The history of research into antioxidants’ effects on heart disease has been a checkered one.
People who’ve taken supplemental antioxidants – mainly selenium and vitamins C and E – in clinical trials have generally not enjoyed reduced rates of heart disease, heart attacks, or cardiac death.
But the heart-health record for antioxidant-rich foods is another matter … judging by the numerous positive population studies and a modest number of clinical trials.
We’ve reported on some of the studies linking antioxidant-rich foods to reduced heart risks and/or improvements in other key bodily influences on cardiovascular and metabolic health ... such as artery health, blood chemistry, inflammation, blood pressure, and more.
To peruse those, click on the heart-related sub-categories listings under the Omega-3 Fatty Acids, Foods & Health, and General Health Topics categories, found on the right side of our News Archive page.
Cocoa, tea, berries, red wine, and extra virgin olive oil rank high among the foods studied, because they are unusually rich in certain powerfully healthful polyphenol compounds.
(Vitamin E is actually a complex of several polyphenol-class chemicals, and it’s the only dietary vitamin or internal antioxidant chemical that falls into the phenol family.)
A class of polyphenols called flavonoids – and especially a sub-category called flavanols – exert beneficial “nutrigenomic” influences on genes that affect inflammation, oxidation of cholesterol, blood stickiness, and other aspects of cardiovascular health.
Earlier this month, scientists from Sweden reported finding a strong link between higher intake of food-borne antioxidants and a significantly reduced risk of heart attack among women.
Before getting to the details, let’s review the often-misunderstood subject of women and heart disease.
Women and heart disease: Myths and missed diagnoses
Heart attacks are most often associated with men … but women are also prone to coronary heart disease and resulting heart attacks, strokes, or sudden death.
Even though it’s the number one killer of women over age 25, only 13 percent of women view heart disease as a particular health threat.
Dangerously, women's symptoms frequently differ from men’s, in ways that make diagnosis more difficult.
Women may report fatigue, sleep disturbances and shortness of breath, all of which may be dismissed as irrelevant to heart disease … or mistakenly attributed to benign conditions.
There are distinct differences between the ways in which heart disease manifests in the genders, as we explained in “Women’s Heart Risks Form Focus of ‘Wear Red’”.
You’ll find that piece and articles about dietary influences on heart disease in the General Heart Health section of our news archive.
One of those, “Women’s Heart Risk Falls as Flavonoid Intake Rises”, summarized the first study to look for relationships between women’s intake of flavonoid-type polyphenols from foods and their rates of heart attack.
Now, a similar, 10-year-long population study from Sweden’s Karolinska Institute has found that a diet rich in antioxidants, mainly from fruits and vegetables, can significantly reduce the risk of heart attack.
Study links food-borne antioxidants to reduced heart attacks in women
According to lead investigator Alicja Wolk, M.D., “Our study was the first to look at the effect of all dietary antioxidants in relation to myocardial infarction [heart attack].
Total antioxidant capacity measures in a single value all antioxidants present in diet and the synergistic effects between them.” (EHS 2012)
The Karolinska Institute team followed 32,561 Swedish women aged 49-83 for 10 years, from September 1997 through December 2007 (Rautiainen S et al. 2012).
Participating women reported how often, on average, they consumed each of numerous types of food or beverage during the previous year.
The investigators estimated the total antioxidant capacity of the women’s diets, based on the “oxygen radical absorption capacity” (ORAC) values for foods in a U.S. Department of Agriculture database.
ORAC tests measure the power of chemicals – such as vitamin C, vitamin E, or foods rich in antioxidant polyphenols and carotenoids – to neutralize free radicals in a test tube.
(ORAC tests are imperfect measures of a substance’s effects in the body … but we lack good databases of better tests using live human cells, and ORAC values provide a reasonable measure of the amount and potency of antioxidants in a food.)
No equivalent database of Swedish foods exists, but the extent of overlap between the two nation’s common foods was adequate to allow the team to make good estimates.
The women’s diets were categorized into five groups, ranked from lowest to highest total antioxidant capacity.
The women with the highest total antioxidant capacity diets consumed almost seven servings of fruits and vegetables per day.
This was nearly three times more fruits and vegetables than the women whose diets had the lowest antioxidant capacity, which averaged only 2.4 daily servings of fruits and vegetables.
And when the antioxidant capacity of the participants’ diets was compared with their heart heath at the end of the decade, the women with the highest-antioxidant diets had a 20 percent lower risk of heart attack.
Clinical trials testing high doses of antioxidant supplements have failed to see any benefit on coronary heart disease … in fact, some trials see higher mortality rates in certain types of people taking high-dose vitamin E, beta-carotene, or selenium supplements.
But as Dr. Wolk said, “In contrast to supplements of single antioxidants, the dietary total antioxidant capacity reflects all present antioxidants, including thousands of compounds, all of them in doses present in our usual diet, and even takes into account their synergistic effects.” (EHS 2012)
In a commentary accompanying the article, Pamela Powers Hannley, MPH, observed that with the industrialization of our food supply, Americans began to consume more total calories and more calories from processed food high in fat and sugar.
As a result, she wrote, obesity rates began to climb steadily: “Although weight-loss diets abound in the US, the few which emphasize increasing intake of fruits and vegetables actually may be on the right track.
Yet only 14 percent of American adults and 9.5 percent of adolescents eat five or more servings of fruits or vegetables a day.” (EHS 2012)
For once the USDA has it right … eat five servings of fruits and vegetables a day. And to get the biggest antioxidant bang, favor colorful foods such as dark, leafy greens (spinach, chard, kale, collards), berries, beans, cocoa, tea, carrots, beets, broccoli, red wine, whole grains, and extra virgin olive oil.
As well as being heart-healthier, your meals will be more varied, attractive, and flavorful, to boot!
- Bhupathiraju SN, Tucker KL. Coronary heart disease prevention: nutrients, foods, and dietary patterns. Clin Chim Acta. 2011 Aug 17;412(17-18):1493-514. Epub 2011 May 7. Review.
- Curin Y, Andriantsitohaina R. Polyphenols as potential therapeutical agents against cardiovascular diseases. Pharmacol Rep. 2005;57 Suppl:97-107. Review.
- Elsevier Health Sciences (EHS). Diet high in total antioxidants associated with lower risk of myocardial infarction in women. Sept. 21, 2012. Accessed at http://www.eurekalert.org/pub_releases/2012-09/ehs-dhi092112.php
- García-Lafuente A, Guillamón E, Villares A, Rostagno MA, Martínez JA. Flavonoids as anti-inflammatory agents: implications in cancer and cardiovascular disease. Inflamm Res. 2009 Sep;58(9):537-52. Epub 2009 Apr 21. Review.
- Majewska-Wierzbicka M, Czeczot H. [Flavonoids in the prevention and treatment of cardiovascular diseases]. Pol Merkur Lekarski. 2012 Jan;32(187):50-4. Review. Polish.
- Rautiainen S, Levitan EB, Orsini N, Åkesson A, Morgenstern R, Mittleman MA, Wolk A. Total Antioxidant Capacity from Diet and Risk of Myocardial Infarction: A Prospective Cohort of Women. The American Journal of Medicine. Volume 125, Issue 10, Pages 974–980.doi: 10.1016/j.amjmed.2012.03.008