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The Science of Organic Foods-Are they Really Better for You?

During a recent diet consultation, one of my clients asked “Should I buy organic?” Before I could respond, I asked my client what her motivation was for purchasing organic. Her response was, “I heard organic foods are more nutritious compared to conventional foods.” Her motivation for purchasing organic was clear to me, so I began our consultation by explaining the definition of organic.

What does the term Organic Mean?

When I think about the term organic, it can most simply be defined as how our food is produced, but trust me, the definition gets more technical. According to the Environmental Working Group (1), organic is a designation provided by the U.S. Department of Agriculture to certify food that were produced without synthetic chemicals or fertilizers, genetic engineering, radiation or sewage sludge. This means that organic farmers use natural processes and materials when developing farming systems that contribute to soil, crop and livestock nutrition, weed and pest management, while also attaining production goals (2). Organic farmers do not use any synthetic pesticides, fertilizers, hormones or antibiotics to grow anything. Furthermore, organic meats, poultry, eggs and dairy products must come from animals allowed to graze outdoors and consume organic feed. This is all much different in comparison to the production of conventional foods which allow fertilizers and pesticides for growth.

Why are Organic Foods So Expensive?

Have you ever wondered why organic foods are more expensive compared to conventional foods? Growing organic foods is a process that requires higher labor costs to help with weed and pest management. Animals that are raised to produce organic meats also require more expensive feed. Finally, there is also a fee for organic certification (3). A recent cost- analysis from Consumer Reports found that organic produce such as apples and bananas were up to 60% more expensive compared to conventional produce, while organic eggs were a whopping 196% more when compared to non-organic eggs (4). However, not all organic foods were found to be more expensive when compared to conventional foods. Items such as honey and extra virgin olive oil were found to either cost the same or less when compared to non-organic honey and extra virgin olive oil (4).

Are Organic Foods More Nutritious Comapred to COnventional Foods?

The results from scientific studies that compare the nutrition content of organic foods vs. conventional are mixed. For example, in 2012, a large meta-analysis published from Stanford University described that the published literature lacks strong evidence to support that organic foods are more nutritious when compared to conventional foods (5). On the other hand, an earlier study from Hoefkens and colleagues found that organic tomatoes had higher concentrations of Vitamin C when compared to conventionally grown tomatoes (6). At this point, conclusive scientific evidence does not exist to support the idea that organic foods are more nutritious when compared to conventional foods.

My Take Home Messages on Organic Foods

Eating organic is a personal choice and certainly not everyone can afford to eat organic. While the science, at this point, does not conclusively show that organic foods are actually more nutritious in comparison to conventional foods, we do know that some conventionally grown fruits and vegetables have higher levels of pesticide residues (3). Each year, the Environmental Working Group, tests more than 10,000 pesticides in fruits and vegetables and develops a Dirty Dozen List as well as a Clean 15 list (3). The Dirty Dozen List identifies 12 types of conventional produce that have higher levels of pesticide residues (See the list below). On the other hand, the Clean 15 list provides some guidance to consumers looking to shop on a budget while purchasing conventionally grown produce with the least amount of pesticide residues. Whether you choose to purchase organic or conventional produce, remember that the Food and Drug Administration (FDA) recommends washing all fresh produce, regardless of whether or not the produce is organic and conventional (3).

The Dirty Dozen

Strawberries, Apples, Nectarines, Peaches, Celery, Grapes, Cherries, Spinach, Tomatoes, Sweet bell peppers, Cherry tomatoes, Cucumbers

The Clean 15

Avocados, Sweet corn, Pineapples, Cabbage, Sweet peas (frozen), Onions, Asparagus, Mangos, Papaya, Kiwi, Eggplant, Honeydew Melon, Grapefruit, Cantaloupe, Cauliflower


1. Environmental Working Group. What does organic mean? Accessed February 9, 2017

2. U.S. Department of Agriculture. Introduction to Organic Farming Practices. Accessed February 20, 2017.

3. Thalheimer JC. The Organic Foods Debate-Are they Healthier Than Conventional? Today’s Dietitian. Accessed February 20, 2017.

4. Consumer Reports (CR). The cost of organic food. Accessed February 7, 2017.

5.Smith-Spangler et al. Are Organic Foods Safer or Healthier Than Conventional Alternatives?: A Systematic Review. Annals of Internal Medicine 2012;157(5):348-366.

6.Hoefkens et al. Consuming organic vs. conventional vegetables: the effect on nutrient and contaminant intakes. Food Chem Toxicol. 2010;48(11):3058-66.

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