Once credited with power to prevent cancer and combat high cholesterol, over the last few years, evidence that soya is far from a superfood has begun to emerge. And it’s not just the potentially negative health impact of the bean that has former supporters up in arms: it’s the environmental impact. In the UK we rely heavily on soya, or soy, and it's not just for vegetarian food. It is a hidden product in many foods and everyday items such as soap. It is a cheap source of protein for people as well as animals and according to Greenpeace, 80 per cent of soya worldwide is used for the livestock industry. WWF add that the UK consumption alone requires an area the size of Yorkshire to be planted with soya every year. So how did soya go from super crop to super bad?

Deforestation and slavery

Brazil, the second biggest grower and the biggest exporter of soya, is such a big player in the industry that there are major concerns about how this is affecting the Amazon Rainforest. According to Greenpeace, in 2005 around 1.2 million hectares of soya was planted in the Brazilian rainforest. Sarah Shoaka from Greenpeace's Forest Network says that deforestation has been decreasing on the whole in Brazil since 2008. This is mainly because of the enforcement of a soya moratorium that bans soya produced as a result of deforestation from entering the market place. However, Shoraka warns that this positive trend may be changing: 'The whole of last year deforestation in the main areas for soya including Matto Grosso – the state which is the biggest soya producer – increased for the first time in a while.' Greenpeace think the main reason for this is proposed changes to the controversial Forest Code which governs how much forest each farm has to protect from the land that they own. 'They want to give an amnesty to people that have deforested in the past and obviously that has created a big incentive for people to deforest before the law goes through.'

Along with deforestation, there are also concerns about the use of agrochemicals in soya production – risking pollution to water supplies and soil – as well as labour issues and tension over resources. Greenpeace's Eating Up the Amazon report also says, chillingly, that modern-day slavery is also a serious problem in the region. So what’s being done about it? To combat the issues associated with soya production, the WWF and others set up the Roundtable on Responsible Soy Association (RTRS) in 2006 to provide an opportunity for stakeholders to join together to find solutions. They offer a certification scheme to businesses involved in soya production. But Shoraka says she does not see RTRS as a viable solution. 'While certification schemes can help companies trace back where their soya is coming, from it isn’t at all for protecting the forest.' The ultimate goal, she argues, should be a Brazilian law that prohibits all forms of deforestation.

Ben Zeehandelaar, Outreach and Communications Manager at RTRS, says it is strict on deforestation. 'If a company does something against our objectives or standards then the company can not continue with RTRS,’ he insists. ‘If a company is certified and an auditor finds that it is deforesting part of its property that it shouldn’t, they lose their certification.' He is aware of the criticisms made against RTRS but says there is no real multi-stakeholder alternative to it that can be part of the mainstream value chain. Genetically modified (GM) soya is another issue that divides opinion. RTRS includes GM soya, and Zeehandelaar says this is because the issues around deforestation such as the use of agrochemicals and social impacts are just as relevant to GM soya as they are to non GM. 'To leave out genetically modified would leave out a large part of the problems that occur today,' he explains.

Dangerous dining?

But the most controversial part of the soya debate is that surrounding its impact on human health. The main reason for concern is the isoflavones, a type of phyto-oestrogen, present in significant quantities in soya. According to Kate Arthur, a spokesperson for the British Dietetic Association (BDA), the issue is that these phyto-oestrogens are often confused with human oestrogen. 'There have been studies done on soya isoflavones, or plant oestrogens, and fertility but all those studies have been on animals or in test tubes,’ she explains. ‘All the human data out there suggests that soya is safe to consume.' Dr Kaayla Daniel, nutritionist and author of The Whole Soy Story is more concerned. 'Thousands of studies link soy to malnutrition, digestive distress, thyroid problems, cognitive decline, reproductive disorders, immune system breakdown, even heart disease and cancer,’ she argues. ‘Possible benefits are far outweighed by proven risks.' The Vegan Society’s Amanda Baker says that soya needs to be looked at in a more level-headed way. 'What we do know is that soya is a good source of protein and including a moderate amount of soya protein can help to reduce cholesterol levels,’ she comments. ‘Really, other claims both positive and negative are almost entirely controversial – they're not proven.'

In 2003, the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment released a report identifying three groups of people who, evidence suggested, were potentially at risk. These were infants fed on soy-based formula, people with hypothyroidism and women with breast cancer. With babies, the fear is that the high levels of isoflavones may affect development. The BDA says soya is fine from the age of six months but before that, breast milk is best. Arthur also says soya is a good option for those avoiding dairy as it contains amino acids and is often fortified with things like calcium and vitamin D. The Department of Health agrees but says breast milk it better up to a year old and that people should speak to their GP about alternatives.

But despite the potential risks for children, the soya debate shows no signs of abating. One of the most popular arguments in soya's favour is that Asian populations have eaten it for thousands of years with no issues. According to the WWF, China is responsible for 37 per cent of global soya imports. 'We haven’t seen any negative effects on their health,’ says Arthur. ‘In fact, we see quite a few positive effects in relation to heart disease and certain cancers like breast cancer.’ Daniel says this is a myth and that the first soya foods were only invented 3,000 years ago. 'They have different health challenges, not fewer,’ she comments. ‘Asians have lower rates of breast, prostate and colon cancers, but higher rates of thyroid, esophageal, pancreatic, liver and stomach cancers. If we are going to credit soy for the lower rates of some cancers, we need to blame it for higher rates of other types.’ She says processed food is best avoided for everyone but 'old fashioned' products like miso are healthy in the context of richly varied omnivorous diet. ‘A little tofu once in a while is usually not a problem.' Although Baker does not believe soya to be harmful, she says keeping processed food to a minimum is always advisable. 'Things like soya based sausages are also going to be high in salt and they're possibly going to be using soya protein isolate rather than the whole soya bean,' she says.

So what now?

There is still no easy way for consumers to tell the environmental impact of the soya they are buying. Zeehandelaar says that as soya is such a hidden product, RTRS certification is likely to stay at institutional level. This, says Shoaka, is why Greenpeace is working on the soya moratorium. 'In terms of tracing back where [soya is] coming from, it's very difficult so that's why we took the approach of trying to get the biggest users together and to get them to push for the solution.' She also notes that when eating meat you cannot know where its feed has come from, which, as Zeehandelaar points out, is less efficient than eating the soya directly. Daniel says there have been cases of people with severe soya allergies reacting to eating products from animals fed with soya but adds: 'I strongly recommend supporting our local farmers and getting meat and dairy from grass-fed, pastured animals.'

One of the WWF's proposals for helping to reduce the negative impact of UK soya consumption is changing the regulations that currently ban the use of waste products in livestock feed to provide an alternative. The rules were put in place after the BSE crisis in the 90’s as there were concerns about cross contamination. Pastures New, a report by Friends of the Earth, says that part of the solution could be more home grown soya. The report, based on research by the Royal Agricultural College and published in 2010, says that 50 per cent of what is used for animal feed in the UK could be replaced with home gown alternatives. Finding the truth about soya is like looking for a needle in a haystack and while the environmental concerns seem to be almost universally recognised, the impact on health is a muddier issue. While studies continue, it seems that, unless there is a medical issue preventing it, aiming for a balanced and varied diet is the best approach. Moderation is key – it’s unlikely that the odd glass of soya milk will send you to an early grave – but it might have a chilling effect on the planet.