Yes. Consumption of organically grown food is a great way to reduce your exposure to contaminants commonly found in foods that have been grown using conventional agricultural practices. These contaminants may include not only pesticides - many of which have been classified as potential cancer-causing agents - but also heavy metals such as lead and mercury, and solvents like benzene and toluene. Minimizing exposure to these potential toxins is an important benefit for your health. Heavy metals can damage nerve function, contributing to diseases such as multiple sclerosis, and interfere with hemoglobin production in a way that increases risk of anemia. Solvents can damage white blood cell function and lower the immune system's ability to resist infections.
In addition to lessening your exposure to these potentially harmful substances, organically grown foods, on average, contain higher levels of many nutrients including vitamins and minerals.
These two aspects of the organic consumption - decreased intake of contaminants and increased intake of nutrients - have both been topics of controversy in research. While we understand the reasons for this controversy, we are also firmly convinced that organically grown foods contain significantly fewer contaminants than their conventionally grown counterparts, as well as significantly richer nutrient content.
Let's take the contamination aspect first. One of the largest scale studies, conducted by the U.S. Department of Agriculture on more than 94,000 food samples, found at least one pesticide residue on approximately 75% of conventionally grown fruits and vegetables, in comparison to approximately 25% of organically grown vegetables. Almost half of the pesticide residues found on organically grown vegetables involved DDT or its metabolites. (DDT is a pesticide that has been banned for 40 years for use on food, but because it can be very persistent in the environment, it often shows up in foods decades later.) When DDT and related pesticides were excluded from the results, the percentage of organically grown foods with pesticide residues dropped to about 13%. Studies have been conducted in countries throughout Europe and the Mediterranean comparing one or two specific, organically grown foods to their conventional counterparts, and the results have consistently shown lower contaminant levels in the organically grown foods.
With respect to nutrient content, organically grown fruits and vegetables - on average - appear to contain about 15% higher levels of nutrients than conventionally grown fruits and vegetables. Results in this area have not always been consistent, however, and in some cases, conventionally grown fruits and/or vegetables have been analyzed as having higher nutrient levels than organically grown vegetables. One early piece of research in this area - a review of 34 studies comparing the nutritional content of organic versus non-organic food - was published in 1998. In this research, compared to conventionally grown food, organically grown food was found to have: similar or slightly lower amounts of protein, but higher protein quality (in terms of amino acid composition); higher levels of vitamin C in about half of all studies; and 5-20% higher mineral levels for a majority of minerals. Higher flavonoid content has also been shown in one study of organic versus non-organic foods.
From our perspective at the World's Healthiest Foods, we are not surprised at either set of results. Organics regulations are quite extensive in their lists of prohibited substances, and lower levels of contaminants in certified organic foods make perfect sense. Foods depend on soil and water for their nourishment, and cleaner soil and water means cleaner food. It's that simple.
The nutrient concentrations in organic versus non-organic food are another matter, however. Here the relationship is not so simple. Soil quality can vary greatly from region to region, and many differences in soil quality cannot be overridden by organic farming practices. Neither can genetic tendencies in plants, which can be very closely connected with the plants' harvest-stage nutrient content. In short, nutrient composition in plants is the result of many different factors that interact in a complex way, and organic farming practices - while beneficial - would not be expected to function like an "overriding factor" in terms of nutrient content. The idea of an average improved nourishment level of 5-20% makes good sense to us given this complicated mix of factors.
When you combine a significantly lower exposure to food contaminants with a 5-20% greater intake of nutrients, what you get is a winning combination. That's exactly the way we think about certified organic foods with respect to health: they are a winning combination, and clearly deserve a place in your meal plan.
