Growing Healthier Food

Growing Healthier Food

Increasing Antioxidant Levels through Organic Farming and Food Processing

By Charles M. Benbrook, Ph.D., Chief Scientist,

The Organic Center

Science is digging deeper into the roots of food quality.  Thousands of scientists worldwide are probing the secrets of antioxidants in food.  Why do plants produce them? What factors govern their levels?  How do they promote human health?  These natural plant chemicals help prevent or reduce tissue damage in cells caused by free radicals.  Free radicals are oxygen and nitrogen-based molecules with unpaired electrons that are generated by several of the body’s metabolic processes.  Antioxidants inhibit damaging reactions within human cells by providing the positively charged atoms needed to neutralize free radicals.  They bring stability to cells in the throes of inner chaos.

Plants produce more than 50,000 “secondary plant metabolites” (SPMs) in response to stresses in the environment.  Some 4,000 of these SPMs are polyphenol flavonoids and many of these are antioxidants.  Plants provide essentially all dietary sources of antioxidants.  Antioxidants in milk and meat are initially from the plant-based feed consumed by farm animals.

By lessening free radical damage in human tissues, antioxidants reduce inflammation and can lessen joint and muscle pain. Through this mechanism, antioxidants can play a role in promoting cardiovascular health, lessen the risk and severity of neurodegenerative diseases like Alzhiemer’s and Parkinston’s disease, and in general, help slow the aging process.

carrots
Diversity of carrots contain very different mixes of antioxidants, which include the pigments giving food its bright colors.


 A wide range of studies has shown that plant antioxidants are also anti-proliferative (i.e., they slow the proliferation of cells). In this way, antioxidants can prevent or slow the growth of some cancerous tumors. And recent research suggests that some plant polyphenols can increase the sensitivity of the body to insulin, thereby delaying the onset of type II diabetes or slowing the progression of this increasingly common disease.

The many health benefits associated with antioxidant consumption is why the U.S. government has recently recommended as part of the new dietary guidelines – see “My Pyramid” on the web -- that the average American double consumption of fruits and vegetables.  The uniquely broad array health benefits associated with antioxidants also explains the enormous investment in science searching for the magic ingredient in blueberries, or cucumbers, or tomatoes that will help prevent disease or promote graceful aging.

The Organic Center carried out a State of Science Review (SSR) on the impact of organic farming methods, and organically acceptable food processing techniques, on average antioxidant levels in food.  The January 2005 Executive Summary and full report are freely available on the Center’s website.  We found that a shift to organic farming methods can increase average antioxidant levels from a few percent to over 200 percent, with the average increase being about 30 percent.  We also document that organically acceptable food-processing methods can lessen the percent of antioxidants lost when fruits and vegetables or grains are processed and cooked, sometimes dramatically.

Antioxidant Levels Vary Widely

ketchup
USDA scientists have discovered that organically
grown tomatoes produce catsup with higher
levels of lycopene and other antioxidants.  The
bright red color and rich taste of organic catsup,
compared to conventional brands, is linked to the higher antioxidant capacity.
The ten foods richest in antioxidants include blueberries, plums, broccoli, strawberries, and red cabbage.  These antioxidant-dense foods provide, on average, 35 times more antioxidant capacity per calorie than the ten foods that rank lowest on the scale of antioxidant capacity per calorie.  Low-antioxidant foods include cucumbers, granola, cereal, canned corn, and lima beans. 

So why not simply add antioxidant supplements to the diet?  Dietary supplements do not appear to deliver the full range of health-promoting benefits that stem from consumption of whole foods that are rich in antioxidants. In addition, plant antioxidants modulate a number of biosynthetic processes in the human body.  To optimally promote health though, they must be present in the right proportions relative to a variety of other vitamins, minerals, fats and proteins.

Because antioxidants cannot substitute for each other and some do not last long once ingested, people need to consume antioxidants in plant-based foods with most meals in order to sustain optimal levels in the body.  A variety of strategies should be pursued to increase average antioxidant intakes including, first and foremost, eating additional servings of a diverse selection of fruits and vegetables.  Buying locally grown and fresh produce that has been harvested relatively ripe is another proven strategy to increase antioxidant intakes. 


Many mysteries about antioxidants remain buried in the root system of food quality.  The Organic Center is monitoring ongoing studies to map this new territory because we are confident that new tools and techniques will emerge to help organic farmers and food companies deliver more nutritional value per serving of a wide range of foods.  Stay tuned for progress reports and new insights.