This is the 1st article in the series: “7 reasons to choose organic – an in-depth look at the issue of organic vs conventional produce.”
Let’s takes a closer look at what’s on your food.
Do you ever think about how many toxic chemicals are in the foods you eat, and whether there is any real cause for concern about this?
Maybe you’ve seen articles that have you terrified about every non-organic strawberry you put in your mouth. And just as many articles telling you that organic is a waste of money because levels of pesticide in Australian produce are low, and therefore nothing to worry about.
After all, that’s why we have government regulators overseeing the use of agricultural and industrial chemicals. And one would expect that if there is conclusive evidence of harm they will be taking action.
Chemicals are everywhere, at least according to the world-view of a chemist, because they are one of the basic building blocks of life.
However that doesn’t stand as an argument for the safety of all chemicals, and in particular those synthesised in labs, even if they apparently mimic naturally occurring chemicals.
The main reason people choose to eat organically is to avoid eating industrially produced chemicals generally considered poisonous, particularly in large doses.
Are you convinced that it’s worth paying the extra to eat organics?
This is the short of it:
300,000+ tonnes of pesticides are used on Australian crops each year, and pesticide use has become an ordinary, and some think indispensable, part of food production. It means we have the perfect fruits and vegetables we’re now used to. It also helps alleviate food waste.
However there is increasing evidence that farmers using pesticides face both short and long-term health issues.
Those who live in farming regions with high pesticide use have higher rates of reproductive issues and birth defects, and growing children face more developmental issues due to pesticide use.
While many pesticides have been regulated on the basis of short-term testing of their active ingredients, products are often combined for efficiency and these effects have not been studied. In addition, most pesticides were approved decades ago and since then science has developed a greater understanding of endocrine disrupting chemicals where very minute amounts of a substance might not poison us but can still interfere with the way our bodies function.
Add to this the fact that our systems are rarely detoxing one basic chemical substance such as the active ingredient of a single pesticide. Instead our detoxification pathways must deal with a plethora of toxic substances that range from pesticides on food to pollutants in the air and water, and even chemicals in personal care products and dry-cleaning – to name but a few “environmental stressors”. Medical scientists now recognise that the failure of our bodies to deal with this toxic chemical burden is producing myriad health challenges.
Pesticides are also implicated in many environmental problems, such polluted waterways, depleted soils, and the reduction of biodiversity (eg: bees and amphibians under threat). There is a rise in weed resistance and unhealthy plants that are more susceptible to disease and pests – conditions that are, ironically, treated with more pesticides.
N.B. much of the research cited in this article was conducted prior to 2016 (when it was first published). Since then, advances in science and exposure of industry corruption has only reinforced these findings not mitigated them.
In this post we’ll be looking at:
- What evidence is there that any chemical residues found in foods are bad for us?
- What chemicals are being used in conventional food production?
- Are government regulations adequate?
- How can you know if organics really are free of nasty chemicals?
Pesticides include herbicides, insecticides, fungicides and growth promotants.
Basically, they’re any substance or mixture used to destroy, suppress or alter the life cycle of a pest.
They may be naturally sourced (such as pyrethrum) or synthetically produced in a lab. They can also be organisms.
The bacterium Bacillus thuringiensis (aka Bt) is used to control a number of insect pests, and is also genetically engineered into a crop, so the crop itself becomes the pesticide.
Any pesticides permitted for use by organic farmers (and there are a few) must be:
- naturally occurring,
- able to break down quickly so they don’t remain as residue in food, and
- not suspected of being unsafe for humans.
Because, surprisingly, a vast number of pesticides in use in conventional farming are of questionable safety, if not downright deadly!
Government data from 2002 estimated that almost 300,000 tonnes of pesticides are used on Australian farms annually.
These quantities have been rising since the 1970s and, since this data was compiled almost 2 decades ago, it’s likely that now we’re using even more.
That’s a lot of pesticides – so which ones should you be concerned about?
Over 8000 pesticide and veterinary products are registered by the Australian Pesticide & Veterinary Medicine Authority (APVMA) for use in fruit & veg production, wheat & grains, livestock, forestry, parks & gardens, commercial premises, and households.
You’ll find organophosphates, such as chlorpyrifos, have been used on your conventional fruit and vegetables to control bugs. Chlorpyrifos may also have been used to kill the insects in the stored grain when it’s processed at a conventional flour mill.
In Australia 2,4-D may be sprayed on non-organic wheat for weed control in early growth stages. Diquat and Glyphosate-based herbicides are registered for late crop use ( 7 days before harvest) on conventional legumes and pulses, (chickpeas, lentils, adzuki, mung and soy beans etc), and wheat to control weeds and dry out the crop prior to harvesting.
In USA and parts of northern Europe, where autumn cereal crops are grown, glyphosate based herbicides are increasingly used to dry-down wheat, barley, oats and edible pulses to speed up the harvest. In fact Monsanto, one of the manufacturers of glyphosate based pesticides, provides a pre-harvest guide on when and how to use Roundup for this application. Because it’s considered a safe herbicide it’s permitted for use even up to 3 days prior to harvest. However, glyphosate has become the world’s most popular herbicide, with a 72% increase in its use in the last decade. The vast amounts now being applied to many food crops have increased the residues in what we’re consuming, and the safety of glyphosate has been increasingly under challenge of late.
Other herbicides (weed-killers) like paraquat, metolachlor and atrazine are mostly used before crop planting or after harvest. Some are lethal for humans, even in small amounts and full safety protection must be worn when using them. While spraying before planting would mean the chemicals aren’t on the leaves of the actual plants, they are in the soil. Some degrade quickly in sunlight or are metabolised by soil microorganisms.
Others such as neonicotinoid insecticides may have a half-life of up to 19 years, and organochlorine pesticides (aldrin, chlordane, DDT, dieldrin, and endosulfan) persist in the environment long after the substance has been banned.
However, pests still remain an issue for farmers, with pesticides offering considerable cost benefits.
They not only prevent crop loss, they also ensure we can purchase the kinds of perfect fruit and vegetables we’ve come to expect.
Pesticides – what’s the evidence against them?
Many industrial chemicals have become an ordinary, and some think indispensable, part of food production.
The vast majority of pesticides continue to be used in Australia despite documented evidence of harm.
And it’s only after decades, when the weight of studies (all of which require funding and resourcing) have proved their dangers, are efforts made to reduce their use or ban them altogether.
It’s hardly surprising that organic farmers cite the chemicals used in farming, and concerns for their family’s health, as the main reason for going organic.
Studies show that farmers face higher risks for several diseases
Parkinson’s Disease and pesticides
- Farmers have higher rates of Parkinsons Disease (PD) even from a younger age.
- Studies suggest it may have much to do with the way pesticides interact with particular genetic propensities.
Chronic kidney diseases is an increasing danger for agricultural workers.
- Organophosphate and organochlorine herbicides have been linked with the prevalence of chronic kidney disease and renal failure in farmworkers.
- The problem is now considered an epidemic from Sri Lanka to India to Mexico, with researchers urgently seeking the causes.
- A 2013 study proposed that Roundup’s ability to chelate cadmium and arsenic from the soil contaminates well-water drunk by the entire village.
- A 2015 study of 55,580 licensed pesticide workers in the US showed a link between kidney failure and pesticides (such as atrazine and paraquat), widely used in Australia on sorghum, millet, maize, rice and seed crops (albeit with restrictions).
Non-Hodgkin Lymphoma and other cancers are linked to pesticide use.
- A 2013 systematic review of pesticides found a large number of studies implicating pesticides in the increased risk of cancers such as leukemia, Non-Hodgkin Lymphoma, brain, colon, prostate and lung cancer, amongst others.
- A 2014 overview of 3 decades of research argued that ‘compelling evidence’ links Non-Hodgkin Lymphoma (NHL) with the use of 2,4-D, as well as glyphosate.
If it’s bad for farmworkers can it be any good for you?
Many pesticides are endocrine-disrupting chemicals (EDCs).
- The endocrine system has evolved to respond to extremely low doses of unbound active hormones. Hormone mimics, described as endocrine disruptors, influence the body’s own hormonal messengers and thus, how our cells develop since even small changes in hormone concentration can have important consequences. Known offenders include bisphenol A (BPA) found in food can linings and cash register receipts, phthalates found in plastics and cosmetics, flame retardants, and pesticides such as atrazine. In fact these chemicals are so common that it’s almost guaranteed you have them hiding in your body.
- Glyphosate effectively substitutes for oestrogen in stimulating the growth of hormone-dependent human breast cancer cells, even at minute levels. In fact, as researchers point out, such behaviour is typical of endocrine-disrupting chemicals where minute levels well below residual limits “can actually cause their own distinct problems”.
- In 2015 the Endocrine Society released a statement that ties EDCs to diabetes and obesity, both of which are major threats to quality of life in the developed world.
What role do pesticides play in the growing problem of anti-biotic resistance?
- The authors of a 2014 study found the ‘whatever doesn’t kill you makes you stronger’ rule applies when E.coli and Salmonella are exposed to Kamba, 2,4-D and Roundup. Because these chemicals didn’t kill the bacteria, they actually empowered their resistance to antibiotics.
Industrial chemicals and pesticides induce reproductive issues and birth defects.
- Banned organochlorines are already recognised teratogens (causing birth defects), but the systematic review by Mostafalou and Abdollahi indicates that other endocrine-disrupting pesticides still in use, like the herbicide atrazine, are toxic to human and animal reproduction. Reproductive dysfunctions reported from pesticide use include altered sperm, de-masculinisation in amphibians, and elevated rates of miscarriage. It’s highly likely this is related to the endocrine-disrupting capability of these chemicals.
- Even the ‘safe’ herbicide Roundup (glyphosate) has been linked with birth deformations in piglets, as well as frogs and chickens. Researchers in the frog and chicken study demonstrated that Roundup caused abnormal activity in the Vitamin A (retinoic acid) signalling pathway, which affects genes needed for the embyro’s development.
- When several animal studies show glyphosate impacting sperm health in rats, even if the mechanism is unclear it’s not simply imaginative to suspect it of affecting other male mammals.
- Is glyphosate involved in the higher incidences of congenital abnormalities such as spina bifida, cleft palate and Down’s syndrome in regions of Argentina and Paraguay where intensive GM soy production means heavy use of Roundup? Researchers noted that birth defects had increased threefold and cancer rates fourfold in the last decade up to when the study was published in 2010.
- Doctors observed birth defects up to 10x the national average on the Hawaiian island Kauai, where agro-chemical corporations Dow, Syngenta, et al, test the pesticide resistance of GMO corn with high doses of undisclosed chemicals. Their concerns have been ignored or dismissed by local government.
- Also in 2015, a report by the International Federation of Gynecology and Obstetrics (FIGO) stated that, around the world, women’s exposure to toxic environmental chemicals, during pregnancy and while breastfeeding, threatens the health of their children.
- According to FIGO, there’s enough evidence to link chemicals like pesticides and plastics to miscarriage, still births, increased cancer rates, and neurodevelopmental problems in children.
“We are drowning our world in untested and unsafe chemicals and the price we are paying in terms of our reproductive health is of serious concern.”
Gian Carlo Di Renzo, physician and lead author of the FIGO opinion
Children face more developmental issues when they’re exposed to pesticides
- Allergies, asthma, lowered IQ, attention disorders, and increase in violent anti-social behaviours into adulthood are issues faced by children exposed to industrial chemicals in utero, and up to age 7.
- In their 2014 systematic review, Grandjean and Landrigan showed mounting evidence that acute pesticide poisoning and low-level toxicity is so commonplace in children it’s causing permanent ‘neurobehavioural deficits’ that threaten to become ‘pandemic’.
- The persistence of banned organochlorine pesticides (DDT, endosulfan etc) means they continue to impact the developing brain of the unborn or young child.
- According to Grandjean and Landrigan these children are more likely to develop neurodegenerative diseases such as Parkinson’s in later life.
- Adults exposed to these organochlorines, back when they were commonly used in agriculture and public places, also face reduced IQ in old age.
- The organophosphate chlorpyrifos (used on fruit, vegetables and even for storage of grains) and other organophosphates have been associated with microcephaly (small head circumference at birth). The Zika virus brought attention to microcephaly, which is an indication of slowed brain growth in utero. However studies have shown for years that this condition is associated with a variety of toxins and pesticides, including glyphosate and atrazine.
- Chlorpyrifos exposure in utero has also been linked to nervous system issues which affect children’s ability to learn motor skills such as hand writing.
- A 2015 Spanish study found that boys are more affected by pesticide exposure than girls. Even a small increase in pesticide use (10 hectares p.a.) around the baby’s residence was associated with decreased IQ and verbal comprehension as they matured.
Neurodevelopmental problems affect children’s learning and quality of life. When they persist into adulthood they impact the welfare not only of the individual but of the society as a whole.
“Children worldwide are being exposed to unrecognised toxic chemicals that are silently eroding intelligence, disrupting behaviours, truncating future achievements, and damaging societies.”
Neurobehavioural effects of developmental toxicity, Philippe Grandjean, MD, Philip J Landrigan, MD, The Lancet, Volume 13, No. 3, p330–338, March 2014
Industrial chemicals: more dangerous together than alone
It is not uncommon for pesticides to be combined and applied at once, as this efficiently treats different problems.
Considering that regulatory approval processes are based only on studies of an active ingredient (eg: glyphosate), and no testing is conducted on the full herbicide formula (eg: Roundup), or its interaction with other pesticide products, this should set off some alarm bells.
In fact, these kinds of synergistic processes, alongside the cumulative effect of multitudes of chemicals over the years, are shaping up to be the real concern.
Even if you don’t live anywhere near a farming area, and your exposure to pesticides is a lot less, we are now learning that it’s combinations and long term accumulation that are the real issue.
“Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies.”
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead. Carcinogenesis. 2015 Jun;36 Suppl 1:S254-96. doi: 10.1093/carcin/bgv039.
For this reason, ‘chemical body burden’ is becoming a bit of a buzz phrase amongst health reasearchers.
A variety of toxic chemicals accumulate in your body over time, and it’s not just what you eat either. They’re in many self-care products, household products, and sprayed on gardens in your neighbourhood.
Some argue that if pesticide residues show up in urine, it means the body is doing a good job of eliminating them. However the Spanish study mentioned previously, showed that higher levels of pesticide metabolites in urine were associated with a poorer IQ and verbal comprehension.
And according to Mostafalou & Abdollahi we should be looking at what they’re doing in our bodies before we’re able to eliminate them. These include genetic damages, epigenetic modifications, endocrine disruption, mitochondrial dysfunction, oxidative stress, and more.
Many of the mechanisms of action are still unknown, and these need to be understood in order to conclusively show the dangers.
In vitro, animal, and human studies have already identified several classes of pesticides that modify epigenetic markers.
Epigenetics is the study of inheritable changes in gene expression that don’t change the actual DNA. It shows why some people are more vulnerable than others and how this vulnerability can be passed on to later generations.
In other words, your grandfather’s exposure to pesticides can impact your health too.
Does living stress-filled lives affect how our bodies handle pesticides?
It’s now well known amongst health professionals that chronic stress (specifically the way we deal with the daily stressors of modern life) affects our body in multiple ways, with a flow on effect for our general health.
Epigenetics complicate genetic theory by showing it’s not just one gene or even one substance that is responsible for a health issue.
The affects of pesticides on epigenetic expression can be exacerbated by stress, both of the emotional and the environmental kind (such as air pollution, water quality, radiation exposure etc).
Isn’t there enough proof to condemn toxic pesticides?
Even though studies, over many years, link specific chemicals and pesticides with various chronic diseases and other health disorders, there is an ongoing ‘tennis match’ in academia over whether these effects are actually proven, or have been debunked by other studies.
Grandjean & Landrigan point out that the momentum of academic research tends towards an inertia induced by scepticism.
It’s also hampered by resources because results must be extensively replicated before something is accepted as truth.
The pesticide industry continues to argue that the benefits of pesticides outweigh the ‘unproven’ health effects.
Despite the fact numerous studies flag dangers and point to the need for more research, agri-industry and regulators consider that these links are not conclusively proven, particularly in the case of relatively ‘safe’ pesticides, like glyphosate, where the mechanisms affecting humans are still speculative.
“the existence of more than a few dozen reports on the association of one case like brain cancer with exposure to pesticide is enough to create concern even without finding a direct link.”
Pesticides and human chronic diseases: evidences, mechanisms, and perspectives. Mostafalou S, Abdollahi M.; Toxicology and Applied Pharmacology. 2013, Apr 15; 268(2):157-77.
The potential for pesticides to impact eco-systems and the health of entire communities is an exponentially greater threat than the health consequences of smoking.
It took decades for the links between cigarettes and cancer to be accepted by mainstream researchers. And as we wait for proof, industrial and agricultural chemicals continue to saturate our environment and our bodies with toxins.
Researchers acknowledge that, for example, there are major challenges in designing studies that observe the low-dose effects of EDCs in the human population because the impacts of chemical exposures are dependent on timing of exposure (such as in utero or in adulthood), and individual sensitivities related to genetics, epigenetics, geographic locations, other dietary factors, physiological and psychological stressors, etc. In addition, they point out that a single chemical, or synergistic mix, can effect several body systems simultaneously.
A lack of scientific understanding about these complex interactions means we just don’t yet know enough about the synergistic and cumulative effects of the industrial chemicals we’re immersed in on a daily basis.
It is much harder to study real world complexities than it is to study a specific chemical in a laboratory.
While correlation doesn’t prove causation, it does point to the need for a more a cautionary approach – as well as for more research. Particularly when it comes to children’s development, and the potential for this to have long-term impacts on society.
If we consider the real cost of pesticides are they worth it?
The argument that, without conclusive proof, benefits still outweigh a pesticide’s questionable health effects is often presented by the corporations who continue to make substantial profits from the use of agri-chemicals.
After the initial (mostly short-term studies) which indicate safety, their product is widely accepted and used. The burden of proof then rests with medical researchers to prove suspicions about a pesticide’s negative effects.
As you can imagine, the world’s most widely used herbicide glyphosate is now under pressure with the 2015 IARC (international Agency for Research on Cancer) declaration of it as a ‘probable human carcinogen’. Major corporations like Monsanto, Syngenta (producer of lethal paraquat) and Bayer (producer of bee-killing neonicotinoids) face increasing pressure on their profits as studies continue to confirm the dangers posed by these chemicals.
Rather than funding their own long-term studies, which would be a responsible approach, the ag-chemical companies’ main line of defence is to employ their own scientists to challenge the design, data and interpretations of any independently funded studies that show their product in a bad light.
And as long as profits are at stake, concerned scientists will continue to labour under the burden of having to prove the toxicity of chemicals that are commercially lucrative.
July 2017 update: rediscovered & newly digitised chemical industry and regulatory agency documents reveal systematic deception on part of regulators and manufacturers when it comes to the known toxicity of a host of pesticides and other chemicals. Over 20,000 documents obtained from US government agencies and chemical manufacturers can be viewed at https://www.poisonpapers.org/.
“Untested chemicals should not be presumed to be safe to brain development, and chemicals in existing use and all new chemicals must therefore be tested for developmental neurotoxicity.”
Neurobehavioural effects of developmental toxicity, Dr Philippe Grandjean, MD, Philip J Landrigan, MD; The Lancet, Volume 13, No. 3, p330–338, March 2014
Clearly pesticides bring enormous benefit to a farmer’s bottom line in terms of preventing crop loss and improving yields. Their benefits also have a flow-on effect for processors and retailers by improving the appearance and shelf-life of food.
However there are other ways to approach these issues, and the will-power to do so may have to come from pressure exerted by consumers concerned about their health and their children’s health.
At an academic level it may have to come from the growing body of research that shows the social cost of these toxic chemicals for society as a whole.
A recent study by France’s Institute for Agricultural Research disputes the economic benefits of pesticides by considering not only regulatory costs, but health care costs, as well as environmental and ‘defensive’ costs (such as spending the extra money on organic food).
“The effects of dosing whole landscapes with chemicals have been largely ignored by regulatory systems. This can and should be changed. …Vigilance on the scale that is required for medicine does not exist to assess the effects of pesticides in the environment… Yet (we have) no systematic monitoring of pesticide residues in the environment. There is no consideration of safe pesticide limits at landscape scales.”
Dr Alice Milner and Prof Ian Boyd (chief scientific adviser to the UK’s Department of Environment, Food and Rural Affairs).
Doesn’t Australian produce have low level of pesticides?
All pesticides in use in Australia have undergone initial tests for acute toxicity that enable them to pass regulations – as did big offenders like DDT – which is how they come to be commonly accepted. This regulation process means farmers have been using various pesticides for decades, fairly confident that they are doing no harm to self or environment.
Even when the limitations of initial testing have become apparent, it can still take decades of use before regulatory authorities consider there is enough research proving links between diseases and the use of specific pesticides.
However, the real risks can be in the interactions between different chemicals, and the accumulation of them in our bodies
While a one off encounter with a level of pesticide below the maximum regulated limit won’t kill you, what’s the impact of these encounters over our lifetime?
It’s already recognised that endocrine-disrupting effects can occur at much lower levels than what’s considered poisonous.
A paper from 2012 challenges the traditional assumption behind toxicology testing that “the dose makes the poison”. In reviewing the studies of endocrine disruptors, researchers found that the regulatory risk assessments based on the ‘threshold dose’ (maximum levels of exposure before harmful effects are observed) do not work when it comes to EDCs. Their conclusions state that “fundamental changes in chemical testing and safety determination are needed to protect human health”.
“Many groups and public lead alliances have expressed serious concerns about the way pesticides are regulated in Australia and about the implications for human health and the environment; several dozen pesticides banned in Europe are currently registered and used commonly in Australia.”
The real cost of pesticides in Australia’s food boom, N.Schellhorn, A.Renwick, S.Macfayden, The Conversation.
Pesticide regulation is based on maximum residue limits – but are our regulations adequate?
The consumer advocacy group Choice believes that Australia lags behind the precautionary principle other countries use to safeguard public health. It offered the example of the toxic pesticide endosulfan, which Australia only banned in 2010, long after it was no longer used in more than 60 countries, including New Zealand and the EU.
While Australian authorities banned the lethal dioxin-containing pesticide 2,4,5-T they still allowed unrestricted use of 2,4-D until 2013. ABC’s Four Corners found evidence that 2,4-D herbicides with unacceptable levels of dioxin were being used on Australian farms. And that this may have been due to a lack of policing of cheap imports.
Organic is one way to reduce your body’s chemical load
- A preliminary study by Liza Oates at RMIT in Melbourne showed that switching to an organic diet for as little as a week could reduce pesticide residues by 89%.
- A US study published in May 2015 followed 4,500 people in six cities to determine organophosphate pesticide exposure through food. Those who ate more organic food had lower levels of these pesticides’ metabolites in their urine. These researchers have now gone on to investigate the impact of organophosphate exposure on memory and other neuro-cognitive functions. I’ve already mentioned several studies that have already looked at this in children’s development.
- More recent research by Marc Cohen from RMIT, who supervised Oates’ 2014 study, has measured ‘dramatic’ changes in health, including improvements in depression and anxiety, sleep and cognitive function, after just a week of organic food.
- A Danish supermarket sponsored a family to eat only organic food for 2 weeks and they saw their pesticide metabolites drop to zero. While this isn’t a scientific study the results fit what the tests above have discovered.
How can you be sure organic is free of synthetic & toxic chemicals?
- Australian Certified Organic certifies Kialla Pure Foods. You can download a copy of the ACO standard booklet from their website.
- To find out what processes are in place to make sure organic providers follow the rules, watch this video interview with Michael Baker from ACO.
- The consumer organisation Choice investigates concerns about levels of pesticide and other chemical residues in produce.
- Make sure your produce is certified organic not simply claiming to be.
- Check for the compliance logo or certification number on the product – you’ll find a list of organic certifiers here. Legally all organic produce must display one of these logos and their own cert number.
What you can do now to protect yourself and your family
It’s virtually impossible to avoid chemicals – a child born in the last decade has been immersed in a soup of chemicals since conception.
There are many chemicals, including pesticides, where their negative effects aren’t conclusively proven. In some cases this is because they’re relatively new. Do you want to wait 20 years to find out?
Regardless of whether there is absolute proof, it is increasingly accepted that certain chemicals have a negative impact on our organs, brains, fertility, etc.
You can take action to reduce this chemical burden on your bodies wherever possible. One way to do this on a daily basis is to choose to eat organic food and to use organic personal care, household pesticides and cleaning products.
And it’s advisable not to get too stressed about it either!
By reducing the burden of toxicity – and stress – on our bodies we support it in doing what it does best: restoring balance and thus health.
Read reason no 2 for choosing organics: because they are non-GMO. Why is this important?