21
Apr
New Report Shows Organic Foods Higher in Nutrients
(Beyond Pesticides, April 21, 2008) A comprehensive review of 97 published studies comparing the nutritional quality of organic and conventional foods shows that organic plant-based foods (fruits, vegetables, grains) contain higher levels of eight of 11 nutrients studied, including significantly greater concentrations of the health-promoting polyphenols and antioxidants. The team of scientists from the University of Florida and Washington State University concludes that organically grown plant-based foods are 25% more nutrient dense, on average, and hence deliver more essential nutrients per serving or calorie consumed. The findings are published in the Organic Centers’ report, New Evidence Confirms the Nutritional Superiority of Plant-based Organic Foods.
Nutrient levels were studied in 236 matched pairs of foods with scientifically valid results on the levels of ten nutrients, plus nitrates (high levels are undesirable because of food safety risks). Each matched pair contains a crop grown organically and another crop from a nearby conventional farm with similar soils, climate, plant genetics, irrigation systems, and nitrogen levels. In addition, the team ensured that the crops were picked at a comparable level of maturity, handled the same way after harvest, and tested in the same form using the same methods.
The team reviewed the study design and analytical methods used in 97 published, peer-reviewed studies appearing since 1980 (40 of which have been published since 2001).
The team identified eight or more valid matched pairs for ten nutrients, plus nitrates including:
- Four measures of antioxidant activity;
- Precursors of three vitamins A, C and E;
- Two minerals (phosphorous and potassium);
- Nitrates (higher levels are undesirable); and
- Total protein.
There were 191 matched pairs in which the antioxidant, vitamin and mineral levels are compared. The organic food is more nutrient dense in 119 of these pairs, or 62%, compared to 36% of the conventional matched pairs with more nutrients. There are no differences in 2% of the pairs. The conventional samples contain modestly higher levels of protein in 85% of 27 matched pairs (an advantage), but also much higher levels of nitrates in 83% of 18 matched pairs (a nutritional and food safety disadvantage). Matched pairs comparing potassium, phosphorous, and total protein account for over 75% of the 87 matched pairs in which the conventional food is more nutrient dense. In general, compared to vitamins and antioxidants, these three nutrients are of less importance because they are present in the average American diet at adequate to excessive levels, according to the report authors. The organic food is more nutrient dense in 75% of the matched pairs comparing total antioxidant capacity, total polyphenols, and two key flavonoids, quercetin and kaempferol.
Several methods were used to place the magnitude of the differences in nutrient levels between organic and conventional foods into perspective. In two-thirds of the matched pairs favoring the conventional food, the differences in favor of conventional are under 10%, compared to 26% of the matched pairs in which the organic food is more nutrient dense by a margin under 10%. The premium in favor of the conventional food is 21% or greater in just 15% of the matched pairs in which the conventional food is more nutrient dense, whereas in the more nutrient dense organic food matched pairs, 41% favor organic by 21% or more, and 24% of the pairs are 31% or more nutrient dense. The largest differences are in the case of the flavonoid quercetin, where the organic foods are 2.4-times more nutrient dense on average, and nitrates, where levels are 1.8-fold lower in organic foods (a desirable nutritional feature).
Nutrient levels were studied in 236 matched pairs of foods with scientifically valid results on the levels of ten nutrients, plus nitrates (high levels are undesirable because of food safety risks). Each matched pair contains a crop grown organically and another crop from a nearby conventional farm with similar soils, climate, plant genetics, irrigation systems, and nitrogen levels. In addition, the team ensured that the crops were picked at a comparable level of maturity, handled the same way after harvest, and tested in the same form using the same methods.
The team reviewed the study design and analytical methods used in 97 published, peer-reviewed studies appearing since 1980 (40 of which have been published since 2001).
The team identified eight or more valid matched pairs for ten nutrients, plus nitrates including:
– Four measures of antioxidant activity;
– Precursors of three vitamins A, C and E;
– Two minerals (phosphorous and potassium);
– Nitrates (higher levels are undesirable); and
– Total protein.
There are 191 matched pairs in which the antioxidant, vitamin and mineral levels are compared. The organic food is more nutrient dense in 119 of these pairs, or 62%, compared to 36% of the conventional matched pairs with more nutrients. There are no differences in 2% of the pairs. The conventional samples contain modestly higher levels of protein in 85% of 27 matched pairs (an advantage), but also much higher levels of nitrates in 83% of 18 matched pairs (a nutritional and food safety disadvantage). Matched pairs comparing potassium, phosphorous, and total protein account for over 75% of the 87 matched pairs in which the conventional food is more nutrient dense. In general, compared to vitamins and antioxidants, these three nutrients are of less importance because they are present in the average American diet at adequate to excessive levels, according to the report authors. The organic food is more nutrient dense in 75% of the matched pairs comparing total antioxidant capacity, total polyphenols, and two key flavonoids, quercetin and kaempferol.
Several methods were used to place the magnitude of the differences in nutrient levels between organic and conventional foods into perspective. In two-thirds of the matched pairs favoring the conventional food, the differences in favor of conventional are under 10%, compared to 26% of the matched pairs in which the organic food is more nutrient dense by a margin under 10%. The premium in favor of the conventional food is 21% or greater in just 15% of the matched pairs in which the conventional food is more nutrient dense, whereas in the more nutrient dense organic food matched pairs, 41% favor organic by 21% or more, and 24% of the pairs are 31% or more nutrient dense. The largest differences are in the case of the flavonoid quercetin, where the organic foods are 2.4-times more nutrient dense on average, and nitrates, where levels are 1.8-fold lower in organic foods (a desirable nutritional feature).
“We have carried out many careful comparisons of both nutrient levels and biological activity of antioxidant polyphenols in organic and conventional foods over the last five years,” said Neal Davies, Ph.D., professor in the School of Pharmacology at Washington State University, and a study co-author. “Not only are we seeing a general trend in favor of the nutrient density of organic food, but also evidence that nutrients are often present in organic foods in a more biologically active form.”
Besides nutritional values, there are a number of reasons to support organic agriculture, For example, a study published in the February 2008 issue of Environmental Health Perspectives finds that children who eat a conventional diet of food produced with chemical-intensive practices carry residues of organophosate pesticides that are reduced or eliminated when they switch to an organic diet.
TAKE ACTION: Buy organic foods for yourself and your family whenever possible. If organic foods are not easily accessible to you due to cost or distribution, consider buying organic for the foods you eat the most. To make sure your food is organic, look for the USDA Organic label. For more information on organic agriculture, see Beyond Pesticides Organic Food pages.
