Sophie Leicester's essay was chosen as the best essay on the topic in the last academic year.
Discuss the nutritional differences in foods produced by organic and conventional farming methods.
The Food Standards Agency (FSA) currently state that there is no scientific evidence to prove that organic food is healthier or safer than food produced by conventional farming methods (FSA 2008). This essay will explore two of the major issues surrounding the debate – that of avoidance of pesticide residue and greater nutritional benefits of organic food.
Organic farming seeks to avoid the use of synthetic fertilizers and pesticides and instead rely on an ecologically sound approach. The Soil Association (2008) believes in a holistic approach to farming, claiming better taste, health and advantages for the environment, and seeks to improve soil and avoid pest damage through management and farming techniques (see Appendix 1).
Organophosphates are the most widely used group of insecticides in the world (Pesticides Trust 1996). Working by inhibiting the action of acetylcholinesterase (AChE), a neurotransmitter, in nerve cells, they may be related to various diseases including cancer, and mental, neurological and reproductive effects (Cohen 2007). Exposure to these chemicals has been linked to suicide (Jaga Dharmani 2007), reproductive disorders (Frazier 2007), cognitive and behavioural functioning in children (Lizardi et al 2008), childhood leukemia (Monge et al 2007), reduced semen quality (Swan et al 2003), among many others. Lopez et al (2007) showed agricultural workers showed decreased antioxidant enzyme activity which, it is proposed, may be linked to the adverse health effects. While the FSA claim all foods, both organic and conventional, have residues below recommended levels (FSA 2008) (see Appendix 2), even low level exposure may cause neurotoxicity (Jamal et al 2002) and have an adverse impact on fertility and the development of the fetus (Peiris-John, Wickremasinghe 2008). Lu et al, (2006) and Curl et al (2003) show that for children particularly, exposure to pesticides occurs through diet and an organic diet significantly reduces exposure levels. Cohen (2007) argues that children may be susceptible to adverse affects of exposure due to underdeveloped detoxification pathways and longer life expectancy to develop diseases with long latency periods. Therefore particularly vulnerable groups include those taking preconceptual care, breastfeeding and pregnant women, children, as well as those with compromised detoxification systems e.g. cancer patients.
There appears to be little research on the combined effects of the different substances in the body, and the Committee on Toxicity of Chemicals in Food, (2002), commissioned by the FSA, recommend changes should be made to carry out combined risk assessments of exposures to more than one pesticide, assuming chemicals with the same toxic action will act cumulatively.
Many further issues surround this topic, full discussion of which are beyond the scope of this essay. For example, among other issues, use of nitrate fertilisers may contaminate water, potentially causing health issues (see Appendix 3); use of prophylactic antibiotics in conventional farming may lead to antibiotic resistant disease in both animals and humans; growth hormones may be passed on to people who consume the meat and have adverse effects on health; genetically modified food, which has not been subject to rigorous testing, may create situations where genes are transferred across species (World Wildlife Fund 2003).
Also, food additives have been linked to many illnesses, including affects on behaviour. However, any adverse impact of these issues is not relevant with organic food, which therefore must be a consideration in its favour.
The Soil Association (2008) claim significantly increased nutritional value in organic foods. The practice of mono-cropping for conventional crops inhibits the development of soil quality (Department of food and rural affairs 2008) which is likely to impact on the nutritional benefits of the foods grown. A comparative study (Gyorene et al 2006) claims organic crops contain significantly higher amounts of certain antioxidants such as Vitamin C, polyphenols and flavanoids, minerals and have higher dry matter content than conventional ones, as well as lower levels of pesticide residues, nitrate, and some heavy metal contaminations. Other studies also support these statements.
There seems to be some consistent agreement on the increase in Vitamin C, and other antioxidants such as beta carotene, Vitamin E, and flavanoids, as well as lower nitrate content (Williams 2002).
Mitchell et al (2007) showed that long term studies need to be undertaken, because as soil quality improves over time with organic farming, so do levels of nutrients in the tomatoes. Hajslova et al (2005) pointed out other factors which impact on nutrient quality such as geographical variation and changes in climate. Those studies that are more cautious (Williams 2002, Bourne Prescott 2002) call for further research in this area and the FSA themselves are currently undertaking such research (FSA 2008).
Mukherjee et al (2007) claim the possibility of greater faecal contamination from manure based fertilisers in organic food. However, the study involved a much larger proportion of organic than conventional farms, and other studies (Bourne Prescott 2002) show no evidence that organic foods are more susceptible to microbial contamination than conventional foods.
Organic farming systems can also affect the fat composition of dairy and other animal products, and appear to improve nutrient value in terms of fatty acids eg, improving the omega 3 to 6 ratio, linked to many health benefits (see Appendix 4). Faucitano et al 2008 showed that beef production systems that relied more on forage produced beef of higher nutritional quality in terms of higher omega 3 to 6 ratios. Jahreis et al (1997) showed milk from farms which used an ecological farming system had significantly higher amounts of conjugated linoleic acids (CLA), which have been shown to have antioxidant and anti-cancer properties. Rist (2007) also found that breastfeeding mothers increased the amount of CLA in their breastmilk as they switched to an organic diet, presumably from greater intake of these acids through organic food. The omega 3 content of fish can be manipulated in farmed fish through different feeds, but the pollutant content of even organically farmed fish makes wild fish a healthier option (Shaw et al 2006).
Organic farming methods seem able to produce food that can be both nutritionally higher quality and possibly safer. The impact of organic farming on the environment is positive, encouraging biodiversity and sustainability (Soil Association 2008). While both cost and the practicalities of feeding people on a global basis must not be ignored, those issues are beyond the scope of this essay (see Appendix 5).
Discussion of the evidence seems to conclude that particularly for vulnerable groups such as pregnant or breastfeeding women, children, and those with long term illnesses, organic food would be preferable and desirable if possible. However, for the majority of people, the impact of a healthy diet, whether organic or conventional, would be of paramount importance.
Appendix 1
Organic farming techniques
In their article ‘Organic Agriculture’ (2001), Brown and Haward outline the main principles of organic farming techniques.
- These rely on optimising the health of the crops, through increasing soil fertility by building up the organic matter, maintaining soil structure, replenishing nutrients, reducing loss of nutrients by erosion and leaching (Brown Haward 2001 : 64).
- Crop rotation ensures that soils don’t lose the same nutrients to the crops each year and also that the same diseases and pests that target individual crops don’t build up.
- Sowing legumes or green manure crops put nitrogen back in the soil for future crops to use as well as avoiding erosion in sites that are fallow.
- Manure and compost made from waste vegetable matter also build up the nutrients in the soil. Identified soil deficiencies such as potassium, can be replenished with natural substances such as potash.
- Choosing to grow resistant crop varieties also helps avoid the use of chemicals to build successful crops.
- Some natural substances act as pesticides eg soft soap against aphids.
Appendix 2
Pesticide residues – organic and conventional foods
- The Pesticides Safety Directorate is a government organisation that is responsible for monitoring the safety of pesticide use in this country.
- They claim that 2/3 of the food monitored is completely free from residues, and that the Maximum Residue Level for pesticides which is set in this country is significantly below the safety levels for the pesticide (Pesticide Safety Committee 2008).
- However, the Soil Association claim that the amount of residues that are being found, even if below the MRL, are unacceptable to the public and may cause health problems, as not enough is known about cumulative or cocktail affects.
- Examples of the amount of residue found include lemons where in 2001 100% contained detectable residues with 90% containing multiple residues; potatoes, where in 2003 41% contained residues with 13% containing multiple residues, and prepacked salad where in 2004 40% contained residues with 18% containing multiple residues (Soil Association 2008).
Nitrate fertilisers
The U.S. Environmental Protection Agency (U.S. EPA) (2006) claim that excessive levels of nitrate in drinking water can cause serious illness and deat, due to the conversion of nitrate to nitrite in the body, which interferes with oxygen carrying capacity. Children, with lower body weight and smaller blood volume, are particularly vulnerable to this. They also claim that a lifelong exposure to higher than safety levels of nitrates can cause damage to the spleen among other health issues.
They are also:
- Expensive to produce.
- Bad for the environment to produce
- Don’t replace nutrients in the soil or enhance soil quality, leaving soils barren and lacking in nutrients, leading to reliance on the expensive fertiliser to grow food
- Damage the environment – flow off causes eutrophication of water supplies (overgrowth of algae, damaging the biodiversity of the environment)
- Produce Nitric Oxide – a greenhouse gas
Appendix 4
The importance of the omega 3 to 6 ratio
Humans have evolved with a diet where the ratio of omega 3 to 6 is approximately 1. Simopoulos (2002) suggests that the current ratio in Western diets is approximately 15:1. He claims that this deficiency in the protective omega 3 oils is linked to many degenerative diseases, and produces studies which show that manipulating the ratio of omega 3 to 6 levels to lower ratios have many beneficial effects on diseases such as rheumatoid arthritis and breast cancer.
The omega 3 cascade in the body produces the prostaglandins 1 and 3 which are anti inflammatory and therefore have a protective effect on many of the chronic diseases which are inflammatory in nature.
Appendix 5
Feeding the world
The Soil Association (2008) claim that organic farming is a possible solution to poverty and starvation, an alternative to both conventional farming and the production of GMO foods, as it is a system that doesn’t rely on expensive chemical inputs in the forms of fertilisers or pesticides. It is sustainable and relies on maintaining soil fertility. Yields have also been shown to be higher than conventional methods when used in developing countries, and the Soil Association claim that more should be done to encourage sustainable organic farming in developing countries.
References available on request.
