The study’s conclusions that antioxidants may help prevent heart failure cannot be extended to antioxidant supplements, said the researchers from Harvard, the Karolinska Institutet, and the University of Alabama, because a lack of data for supplements.
Commenting independently on the study’s findings, Alex Schauss, PhD, senior research director at AIBMR Life Sciences, told NutraIngredients-USA that the data has implications for the ORAC assay.
“In terms of the recent controversy regarding the ORAC assay, it is noteworthy that the authors determined the total antioxidant capacity of the diet in the 33,713 women studied, using the ORAC assay,” he said. “Data provided by ORAC of foods helped reveal the inverse relationship between antioxidant-rich food consumption and risk of heart failure.
“At a time when some critics have urged an end to the use of the ORAC assay in determining the antioxidant capacity of supplement ingredients, it is particularly noteworthy that the study failed to determine whether antioxidants from supplements would provide the same benefit because, as the authors point out, they ‘did not have ORAC values for dietary supplements; thus, our results do not apply to antioxidant supplements’,” said Dr Schauss.
“Hence, the advice by food scientists to use ORAC to measure a supplement ingredient’s free-radical scavenging capacity, might flush out relationships between what supplements decrease or increase the risk to a wide range of diseases in similar population-based long term studies.
“To fail having such data risks missing the opportunity to find out if antioxidant supplementation provides benefits similar to that seen for antioxidant-rich foods.”
Led by Dr Susanne Rautiainen, the researchers analyzed data from 33,713 women from the Swedish Mammography Cohort aged between 49 and 83. Dietary intakes were calculated from food-frequency questionnaire, and the dietary total antioxidant capacity was estimated from the ORAC measurements of the foods.
Over 11.3 years of follow-up, 894 cases of heart failure were documented. After crunching the numbers, the researchers calculated that women with the highest average antioxidant capacities were 42% less likely to develop heart failure, compare with women with the lowest average antioxidant capacities.
“Antioxidants are thought to protect against cardiovascular disease by preventing oxidation of lipids and endothelial damage, which can lead to atherosclerosis, and by preserving the nitric oxide pool, which promotes vasodilatation and potentially reduces blood pressure,” wrote Dr Rautiainen and her co-workers.
“Heart failure shares risk factors with coronary artery disease; however, elevated blood pressure is of particular importance in the development of heart failure.”
Dr Schauss added: “The study by Rautianinen and colleague provides additional evidence that consuming a diet rich in antioxidant-containing foods, lowers the risk of dying from heart failure, even when adjusting for confounders such as smoking, BMI, physical activity, and educational level.”
Heart failure affects 5.7 million people in the United States, half of whom die within five years of diagnosis, according to data from the US Centers for Disease Control and Prevention (CDC).
Source: The American Journal of Medicine
Published online ahead of print, doi: 10.1016/j.amjmed.2013.01.006
“Total Antioxidant Capacity of Diet and Risk of Heart Failure: A Population-based Prospective Cohort of Women”
Authors: S. Rautiainen, E.B. Levitan, M.A. Mittleman, A. Wolk