Timing of antioxidants & food related oxidative stress
Consuming antioxidant-rich foods during meals reduces the oxidative stress associated with eating. The US Department of Agriculture (USDA) researchers measured the blood antioxidant capacity (AOC) in five clinical trials, and found that consumption of antioxidant-rich foods reduced oxidative stress after a meal of rich in carbohydrates, protein, and fat.
Certain berries and fruits such as blueberries, mixed grape and kiwifruit, are associated with increased plasma AOC. The consumption of an energy source of macronutrients containing no antioxidants was associated with a decline in plasma AOC (Ron Prior in the Journal of the American College of Nutrition).
To determine if the meals containing the different fruit or berries increased the hydrophilic (water-soluble) or lipophilic (fat soluble) antioxidant capacity, measured as Oxygen Radical Absorbance Capacity (ORAC), five clinical trials were conducted with blood samples taken from the subjects before and after the meal.
Neither dried plums (prunes) nor dried plum juice altered either measure of antioxidant activity. Blueberries or mixed grape consumption (12.5 and 8.6 millimole Trolox Equivalents (TE AOC), respectively) with the meal was associated with a increase in hydrophilic AOC. Blueberries also increased the lipophilic AOC.
Cherries, eaten with the meal and providing 4.5 millimoles TE AOC, increased the lipophilic, but not the hydrophilic, AOC.
A control meal, rich in the macronutrients - carbohydrates, protein and fat - consumed without antioxidants was found to result in a decrease of blood AOC, showing an increase in oxidative stress.
What you eat with your main meals is therefore important. Phytochemicals in foods have varying degrees of bioavailability and generally are cleared from the blood 2-4 hours after they're eaten. Antioxidant-rich foods taken through the dat can help combat oxidative stress. About 2.5 servings of antioxidant containing fruits and/or vegetables in a meal are needed to prevent oxidative stress following the meal. The more calories you take in the more dietary antioxidants you need.
We should therefore incorporate fruits and vegetables and other whole foods like grains and nuts into every meal to get the full phytochemical benefits needed to fight oxidative stress and inflammation.
Journal of the American College of Nutrition Volume 26, Number 2, Pages 170-181 "Plasma Antioxidant Capacity Changes Following a Meal as a Measure of the Ability of a Food to Alter In Vivo Antioxidant Status" Authors: R.L. Prior, L. Gu, X. Wu, R.A. Jacob, G. Sotoudeh, A.A. Kader, R.A. Cook