a red traffic light and nothing has ever happened to me, so it must be OK. Well, if that is the case, why aren't we all doing it?" she says.