Eating Strawberries Daily Improves Cognitive Performance in Older Adults

In one of the first clinical studies designed to determine whether dietary strawberry intake could reverse age-related motor and cognitive decline among healthy older adults, USDA researchers have demonstrated that supplementing older adults’ diets with about two cups per day of strawberries can improve cognition even in the absence of neurological dysfunction.

The research was conducted at the USDA Human Nutrition Research Center on Aging at Tufts University and presented at the recent Society for Neuroscience annual meeting in Chicago.

Thirty-seven healthy men and women, age 60-75, consumed either the equivalent of about two cups per day of fresh strawberries in the form of a freeze-dried powder, or an equal amount of a calorie matched control powder containing no strawberries, for 90 days. The participants maintained their normal diet, other than refraining from consuming any berries or berry products during the study. Mobility and cognitive testing was done at day 0, 45 and 90 of the study.

Participants completed a series of mobility tests during standing and while walking at their preferred speed on a specially-equipped treadmill. They also completed a series of cognitive and learning tests.

Dietary intervention with strawberry for 90 days led to improvements in spatial memory and word recognition among healthy older adults. However, this intervention did not produce measurable improvements in mobility, perhaps due to the strict inclusion/exclusion criteria required for safe treadmill walking.

Overall the study results suggest that dietary intervention with strawberry fruit may be an effective means of combating age-related cognitive decline.

Miller, et al. Effects of Strawberry Supplementation on Mobility and Cognition in Older Adults. Presented at Society for Neuroscience Annual Meeting, October 2015.

Link to Session

Strawberries and Blueberries Improve Memory and Motor Function in Aging

A new publication from the USDA Human Nutrition Research Center on Aging at Tufts University further demonstrates the protective effects of a strawberry or blueberry supplemented diet in a preclinical model of aging. The results provide more evidence for the role of berry polyphenols in reducing oxidative stress and inflammation, drivers of age-related declines in cognitive and motor skills. Aged rats were fed either a control diet, strawberry diet, or blueberry diet for eight weeks and performed tests to measure memory and motor skills. Both motor and cognitive performance, in particular working memory (short-term memory), were improved by berry supplementation.

The types and relative amounts of polyphenols in the berries may be responsible for different effects on motor skills. In the motor tests, the blueberry diet group was better on the rod walk, which measures psychomotor coordination and the integrity of the vestibular system, whereas the strawberry group was better on the plank walk, which assesses more general balance and coordination. Both supplemented groups showed positive effects on the rotarod test, which is a measure of fine coordination, balance and resistance to fatigue. Both strawberry and blueberry diets showed positive effects on the cognitive tests and neurogenesis.

Shukitt-Hale, The beneficial effects of berries on cognition, motor behaviour and neuronal

function in ageing. British Journal of Nutrition, September 2015.

Link to abstract:

Eating Strawberries Can Decrease Your Risk of Developing Diabetes

New research recently unveiled at the American Diabetes Association’s 75th Scientific Sessions looked at the association between eating strawberries and the risk of developing diabetes. Harvard University researchers from Brigham and Women’s Hospital examined data from the Women’s Health Study, which included over 37,000 nondiabetic middle-aged women.  At the start of the study, the women reported how often they ate strawberries: 25 percent rarely or never, 43 percent 1-3 servings each month, 25 percent 1 serving per week, and 7 percent fewer than 2 servings weekly. The study followed up with the women over 14 years later and found that over 2,900 of these women developed diabetes. Compared to women who rarely or never ate strawberries, those who ate strawberries at least once month had a lower risk of developing diabetes.

Further, researchers were able to look at the women’s hemoglobin A1c, a marker for high blood sugar and ultimately diabetes. Researchers found that women who ate more strawberries were less likely to have a higher hemoglobin A1c (at or above 6%), lowering their risk of diabetes. Harvard researcher Howard Sesso, ScD, MPH, who presented the results, said, “We found that eating even a modest amount of strawberries on a weekly basis was associated with a decreased risk of developing diabetes.”

Link to the study abstract:

New Studies Show Eating Strawberries May Stave off Heart Disease and Diabetes

New research presented at the recent Experimental Biology 2015 conference in Boston provides new reasons for consumers to choose strawberries. Two new studies focus on the benefits of eating strawberries daily to help reduce the risk of diabetes and heart disease, two chronic diseases with significant public health impact in America.

The first study, conducted at the Institute for Food Safety and Health (IFSH) at Illinois Institute of Technology, examined the effects of strawberries on insulin resistance, a major risk factor for type 2 diabetes. Previous studies suggest that eating foods with anthocyanins, one of the most powerful anti-inflammatory antioxidants, may help lower insulin resistance and the risk for type 2 diabetes. Strawberries are one of the major food sources of anthocyanins many Americans enjoy regularly.

In this study, 23 obese adults were randomly assigned to one of four groups. Each group drank a beverage containing differing amounts of freeze-dried strawberry powder. Blood was drawn on several occasions 6 hours after consuming the freeze-dried strawberry drink. Data revealed that insulin was significantly lowered in the group who drank the highest concentration of the freeze-dried strawberry beverage. Further, while researchers found no difference in oxidative stress as measured by the ORAC, a method of measuring antioxidant capacities of different foods, there was a modest but significant decrease in LDL (or “bad” cholesterol). Additionally, a marker for inflammation called IL-6 was found to be reduced in the group with the less severe insulin resistance. Scientists concluded that 3 servings of strawberries per day – about 24 strawberries – can help decrease insulin resistance and lower the risk of type 2 diabetes.

Two-thirds of Americans are obese or overweight, both which have been associated with a higher risk of heart disease. The second study, conducted at Oklahoma State University, examined the effects of strawberries on heart disease risk factors. Previous studies have shown that eating foods high in flavonoids, like strawberries, can help reduce the risks of heart disease. In this study, 60 adults drank one of four drinks with varying amounts of freeze-dried strawberries over 12 weeks. Data revealed a greater decrease in total cholesterol and LDL (or “bad” cholesterol) in those who drank the high dose verses the low dose freeze-dried strawberry drink. Further, glutathione (an anti-oxidant biomarker) levels were higher in those same individuals, and catalase activity was lower. Scientists concluded that about 3½ to 4 servings of strawberries daily – about 28 to 32 strawberries – can help lower the risk for heart disease by positively affecting antioxidant biomarkers that influence risk factors.


Park, et. al. Strawberry polyphenols and insulin resistance: a dose-response study in obese individuals with insulin resistance. Presented at Experimental Biology 2015, March 30, 2015.

Morris, et. al. Dietary strawberries increase glutathione in obese participants with above optimal serum lipids. Presented at Experimental Biology 2015, March 31, 2015.

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.

Strawberries May Help Lower Cholesterol and Cardiovascular Disease Risk Factors

Research suggests that anthocyanins—the most prominent flavonoid in the diet—and the consumption of anthocyanin-rich foods such as strawberries may play an important role in helping reduce the risk of cardiovascular disease.  To evaluate the effects of specific amounts of strawberries on cardiovascular risk factors, researchers at Oklahoma State University conducted a 12-week, randomized controlled study of a strawberry-supplemented diet in a group of overweight/obese adults with abdominal adiposity and elevated lipid levels.  Daily strawberry supplementation (as freeze-dried strawberries (FDS)) was evaluated in two amounts:  a low dose (25 g FDS) equivalent to about one and three-fourths cup (250 g) of fresh strawberries, and a high dose (50 g FDS) equivalent to about three and one-half cups (500 g) of fresh strawberries.  Sixty participants were randomly assigned to consume a strawberry beverage (low-dose (LD-FDS), high-dose (HD-FDS)) or a calorie- and fiber-matched control beverage (LD-C, HD-C) daily for 12 weeks as a snack to their usual diet.

After 12 weeks, high-dose strawberry supplementation (HD-FDS) was shown to significantly reduce total and LDL cholesterol levels and NMR-derived small LDL particle concentrations as compared with the lower-dose strawberry group.  Both the low- and high-dose strawberry supplementation were shown to be equally effective in decreasing lipid peroxidation compared with the control groups, as measured by malondialdehyde (MDA), a well-established marker of oxidative stress.  As the first 12-week study to report the total and LDL cholesterol-lowering effects of a higher amount of strawberries in obese adults, the researchers suggest that a strawberry-supplemented diet may be of clinical significance as a nutritional strategy to help reduce cardiovascular disease risk.

Basu A, Betts NM, Nguyen A, Newman ED, Fu D, Lyons TJ.  Freeze-dried strawberries lower serum cholesterol and lipid peroxidation in adults with abdominal adiposity and elevated serum lipids. J Nutr. Published ahead of print March 26, 2014 as doi: 10.3945/jn.113.188169.

Strawberries Help Lower Risk Factors for Cardiovascular Disease and Improve Biomarkers of Oxidative Stress

Researchers from the Università Politecnica delle Marche (UNIVPM) in Italy and the Universities of Salamanca, Granada and Seville in Spain evaluated the protective effects of strawberries on cardiovascular health by adding about three and a half cups (500 grams) of fresh strawberries to the daily diets of 23 healthy men and women for one month.  Results showed that strawberry consumption positively impacted lipid profiles by significantly reducing total cholesterol, low-density lipoprotein (LDL) cholesterol and triglycerides levels by 8.78 percent, 13.72 percent and 20.80 percent, respectively. High-density lipoprotein (HDL) cholesterol remained unchanged. The strawberry intervention also improved antioxidant biomarkers and had a positive effect on antihemolytic defenses and platelet function.  The results suggest a protective role of a strawberry-supplemented diet to significantly improve biomarkers of oxidative stress and cardiovascular disease, which may in part be explained by the fruit’s high anthocyanin content and antioxidant capacity.

Alvarez-Suarez MJ, Giampieri F, Tulipani S, et al.  One-month strawberry-rich anthocyanin supplementation ameliorates cardiovascular risk, oxidative stress markers and platelet activation in humans.  J Nutr Biochem. 2014;25:289-294.


Study Finds Strawberries May Inhibit Oral Cancer Formation in an Animal Model

Strawberries contain a wide array of components that have been studied for their chemopreventive potential, including vitamins C and E, dietary fiber and phytochemicals such as ellagic acid, shown in laboratory studies to exhibit the ability to prevent cancers of the skin, bladder, lung, esophagus and breast.

Researchers from The Ohio State University investigated the effects of strawberries on tumor formation in an animal model of oral cancer developed to mimic conditions found in human oral mucosa after exposure to carcinogens such as tobacco and alcoholic beverages.  Hamsters were given 5% or 10% lyophilized strawberries (LS) in their diet prior to, during and following or only following 12 weeks of carcinogen treatment.  After 12 weeks of treatment, there were significantly fewer tumors found in the LS-treated groups as compared with the carcinogen controls, and histological examination revealed a significant reduction in the number of early lesions.  The fact that little or no reduction in the size of large tumors was seen suggests that the maximum effect of LS was on early-developing tumors.  Also, adding LS following 12 weeks of carcinogen treatment did not result in the reduction of any pre-existing dysplastic lesions, suggesting that the progression to malignancy of both pre-existing and newly-arising dysplasia was inhibited by LS. Researchers also noted a modification in gene expression related to the development of oral cancer.

These data show for the first time that incorporating strawberries (as LS) in the diet is effective in inhibiting the development of oral cancer in an experimental model.

Casto BC, Knobloch TH, Galioto RL, Yu Z, Accurso BT, Warner BM. Chemoprevention of oral cancer by lyophilized strawberries. Anticancer Res. 2013;33(11): 4757-4766.

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),

The Role of Berries in Type 2 Diabetes Prevention: Improving Insulin Response after Meals

The additive and synergistic combinations of plant phytochemicals have been identified to provide health benefits associated with chronic disease risk reduction, including type 2 diabetes and cardiovascular disease. Attenuating insulin resistance, along with oxidative stress and inflammation, has been identified as a mechanism that underlies this protective effect. Studies have documented favorable postprandial (post-meal) effects of strawberries, a polyphenol-rich fruit, on glucose and lipid profiles as well as on mediating the inflammatory response and improving insulin action.

To build upon their previous research findings that whole berries optimize postprandial glucose and insulin responses to sucrose in healthy adults, researchers from the University of Eastern Finland conducted a series of three meal studies to identify the effects of berries on postprandial metabolic responses to starch. The three randomized, controlled crossover studies were conducted with 13 to 20 healthy female subjects who consumed reference meals that provided 50g of starch as white wheat bread (WB) or rye bread (RB), meals with WB and RB served with 6 different berries, or meals with WB or RB served with a mixture of four berries (strawberries, bilberries, cranberries and black currents).

Among berries rich in the ellagitannin polyphenols, only strawberries were found to have a significant effect on insulin response to WB, which suggests that total ellagitannin content is not a driving factor in lowering insulin response. The berry mixture was shown to have a similar insulin-lowering effect on both breads, despite the known differences in insulin responses between WB and RB. Finding no association of the insulin-lowering capacity and the polyphenol composition of the berries, the researchers suggest that the role of acidity and organic acid content of berries be addressed in future studies.

They concluded that consuming foods and food combinations that elicit a lower postprandial insulin response—such as the bread and berry pairings—may offer short- and long-term metabolic benefit for the prevention of type 2 diabetes, particularly for those high risk of developing the disease. Torronen R, Kolehmainen M, Sarkkinen E, Poutanen K, Mykkanen H, Niskanen L. Berries reduce postprandial insulin responses to wheat and rye breads in healthy women. J Nutr. 2013; 143: 430-436.

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