Antioxidant Peer-Reviewed Research

Research Supporting the Health Benefits of Antioxidants

Medical research into the health benefits of traditional diets, such as the Japanese, Mediterranean and Scandinavian diets, demonstrates the cancer-fighting, anti-aging, immunity, and cardiovascular protective properties of antioxidants. In particular, this research suggests that a balanced diet of foods containing certain powerful antioxidant subclasses can make a real difference in promoting health.

The following peer-reviewed research studies examine the health benefits attributable to consumption of antioxidants. These studies were beneficial resources in the development of the SCS Antioxidant Superfood Certification Program, including the determination of a daily intake targets for essential antioxidants.

List of References

Anthocyanins
  • Dietary Intake and Major Food Sources of Polyphenols in Finnish Adults.
  • A study to determine the avg level of polyphenol consumption across a human population, and what food sources were the largest contributors to polyphenol consumption. Coffee and cereal are noted as the main contributors to total polyphenol intake. Blue and back berries were the main contributors to anthocyanin intake.
  • Authors: Ovaskainen, Marja-Leena, Riitta Törrönen, et al.
  • Published In: Journal of Nutrition. 138.3 (2008): 562-566.
  • Dietary intake of 337 polyphenols in French adults.
  • This study was conducted to measure the dietary intake of broad spectrum of unique polyphenols. Results show intake numbers for 337 types of polyphenol.
  • Authors: Pérez-Jiménez, Jara, Léopold Fezeu, et al.
  • Published In: American Journal of Clinical Nutrition. 93. (2011): 1220-1228.
  • Polyphenols: food sources and bioavailability.
  • In this study, the nature and contents of various polyphenols present in food sources and the influence of agricultural practices and industrial processes are reviewed. Also, the bioavailability profile of various polyphenols is reviewed. The conclusion state that the health effects of polyphenols depend on both their respective intakes and their bioavailability.
  • Authors: Manach, Claudine, Augustin Scalbert, et al.
  • Published In: American Journal of Clinical Nutrition. 79. (2004): 727–47.
  • Tart Cherry Juice Decreases Oxidative Stress in Healthy Older Men and Women.
  • A study measuring the impact of anthocyanin on the capacity of older adults to resist oxidative damage during times of stress. Participants were asked to consume tart cherry juice containing anthocyanin at intervals. Results suggest that consumption of tart cherry juice improves antioxidant defenses in older adults.
  • Authors: Traustadóttir, Tinna, Sean Davies, et al.
  • Published In: Journal of Nutrition. 130.10 (2009): 1896-1900.
Flavan-3-ol
  • A Green Tea Extract High in Catechins Reduces Body Fat and Cardiovascular Risks in Humans.
  • A study to determine whether a green tea extract high in catechins reduces body fat and cardiovascular risks in humans. Subjects—obese Japanese men and women—were asked to ingest either 583 mg or 96 mg of catechins per day through green tea. Results indicate that the continuous ingestion of green tea extract high in catechins led to the reduction of body fat, blood pressure, and LDL cholesterol.
  • Authors: Nagao, Tomonori, Tadashi Hasi, and Ichiro Tokimitsu
  • Published In: Obesity. 15.6 (2007): 1473-83.
  • Catechin Safely Improved Higher Levels of Fatness, Blood Pressure, and Cholesterol in Children.
  • A study to evaluate the effects of a catechin-rich beverage on body fat and cardiovascular disease risk factors in obese children and to verify the safety of its use. Subjects—obese Japanese children—were instructed to go ingest 576mg of catechins per day via beverage. Results of the study suggest that indgestion of a catechin-rich beverage ameliorates serious obesity and cardiovascular disease risk factors without raising any safety concerns in Japanese children.
  • Authors: Matsuyama, Takeshi, Yuriko Tanaka, et al.
  • Published In: Obesity. 16.6 (2008): 1338-48.
  • Distribution and Major Sources of Flavonoid Intakes in the Middle-Aged Japanese Women.
  • A study to investigate the effect of a soy isoflavone on insulin sensitivity and other diabetes indicators. Subjects were asked to participate for 24 months in a specific exercise and diet regimen, in addition to taking a daily oral soy isoflavone supplement. Results indicate that diet, physical exercise and a daily oral intake of soy isoflavones does improve insulin sensitivity in early posmenopausal women
  • Authors: Otaki, Naoto, Mitsuru Kimira, et al.
  • Published In: Journal of Clinical Biochemistry and Nutrition. 44.3 (2009): 231-238.
  • Effect of tea catechins on postprandial plasma lipid responses in human subjects.
  • A study to examine the impact of a theaflavin-enriched grean tea extract on the lipids on lipoproteins of subjects with high cholesterol. Subjects were assigned to receive a daily capsule containing theaflavin enriched green tea extract of 375mg. Results showed that theaflavin-enriched green tea extrac, when combined with a proper diet, will help lower LDL cholesterol in adults
  • Authors: Unno, Tomonori, Motori Tago, et al.
  • Published In: British Journal of Nutrition. 93.4 (2005): 543 547.
  • Effects of Catechin Enriched Green Tea on Body Composition.
  • Study to examine the effects of high volume catechin green tea extract on body composition in moderately overweight Chinese people. Subjects were given green tea extract beverages several times a day for 90 days. Results indicate that two servings of extra high catechin GT leads to improvements in body composition.
  • Authors: Wang, Hongqiang, Yibo Wen, et al.
  • Published In: Obesity. 18.4 (2010): 773-9.
  • Estimation of Dietary Sources and Flavonoid Intake in a Spanish Adult Population (EPIC-Spain).
  • A study to estimate the quantitative intakes of polyphenols by using analyzed concentrations together with individual food consumption records to determine major dietary sources. The results give additional support to the recommendations for a varied diet with fruits, berries, cereals, and vegetables.
  • Authors: Zamora-Ros, Raul, Cristina Andres-Lacueva, et al.
  • Published In: Journal of the American Dietetic Association. 110.3 (2010): 390-398.
  • Green Tea Catechin Consumption Enhances Exercise-Induced Abdominal Fat Loss in Overweight and Obese Adults.
  • A study to evaluate the influence of a green tea catechin beverage on body composition in overweight and obese adults during exercise induced weight loss. Subjects were instructed to receive a beverage containing catechins every day for 12 wk, and maintain a strict exercise regimen. Findings suggest that green tea catechin consumption engances exercise induced changes in abdominal fat.
  • Authors: Maki, Kevin, Matthew Reeves, et al.
  • Published In: Journal of Nutrition. 139.2 (2009): 264-270.
  • Prospective Double-Blind Crossover Study of Camellia Sinensis (Green Tea) in Dyslipidemias.
  • A study to investigate the effects of green tea in patients with excess fat and cholesterol in the blood. Subjects were given daily tablets of 250mg green tea extract for 16 weeks. Results indicate a beneficial effect from green tea, with significant reduction of total cholesterol and LDL cholesterol in eight weeks.
  • Authors: Gesiani de Almeida Pierin, Batista, Cláudio Pereira da Cunha, et al.
  • Published In: Arquivos Brasileiros de Cardiologia. 93.2 (2009): 121-7.
  • Tea Catechin Consumption Reduces Circulating Oxidized Low-Density Lipoprotein.
  • Study evaluates the effect of catechin intake on LDL cholesterol. Subjects were given daily 500mg capsules of catechin for four weeks. Results indicate that the mechanism of the beneficial effects of green tea on coronary artery disease might result from a decrease in plasma oxidized LDL.
  • Authors: Inami, Shigenobu, Masamichi Takano, et al.
  • Published In: International Heart Journal. 48.6 (2007): 725-732.
Flavanone
Flavone
  • Effect of Citrus Flavonoids and Tocotrienols on serum cholesterol levels in hypercholesterolemic subjects.
  • This study examines the effect of flavanoids and palm tocotrienols on human cholesterol levels. Subjects were required to consume 270mg of citrus flavanoids plus 30mg tocotrienols for periods of either 4 or 12 weeks. Results suggest that citrus flavanoids and tocotrienols improve cardiovascular health.
  • Authors: Roza, James, Zheng Xian Liu, and Najla Guthrie.
  • Published In: Alternative Therapies in Health and Medicine. 13.6 (2007): 44-48.
Flavonol
  • Quercetin Reduces Blood Pressure in Hypertensive Subjects.
  • A study to determine whether the bioflavanoid quercetin reduces blood pressure in hypertensive patients. Subjects were given 730mg of quercetin for 28 days. Results show that quercetin supplementation reduces blood pressure in hypertensive subjects.
  • Authors: Edwards, Randi, Tiffany Lyon, et al.
  • Published In: Journal of Nutrition. 137.11 (2007): 2405-2411
Isoflavone
  • Beneficial Effects of Soy Phytoestrogen Intake in Postmenopausal Women With Type 2 Diabetes.
  • A study to determine the effect of phytoestrogen on cardiovascular disease in post-menopausal women with type 2 diabetes. Subjects were given dietary supplements with 30g per day of phytoestrogens for a two week period. The results show that dietary supplementation with soy phytoestrogens improves the cardiovascular risk profile of women who are overweight and menopausal.
  • Authors: Jayagopal, Vijay, and Paula Albertazzi.
  • Published In: Diabetes Care. 25.10 (2002): 1709-1714.
  • Distribution and Major Sources of Flavonoid Intakes in the Middle-Aged Japanese Women.
  • A study to determine the relationship between intake of isoflavones and specific blood chemistry metrics amongst a population of Japanes post menopausal women. Subjects received a health check up and blood sampling for the study. Results suggest that a high consumption of both flavonoids and isoflavones by Japanese women may contribute to their low incidence of coronary heart disease compared with women in other countries.
  • Authors: Otaki, Naoto, Mitsuru Kimira, et al.
  • Published In: Journal of Clinical Biochemistry and Nutrition. 44.3 (2009): 231-238.
  • Effect of a Daily Supplement of Soy Protein on Body Composition and Insulin Secretion in Postmenopausal Women.
  • A study to determine the effect of daily soy supplementation on body composition, body fat distribution, and glucose and insulin metabolism in non diabetic, post menopausal women. Subjects were asked to drink a shake containing soy protein. Results suggest that a daily supplement of soy protein reduces the gain in total abdominal fat and subcutaneous abdominal fat.
  • Authors: Sites, Cynthia, Brian Cooper, et al
  • Published In: Fertility and Sterility. 88.6 (2007): 1609-1617.
  • Metabolic effects of soy supplementation in postmenopausal white and African American women: a randomized, placebo-controlled trial.
  • A study to determine the effect of daily soy supplementation on fat levels, metabolism, and circulatory health in obese and menopausal Caucasian and African American women. Subjects were asked to consume a daily shake supplement containing either soy protein plus isoflavones. Results show that African American and Caucasian women respond differently to soy supplementation, where Caucasian women experienced reduced visceral fat compared to African American women, but African American women lost more weight.
  • Authors: Christie, Daniel, Jan Grant, et al.
  • Published In: American Journal of Obstetrics & Gynecology. 203.2 (2010): 153.e1-153.e9.
  • Soy isoflavone supplementation and bone mineral density in menopausal women: a 2-year multicenter clinical trial.
  • A study to investigate the effect of a soy isoflavone on insulin sensitivity and other diabetes indicators. Subjects were asked to participate for 24 months in a specific exercise and diet regimen, in addition to taking a daily oral soy isoflavone supplement. Results indicate that diet, physical exercise and a daily oral intake of soy isoflavones does improve insulin sensitivity in early postmenopausal women.
  • Authors: Wong, William, Richard Lewis, et al.
  • Published In: American Journal of Clinical Nutrition. 90. (2009): 1433-9.
  • Soy isoflavones improve insulin sensitivity without changing serum leptin among postmenopausal women
  • A study to determine whether the bioflavanoid quercetin reduces blood pressure in hypertensive patients. Subjects were given 730mg of quercetin for 28 days. Results show that quercetin supplementation reduces blood pressure in hypertensive subjects.
  • Authors: A study to test the effect of soy isoflavone supplementation on bone health. Subjects were given soy isoflavone supplements of 80 or 120mg for a period of 24 months. Results show that soy isoflavone supplements reduce whole-body bone loss.
  • Published In: Climateric
Proanthocyanin
  • Beneficial Effects of Grapeseed Extract on Malondialdehyde-Modified LDL.
  • A study to examine the effects of grape-seed extract on cholesterol levels. Subjects were given varying doses of grape seed extract daily for a 12 week period. Results of the study indicate that tablets containing grape seed extract exerted reducing effects on LDL levels, and might be useful in preventing arteriosclrerosis.
  • Authors: Sano, Atsushi, Riichiro Uchida, et al
  • Published In: Journal of Nutritional Science and Vitaminology. 53.2 (2007): 174-182.
  • Impact of cocoa flavanol consumption on blood pressure responsiveness.
  • A study to investigate whether consumption of cocoa flavanols can modify blood pressure responsiveness. Subjects were put into various groups and asked to consume either low flavanol or high flavanol cocoa beverages every 3 or every seven days. Results indicate that cocoa flavanols may decrease cardiovascular risk and enhance the cardiovascular benefits of moderate intensity exercise in at risk individuals.
  • Authors: Berry, Narelle, and Kade Davison.
  • Published In: British Journal of Nutrition. 103.10 (2010): 1480-1484.
  • Oral Intake of Proanthocyanidin-Rich Extract from Grape Seeds Improves Chloasma
  • A study to examine the reductive effect of proanthocyanidin on chloasma. Subjects were given grape seed extract twice daily for nearly a year. Results indicate that grape seed extract is useful for improving chloasma
  • Authors: Yamakoshi, Jun, Atsushi Sano, et al.
  • Published In: Phytotherapy Research. 18.11 (2004): 895-899.
Lutein
  • Dietary Carotenoids, Vitamins A, C, E and Advanced Age-Related Macular Degeneration.
  • Study to evaluate the relationships between carotenoids and vitamins A,C, and E and risk of age-related mascular blindness (AMD). Subjects all had early stage AMD. Subjects diets were surveyed and studied. Results show that increasing the consumption of foods rich in certain carotenoids may decrease the risk of developing advanced AMD
  • Authors: Seddon, Johanna, Umed Ajani, et al.
  • Published In: Journal of the American Medical Association. 272.18 (1994): 1413-1420.
  • of Eggs with Lutein.
  • A series of expiraments designed to test the feasibility of introducing lutein into chicken eggs by giving checkens lutein supplements. Subjects were laying hens given varying levels of lutein supplements. Results of the study show that lutein concentration in chicken egg yolks can be increased by adding lutein to the diets of laying hens.
  • Authors: Leeson, S., and L. Caston.
  • Published In: Poultry Science. 83.10 (2004): 1709-1712.
  • Lutein & Zeaxanthin.
  • Overview of lutein and zeaxnthin and how they relate to eye health.
  • Authors: American Optometric Association.
  • Published In: American Optometric Association
  • The influence of supplemental lutein and docosahexaenoic acid on serum, lipoproteins, and macular pigmentation.
  • The objective of this study was to determine whether lutein and docosahexaenoic (DHA) was conducive to eye health by preventing age-related mascular degeneratin (AMD). Subjects were given supplements of lutein, DHA, or lutein + DHA for four months, and their mascular pigment optical density levels were monitored. Results suggest that lutein and DHA may aid in prevention of age-related macular degeneration.
  • Authors: Johnson, Elizabeth, Hae-Yun Chung, et al.
  • Published In: The American Journal of Clinical Nutrition. 87. (2008): 1521-9.
Lycopene
  • A Dose-Response Study on the Effects of Purified Lycopene Supplementation on Biomarkers of Oxidative Stress.
  • A study to test the effects of different doses of purified lycopene supplements on general health metrics (biomarkers of oxidative stress). Subjects were asked to go on a lycopene restricted diet for 2 weeks and then on a lycopene supplemented diet for 8 weeks. Results indicate that lycopene supplements do decrease negative health metrics (oxidative damage).
  • Authors: Devaraj, Sridevi, and Surekha Mathur.
  • Published In: Journal of the American College of Nutrition. 27.2 (2008): 267-273.
  • Antioxidant Effects of Lycopene in African American Men with Prostate Cancer or Benign Prostate Hyperplasia: A Randomized Controlled Trial.
  • Study to test whether oral administration of lycopene lowers markers of oxidative stress (which are indicators of general health) in prostate cancer patients. Subjects were African American early stage prostate cancer patients, and were assigned to receive 30mg/day of lycopene in tomato concentrate for 21 days prior to prostate biopsy. Results indicate that lycopene supplements had no significant effects on markers of oxidative stress in the subjects of this group. Results indicate that a constituent element in tomato sauce, possibly lycopene, could potentially play a role in treatment of prostate cancer
  • Authors: Breemen, Richard, Roohollah Sharifi, et al.
  • Published In: Cancer Prevention Research. 4.5 (2011): 711-718
  • Oxidative DNA Damage in Prostate Cancer Patients Consuming Tomato Sauce-Based Entrees as a Whole-Food Intervention.
  • A study examining the effects of tomato sauce-based dishes on lycopene uptake and oxidative damage in patients already diagnosed with prostate cancer. Subjects were asked to eat one meal with tomato sauce per day for three weeks before prostate surgery. Results of the study suggest that a constituent element of tomato sauce, possibly lycopene, might aid in the treatment of prostate cancer.
  • Authors: Chen, Longwen, Maria Stacewicz-Sapuntzakis, et al.
  • Published In: Journal of the National Cancer Institute. 93.24 (2001): 1872-9.
  • Role of Lycopene as Antioxidant Carotenoid in the Prevention of Chronic Diseases: A Review.
  • This review summarizes the background information about lycopene and presents the most current knowledge with respect to its role in human health. Lycopene’s function as an antioxidant might not be the primary mechanism that is responsible for its positive health benefits.
  • Authors: Rao, A.V., and S. Agarwal
  • Published In: Nutrition Research. 19.2 (1999): 305-323.
  • Tomato juice decreases LDL cholesterol levels and increases LDL resistance to oxidation.
  • A study to determine the effects of increased dietary intake of tomato products on LDL cholesterol levels. Subjects were put on a 3 week low tomato diet, and then subsequently put on a 3 week high tomato diet. Results indicated that a high dietary intake of tomato products significantly reduced LDL cholesterol levels.
  • Authors: Silaste, Marja-Leena, and Georg Alfthan.
  • Published In: British Journal of Nutrition. 98.6 (2007): 1251-1258.