From sperm counts to obesity, scientists are only beginning to understand the long-term health effects of many chemicals in everyday use. How to survive the war at home?
“It astounded me that I’d gone through school and university – all those years of education – and still had no idea what was in the things I was putting on my body or cleaning my home with. So I started reading and researching,” Sydney-based Stuart says.
With every product she examined, Stuart asked three questions. How is it made? What is it made of? And am I okay with that? Out went the personal-care items laced with phthalates (endocrine-disrupting gelling agents) and parabens (preservatives), household cleaners containing the toxic solvent butoxyethanol and toothpaste with added triclosan to beat gingivitis. Out went non-stick pans and dental floss coated with polytetrafluoroethylenes (PTFEs) and cans of food lined with bisphenols.
Reducing such potentially harmful chemicals from her own life was only the beginning. Now 42, Stuart has built a business advising other people how to make the same changes. She has a website, lowtox life.com, with podcasts and information, is a consultant to businesses, takes workshops, has written a book, Low Tox Life: A Handbook for a Healthy You and a Happy Planet (Murdoch Books, $36.99), and runs an online course, Go Low Tox.
“The first e-course was in October 2014 and 370 people turned up,” Stuart says. “At that point it was still a hippy niche and we were so excited to have found each other. Since then we’ve had 3000 students through the course.”
Stuart emphasises that she isn’t about fear mongering or alarmist claims. Her interest is in helping people decode the long chemical names on ingredient lists so they can make an informed choice. To that end, she spends a lot of time wading through the latest science and trying to keep up. “There is so much information out there and things are constantly changing.”
With 60,000 followers on Facebook, and enough interest in her work to have hired a small team of part-timers, Stuart considers herself an educator. Her demographic is people aged 28-45; new parents often come to her concerned about what their babies are being exposed to.
According to the United Nations Environment Programme, humans use more than 100,000 different chemical elements and compounds, many of which have not been assessed for their effects on human health and the environment. They are in almost every product we buy, and managing them is a global problem.
“Many chemicals have been researched extensively and are harmless,” Stuart says. “Are some of them sufficiently dubious to have us exercise caution? Yes, they are.”
Take just one, triclosan. This is an anti-bacterial and anti-fungal agent used in more than 2000 consumer products including some soaps, detergents, toothpaste, mouthwashes and toys. In New Zealand, scientists have called for it to be banned as it can affect hormone function, damage the liver and kidneys and is a suspected carcinogen – it has been shown to promote the growth of human breast cancer cells in lab dishes and breast cancer tumours in mice.
One of the problems with triclosan is that it kills both good and bad bacteria. Now, thanks to a study from the University of Massachusetts Amherst, there is evidence it is having an adverse effect on our gut health.
Lead author Guodong Zhang’s focus is the prevention of inflammatory bowel disease and colon cancer. There are rising rates of both, and the theory was that something environmental or chemical might be responsible. “We know the bacteria in the gut are very critical and triclosan is an anti-microbial, known to be able to disrupt those bacteria,” Zhang says.
He found that feeding triclosan to mice changed the composition of their gut microbiome, causing colon inflammation and accelerating the rate of colitis and the growth of tumours. The mice were fed triclosan either through diet or drinking water. The concentration of triclosan in their plasma was measured after treatment and found to be similar to levels recorded in human studies. The only animals whose colons weren’t affected were the germ-free mice, which had no microbiome, and those genetically engineered to be without a specific receptor.
A lot of triclosan is manufactured every year, and it isn’t disappearing. It has been named one of the top-10 pollutants in US rivers and a US National Health and Nutrition Survey detected it in the urine of 75% of the people tested. Last year, researchers at the University of Massachusetts found that it accumulates in toothbrush bristles and is released into the user’s mouth for about two weeks after they switch to a triclosan-free brand.
“This compound is everywhere,” Zhang says. “If you wash your hands or brush your teeth with it, then it flushes into the wastewater. It’s very resistant to degradation in treatment plants so eventually it returns to the environment. Since it’s stable, and lasts for such a long time, if we continue to use it in large amounts, it will become a serious environmental and human-health problem.”
It’s fair to say his research hasn’t elicited a rapturous response from the chemical industry. “We received many complaints from the companies,” says Zhang, who wants to know more about triclosan, including its effect at lower concentrations and which specific gut bacteria it is affecting.
In 2016, triclosan was among 19 anti- microbials banned by the US Food and Drug Administration from use in over-the-counter handwashes because there was no proof they were any more effective in preventing the spread of germs than plain soap and water. The FDA deferred rule-making on three other compounds while awaiting more evidence. Zhang has since been involved in research to show those three remaining anti-microbials – benzalkonium chloride (BZK), benzethonium chloride (BEC) and chloroxylenol (PCMX) – could also exacerbate development of inflammatory bowel disease and associated colon cancer.
So what about New Zealand? It’s not that triclosan isn’t on our Environmental Protection Authority’s radar, it’s just that the regulator has bigger problems. The anti-microbial doesn’t even make it onto a priority list of 300 chemicals of concern it would like to see banned or restricted. Those are mainly herbicides and pesticides used in agriculture, although the list is due for updating.
“We’re publishing this list to demonstrate to the public and to industry which chemicals we are going to focus on,” says Fiona Thomson-Carter, general manager of the EPA’s hazardous substances and new organisms group. “They’re the true nasties we want to get out of New Zealand.”
The EPA is beefing up resources to begin to tackle that list but, even so, it is going to take a while. Funding is always an issue; reassessing a substance costs $50,000 or more. And any environmental risks have to be considered alongside economic benefits. “It’s a constant balancing act,” says Thomson-Carter.
Rather than an outright ban, controls may be put in place to manage a substance more safely. Take neonicotinoids, for instance. Links have been found between these widely used insecticides and the declining bee population, but the alternative for our agricultural industry is organophosphates, which are more hazardous. “So, rationally, [neonicotinoids] are the best option we have, as long as controls are adhered to,” Thomson-Carter says.
Some of the problems the EPA is grappling with have been decades in the making – legacy chemicals that were once deemed safe. The authority also has work to do ensuring compliance, so that contaminants that have been banned – such as PFOS, once used in firefighting foam and stain repellents – don’t continue to be used or stored and are safely disposed of. Then there are the applications to import or manufacture new chemicals, or use existing hazardous substances in a different way; all have to be assessed and approved.
So, although the EPA has established grounds for reassessing triclosan, no one has come forward offering funding and there are 300 other chemicals believed to be more hazardous to human and environmental health already in the queue.
“It isn’t that we’re deliberately ignoring nasty chemicals,” Thomson-Carter says. “We have to think about our absolute priority – what are the most harmful substances we have to manage better?”
The Government has also asked the EPA to consider adding glyphosate – used in the weedkiller Roundup – to its list of hazardous substances. That follows a US court’s decision to award a groundskeeper $430 million on the basis that heavy exposure to glyphosate contributed substantially to his cancer (non-Hodgkin’s lymphoma) and that Roundup manufacturer Monsanto failed to adequately warn of the product’s potential risks. Monsanto plans to appeal the verdict and opinion remains divided on the safety of glyphosate. However, the chemical has been classed as a probable human carcinogen by the World Health Organisation and there is evidence it is an endocrine disruptor. There is also the possibility that other additives in Roundup may be reacting with the active ingredient, glyphosate, to accelerate carcinogenic effects.
The fact that US activist organisation the Environmental Working Group has now reported finding significant levels of glyphosate in popular breakfast cereals, oats and snack bars marketed to children is expected to ramp up pressure to reassess the safety of the weedkiller.
Besides influencing the risk of cancer, daily repeated exposure to common chemicals may be doing everything from lowering sperm counts, triggering asthma and affecting thyroid function to disrupting the immune system.
Bruce Blumberg, a professor of developmental and cell biology at the University of California, Irvine, has evidence that chemical use is also contributing to the obesity epidemic. In 2003, he was sitting sleepily in a long meeting in Japan when the mention of a chemical called tributyltin woke him up. For 40 years, it had been used as a biocide in antifouling paint on the hulls of ocean-going vessels. There was solid evidence this marine pollutant was an endocrine disruptor in sea snails, causing female snails to grow a penis.
Blumberg wondered what effect exposure to this common chemical – it is also used in vinyls, plastics and wallpaper – would have on mice. Back in his lab, he found out. It turned out that tributyltin activated a hormone receptor that is a master regulator of fat cell development. Mice exposed to the chemical put on weight. And the effect of this exposure was heritable – their children and grandchildren were also fatter as a result.
That led to Blumberg coining the word obesogen. “There are 50 chemicals so far that have been identified as obesogens in living creatures,” he says. “And that’s got to be a great underestimate because we didn’t set out to identify how many there were, we only found those by accident.”
Obesogens reprogramme how our cells work in two main ways: they can promote fat accumulation through increasing the number and size of fat cells, or they can make it more difficult to lose fat by changing our ability to burn calories.
Although tributyltin is the only one for which there is evidence of such longevity of effect, obesogens identified so far include nine fungicides used on fruits and vegetables, compounds in plastic such as bisphenol A, and phthalates used in everything from food packaging to cosmetics.
“There are many sources and, trust me, no one is measuring the levels of any of these chemicals in any people anywhere,” Blumberg says.
He is concerned that we are not looking at the effects of exposure to low levels of endocrine-disrupting chemicals over long periods of time, and points out that it will be impossible to predict how much they might be contributing to the obesity epidemic until we know who is exposed to how much.
Blumberg has recently published a book, The Obesogen Effect: Why We Eat Less and Exercise More but Still Struggle to Lose Weight. Though he isn’t absolving people of personal responsibility, he believes that calorific intake and physical activity aren’t the only factors at play – because there was another interesting thing about the lab mice exposed to tributyltin: the ones that ate a normal diet afterwards gained a little weight; those fed a higher-fat diet became obese very quickly.
“So, combine those chemicals that are changing how our metabolism works with a diet that wasn’t so good to begin with and you have a bigger effect,” he says. “Chemicals don’t make you obese. They make you more likely to become obese given normal living habits.”
He believes early exposure – from conception to puberty – is most concerning, as that is when the body develops its baseline level of fat cells. He aims to find out more, particularly about the epigenetic changes he thinks are behind the transgenerational effects of tributyltin. What we know about the impact of endocrine-disrupting chemicals isn’t even the tip of the iceberg, he says. “It’s the top two snowflakes.”
In Blumberg’s home, there are no non-stick pans, stain repellents or chemical cleaners. Plastics are shunned, he avoids packaged foods and tries to eat organic produce as much as possible, “not because it’s more nutritious – although it might be – but because it’s less contaminated, for sure”.
Given that endocrine-disrupting chemicals are everywhere, can such lifestyle changes actually make a difference, or do they simply make us feel a bit better?
Portuguese environmental scientist Ana Catarina Sousa is keen to get the message out that reducing exposure to obesogens is not only feasible but also simple. She and her team reviewed the existing research and identified the most important sources of exposure indoors as diet, house dust and everyday products such as cleaning chemicals, kitchenware and cosmetics.
“Dust is really important,” Sousa says. “We don’t realise it but we ingest a lot each day and it is a concentration of many contaminants. This we can control easily by vacuum cleaning regularly and dusting with a damp cloth. No chemicals needed.”
Completely reducing exposure is impossible. “But small changes can have a huge impact,” says Sousa. “Your house is the easiest environment to control. We spend most of our time there – we sleep at home – so it’s the best place to start.”
The hope for the future is “soft chemistry” – environmentally friendly and inspired by natural processes. Such chemicals are being developed in labs around the world and Thomson-Carter says the EPA wants to encourage industry to introduce them into New Zealand.
There is pressure mounting from other quarters. Last month, the American Academy of Pediatrics released a statement and report expressing concerns about chemicals used as food additives or in packaging and plastics, calling for improvements in the regulatory system. It recommended that families reduce exposure to chemicals by, among other things, avoiding microwaving food in plastics or placing plastics in the dishwasher.
In New Zealand, retailer Mitre 10 recently followed Bunnings by phasing out insecticides containing neonicotinoids and replacing them with products for home gardeners that don’t pose the same risk to bees.
Meanwhile, Low Tox Life’s Alexx Stuart is a big believer in changing the world one shopping basket at a time. She sees the choices we make every day as the new face of activism. Reject the toothpaste with triclosan, the shampoo with phthalates, the cosmetics preserved with parabens, the highly fragranced laundry detergents, the chemical stain repellents and processed over-packaged foods to force multi-nationals to take notice and manufacture safer alternatives.
“They’re not going to make what we’re not going to buy,” Stuart says.
This article was first published in the September 1, 2018 issue of the New Zealand Listener.