Great Mythconceptions Read online

  References

  ‘Graphite, Lead, Conrad Gesner,’ Encyclopaedia Britannica, (DVD), © 2004.

  ‘How the lead gets into a pencil’, How Is It Done?, Readers Digest Association, London, UK, 1990, p. 13.

  Binney, Ruth, The Origins of Everyday Things, Readers Digest Association, London, UK, 1998, p. 223.

  Petroski, Henry, The Pencil: A History of Design and Circumstance, Alfred A. Knopf, New York, 1989.

  Milk Makes Mucus

  There are many myths about the cow, an important economic animal in our society. One of the more popular myths is that ‘milk makes mucus’. This usually means that if you have a cold, and then drink milk (or take other milk products), your nose will start generating huge quantities of lovely green mucus. But there doesn’t seem to be any link between milk and mucus — apart from the fact that they both begin with the letter ‘m’.

  Mucus is a viscous liquid, that is, it is fairly thick and slow-moving — like honey. It usually wets, lubricates and protects many of the ‘pipes’ in our body that are related to moving food, air, urine and sexual juices around. Mucus consists of water, a special protein called mucin, dead white blood cells, cells that have been shed from the surface of the local ‘pipe’, various chemicals from the immune system (such as antibodies) and inorganic salts.

  There are several types of mucous glands in different locations around the body, and they each make their own specialised type of mucus. In the stomach, a thick layer of mucus stops the acids from digesting the stomach. (After all, if the acids can dissolve meat, what stops them from dissolving the stomach itself? The answer is mucus.) In the mouth, mucus stops the moist, inside surfaces from drying out, and also helps the food slide down. In the nose, mucus is an important part of our air-conditioning system. Not only does the mucus system trap bacteria, small particles and dust, but it also brings the incoming air up to around 100% humidity by the time it hits the back of the throat.

  And when you have a cold, the mucous-producing cells in the nose make more mucus.

  Dr Carole Pinnock and her colleagues from the Royal Adelaide Hospital in South Australia explored the widely-held belief that ‘milk makes mucus’. They started with 60 healthy volunteers aged 18–25 years, whose milk consumption ranged from zero to 11 glasses of milk per day. The investigators squirted Rhinovirus-2 (one of the many viruses that can cause the common cold) up the noses of the volunteers and supplied them with tissues and plastic bags to collect the ‘nasal debris’. They found that the weight of mucus dribbled and blown out of the nose varied between zero and 30.4 g, and that the maximum mucous production happened on the third day after infection.

  Dr Pinnock also found there to be absolutely no relationship between how much milk the volunteers drank, and how much mucus they produced. Interestingly, the volunteers who believed that ‘milk makes mucus’ claimed that they coughed more often and were more congested. However they did not produce any more nasal mucus than their more sceptical fellow volunteers.

  Some studies have shown that milk products are unlikely to ‘have a specific bronchoconstrictor effect in most patients with asthma’ — in other words, milk will not close up the airways. And other studies showed that milk does not cause ‘acute or delayed asthmatic symptoms or deterioration of pulmonary function’.

  Milk has many benefits. In Western societies, milk and other dairy products supply up to 50% of vitamin A needed by young children and adults, over 50% of the calcium, 33% of the riboflavin, and 20% of the protein, vitamin B12 and retinol. So, if you don’t have a true ‘milk allergy’, denying yourself dairy products can compromise your nutritional status.

  Why do so many people believe that milk causes mucus? Probably for the simple reason that it looks a little like mucus.

  References

  Low, P. P., Rutherfurd, K.J., Gill, H.S. & Cross, M., ‘Effect of dietary whey protein concentrate on primary and secondary antibody responses in immunized BALB/c mice’, International Immunopharmacol, March 2003, pp. 393–401.

  Pinnock, C.B., Graham, N.M., Mylvaganam, A. & Douglas, R.M., ‘Relationship between milk intake and mucus production in adult volunteers challenged with rhinovirus-2’, American Review of Respiratory Diseases, February 1990, pp. 352–356.

  Tampon Tampering

  In 1998, I got my first (of many) emails about the dangerous products in tampons. Tampon manufacturers were accused of deliberately including asbestos in tampons to produce more bleeding, thus increasing tampon sales. It’s easy to understand why women would be concerned about the quality of their tampons. After all, they use them internally, and most women have heard of Toxic Shock Syndrome (although it is incredibly rare).

  The source of this information in the email was said to be ‘a woman getting her PhD at the University of Colorado’. This person was never identified.

  Although the email has been slightly modified over the years it keeps resurfacing. Nowadays I don’t hear the asbestos claim too frequently, but there are plenty of other claims levelled at tampons.

  People often ring my Triple J science talk-back show asking if tampons are made from ‘dangerous’ rayon, or laced with cancer-causing dioxins. One version of the email claims that rayon ‘is a highly absorbent substance, and therefore when fibres are left behind in the vagina, it creates a breeding ground for the dioxin’. This is ridiculous. Dioxins are a family of chemicals. They are not living creatures, and cannot breed.

  And what about the claim that rayon sheds fibres? When you run cotton or rayon T-shirts through your clothes dryer, you’ll find a lot more lint collected after the cotton load than after a rayon load. And anyway, on the spectrum between ‘natural fabric’ and ‘synthetic fabric’, rayon is much closer to the ‘natural fabric’ end. Rayon is made of cellulose fibres which come from wood pulp — so you can’t really hit it with the ‘synthetic is bad and natural is good’ equation.

  The dioxin claim has (like all good myths) a tiny element of truth in it. There are some dioxins in tampons. But there are dioxins virtually everywhere in our environment — what matters is the quantity. It turns out that there are higher levels of dioxins in your body, than there are in tampons. In 1995, the United States FDA (Food & Drug Administration) measured dioxin levels in cotton and rayon used to make tampons. The dioxin levels ranged from ‘non-detectable to one part in three trillion’. To put it in plain English, one part in three trillion is roughly one teaspoonful in a lake 10 metres deep and one kilometre square. This is less than the exposure to dioxins that you get from the activities of daily living. Today, Johnson & Johnson bleach their tampons, using a process that does not produce dioxins.

  The ‘inventor’ of the tampon, Dr Earle Cleveland Haas, was selected in 1969 by the London Sunday Times as one of the ‘1000 Makers of the 20th Century’. In 1929, Dr Haas, from Denver Colorado, tried to relieve the discomfort that his female patients suffered while wearing external pads during menstruation. He eventually devised a cotton cylinder that could be inserted into the vagina with a disposable applicator. He sold the patents and trademark to Gertrude Tenderich, who was the first president of the Tampax Sales Corporation, which was established on 2 January 1934.

  And Dr Haas? He kept on trying to improve tampons, right up until he died in 1981, at the age of 96.

  The Email

  Disclaimer from Dr Karl: This is an edited version of the notorious ‘tampon’ email. As the email travels around the word, people sometimes change it slightly before passing it on. The following version covers the essential parts of the email.

  Dear Friends: I am passing this along because this information may improve your life and I care about you.

  Have you heard that tampon makers include asbestos in tampons? Why would they do this? Because asbestos makes you bleed more, and if you bleed more, you’re going to need to use more. Why isn’t this against the law, since asbestos is so dangerous? No wonder so many women in the world suffer from cervical cancer and womb tumours.

  A woman getting her PhD at the University of Colorado at Boulder sent the following:

  ‘I am writing this because women are not being informed about the dangers of something most of us use — tampons. I am taking a class this month and I have been learning a lot about biology and women, including much about feminine hygiene. Recently we have learned that tampons are actually dangerous.

  HERE IS THE SCOOP: Tampons contain two things that are potentially harmful: rayon (for absorbency) and dioxin (a chemical used in bleaching the products). The tampon industry is convinced that we, as women, need bleached white products in order to view the product as pure and clean. The problem here is that the dioxin produced in this bleaching process can lead to very harmful problems for a woman. Dioxin is potentially carcinogenic (cancer-associated) and is toxic to the immune and reproductive systems. It has also been linked to endometriosis and lower sperm counts for men — for both, it breaks down the immune system.

  Rayon contributes to the danger of tampons and dioxin because it is a highly absorbent substance.

  Therefore, when fibres from the tampons are left behind in the vagina (as it usually occurs), it creates a breeding ground for the dioxin.’

  References

  Haas, Dr Earle, US Patent no. 1 926 900, 12 September 1933.

  Mikkelson, Barbara, ‘Asbestos in tampons’, Urban legends homepage: www.snopes.com/toxins/tampon.htm

  Hindenburg and Hydrogen

  In the mid-1930s, if you could afford to fly across the Atlantic Ocean, there were two choices — noisy, small and cramped aeroplanes, or quiet and spacious airships that got their lift from huge bladders filled with hydrogen gas. Back then, it was still an even bet as to which technology would not become obsolete — the faster and noisier aeroplane, or the slower and more relaxed
lighter-than-air airship.

  Following a disastrous event in 1937, the aeroplane became the favoured technology. The enormous hydrogen-filled Nazi airship, the Hindenburg, was slowly manoeuvring in to dock at a 50-metre high mast at the Lakehurst Air Base, in New Jersey. This was the Hindenburg’s twenty-first crossing of the Atlantic Ocean. Suddenly, there was a spark on the Hindenburg, and then flames. Newsreel film crews captured the sudden disaster as the Hindenburg burst into enormous plumes of red-yellow flames, and collapsed to the ground. Over 30 of the 97 people on board died. The disaster was blamed on the extreme flammability of the hydrogen lifting gas that filled most of the airship.

  Hydrogen’s reputation (as extremely flammable) still troubles car manufacturers today, as they explore the use of hydrogen as a safe, non-polluting alternative to fossil fuels for powering cars. But it turns out that the extreme flammability of hydrogen is a mythconception.

  The Hindenburg was the largest aircraft ever to fly — longer than three football fields (about 250 m long). It was powered by four enormous 1200-HP V-16 Mercedes-Benz diesel engines that spun six-metre wooden propellers. It cruised at 125 kph (faster than ocean liners and trains), and when fully loaded with fuel, had a range of some 16 000 km. It was opulently furnished and almost decadently luxurious — each of the 50 cabins had both a shower and a bath, as well as electric lights and a telephone. The clubroom had an aluminium piano. The public rooms were large and decorated in the style of a luxury ship — and the windows could be opened. It was a little slower than the aeroplanes of the day — but it was a lot more comfortable.

  The Hindenburg was painted with silvery powdered aluminium, to better show off the giant Nazi swastikas on the tail section. When it flew over cities, the on-board loudspeakers broadcast Nazi propaganda announcements, and the crew dropped thousands of small Nazi flags for the school children below. This is not surprising, because the Nazi Minister of Propaganda funded the Hindenburg.

  At that time, the US government controlled the only significant supplies of helium (a nonflammable lifting gas), and refused to supply it to the Nazi government. So the Hindenburg had to use flammable hydrogen.

  As the Hindenburg came in to land at Lakehurst on 6 May 1937, there was a storm brewing, and the enormous amount of static electricity in the air charged up the aircraft. When the crew dropped the mooring ropes to the ground, the static electricity was earthed, which set off sparks on the Hindenburg.

  The Hindenburg was covered with a cotton fabric, that had been waterproofed. To achieve this, the fabric had been swabbed with cellulose acetate (which happened to be very flammable) and then covered with aluminium powder (which nowadays is used as rocket fuel to propel space shuttles into orbit). Indeed, the aluminium powder consisted of tiny flakes, which made them very susceptible to sparking. It was inevitable that a charged atmosphere would ignite the flammable skin of the airship.

  The Hindenburg burned with a red flame. But hydrogen burns with an almost invisible bluish flame. In the Hindenburg disaster, as soon as the hydrogen bladders were opened by the flames, the hydrogen inside would have escaped up and away from the burning airship — and would not have contributed to the ensuing fire. The hydrogen was totally innocent. In fact, in 1935, a helium-filled airship with an acetate-aluminium skin burned near Point Sur in California with equal ferocity. The Hindenburg disaster was not caused by a hydrogen explosion.

  The lesson is obvious — the next time you build an airship, don’t paint the inflammable acetate skin with aluminium rocket fuel.

  Hydrogen

  Hydrogen is the most abundant element in the Universe — about 75% of all the mass in the Universe. But it’s only the ninth most abundant element on Earth, and makes up just under 1% of the mass of our planet.

  Hydrogen is an odourless, colourless and tasteless gas and is also the simplest and lightest chemical element.

  It seems that Paracelsus, the 16th century German-Swiss alchemist and doctor, may have handled hydrogen. He discovered that when he dissolved a metal in acid, it produced a gas that would burn. In 1766, the English chemist Henry Cavendish went one step further with this gas, which was then called ‘inflammable air’ or ‘phlogiston’. He actually measured the amount of gas that he got from a certain amount of acid and metal, and even measured its density. In 1776, J. Waltire noticed that when he burnt hydrogen, he also made some droplets of water. It was the French chemist Antoine-Laurent Lavoisier who came up with the name ‘hydrogen’, from the Greek, meaning ‘water generator’.

  Liquid hydrogen is used as a rocket fuel, and when it burns with oxygen it produces temperatures of around 2600ºC. Hydrogen was once used to fill balloons, but is now mostly used to make ammonia and methanol, to remove sulphur from petrol, and to make food products such as margarine.

  References

  ‘Hindenburg burns in Lakehurst crash: 21 known dead, 12 missing; 64 escape’, New York Times, 6 May 1937, p. 1.

  Lemley, Brad, ‘Lovin’ hydrogen’, Discover, November 2001, pp. 53–58.

  Antiperspirant and Cancer

  In Australia, breast cancer will affect more than one in every 12 women. Over the past two decades, thanks to improved diagnostic methods, the reported incidence of breast cancer has been increasing. A popular rumour claims that the increase in breast cancer is caused by the increasing use of antiperspirants — and this old mythconception received a new burst of life with the advent of the Internet and email.

  Each armpit has about 25 000 sweat glands, which can produce about 1.5 ml of sweat every 10 minutes. Sweat is mostly salt water, with microscopic amounts of various chemicals. Each square centimetre of your armpit has about one million bacteria. They use the sweat to reproduce themselves and release waste products — some of which are the dreaded smells of body odour. Most antiperspirants use some kind of aluminium chemical, which seems to work by turning into an insoluble aluminium hydroxide gel inside the sweat glands. This gel physically blocks the sweat from getting out, and therefore stops the production of bacteria and body odour.

  Part of the ‘science’ behind this antiperspirant/cancer myth is the claim made in a circulating email that ‘the human body has a few areas that it uses to purge toxins: behind the knees, behind the ears, groin area and armpits. The toxins are purged in the form of perspiration.’ This is totally incorrect. Actually, it is the kidneys that get rid of unwanted metabolic by-products (the toxins). In fact, the main purpose of perspiration is to act as a cooling mechanism.

  The email goes on to say that because the toxins can’t escape via the armpits, they lodge in the lymph nodes between the armpits and the upper outer quadrant of the female breast — which is the part of the breast closest to the lymph nodes. ‘… this causes a high concentration of toxins and leads to cell mutations: aka cancer.’ Pathologists around the world have examined millions of lymph nodes from breast cancer patients — and while they have seen cancer cells that have travelled from the breast to the lymph node, they have not found high concentrations of these toxins.

  The email also claims that the cancer then spreads from the lymph nodes to the breast and that ‘nearly all breast cancer tumours occur in the upper outside quadrant of the breast area’. Wrong again. First, lymph node fluid flows in the opposite direction — from the breast to the lymph nodes. Second, the real figures are that about 60% of breast cancers happen in the upper outer quadrant. This is probably because that’s where 60% of the total breast tissue is.

  Dana K. Mirick and her colleagues addressed this myth in their paper ‘Antiperspirant use and the risk of breast cancer’, in the Journal of the National Cancer Institute, in October 2002. They compared 813 patients — diagnosed with breast cancer between November 1992 and March 1995 — with 793 healthy women (who were matched with the patients by five-year age groups). They found that the risk for breast cancer was not increased by any combination of using an antiperspirant, a deodorant or shaving.