ORGANIC CENTER REPORT INDICATES ORGANIC FOODS HAVE ELEVATED LEVELS OF ANTIOXIDANTS FOSTER, R.I. (January 26, 2005) - The Organic
Center's second State of Science Review (SSR) concludes that organic
farming methods have the potential to elevate average antioxidant
levels, especially in fresh produce. Charles Benbrook, Ph.D., compiled and
analyzed existing scientific information for his report, Elevating
Antioxidant Levels Through Organic Farming and Food Processing. The
report reveals that on average, antioxidant levels were about 30 percent
higher in organic food compared to conventional food grown under the
same conditions. An executive summary and the entire report can be found
at:
http://www.organic-center.org/science.htm?articleid=54.
The report's findings are particularly useful for
consumers who wish to consume higher levels of antioxidants in fresh fruits
and vegetables, without additional caloric intake. The USDA is
currently recommending higher daily intake of fruits and vegetables,
especially those that are antioxidant rich. The report's tables include
rankings of common foods according to their total antioxidant capacity per
calorie and per typical serving. Consumers who seek out foods high in
antioxidant content can meet recommended antioxidant intake levels
with less than 10 percent of their daily caloric intake.
"Because of the many potential health benefits
associated with antioxidant consumption, increasing average daily
antioxidant intake through the diet has emerged as an important health
goal," says Benbrook. "This goal was a major factor shaping the
new USDA Dietary Guidelines for Americans, which increase the average
recommended intake of fruits and vegetables to at least nine servings per
day from the original five*. By generating higher concentrations of
antioxidants in fresh produce and other organic foods, organic farming
can help people increase their daily consumption of antioxidants
without a proportional increase in calories."
This report reviews, among other data, 15 quantitative
comparisons of antioxidant levels in organic versus conventional
fruit and vegetables. Organically grown produce had higher levels in 13 out
of 15 cases. On average, the organic crops contained about one-third
higher antioxidant and/or phenolic content than comparable conventional
produce. Several studies found levels of specific vitamins, flavonoids
or antioxidants in organic foods to be two or three times the level
found in matched samples of conventional foods. In studies making
direct comparisons of levels of antioxidants in organic versus conventional
produce, higher levels are often found in organic produce but the
converse is rarely true.
Organic farming techniques can increase antioxidant
content A wide range of factors can influence the mix of
antioxidants that a plant manufactures, as well as the levels the plant
produces at any given point. In general, factors that impose stress on
plants tend to trigger a plant's innate defense mechanisms and these
mechanisms are driven by and/or entail the synthesis of antioxidants.
Studies reviewed in this SSR provide evidence that
several core practices on organic fruit and vegetable farms - use
of compost, cover crops, slow release forms of nitrogen - can increase
antioxidant and polyphenol content compared to conventional practices
that depend on commercial fertilizers and pesticides. The prohibition
of pesticides in organic farming practices provides additional benefits
to consumers who choose organic.
"Harvesting fruits and vegetables at optimal ripeness
and consuming them in less-processed forms, without removing skins
or peals, will preserve a greater portion of their antioxidants,
"says Benbrook. "The outer layers of fruits and vegetables generally
contain the highest concentrations of antioxidants, but many consumers
peal their conventionally-grown fruits and vegetables to help
reduce levels of pesticide residues. Seeking out organic produce can
therefore deliver a dual benefit to consumers by maximizing antioxidant
intake and minimizing pesticide dietary exposure."
Organic processing methods may also increase
antioxidant levels There are significant differences between some of the
food processing methods and technologies used in manufacturing
conventional foods in contrast to those allowed and used in producing
organic processed foods. Some of these differences are known to have an
impact on antioxidant levels. For example, the synthetic
chemical hexane is often used in extraction of oils from crops in conventional
oil processing plants, but is prohibited in organic oil processing.
Hexane is known to promote removal of certain antioxidants.
High-temperature and high-pressure processing
technologies also tend to remove significant portions of the antioxidants
present in fresh foods. Organic processing plants often use lower pressure,
cold-pressing methods to extract juices and oils. The resulting
food products are generally richer in flavor and retain more nutrients,
including antioxidants.
Though there is much more to learn, the current state
of science supports the conclusion that organic farming methods
can and often do result in higher antioxidant levels in fruits and
vegetables. This health benefit for consumers joins the list of other
well-documented reasons to buy organic, including the reduction of
farm worker and consumer exposures to pesticides, the impacts of
pesticides on the environment, and the prevention of problems associated
with hormone and antibiotic use in livestock farming.
Many consumers report that they enjoy the richer
flavors in organic food and instinctively sense that organic foods are
better for them; this SSR confirms that there are good reasons to focus
additional scientific resources on gaining a more comprehensive
understanding of the taste and health-oriented benefits associated with
elevating average antioxidant levels in food.
Research on antioxidant levels in organically grown
food is among the Organic Center's top research priorities. The Center
has initiated and funded three new research projects in 2004 focused on
the impact of organic farming methods and food processing
technologies on the antioxidant content of food. Detailed information
about the Center's antioxidant-related projects can be found at
http://www.organic-center.org/stateofscience.htm.
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