The higher the price, the greater the health benefits? Not necessarily, says a new study published in the Sept. 4 issue of Annals of Internal Medicine. An extensive review of studies on organic food found that the options aren’t living up to the health hype.
Unsure of how to answer their clients’ questions about the benefits of organic foods, a team of health experts at Stanford University set out to review the existing body of research surrounding organic versus conventionally-grown foods. They started with thousands of papers and narrowed them down to 237 of the most relevant ones to analyze — including 223 studies comparing the quality of the foods (in terms of nutrient levels or the bacterial, fungal or pesticide contamination of various products) and 17 studies involving people consuming organic versus conventional diets.
Here’s what the meta-analysis revealed:
Regular foods are just as nutritious as organic foods. Contrary to public perception, organic foods aren’t higher in vitamins, minerals or key nutrients like omega-3 fatty acids (in the case of organic milk) than their non-organic counterparts.
There is one exception: organic foods are higher in phosphorus. However, few people have a phosphorus deficiency so researchers didn’t consider this finding relevant.
All foods contain some pesticide residue, but organics contain less. Researchers found that organic produce has a 30 per cent less risk of contaminants than conventionally grown food, but no organic food is completely free of pesticides. (This fact shouldn’t surprise Canadians: a 2011 CBC News article reported that Canadian Food Inspection Agency studies show pesticides in organic foods.)
Researchers did note that a pair of studies involving children found that youngsters who ate organic diets had less pesticide residue in their urine than their cohorts who ate conventional diets — but experts aren’t clear on what those findings mean.
Still, all foods studied had pesticide levels that are considered safe.
Organic meats have a lower risk of superbugs. All meat can potentially contain germs, but researchers found that non-organic meats had a one third higher change of containing antibiotic resistant bacteria. Some experts feel that antibiotic use in animals is part of the superbug problem. For consumers, it can mean food poisoning outbreaks are harder to treat.
The bottom line: “There isn’t much difference between organic and conventional foods, if you’re an adult and making a decision based solely on your health,” said Dena Bravata, one of the study’s senior authors, in a Stanford University press release about the study.
However, the goal of the study wasn’t to discourage people from
purchasing organic foods, Bravata notes. Aside from health, there are
many other reasons for choosing organics — such as animal welfare,
sustainable farming practices, the impact on the environment and taste.
More to the story?
If you’re feeling a little disappointed by the results, be aware than this review was an analysis of existing studies — not new information. The researchers note there are some gaps. For instance, the studies they analyzed were diverse and used different testing methods or evaluated different things. There were relatively few studies involving humans. There’s always the potential for “publication bias” too — that is, some studies get published and others don’t.
Furthermore, there is a lot of variation among the foods themselves — including where they were grown, soil conditions and weather. There is a lot of variation among organic farming practices too.
There’s also the potential for contamination from other sources. For example, people who had pesticides show up in their urine might have absorbed them from other sources — such as insecticide use in the home.
Researchers also didn’t have any evidence of the long-term effects of organic versus non-organic foods — that kind of research hasn’t been done yet. The longest studies they analyzed were two years in length, but some were as short as two days. No one knows how organic foods will measure up in the long run, or if they’ll be more beneficial for children (whose bodies are still developing) than older adults.
Also, you might not be convinced there’s such a thing as “safe levels” of pesticides in foods. Some experts warn that no one really knows what’s “safe” or not in the long term. Many people would rather not be lab rats.
Worse yet, studies tend to look at this or that chemical in isolation but experts note we could have any number of chemicals in our body at one time. Researchers are still learning how chemicals interact in our bodies.
So what can consumers do right now? There is still a lot we don’t know about the benefits and risks of certain foods — and it’s ultimately up to individuals to decide what foods they want to consume.
“Our goal was to shed light on what the evidence is,” said lead author Crystal Smith-Spangler. “This is information that people can use to make their own decisions based on their level of concern about pesticides, their budget and other considerations.”
ON THE WEB
For more information on the study, read dietician Leslie Beck’s article in the Globe and Mail.
To find out how organic products are certified, visit the Canadian Food Inspection Agency.
Additional source: the Associated Press