Archive - Antioxidant News

The Effects of Short-term Strawberry Supplementation in Reducing Oxidative Stress

 The Effects of Short-term Strawberry Supplementation in Reducing Oxidative Stress

To help further characterize the biological mechanisms underlying the health-promoting effects associated with strawberry consumption, researchers examined the anti-oxidative effects of a diet rich in strawberries in a group of 18 healthy men and women (age 35 ± 10 years; BMI 23 ± 3 kg/m2) by adding about three and a half cups (500 grams) of fresh strawberries to their daily diets for 2 weeks.  Analyses included measures of blood antioxidant status as well as biomarkers of resistance to endogenous and exogenous oxidative stress in red and mononuclear blood cells.  Findings following the 2-week strawberry intervention included a moderate increase in fasting plasma antioxidant status and vitamin C, together with a significant increase in the lag phase preceding the formation of plasma lipid oxidation products.   A significantly enhanced resistance to oxidative hemolysis was noted in red blood cells, with no significant reduction in ghost lipid peroxidation, a measure of the actions of strawberry phytochemicals in biomembranes.   The researchers conclude that regular consumption of strawberries may play a protective role by enhancing the body’s defenses against oxidative challenges, and suggest conducting larger intervention studies with reduced serving sizes of strawberries to confirm these findings.

Tulipani S, Armeni T, Giampieri F, et al.  Strawberry intake increases blood fluid, erythrocyte and mononuclear cell defenses against oxidative challenge.  Food Chemistry.2014;156:87-93.

Berries and Health: A Critical Review of Berry Fruit Bioactives

Berries are nutrient-rich fruits known to have health-promoting benefits related to their high levels of polyphenols, antioxidants, vitamins, minerals and dietary fiber.  A new article provides a comprehensive review of recent in vitro and in vivo studies that focus on the diverse range of berry phytochemicals and their associated biological effects and mechanisms of action.   Berry fruits are popular and widely consumed in the diet, and some, like strawberries, are recognized as functional foods.

Specifically, strawberries are noted by the authors as the richest source of vitamin C among berry fruits, and for their high concentration of anthocyanins, associated with a lower risk for certain cancers, improved memory and normal aging; and ellagic acid, a phenolic compound reported to have antiviral, antimicrobial and antioxidant activity as well as to provide protection against certain cancers.   Strawberries are also an example of an ellagitannin-rich fruit, which may contribute to its unique biological effects in neuronal function and behavior as reported in animal models.

The authors conclude that a number of studies—both human and animal—support the positive role of berry fruits in human health, offering potential for  protection against various diseases and from the damaging effects of free radicals based on specific biological activities, including anticancer, antimutagenic, antimicrobial, anti-inflammatory and neuroprotective properties.

Nile SH, Park SW, Edible berries: Review on bioactive components and their effect on human health, Nutrition (2013),

Berry Flavonoids May Reduce Risk for Developing Parkinson’s Disease

Eating and drinking foods rich in flavonoids, including berries, tea, apples and red wine, can lower the risk of developing Parkinson’s disease, new research suggests. Researchers at the Harvard School of Public Health in Boston examined the correlation between flavonoid intake and risk of Parkinson’s disease in men participating in the Health Professional Follow-up Study and women in the Nurse’s Health Study. While the highest intake of total flavonoids indicated up to 40% lower risk for men, only consumption of several weekly servings of berries showed a risk reduction in women. Parkinson’s disease is a degenerative condition of the central nervous system, affecting about 500,000 Americans, according to the National Institute of Neurological Disorders and Stroke. Flavonoids are substances found in plant foods that help prevent damage to human cells, known as oxidative damage. Berries such as strawberries are rich in anthocyanins, a type of flavonoid. The anthocyanins in berries have been shown to protect cells from oxidative damage and also have an anti-inflammatory effect, which may be how they help reduce Parkinson’s risk. When researchers looked at the dietary compounds individually, it was clear that berries benefitted everyone, lowering the risk of Parkinson’s disease by about 25 percent for those consuming only two servings of berries a week.

From Neurology®: Habitual intake of dietary flavonoids and risk of Parkinson’s disease X. Gao, A. Cassidy, M.A. Schwarzshild, et al. Neurology 2012;78; 1138;

Published online before print April 4, 2012; DOI 10.1212/WNL.0b013e31824f7fc4

Salk Scientists Say: It’s not an Apple a day after all – it’s Strawberries!

Research has identified a number of bioactive substances in berries. One less well-known flavonoid, fisetin, is showing promise as an antioxidant and anti-inflammatory which has the potential to mitigate multiple complications of diabetes. Researchers at The Salk Institute for Biological Studies fed diabetic-like mice fisetin (in an amount equivalent to eating about 37 strawberries) and saw positive effects in kidney and brain function, and markers of inflammation . Fisetin is unique among natural substances previously tested for diabetic complications, because it impacts so many organ systems affected by the disease. The highest levels of fisetin are found naturally in strawberries. While this is emerging data in an animal model, it further
substantiates the health benefits of frequent consumption of fruit, like strawberries.

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The full text of the article can be found at:

Researchers Confirm Bioavailability of Antioxidants in Strawberries

The bioavailability in humans of antioxidant compounds in strawberries has been confirmed by researchers in Italy and Spain. Twelve healthy volunteers ate 500 grams (about 17 ounces) of strawberries over the course of the day, and blood samples were drawn after four, eight, 12, 16, and 30 days later. The results show that regular strawberry consumption can improve the antioxidant capacity of blood plasma and also the resistance of red blood cells to oxidative stress. Oxidative stress has been shown to be a key fact in the development of cardiovascular disease, cancer, and diabetes. Strawberries contain a large amount of phenolic compounds, such as flavonoids, which have antioxidant properties. This work confirms that those antioxidant compounds survive digestion and metabolism.

The researchers conclude that strawberries should be one of the daily portions of fruit that is an important part of healthy and balanced diet.

This work confirms studies published previously that showed the active compounds in strawberries are bioavailable.

Tulipani S et al. Strawberry consumption improves plasma antioxidant status and erythrocyte resistance to oxidative haemolysis in humans. Food Chemistry, 2011; 128 (1):180.

Ellis CL et al. Attenuation of meal-induced inflammatory and thrombotic responses in overweight men and women after 6-week daily strawberry (Fragaria) intake. A randomized placebo-controlled trial. J Atheroscler Thromb. 2011 Apr 27;18(4):318-27.

Azzini E et al. Bioavailability of strawberry antioxidants in human subjects. Br J Nutr. 2010 Oct;104(8): 1165-73.

Link to abstract –

Emerging Health Areas

Research on the effects of berries on obesity and metabolic syndrome is in its very early stages. Ronald Prior, Ph.D., of the USDA Agricultural Research Center at Arkansas Children’s Nutrition Center described animal studies exploring the effects of feeding whole berries and berry anthocyanins as part of a high fat diet. Strawberry anthocyanins were effective in preventing obesity and correcting the dyslipidemia and hyperpeptinemia of obesity.

Anthocyanins have also been shown to be present in ocular tissues and may improve night vision. Other eye health issues, such as glaucoma and age-related macular degeneration, may benefit from the antioxidant activity of berries.

Overall, the Symposium demonstrated that there is a valid scientific basis for considering berries to be superfruits. California strawberries are grown year- round and are available in supermarkets across the country so can be easily incorporated into a healthy lifestyle. And, as America’s favorite fruit, they have the taste profile that makes strawberries an easy daily choice

More information on the 2009 Berry Health Benefits Symposium can be found at

Spoonfuls of Strawberries Help the Cholesterol Go Down

Strawberries have been found to help lower LDL cholesterol. The study, conducted by David J.A. Jenkins, MD, PhD, backs existing evidence that touts strawberries as one of the most nutrient-rich foods. It showed that the antioxidant power in strawberries can improve and maintain the effectiveness of cholesterol- lowering diets.

The 2.5-year University of Toronto study focused on 28 men and women with high cholesterol who were previously on a diet to lower cholesterol that included soy, oat bran, plant sterols and nuts. One half of the group was instructed to eat approximately 3 cups of strawberries per day for a month while the other group consumed additional oat bran bread during the same time frame.

Results showed that eating strawberries had several positive effects. While continuing to maintain their lowered blood cholesterol and triglyceride levels, the strawberries also reduced oxidative damage to LDL cholesterol. LDL becomes even more damaging when it becomes oxidized. Furthermore, the strawberries improved the taste of the cholesterol- lowering diet. Overall, the research showed that strawberries can improve the effectiveness of diets designed to lower the risk of coronary heart disease.

Jenkins DJ, Nguyen TH, Kendall CW, Faulkner DA, Bashyam B, Kim IJ, Ireland C, Patel D, Vidgen E, Josse AR, Sesso HD, Burton-Freeman B, Josse RG, Leiter LA, Singer W. The effect of strawberries in a cholesterol-lowering dietary portfolio. Metabolism. 2008 Dec;57(12):1636-44.

Flavonoids Improve Health of Blood Vessels

There is no shortage of epidemiological evidence linking increased dietary intake of antioxidants-from berries, wine, dark chocolate and many other plant- based foods to reduced risks of a range of diseases including heart disease, type II diabetes and certain cancers. In addition, a number of studies have confirmed that consuming foods rich in flavonoids, one type of polyphenol antioxidant, improves blood vessel endothelial function among individuals with or without heart disease. Poor endothelial function is a key marker for risk of cardiovascular disease.

Scientists from the University of Western Australia have now been able to confirm what was suspected previously-that flavonoids are responsible for the improved blood vessel function. Researchers fed subjects a 200mg dose of three common flavonoids, (including quercetin, which is present in strawberries) the researchers approximated a reasonable dose that could be achieved by eating flavonoid-rich foods. The subjects did absorb the flavonoids, and they did experience positive changes in blood vessel function, as evidenced by measuring nitric oxide levels. Nitric oxide is a common marker for measuring blood vessel health because the molecule is used by the endothelium to signal surrounding muscle tissue to relax.

Strawberries are a rich source of beneficial flavonoids, including quercetin and ellagic acid. Previous research confirms that eating strawberries increases blood levels of these nutrients, and lowers various markers of cardiovascular disease.

Loke WM, Hodgson JM, Proudfoot JM, et al. Pure dietary flavonoids quercetin and epicatechin augment nitric oxide products and reduce endothelin-1 activity in healthy men. Am J Clin Nutr. 2008;88(4):1018-25.

Strawberry Antioxidants Reduce LDL Oxidation

High concentrations of LDL cholesterol, particularly oxidized LDL cholesterol are a risk factor for cardiovascular disease. Diets to lower cholesterol include foods such as soy, oat bran (a source of viscous fiber), plant sterols and nuts. In an ongoing study at the University of Toronto, researchers found that the Portfolio Diet, which includes all of these foods, can significantly reduce total and LDL cholesterol. A study was conducted to determine the effect of replacing some of the oat bran in the Portfolio Diet with strawberries. Subjects were given either one pound of strawberries or the equivalent amount of calories in oat bran bread daily for one month. Results showed that strawberry supplementation reduced the oxidative damage to LDL, and increased the palatability of the diet while maintaining LDL cholesterol and the ratio of total to HDL cholesterol.

The effect of strawberries in a cholesterol-lowering dietary portfolio. Jenkins DJ, Nguyen TH, Kendall CW, Faulkner DA, Bashyam B, Kim IJ, Ireland C,Patel D, Vidgen E, Josse AR, Sesso HD, Burton-Freeman B, Josse RG, Leiter LA,Singer W. Metabolism. 2008 Dec;57(12):1636-1644.

Strawberries and the 2010 Dietary Guidelines for Americans

Nutritious, low-calorie foods such as strawberries will be enjoying the spotlight even more as obesity continues to be the leading public health concern and the concept of nutrient density gains acceptance. “Nutrient density” has been an important nutritional principle for years, but experts expect the 2010 Dietary Guidelines for Americans to provide more clarification and guidance on how to eat a nutrient-dense diet.

As part of The Nutrient Rich Foods Coalition, California Strawberries are in a prime position to benefit from the scientific research and promotional efforts of this on-trend group. The Coalition, comprised of members that represent the five basic MyPyramid food groups, focuses on supporting scientific and market research to develop tools that help consumers understand the concept of nutrient density and incorporate the concept into their lifestyles.

Given the major focus on obesity prevention going on in the U.S., the nutrient rich foods approach is useful and appealing not just for its emphasis on maximizing nutrition, but because making every calorie count is a cornerstone of a sound weight control program. For additional information on the Nutrient Rich Foods Coalition, visit their website at:

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