ORAC experiment in humans

Tables showing the ORAC scores of various fruits and vegetables have been presented on ASD recently. The method of determining ORAC scores
have been done in the laboratory in controlled conditions (in vitro) and not in living beings, human or non-human (in vivo). Since in the real world of human day to day living, the nitty gritty practical aspect of fruits and vegetables intake is of basic importance, I did a scholar.google.com search of the terms vivo+ORAC - http://tinyurl.com/doq3p - and found 329 references. Amongst these finds was the following. I did not attempt to dig deeply into the other finds.

Effect of Dietary Patterns on Measures of Lipid Peroxidation -
http://www.circ.ahajournals.org/cgi/content/full/98/22/2390.
"Few trials have studied the effects of diets rather than vitamin supplements on lipid peroxidation. To our knowledge, just 2 dietary intervention trials have examined the impact of modifying single nutrients. In a trial of 12 healthy women studied in a metabolic ward, consumption of a diet depleted of dietary carotenes for 2 months resulted in increased rates of lipid peroxidation.22 In the other trial, increased consumption of monounsaturated fatty acids was associated with a lower susceptibility of LDL cholesterol to in vitro peroxidation.23 In a clinical trial of fruit and vegetable consumption, a diet high in fruits and vegetables increased serum antioxidants, including carotenoids and flavenoids24 ; however, the effects on lipid peroxidation were not examined. To our knowledge, no trial has examined the impact of healthy dietary patterns with several desirable factors (rich in fruits and vegetables and reduced in saturated fat, total fat, and cholesterol) on lipid peroxidation. Such a dietary pattern (termed the combination diet in this study) should reduce the extent of lipid peroxidation through 2 mechanisms: by decreasing lipid substrate available for peroxidation (ie, serum lipids) and increasing the concentration of antioxidants derived from diet.

Discussion (excerpt)
Both the combination diet and the fruits and vegetables diet increased the antioxidant capacity of the serum (as measured by the ORAC assay). These results indicate that there are components of the serum that delayed oxidation of the target protein, ß-phycoerythrin,29 and resulted in higher ORAC. Previous studies have demonstrated that flavenoids and tocopherols protect the ß-phycoerythrin against oxidative damage in vitro.31 In our study, the serum levels of several carotenoids including ß-carotene, cryptoxanthin, and zeaxanthin increased in the fruits and vegetables diet and in the combination diet. Lutein increased only in the combination diet (Figure 3). This pattern of change in serum levels of antioxidants is similar to that reported in a clinical trial of nutritional advice to increase the consumption of fruits and vegetables.24 Hence, the higher ORAC observed in our trial could in part be explained by the higher serum content of these dietary antioxidants. It is unlikely that vitamin E had a major influence on ORAC because the diets provided similar amounts of vitamin E and because changes in serum {alpha}-tocopherol were similar across diets. Although it is tempting to attribute the observed changes in ORAC to the individual carotenoids that we measured, one must be cautious about drawing such inferences. First, the DASH diets were not designed to assess the influence of specific nutrients but rather to test the combined effects of dietary patterns. Second, we measured only a few carotenoids, which together represent only a small fraction of those consumed.

In this trial, there were no between-diet differences in MDA (malondialdehyde), a measure of in vitro lipid peroxidation that is associated with conditions that predispose to the development of atherosclerosis (cigarette smoking32 diabetes,33 hyperlipidemia,34 hypertension,35 and obesity36 ). However, it is well recognized that the assay lacks specificity and repeatability.37 Less well recognized is the dependence of this assay on the proportion of fats derived from linoleic PUFAs. As the ratio of polyunsaturated to saturated fatty acids (P/S) in serum lipids increases, formation of lipid peroxidation products will also increase even though total fat and saturated fat decrease.38 In this study, the P/S ratio was 0.5 in the control diet, 0.6 in the fruits and vegetables diet, and 1.3 in the combination diet. This represents a more than doubling of the P/S ratio in the combination diet over the control diet. Such a difference in the P/S ratio may have a major influence on the MDA assay, potentially overwhelming the effects of increased dietary intake of antioxidants. Hence, in this diet intervention study that simultaneously modified fat and antioxidant intake, this in vitro assay is not an appropriate outcome variable."

This study also supports the idea of minimizing omega 6 fatty acids rather than increasing omega 3 fatty acid in order to have a more optimal omega 6 to omega 3 ratio such as found in the traditional Mediterranean diet as well as substituting monounsaturated fatty acids for these PUFA (polyunsaturated fatty acids).

There are some subsequent articles that have cited this article that may be of interest. A couple are listed below.

"Conclusion: Dried fruits and especially figs, are a convenient and superior source of some nutrients, but in the American diet amount to less than 1% of total fruit consumed. Figs are in vivo antioxidants after human consumption. The findings suggest that dried fruits should be a greater part of the diet as they are dense in phenol antioxidants and nutrients, most notably fiber." Dried Fruits: Excellent in Vitro and in Vivo Antioxidants - http://www.jacn.org/cgi/content/abstract/24/1/44

The ORAC score of prunes has been previously discussed in ASD. I have avoided dried fruits since being diagnosed due to their carbohydrate content. A few dates or prunes won't hurt too much and their antioxidant capacity may offset any of the negative aspect.

"Conclusions— This intervention resulted in dramatic improvements in BP, oxidative stress, NO availability, and the metabolic profile within 3 weeks, mitigating the risk for atherosclerosis progression and its clinical sequelae." Effect of Diet and Exercise Intervention on Blood Pressure, Insulin, Oxidative Stress, and Nitric Oxide Availability -
http://circ.ahajournals.org/cgi/content/full/106/20/2530 (Note: This article also has numerous cites linked.)
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Relevant Pages

  • Re: Whole dietary patterns vs. reductionist approach
    ... > Do you realize how many vegetables you need to eat to gain any ... diet intervention I cited, subjects consumed 5 kg/vegetables and fruits ... I think that you mean non-fiber carbohydrate. ...
    (sci.med.nutrition)
  • Re: Whole-Grains provide a lot more fiber, than fruits & vegetables
    ... Whole wheat bread supplies 5 g of fiber for a 100 calories serving. ... Some fruits and vegetables supply more fiber per 100 calories than most ... Effect of a very-high-fiber vegetable, fruit, and nut diet on serum lipids and colonic function. ... We tested the effects of feeding a diet very high in fiber from fruit and vegetables. ...
    (sci.med.nutrition)
  • Re: Whole dietary patterns vs. reductionist approach
    ... >> significant carbohydrate calories? ... Eating A lot vegetables is always a good ... > were derived from sweet fruits, ... No comparison to my diet of choice - ...
    (sci.med.nutrition)
  • Re: Whole dietary patterns vs. reductionist approach
    ... > but these were all from fruits, vegetables, legumes, and to a lesser extent, ... That kind of diet is very close to the healthiest I ... (Nurses' Health Study, Health Professionals' Follow-Up Study) ...
    (sci.med.nutrition)
  • DIET AND HEALTH - Historical
    ... DIET AND HEALTH ... "While dried fruits are not equal in hygienic value to fresh ... Dried fruits make an ideal breakfast food, ...
    (misc.health.alternative)
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