Does aluminium cause Alzheimers? Are there hormone disrupting chemicals in our tap water? Are mobile phones a cancer risk? Does microwaving food in plastic containers put our health at risk?
Here we look at the evidence for and against a number of recent health scares:
Aluminium and Alzheimer’s Disease - The idea that aluminium might be a cause of Alzheimer’s was first raised by researchers in the 1960’s and subsequent research has shown some possible correlation.
However, the Alzheimer’s Society, having reviewed the medical and scientific evidence, concludes, ‘There is circumstantial evidence linking this metal with Alzheimer's disease, but no causal relationship has yet been proved. As evidence for other causes continues to grow, a possible link with aluminium seems increasingly unlikely.’
The Society notes that only about 1% of the aluminium our bodies absorb (for instance from tea, beer, baked products, drinking water, toothpaste, aluminium-based antacids and aluminium cookware) is absorbed and that this 1% is usually quickly excreted via the kidneys.
Their assessment of the research to date is that Alzheimer’s is likely to result from a combination of factors (such as age, genetic predisposition, disease or environmental agents) rather than a single cause.
Endocrine and Hormone disrupting Chemicals - Family doctors in the UK have sometimes recommended that women reaching the menopause drink more tap water, because of the levels of oestrogen now in the public water supply – a good example of the way our bodies may be being exposed to chemicals without this being apparent.
A review article in Integrative and Comparative Biologynotes, ‘Over the last decade, evidence has mounted demonstrating that human-made compounds released into the environment are disrupting endocrine systems of animals.’ Chemicals that are known human endocrine disruptors include DDT and some other pesticides, dioxin and PCBs. Because of their toxicity PCB production was terminated by the US Congress in 1979 and DDT has been banned for agricultural use worldwide.
Another example is PFCs (perfluorocarbons). These are human-made chemicals used in a variety of household products including food containers, carpets, paints and clothing. Science Daily, in a report on research by West Virginia University School of Medicine, notes in passing that a probability sample of U.S. adults found measurable concentrations of PFCs in 98 percent of the participants tested and goes on to comment, ‘PFCs are known to have multiple adverse health outcomes including increased cardiovascular risk and impairment of the immune system.’
The Endocrine Society has issued a Scientific Statement on this issue. In it they conclude, ‘The evidence for adverse reproductive outcomes (infertility, cancers, malformations) from exposure to endocrine disrupting chemicals is strong, and there is mounting evidence for effects on other endocrine systems, including thyroid, neuroendocrine, obesity and metabolism, and insulin and glucose homeostasis.’ The Society also notes, ‘No endocrine system is immune to endocrine disrupting chemicals’ and ‘Effects of endocrine disrupting chemicals may be transmitted to further generations.’
NB An endocrine-disrupting substance is a compound, natural or synthetic, which alters the body’s hormonal and homeostatic systems. The endocrine system is important because this complex network of glands and hormones regulates many of the body's functions, including growth, development and maturation, as well as the way various organs operate.
The Natural Resources Defense Council advises that exposure to endocrine disruptors can occur through direct contact with pesticides and other chemicals or through ingestion of contaminated water, food, or air. It reports that further, studies have found that endocrine disruptors can leach out of plastics and that many endocrine disruptors are persistent in the environment and accumulate in fat.
It suggests a number of things we can do to reduce exposure to endocrine disruptors. These include:
- Not using pesticides in and around the home
- Buying organic food if possible
- Avoiding fatty food and fish from contaminated water
- Not giving young children plastic toys
Mobile Phones - The World Health Organisation has reviewed the potential health risks from mobile phones. It advises that the electromagnetic fields produced by mobile phones are classified by the International Agency for Research on Cancer as possibly carcinogenic to humans and that studies are ongoing to more fully assess potential long-term effects of mobile phone use. However, it notes that, as yet, no adverse health effects have been established as being caused by mobile phone use – including in research conducted by the IARC.
In the event of there proving to be a health risk the WHO advises that this is likely to be reduced by text messaging, using mobiles to send e mails or using a hands free device for conversation ie avoiding holding a handset to your ear to reduce exposure to radiofrequency fields. It also advises that risk can be further reduced by using mobile phones less frequently and by using them in areas where reception is good, as this enables the phone to operate at reduced power.
Given the recent popularity of mobile phone use among younger people, and therefore a potentially longer lifetime of exposure, WHO has promoted further research on this group. Several studies investigating potential health effects in children and adolescents are underway.
NB There is still a degree of controversy about electro magnetic fields more generally (ie not just in mobile phones but also in overhead power lines, electric wiring in buildings, electric appliances etc). The London Hazard Centre takes a cautious view. It comments, ‘The scientific community cannot say conclusively that manufactured EMFs are safe. The Government and the National Radiological Protection Board (NRPB) continue to insist there are no health risks yet the NRPB has stated: "Not all effects (on the body) are attributable to heating or current flow and there are some reports which have linked cancer with low level magnetic field exposure."
The LHC believes that risks to health associated with exposure include an impaired immune system and greater susceptibility to cancer and tumours. It gives a number of examples, including anumber of studies which have shown an increased incidence in cancers, particularly leukaemia, amongst children living near overhead power lines.
The London Hazard Centre’s advice is therefore to minimise exposure, for example by turning off and unplugging electrical equipment when not in use and keeping your distance eg ensuring that places where you spend long periods of time are at least 4 feet from appliances that are "working" e.g. electric clocks, radios, televisions, immersion heaters, storage heaters, sewing machines and electric fires.
Microwaving food in plastic containers - You may have received e mails advising you not to microwave food in plastic containers, as chemicals can leach out of the plastic into the food, causing cancer, reproductive and other health problems. Is this true?
The Harvard Medical School Family Health Guide reports on this. What it advises is that:
- There may be some leakage when food is microwaved in plastic containers, in particular when fatty foods such as meats and cheeses are microwaved, as this causes a chemical called diethylhexyl adipate to leach out of the plastic.
- However, in the USA the FDA is aware of this and so closely regulates the plastic containers and materials that come into contact with food, requiring manufacturers to test the containers and ensure their tests meet FDA standards and specifications. Only containers that pass this test can display a microwave-safe icon, the words “microwave safe,” or words to the effect that they’re approved for use in microwave ovens.
NB There is also European legislation covering this, the UK version being The Plastic Materials and Articles in Contact with Food (England)(No.2)Regulations 2006; and Cancer Research UK shares Harvard’s assessment that microwaving food in appropriate plastic containers shouldn’t cause cancer.
Published 11/08/2011, Review date May 2015