Organic foods higher in vitamins, minerals, phytonutrients, lower in nitrates

Recent studies strongly suggest that organically grown foods offer significantly more benefits than their conventionally grown counterparts.

A review of 41 studies comparing the nutritional value of organically to conventionally grown fruits, vegetables and grains, indicates organic crops provide substantially more of several nutrients, including:

  • 27% more vitamin C
  • 21.1% more iron
  • 29.3% more magnesium
  • 13.6% more phosphorus

The review also found that while 5 servings of organically grown vegetables (lettuce, spinach, carrots, potatoes and cabbage) provided the daily recommended intake of vitamin C for men and women, their conventionally grown counterparts did not. Plus, organically grown foods contained 15.1% less nitrates than conventionally grown foods. Nitrates, a major constituent of chemical fertilizers, bind to hemoglobin and, particularly in infants, can significantly reduce the body's ability to carry oxygen. For more information on nitrates, click Nitrates North Carolina Cooperative Extension Service

In another study whose findings are based on pesticide residue data collected by the U.S. Department of Agriculture, organic fruits and vegetables have only a third as many pesticide residues as their conventionally grown counterparts. Study data, which covered more than 94,000 food samples from more than 20 crops, showed 73% of conventionally grown foods sampled had residue from at least one pesticide, while only 23% of organically grown samples had any residues. When residues of persistent, long-banned organochlorine insecticides such as DDT were excluded from the analysis, organic samples with residues dropped from 23 to 13%. In contrast, more than 90% of USDA's samples of conventionally grown apples, peaches, pears, strawberries and celery had residues.

When it comes to choosing between organic or conventionally grown foods, size is definitely not everything, suggests another study published in Science Daily Magazine. Chemistry professor Theo Clark and undergraduate students at Truman State University in Mississippi found organically grown oranges contained up to 30% more vitamin C than those grown conventionally. Reporting the results at the June 2, 2002, meeting of the American Chemical Society, Clark said he had expected the conventionally grown oranges, which were twice as large, to have twice the vitamin C as the organic versions. Instead, chemical isolation combined with nuclear magnetic resonance spectroscopy revealed the much higher level in organic oranges.

Why the big difference? Clark speculated that "with conventional oranges, (farmers) use nitrogen fertilizers that cause an uptake of more water, so it sort of dilutes the orange. You get a great big orange but it is full of water and doesn't have as much nutritional value."

Eating organic may also help protect against chronic inflammation, a major factor in both cardiovascular disease and colon cancer. Another study, published in the European Journal of Nutrition, found that organic soups sold in the UK contain almost 6 times as much salicylic acid as non-organic soups. Salicylic acid, the compound responsible for the anti-inflammatory action of aspirin, has been shown to help prevent hardening of the arteries and bowel cancer.

Researchers compared the salicylic acid content of 11 brands of organic soup to that found in non-organic varieties. The average level of salicylic acid in 11 brands of organic vegetable soup was 117 nanograms per gram, compared with 20 nanograms per gram in 24 types of non-organic soup. The highest level (1,040 nanograms per gram) was found in an organic carrot and coriander soup. Four of the conventional soups had no detectable levels of salicylic acid.

Research at Great Lakes meeting shows more vitamin C in organic oranges than conventional oranges, adapted from American Chemical Society Press Release, Science Daily News, June 2, 2002.

Worthington V. Analyzing data to compare nutrients in conventional versus organic crops. J Altern Complement Med. 2002 Oct;8(5):529-32.

PMID: 12470430

Baker BP, Benbrook CM, Groth E 3rd, Lutz Benbrook K. Pesticide residues in conventional, integrated pest management (IPM)-grown and organic foods: insights from three US data sets. Food Addit Contam. 2002 May;19(5):427-46.

PMID: 12028642

Baxter GJ, Graham AB, Lawrence JR, Wiles D, Paterson JR. Salicylic acid in soups prepared from organically and non-organically grown vegetables. Eur J Nutr. 2001 Dec;40(6):289-92.

PMID: 11876493

This page was updated on: 2005-04-21 21:43:53
© 2002 The George Mateljan Foundation