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Organic Food: Nutritional Value and Safety

by Sarah Merson(more info)

listed in organic food, originally published in issue 61 - February 2001

Is organic food nutritionally 'better' for us? Is it safer? Is there any evidence?

Everywhere we look we see 'organic'. From the supermarket shelves to headline news, 'organic' is a term that is fast flooding our domestic kitchens, has high priority on our political agenda and is part of our everyday lives. When we consider what organic produce represents to us, we know that organic carrots invariably cost more than conventionally grown carrots and that 'organic' produce seems to be the buzzword amongst top chefs of today, but do we know what bearing eating an organic diet has on our health and well-being? Is organic food nutritionally 'better' for us? Is it safer? Is there any evidence?

This abundance of 'organic', lack of public knowledge, the nutritional validity debate and the controversy surrounding the topic led me to look into it further. In knowing that the consumption of organic food is a relatively new phenomenon, there can be little or no research that has been carried out on people who have eaten organically for a prolonged period of time, therefore making it difficult to access the health benefits. This makes a starting point for analysis somewhat sceptical. With this, we must consider that it is aspects of lifestyle on the whole that add consequence to an individual's health and well-being. (Editor's note: see especially the previous article Which Food is Best?). When we live in a world of toxins and contamination, in order to evaluate a person's 'health' status we must account not only for nutrition but for everything from air and water pollution to stress levels and genetic influence. However, whilst there is no sound research history on the nutritional values of organic food, judging by the increasing levels of organic farm conversion in the UK – 180,000ha[1] in 1999 to 540,191 ha[2] currently – it is clear that there is a steep marked increase in popularity. Similarly, in the US, organic food sales are currently at about $6 billion with future growth rate estimated at 20-25%.3

Organic basket

The Soil Association has developed from the philosophy where 'organic agriculture is a safe, sustainable farming system, producing healthy crops without damage to the environment' and 'animals are reared without the routine use of the array of drugs, antibiotics and wormers which form the foundation of most conventional livestock farming'; it has become the official stamp of organic produce in the UK. With this we can be sure that the growing of an organic vegetable avoids the use of artificial chemical fertilizers and pesticides on the land. We know, therefore, not so much what the vegetable does contain but rather what it does not contain.

Is Pesticide-Free Organic Food Safer Than Conventionally Farmed Foods?

Most of our food is produced on an industrial scale, using artificial fertilizers – which leach into and contaminate groundwater, lakes and streams – and pesticide, herbicide and fungicide chemicals, which carry poison/hazardous warnings on their containers and require protective clothing and a licence when used. The cumulative long-term effects of exposure to pesticides in our daily lives are still vastly unknown. However, some pesticides, like lindane and carbendazim, which until now have been used in the UK, are known to have hormone-disrupting effects.[4] Also, last year, the Royal Society published a report on hormone-disrupting chemicals and recommended a precautionary approach. In particular they said that measures should be taken to ensure pregnant women's exposure to these chemicals is reduced. By eating organic food exposure to xenoestrogens is reduced[5] and therefore the risk of hormone disruption is minimized.

A diet of organic food should eliminate the main source of exposure to pesticides. Such is the emphasis on eliminating pesticides from food that charities such as Sustain – the alliance for better food and farming – are running campaigns like the Organic Food & Farming Targets Bill. This aims to 'have a strategy in place to ensure 30% of land is in organic production and 20% of the food we eat is organic by 2010'.[6] Sustain consider that demand for organic food in the UK is growing at 40% each year, but around 70% of organic food is imported. In this case our UK farmers are clearly losing out and this is the motivation behind the Targets Bill where aims for increased organic production are calculated by looking at the current growth in demand and by studying the progress of other European countries. Sweden, which has the greatest proportion of in-conversion organic land, currently 11.2%,[7] set targets during the 1990s. Sustain see these targets as realistic and achievable goals for the UK Government to work towards, and where enquiries to the Organic Conversion Information Service (OCIS) for England have more than doubled, from 111 in February 1997 to 290 in February 2000,[8] the interest is most definitely there.

Organic food delivery

In September 2000, Friends of the Earth published news from a government report that there has been a significant increase in the quantity of fresh fruit and vegetables containing pesticide residues. Traces of pesticides were found in 43% of fresh fruit and vegetable samples. Last year's figure was 33%.[9] The results are contained in the 1999 report from the Working Party on Pesticide Residues. Sandra Bell, Real Food Campaigner at Friends of the Earth, said: 'The public will be dismayed to learn that almost half the fresh fruit and vegetables they are eating contain pesticides'.

Farmers and local authorities together used nearly 25,744 tonnes of pesticide active ingredients in the UK during 1999, made up of some 400 different pesticide chemicals.[10] A proportion of this total ends up in water sources and therefore infiltrates into our conventionally farmed food chain. However, regulators are now realizing that the presence of some pesticides in water, however carefully farmers use them, is almost inevitable even on organic farms. Careful use can reduce the amount of pollution, but can never prevent it completely. In fact, each year it costs water companies over £100m to clean up pesticides from our water[11] – this cost is passed on in water bills.

Levels of Pesticide Residues – Proving Unsafe?

Although rare, pesticide residues have been detected in organic food in some MAFF surveys. Organic food can be contaminated with pesticides by cultivation on previously contaminated soil; by unauthorized use of pesticides by the organic farmer; by spray drift from nearby conventional farms; by application of contaminated sewerage sludge or by contamination during transport, processing and storage.

As pesticide levels in conventional food have been either negligible or below the maximum residue level in most studies, it is not strictly correct to claim that conventional food is more contaminated than organic food. There are studies showing a lower pesticide content in organic food and others that show no difference in pesticide content. Organochlorine pesticides provide a valid platform for research as they are persistent and degrade very slowly and are thus more likely to remain as residues than other kinds of pesticides. However, when no one knows what long-term effect pesticides may have on our health, we should be extra-cautious when Government advisors say that pesticide residue levels are safe.

Some Hard Evidence Against Pesticides

The banning of lindane across the EU shows considerable action against its detrimental effects. 'We have been warning for many years that lindane should be banned', said David Buffin of PAN UK. 'This insecticide was developed in the 1940s when cheap and relatively hazardous chemicals were considered acceptable. It should have no place in the 21st century.' Lindane has been described by the International Agency for Research on Cancer as a possible human carcinogen and has been linked with breast cancer and birth defects. The Standing Committee's vote followed a report written for the EU by the Austrian government in 1998, which concluded that there was no safe limit of exposure for lindane and recommended a Europe-wide ban.

Data from published literature[12] suggests that:

  • lindane can have effects on female hormone levels, and can also affect sexual behaviour;
  • oral dose levels of greater than or equal to 10mg/kg body weight/day cause behavioural changes in developing rats;
  • lindane induces increased irritability and impairs spontaneous and conditioned behaviour in rats;
  • epidemiology studies examined in the report included toxic effects on blood, on genes, and association with cancer or birth defects. None of the studies provided causal links because of either insufficient details of dose or exposure to lindane or because exposure to other chemicals (mostly other organochlorines) occurred simultaneously;
  • carcinogenicity studies in mice indicate that exposure to lindane increased the incidence of liver and lung tumours.

Despite these suggestions, it is important to remember that the report says none of the mouse cancer studies were fully adequate because of deficient experimental design and insufficient documentation on the results.

The Debate over the Nutritional Value of Organic Food

When the Food Standards Agency produced a paper in September 2000, suggesting there is no evidence in support of the nutritional superiority of organic food, or of its relative safety, an extreme reaction was provoked. The HDRA's (Henry Doubleday Research Association) Chief Executive, Alan Gear, was amongst those who attacked the paper as being misleading and inaccurate.

"I can't imagine how the Food Standards Agency reached its conclusions," said Mr Gear. "Only last year a House of Lords report on organic farming referred to a review of 150 scientific investigations that confirmed that organic vegetables generally contain higher levels of vitamins and less nitrate. And a new report from the Food and Agriculture Organization has shown that organic foods have lower levels of pesticides and veterinary drug residues." He went on, "I would have thought it self-evident that crops produced using pesticides, however carefully applied, are more likely to contain harmful residues than organic crops where such chemicals are banned. The Government's own regular monitoring of foods for pesticides typically detects residues in a third of all samples."

HDRA, which is in the middle of a detailed review of scientific evidence published worldwide on the difference between organic and chemically grown food, has found that, unlike here in the UK, a considerable amount of research is under way on the continent. The HDRA study should be completed by the end of the year and the key findings will be made public. More sophisticated analytical techniques are being developed which show up subtle differences between organic and conventional produce. What is needed, though, is more work into potential links between the quality of food and health.

Warning – Supermarket manipulation
The availability of supermarket organic food is speeding up faster than we know what to do with it. The manipulation of information in marketing campaigns includes an organic range of burgers, chips, cakes and biscuits. Whilst we are learning the benefits of fresh organic foods, supermarkets are misleading us into believing that if a burger is marked ‘organic’ then it is good for us. According to the Food Commission, 50% of teenagers today eat three or four burgers every week and so it seems vital, in the first instance, to educate towards a healthy, balanced diet. Due to market manipulation, we must be extra careful in our understanding of nutritionally healthy organic foods.

Plastic packaging retains organic integrity by reducing cross-contamination and creating a micro-climate. The micro-climate helps to retain moisture (especially effective with leafy vegetables such as lettuce and cabbages); however, as it also preserves the produce for longer, we should be aware of the shelf-life of organic vegetables in our supermarkets. After three or four days the nutritional value of organic vegetables can be in deficit due to the damaging effects of decay. In this case, the potential benefits, as perceived by researchers at Rutgers University, USA, of organic foods having an 87% higher content of magnesium, potassium, manganese, iron and copper,[13] are effectively lost. We should therefore be careful to examine our packaged organic vegetables before buying.

In early 2000 there were reports in the press that a team from the University of Copenhagen had found conclusive evidence that organically grown plants contained higher levels of nutrients than those grown by conventional methods. However, we must bear in mind that this was a very specific study looking only at one small component, polyphenols, in a few foods.[14]

It is clearly undeniable that there are large gaps in the research on the health benefits of organic food. The best way to fill these gaps would be to carry out well-designed epidemiological studies of health outcomes in people. The next best way is to improve the quality of the nutrient content studies by agreeing a protocol that takes all the important variables into account and that avoids the biases of many of the existing comparative studies. Such variables include the array of products used for analysis, the moisture content of the food (this affects the levels of all nutrients), the age of the samples, the soil the food was grown in and how the food was stored, processed and cooked before it was analysed.

One thing is certain, modern living continually bombards us with chemicals – so if we can make certain choices that result in putting less of these into our bodies, why not make them. By eating fresh organic foods we are making those choices.


1. The Organic Food and Farming Report 1999. The Soil Association. 2000.

2. MAFF Press Office – March 2000. Organic Facts & Figures May 2000. The Soil Association. 2000.

3. Brett Angela. Organic News – NFU. Feb 2000.

4. Colborn T et al. Developmental Effects of Endocrine Disrupting Chemicals in Wildlife and Humans. Enviro Health Prospect. Various Trust Pesticides Trust Publications, 1998 and 1999.

5. Olivier Suzannah. You Are What You Eat – Natural Hormone Balance. p62. 2000.

6. Organic Targets – A Strategy for Change. Sustain. May 2000.

7. Lampkin Nicolas. Welsh Institute of Rural Studies, University of Wales, Aberystwyth. (Based on data supplied direct or published up to 28/5/99).

8. Soil Association data on file. March 2000.

9. Bell S. Autumn 2000 Press Release. Real Food Campaign. Friends of the Earth. (

10. Pesticides in Water. Pesticides News. 49. PAN UK. September 2000.

11. PAN UK briefing covering issues related to pesticides in water. Pesticides News. 49. September 2000.

12. Harvey John. Review of Lindane – December 1998. Pesticides News. 43. p3. European Commission. March 1999.

13. Journal of Applied Nutrition. 45. 1993.

14. Organic Food. Position Paper. Food Standards Agency. August 2000.


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About Sarah Merson

Sarah Merson has a diploma in human nutrition and is a freelance health and nutrition writer. She is developing her own unique approach to personal diet and lifestyle therapy with an holistic approach. She has recently begun facilitating Food and Mood workshops in the London area. She can be contacted on Tel: 07971 957461.

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