Organic Milk is Healthier, Says Study
[Source: Telegraph.co.uk]

The study, which analyzed produce from 25 farms, found that organic milk contained 67 per cent more antioxidants and vitamins than ordinary milk...organic milk contained 60 per cent more of a healthy fatty acid called conjugated linoleic acid, or CLA9, which tests have shown can shrink tumors.

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Butler, Gillian; Nielsen, Jacob H; Slots, Tina; Seal, Chris; Eyre, Mick D; Sanderson, Roy; Leifert, Carlo. Fatty acid and fat-soluble antioxidant concentrations in milk from high-and low-input conventional and organic systems: seasonal variation. Journal of the Science of Food and Agriculture 2008 88,8,1431-41.

ABSTRACT
BACKGROUND: Previous studies showed differences in fatty acid (FA) and antioxidant profiles between organic and conventional milk. However, they did not (a) investigate seasonal differences, (b) include non-organic, low input systems or (c) compare individual carotenoids, stereoisomers of tocopherol or isomers of conjugated
linoleic acid. This survey-based study compares milk from three production systems: (i) high-input, conventional (10 farms); (ii) low-input, organic (10 farms); and (iii) low-input non-organic (5 farms). Samples were taken during the outdoor grazing (78 samples) and indoor periods (31 samples).

RESULTS: During the outdoor grazing period, on average, milk from the low-input systems had lower saturated FAs, but higher mono- and polyunsaturated FA concentrations compared with milk from the high-input system. Milk from both the low-input organic and non-organic systems had significantly higher concentrations of nutritionally desirable FAs and antioxidants – conjugated linoleic (60% and 99%, respectively) and linolenic (39% and 31%, respectively) acids, tocopherol (33% and 50%, respectively) and carotenoids (33% and 80%,respectively) – compared with milk from the high-input system. Milk composition differed significantly between the two low-input systems during the second half of the grazing period only; with milk from non-organic cows being higher in antioxidants, and conjugated linoleic acid, and that from organic cows in linolenic acid. In contrast, few significant differences in composition were detected between high-input and low-input organic systems when cows were housed.

CONCLUSIONS: Milk composition is affected by production systems by mechanisms likely to be linked to the stage and length of the grazing period, and diet composition, which will influence subsequent processing, and sensory and potential nutritional qualities of the milk.
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Ten-Year Comparison of the Influence of Organic and Conventional Crop Management Practices on the Content of Flavonoids in Tomatoes

A. E. Mitchell, et al. 2006. Journal of Agricultural and Food Chemistry

ABSTRACT
Understanding how environment, crop management, and other factors, particularly soil fertility, influence the composition and quality of food crops is necessary for the production of high-quality nutritious foods. The flavonoid aglycones quercetin and kaempferol were measured in dried tomato samples (Lycopersicon esculentum L. cv. Halley 3155) that had been archived over the period from 1994 to 2004 from the Long-Term Research on Agricultural Systems project (LTRAS) at the University of California Davis, which began in 1993. Conventional and organic processing tomato production systems are part of the set of systems compared at LTRAS. Comparisons of analyses of archived samples from conventional and organic production systems demonstrated statistically higher levels (P < 0.05) of quercetin and kaempferol aglycones in organic tomatoes. Ten-year mean levels of quercetin and kaempferol in organic tomatoes [115.5 and 63.3 mg g-1 of dry matter (DM)] were 79 and 97% higher than those in conventional tomatoes (64.6 and 32.06 mg g-1 of DM), respectively. The levels of flavonoids increased over time in samples from organic treatments, whereas the levels of flavonoids did not vary significantly in conventional treatments. This increase corresponds not only with increasing amounts of soil organic matter accumulating in organic plots but also with reduced manure application rates once soils in the organic systems had reached equilibrium levels of organic matter. Well-quantified changes in tomato nutrients over years in organic farming systems have not been reported previously.
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Three-Year Comparison of the Content of Antioxidant Microconstituents and Several Quality Characteristics in Organic and Conventionally Managed Tomatoes and Bell Peppers

Alexander W. Chassy, et al. 2006. Journal of Agricultural and Food Chemistry

ABSTRACT
Understanding how the environment and production and cultivation practices influence the composition
and quality of food crops is fundamental to the production of high-quality nutritious foods. In this
3-year study, total phenolics, percent soluble solids, ascorbic acid, and the flavonoid aglycones
quercetin, kaempferol, and luteolin were measured in two varieties of tomato (Lycopersicon esculentum
L. cv. Ropreco and Burbank) and two varieties of bell peppers (Capsicum annuum L. cv. California
Wonder and Excalibur) grown by certified organic and conventional practices in a model system.
Significantly higher levels of percent soluble solids (17%), quercetin (30%), kaempferol (17%), and
ascorbic acid (26%) were found in Burbank tomatoes (fresh weight basis; FWB), whereas only levels
of percent soluble solids (10%) and kaempferol (20%) were significantly higher in organic Ropreco
tomatoes (FWB). Year-to-year variability was significant, and high values from 2003 influenced the
3-year average value of quercetin reported for organic Burbank tomatoes. Burbank tomatoes generally
had higher levels of quercetin, kaempferol, total phenolics, and ascorbic acid as compared to Ropreco
tomatoes. Bell peppers were influenced less by environment and did not display cropping system
differences.