Does organic food have more vitamins than nonorganic food?

Question

Aside from the issue of pesticides there's the claim that organic food has more nutrients, vitamins and minerals than nonorganic food:

Organic food is known to contain 50% more nutrients, minerals and vitamins than produce that has been intensively farmed.
-- source

Given either the US certification or the EU certification for organic food is there evidence that an average organic apple has more nutrients, minerals and vitamins than a nonorganic one? Does it differ between different vegetables and fruits?

Answer 1

In a word, no. There have been no studies to show significant differences in vitamin levels between organinc and conventionally grown foods. The largest discrepency for vitamin levels (not mineral) is due to preparation, processing and shipment methods.

http://www.caseperformance.com/19/nutrient-content-of-organic-vs-conventionally-grown-foods

(I could dig out the specific studies if necessary, though they are well cited in the above article)

As an addition, since there have been additional studies in the meantime the biggest difference appears to be on the specific crop, and the specific field.

After 10 years, the researchers found that tomatoes raised in the organic plots contained significantly higher levels of certain antioxidant compounds.

But this is one study of one vegetable in one field. And when the Stanford researchers looked at their broad array of studies, which included lots of different crops in different situations, they found no such broad pattern.

Source: http://www.npr.org/blogs/thesalt/2012/09/04/160395259/why-organic-food-may-not-be-healthier-for-you

Answer 2

Depends on the food-- Organic Tomatoes have more Vitamin C

A large review in 2006 showed that different vegetables have different contents depending on the farming practices used (ie, organic vs non-organic). Most helpful here, including sources, is Table 2 of that study. In that table, the following statements describe the results of various fruits and vegetables, as well as providing references to each claim:

So, as the chart shows, organic tomatoes have more vitamin C.

The recent claim, as reported by the NYT and NPR, glosses over these levels of minute variation. Note also, that the Stanford study, linked by @vartec and the foundation of the NPR article, discusses health effects in humans, not vitamin content in the fruits themselves.

The conclusions of that review did mirror those of the Standford study, notably:

This review illustrates that tradeoffs exist between organic and conventional food production. Organic fruits and vegetables rely upon far fewer pesticides than do conventional fruits and vegetables, which results in fewer pesticide residues, but may also stimulate the production of naturally occurring toxins if organic crops are subject to increased pest pressures from insects, weeds, or plant diseases. Because organic fruits and vegetables do not use pesticides or synthetic fertilizers, they have more biochemical energy to synthesize beneficial secondary plant metabolites such as polyphenolic antioxidants as well as naturally occurring toxins. In some cases, food animals produced organically have the potential to possess higher rates of bacterial contamination than those produced conventionally since organic production generally prohibits antibiotic use. The prohibition of antimicrobial agents also explains the apparent lower incidence of antimicrobial resistance in bacterial isolates of organic food animals, as some studies have shown a correlation between increased rates of antibiotic use and increased antimicrobial resistance.

So, organic tomatoes have more vitamins, the tradeoffs for producing and eating them may not be good.

Also, it's important to note that the review referenced in @ilvel's answer mimics the results of the 2006 study I posted, namely:

In this chart, note that there is a difference between organic and nonorganic foods as relates to vitamin C concentration.

Answer 3

No, it hasn't.

A team led by Bravata, a senior affiliate with Stanford’s Center for Health Policy, and Crystal Smith-Spangler, MD, MS, an instructor in the school’s Division of General Medical Disciplines and a physician-investigator at VA Palo Alto Health Care System, did the most comprehensive meta-analysis to date of existing studies comparing organic and conventional foods. They did not find strong evidence that organic foods are more nutritious or carry fewer health risks than conventional alternatives

[...]

After analyzing the data, the researchers found little significant difference in health benefits between organic and conventional foods. No consistent differences were seen in the vitamin content of organic products, and only one nutrient — phosphorus — was significantly higher in organic versus conventionally grown produce (and the researchers note that because few people have phosphorous deficiency, this has little clinical significance).

source: Stanford School of Medicine

The referenced study is "Are Organic Foods Safer or Healthier Than Conventional Alternatives?: A Systematic Review" Crystal Smith-Spangler, MD, MS; Margaret L. Brandeau, PhD; Grace E. Hunter, BA; J. Clay Bavinger, BA; Maren Pearson, BS; Paul J. Eschbach; Vandana Sundaram, MPH; Hau Liu, MD, MS, MBA, MPH; Patricia Schirmer, MD; Christopher Stave, MLS; Ingram Olkin, PhD; and Dena M. Bravata, MD, MS