The multi-billion dollar organic food industry is fueled by consumer perception that organic food is healthier (greater nutritional value and fewer toxic chemicals). Studies of the nutrient content in organic foods vary in results due to differences in the ground cover and maturity of the organic farming operation. Nutrient content also varies from farmer to farmer and year to year. However, reviews of multiple studies show that organic varieties do provide significantly greater levels of vitamin C, iron, magnesium, and phosphorus than non-organic varieties of the same foods. While being higher in these nutrients, they are also significantly lower in nitrates and pesticide residues. In addition, with the exception of wheat, oats, and wine, organic foods typically provide greater levels of a number of important antioxidant phytochemicals (anthocyanins, flavonoids, and carotenoids). Although in vitro studies of organic fruits and vegetables consistently demonstrate that organic foods have greater antioxidant activity, are more potent suppressors of the mutagenic action of toxic compounds, and inhibit the proliferation of certain cancer cell lines, in vivo studies of antioxidant activity in humans have failed to demonstrate additional benefit. Clear health benefits from consuming organic dairy products have been demonstrated in regard to allergic dermatitis.
(Altern Med Rev 2010;15(1):4-12)
Organic food consumption is one of the fastest growing segments of U.S. domestic foodstuffs. Sales of organic food and beverages grew from $1 billion in 1990 to $21.1 billion in 2008 and are on track to reach $23 billion in 2009. (1) Consumers generally perceive these foods to be healthier and safer for themselves and the environment. (2,3) A plethora of studies in the last two decades have assessed whether organic foods have higher levels of vitamins, minerals, and phytochemicals than conventionally raised foods and whether they have fewer pesticide residues. Far fewer studies have been conducted to assess either the potential or actual health benefits of eating organic foods.
Factors Affecting Nutritional Content of Produce
Determining the potential nutritional superiority of organic food is not a simple task. Numerous factors, apart from organic versus inorganic growing, influence the amount of vitamins and phytochemicals (phenols, flavonoids, carotenoids, etc.) in a crop. These factors include the weather (affecting crops year-to-year), specific environmental conditions from one farm to the next (microclimates), soil condition, etc. Another major factor not taken into account in the published studies was the length of time the specific plots of land had been worked using organic methods. Since it takes years to build soil quality in a plot using organic methods and for the persistent pollutants in the ground to be reduced, this can significantly affect the outcome of comparative studies. The importance of these different factors is apparent from a review of the recent studies examining the nutrient content in tomatoes.
Differences between Growers and Soil Quality
Of six recent studies of nutrient content of organic tomatoes, only one showed no significant differences between organic and conventional farms. (4) This study, conducted in Taiwan, did find that while there was no difference...