Crops being sprayed by pesticides

Organic food and pesticides and their link to disease

In Health and Nutrition by Andre LeuLeave a Comment

Concern about pesticide residues in food is the major reason given by consumers for purchasing organic foods. They do not trust the assurances given by governments and industry that the pesticide levels in our food are safe.

These concerns have been validated by several recent studies. The most significant has been the 2010 Report by the US President’s Cancer Panel (USPCP). This report stated that environmental toxins, especially chemicals, are the main causes of cancer and raises particular concern over the exposure levels for children.

The report, published by the U.S. Department of Health and Human Services, the National Institutes of Health and the National Cancer Institute also stated that the current methods of testing and regulating chemicals such as pesticides are inadequate.

Pesticides linked to many types of cancers

The USPCP report found that many types of cancer were linked to pesticide exposure:
‘Nearly 1,400 pesticides have been registered (i.e., approved) by the Environmental Protection Agency (EPA) for agricultural and non-agricultural use. Exposure to these chemicals has been linked to brain/central nervous system (CNS), breast, colon, lung, ovarian (female spouses), pancreatic, kidney, testicular, and stomach cancers, as well as Hodgkin and non-Hodgkin lymphoma, multiple myeloma, and soft tissue sarcoma. Pesticide-exposed farmers, pesticide applicators, crop duster pilots, and manufacturers also have been found to have elevated rates of prostate cancer, melanoma, other skin cancers, and cancer of the lip.

‘Approximately 40 chemicals classified by the International Agency for Research on Cancer (IARC) as known, probable, or possible human carcinogens, are used in EPA-registered pesticides now on the market.’

Current testing fails to accurately represent human exposure to harmful chemicals

The report further stated: ‘Some scientists maintain that current toxicity testing and exposure limit-setting methods fail to accurately represent the nature of human exposure to potentially harmful chemicals. Current toxicity testing relies heavily on animal studies that utilize doses substantially higher than those likely to be encountered by humans.’

Testing fails to account for harmful effects of low doses

The science around endocrine disruption (please see article on previous page, ‘Obesity, diabetes, ADHD, some cancers, lowered fertility from some chemicals found in food and water in even more dilute forms’) shows that many chemicals considered to have very little toxicity in parts per million (ppm) have a range of adverse effects in parts per billion (ppb). This is because at these lower levels they can bind with the body’s hormone receptors whereas at the higher levels they are ‘ignored’ by the receptors.

These compounds disrupt hormone systems at levels 1000 times lower than previous research stated was safe. Agricultural chemicals have been shown to mimic hormones such as oestrogen, blocking hormone receptors or stopping hormone activity. These chemicals have been implicated in lower sperm counts, increases in breast, uterine, testicular and prostate cancers and deformities in the genital-urinary tracts in a wide range of species, including humans.

The USPCP report stated: ‘These data – and the exposure limits extrapolated from them – fail to take into account harmful effects that may occur only at very low doses.’

An example of this is Atrazine – one of the world’s most commonly used herbicides. Two peer-reviewed studies conducted by Tyrone Hayes showed that levels 1000 times lower than currently permitted in our food and in the environment cause severe reproductive deformities in frogs.

Sara Storrs and Joseph Kiesecker of Pennsylvania State University confirmed Hayes’ research. They exposed tadpoles of four frog species to Atrazine. ‘Survival was significantly lower for all animals exposed to 3 ppb compared with either 30 or 100 ppb.’ The researchers further stated that: ‘These survival patterns highlight the importance of investigating the impacts of contaminants with realistic exposures and at various developmental stages’.

Dan Qiao et al. of the Department of Pharmacology and Cancer Biology, Duke University Medical Center, found that the developing foetus and the newborn are particularly vulnerable to amounts of pesticide far lower than currently permitted by most regulatory authorities around the world. Their studies showed that the foetus and the newborn possess lower concentrations of the protective serum proteins than adults. A major consequence is developmental neurotoxicity, where the poison damages the developing nervous system.

The scientists stated: ‘These results indicate that chlorpyrifos and other organophosphates such as diazinon have immediate, direct effects on neural cell replication… In light of the protective effect of serum proteins, the fact that the fetus and newborn possess lower concentrations of these proteins suggests that greater neurotoxic effects may occur at blood levels of chlorpyrifos that are nontoxic to adult.’

These concerns were validated by four later studies that showed that prenatal exposure to organophosphate insecticides (OPs) adversely affects the neurological development of children. Each study was conducted independently; however they all came up with very similar results. This was that foetal exposure to small amounts of OPs will reduce the IQ of children.

A study of farm worker families in California has shown that, by age 3.5, children born to mothers exposed to OP insecticides have lessened attention spans and are more vulnerable to attention deficit, hyperactivity disorder (ADHD). Male children were more likely to be impacted.

The studies were conducted by researchers at the Columbia University Center for Children’s Environmental Health, the University of California, Berkeley and the Mount Sinai School of Medicine. Parents should have considerable concern that the Columbia University study found that there was no evidence of a threshold in the observed adverse impact on intelligence. This means that very low levels of exposure could lead to reductions in a child’s intelligence.

Children are exposed to chemical contaminants through the umbilical cord and breast milk

One of the great concerns is that fact that most children are born with cocktails of chemicals in their bodies. ‘Some of these chemicals are found in maternal blood, placental tissue, and breast milk samples from pregnant women and mothers who recently gave birth. These findings indicate that chemical contaminants are being passed on to the next generation, both prenatally and during breastfeeding. Some chemicals indirectly increase cancer risk by contributing to immune and endocrine dysfunction that can influence the effect of carcinogens.

…Children also can be exposed to toxins in utero via placental transfer and/or after birth via breast milk. Tests of umbilical cord blood found traces of nearly 300 pollutants in newborns’ bodies, such as chemicals used in fast-food packaging, flame retardants present in household dust, and pesticides.’ (USPCP report)

Children are at special risk for cancer due to environmental contaminants

One of the critical issues is that children have much higher risk factors from chemical exposure. ‘They [children] are at special risk due to their smaller body mass and rapid physical development, both of which magnify their vulnerability to known or suspected carcinogens, including radiation. Numerous environmental contaminants can cross the placental barrier; to a disturbing extent, babies are born ‘pre-polluted’. Children also can be harmed by genetic or other damage resulting from environmental exposures sustained by the mother (and in some cases, the father). There is a critical lack of knowledge and appreciation of environmental threats to children’s health and a severe shortage of researchers and clinicians trained in children’s environmental health.’ (USPCP report)

Children’s cancer rates are increasing

The USPCP report showed that this is a serious concern due to the increasing rates of cancer in children. ‘Yet over the same period (1975–2006), cancer incidence in U.S. children under 20 years of age has increased.

…Leukemia rates are consistently elevated among children who grow up on farms, among children whose parents used pesticides in the home or garden, and among children of pesticide applicators. Because these chemicals often are applied as mixtures, it has been difficult to clearly distinguish cancer risks associated with individual agents.’

Concern over food residues being too high

Very significantly the majority of people get most of their exposure to pesticides through food, especially fresh fruit and vegetables. According to the USPCP report: ‘Only 23.1 percent of [food] samples had zero pesticide residues detected, 29.5 percent had one residue, and the remainder had two or more. The majority of residues detected were at levels far below EPA tolerances … but the data on which the tolerances are based are heavily criticized by environmental health professionals and advocates as being inadequate and unduly influenced by industry.’

The report recommended that people consume food grown without pesticides, fertilisers and growth hormones. Contrary to popular belief, washing or peeling conventional produce only removes a percentage of the pesticides as they tend to be absorbed through the whole of the produce. Peer-reviewed scientific studies show that eating organic food will reduce the risk significantly as these chemicals can be quickly eliminated from the human body.

A study by University of Washington researchers concluded, ‘The dose estimates suggest that consumption of organic fruits, vegetables, and juice can reduce children’s exposure levels from above to below the U.S. Environmental Protection Agency’s current guidelines, thereby shifting exposures from a range of uncertain risk to a range of negligible risk. Consumption of organic produce appears to provide a relatively simple way for parents to reduce their children’s exposure…’

About the author
Andre Leu

Andre Leu

Andre Leu is the President of International Federation of Organic Agricultural Movements (IFOAM), the world umbrella body for the organic sector. He is Chair of the Organic Federation of Australia (OFA), the peak body for the Australian Organic sector. Andre and his wife own an organic tropical fruit orchard, in Daintree, Queensland, that supplies quality controlled fruit to a range of markets from local to international.

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