New research reveals the difference between organic and conventional produce, and the benefits of eating organic. It looks in particular at crops, meat, milk, and dairy. We also learn that conventional intensive farming is leading to a surprising nutritional loss in certain foods. And claims that an organic diet can prevent some illnesses.
Whether you think organic food tastes better is a personal opinion. But there is no doubt that organic growing principles – feeding the soil not the plant, encouraging wildlife, harnessing nature’s own rhythms to control pests and diseases – are better not just for you, but for the planet.
First, a little history...
In 2009 a report from the US Food Standards Agency, (Dangour et al. 2009) concluded there were no significant differences in nutritional composition between organic and conventional crop and livestock products - apart from a higher nitrogen content in. conventionally produced crops. (Conventional farming uses large quantities of nitrogen-based fertilisers.)
Surprised by this lack of difference, other researchers looked at Dangour's work. They realised his team had looked at only 55 studies - excluding many others because of the terminology around 'organic'. Dangour also accepted studies with mixed breeds, not identical ones. (There can be large differences in nutrient concentrations between different types of the same crop.) So they created a more realistic analysis - and found quite different results. The organic plants alone contained on average 25% higher nutrient concentrations. But chemically produced foods did contain more protein.
Many years later, and a lot more data, leads us to …
Newcastle University has revealed that there are significant nutritional differences between organic and conventional foods. They looked at crops, dairy, and meat. They reviewed all published data to show conclusively that not only was Dangour wrong but there are other positive associations between organic food consumption and a reduced risk of certain diseases. Here is a summary of their results:
- Organic crops and crop-based foods, such as bread, are up to 60% higher in a number of key antioxidants than conventionally-grown crops. These additional antioxidants are the equivalent to eating between 1-2 extra portions of fruit and vegetables a day.
- There is nearly 50% lower toxic heavy metal cadmium in organic crops – but no significant difference for other toxic metals such as arsenic and lead.
- Nitrogen concentrations were lower than in conventional crops. The debate continues on the adverse effect of a persistently high nitrate (and nitrite) intake, with the proposed link to an increased risk of some cancers.
- Conventional fruit has 75% more pesticides traces. Crop based compound foods (such as bread) have 45% more, and vegetables 32%. The worrying 10% of pesticide residue found on organic crops probably results from spray drift.
Milk and dairy
- Organic milk contains substantially more omega-3 fatty acids. These include nearly 60% more nutritionally desirable, very long chain, omega-3 fatty acids, known as EPA, DPA and DHA.
- There were also higher levels of polyunsaturated fat (PUFA), conjugated linoleic acid (CLA), vitamin E (a-tocopherol) and iron in organic milk.
- However, there were lower levels of selenium and iodine. To address this shortfall in iodine, the UK Organic Milk Suppliers Co-operative has increased iodine fortification in dairy feeds. As of 2016, levels are now on a par with conventional milk.
“Omega-3s are linked to reductions in cardiovascular disease, improved neurological development and function, and better immune function," writes Chris Seal, Professor of Food and Human Nutrition at Newcastle University. "Western European diets are recognised as being too low in these fatty acids and the European Food Safety Authority (EFSA) recommends we should double our intake."
Why does organic dairy produce have more omega 3? The Soil Association says “This is because organic animals have to eat a more natural grass-based diet containing high levels of clover. Under organic standards, organic cows must eat a 60% fresh grass-based diet or hay/silage. Clover is used in organic farming to fix nitrogen so that crops and grass grow (instead of manufactured/chemical fertilisers), and research has found that clover also increases the Omega 3 concentrations in meat and milk.”
- Organic meat contains 47% more omega-3 fatty acids, and significantly lower concentrations of the undesirable saturated fatty acids.
- It has significantly higher levels of polyunsaturated fat (PUFA) and omega-6 fatty acids, but lower concentrations of mono-unsaturated fatty acids (MUFA) and a lower omega-6/omega-3 fat ratio.
- Analysis also detected trends towards higher iron (Fe) levels, and lower concentrations of copper (Cu) and the toxic metal cadmium (Cd).
Professor Carlo Leifert, who led the study comments: "Meat is an important source of omega-3 in our diet, especially for individuals who consume little or no fish. Switching to grass-fed organic meat may allow meat consumption to be reduced by around 30% without a reduction in total omega-3 fatty acid intake."
Is the organic diet healthier?
There is growing evidence that eating organically can help with disease prevention, childhood allergies, obesity, certain cancers and pre-eclampsia in pregnant women. A comprehensive European study, called Human health implications of organic food and organic agriculture lists all the research in this area.
However it notes that “ ...It is known that consumers who regularly buy or consume organic food have healthier dietary patterns, such as a higher consumption of fruit, vegetables and wholegrain products and a lower consumption of meat, compared to other consumers. These dietary patterns are associated with various health benefits, which include a reduced risk of chronic diseases such as type 2 diabetes and cardiovascular diseases.”
Here are some examples of research on organic food and Obesity, Non-Hodkin’s lymphoma, Pre-eclampsia and Childhood allergies: (Alfven, T., et al., Allergic diseases and atopic sensitization in children related to farming and anthroposophic lifestyle--the PARSIFAL study. Allergy, 2006. 61(4): p. 414-421. Kummeling, I., et al., Consumption of organic foods and risk of atopic disease during the first 2 years of life in the Netherlands. Br.J.Nutr., 2008. 99(3): p. 598-605. Rist, L., et al., Influence of organic diet on the amount of conjugated linoleic acids in breast milk of lactating women in the Netherlands. Br.J Nutr., 2007. 97(4): p. 735-743. Stenius, F., et al., Lifestyle factors and sensitization in children - the ALADDIN birth cohort. Allergy, 2011. 66(10): p. 1330-1338. Fagerstedt, S., et al., Anthroposophic lifestyle is associated with a lower incidence of food allergen sensitization in early childhood. J Allergy Clin.Immunol., 2015.)
In all the above cases, however, the evidence is not conclusive, as there are no long-term studies. Furthermore, it is inherently difficult to separate organic food consumption from other associated lifestyle factors that may affect human health.
What about non-organic foods?
Even if you don’t eat organic foods, are you still getting a healthy and nutritious diet? Two recent research papers, one in the UK and one in Australia, show that psychological well-being increases with the consumption of fruit and vegetables. The optimum effect comes from eating 7 a day.
However, long-term research shows a worrying trend in the reduction of vital minerals in non-organic vegetable and fruit crops.
A comparison of the mineral content of 20 fruits and 20 vegetables grown in a 50-year period, from the 1930s - 1980s (published in the UK Government’s Composition of Foods tables) shows several marked reductions in mineral content. The average content of calcium in vegetables, for instance, declined by 46% of the original level. Copper levels are down by 76%, Sodium 49%, Iron 27%, and Magnesium 24%,
Quick note - when cooked vegetables were tested, they were first boiled in distilled water. For broccoli in 1991, it was 15 minutes, while in 1940 it was 45 minutes!
Why are minerals important?
We depend on them for energy efficiency, fertility, mental stability, and immunity. Calcium, for instance, builds bones and teeth and promotes blood clotting. Copper builds red blood cells and haemoglobin; metabolizes iron, maintains connective tissue and blood vessels, and may play a role in cancer prevention. Magnesium helps the muscular and nervous systems function, as well as the heart and circulatory system.
In her paper Historical changes in the mineral content of fruits and vegetables, Anne-Marie Mayer argues there are a number of factors that might cause this alarming trend:
- Changes in varieties – modern farming chooses varieties for high yield, not for nutritional value. Similarly, they choose varieties that are not prone to damage on supermarket shelves.
- An increase in the use of chemicals for fertilisers, which depletes the symbiosis of the soil and root systems, and can prevent mineral uptake.
- Changes in our food systems – vegetables and fruits are transported further, and therefore stored for longer.