Tag Archives: blueberries

Blueberry Juice May Lower Blood Pressure

July 8th is National Blueberry Day, and out of respect for this tasty fruit today’s post will review a study which examined the effects of wild blueberry juice in a group of adult women at high risk for diabetes mellitus type 2.

Both wild and cultivated blueberries are native to North America. Depending on altitude, latitude and weather the peak of the blueberry crop can vary from May to August. In the US there are many blueberry festivals which celebrate this delicious fruit. In places like Bethlehem PA, Burgaw NC and South Haven MI, among many others, blueberry lovers gather to celebrate.

The skins of the blueberries contain anthocyanins, which have anti-oxidant properties. Wild blueberries have one of the highest levels of anti-oxidants among fruits and vegetables. In the U.S., Maine is the largest producer of lowbush or wild blueberries, and produces over 100 million pounds annually.

A group from Canada and the U.S. performed a study examining the effects of wild blueberry juice on various cardiometabolic markers. The study population had at least two risk factors for type 2 diabetes, and thus were higher risk.

The study design was a randomized trial, with a placebo control. The subjects drank 240 ml of juice made from lowbush (wild) blueberries, while the control group drank a placebo beverage which was color and flavor matched to the blueberry juice. The blueberries were harvested from Prince Edward Island, Canada. Participants drank the blueberry juice daily for a week, followed by an eight day washout period. Following that workout period, the study group became the control group and vice versa.

Several cardiometabolic markers were monitored during the course of the study, such as serum cholesterol, HDL, LDL, triglycerides, glucose, endothelial function, c-reactive protein, serum amyloid, among others. Vital signs included blood pressure were also monitored.

19 participants, all women, completed the study. The researchers discovered that while the wild blueberry juice did not significantly change cardiometabolic markers, it did lower systolic blood pressure 4.8 mm Hg (4%) compared to the placebo group. While a 4.8 mm Hg reduction in systolic blood pressure may not sound substantial, it is estimated that a reduction of only 3 mm Hg may reduce mortality from heart disease and stroke by 5-8%. 

Drinking the blueberry juice for only 7 days was probably not long enough to effect any significant change on metabolic markers. A longer study seems reasonable given the promising results of this study. This does appear to be a low-risk way to improve one’s health. 

“The smallest seed of faith is better than the largest fruit of happiness.”– Henry David Thoreau

(Source- BMC Nutrition 2017 3:45)

This blog is a review of published medical and scientific literature, and should only be used for informational purposes. It does not constitute medical or health advice, nor does it create a physician-patient relationship with anyone. Discuss any health concerns with your personal physician.

 

 

 

Blueberries and Metabolic Syndrome

July 8th is designated National Blueberry Day, and in recognition of this delicious fruit today’s post will examine a study just published in June on the effect of blueberry consumption on cardiovascular risk factors.

The US is the world’s largest producer of blueberries, producing more that twice the tonnage of blueberries annually than the 2nd largest producer, Canada. The largest blueberry producing state is Washington, followed by Georgia, Michigan and Oregon. Low bush or wild blueberries, and high bush or cultivated blueberries, are all native to North America. Many of the beneficial properties of blueberries are thought to be due to their anthocyanins. Anthocyanins are water-soluble pigments which may appear black, blue, purple or red. Plants rich in anthocyanins include black rice, blueberries and raspberries. Anthocyanins have anti-oxidant properties.

A research group from the UK and Harvard looked at the relationship between blueberry consumption and its effect if any on insulin resistance and markers of cardiometabolic function. A random controlled double blind study was performed, with 138 enrollees, randomly assigned to one of three groups- a group which consumed the dietary equivalent of one cup of fresh blueberries each day, a second group which consumed a dietary equivalent of 1/2 cup of fresh blueberries each day, while the third group consumed a placebo. It is important to note that the study subjects had all been diagnosed with metabolic syndrome and were overweight or obese. The study enrolled both men and women, ages 50-75.

The study lasted six months. The researchers discovered that while metabolic syndrome markers were not significantly changed by blueberry consumption, the group that consumed one cup of blueberries per day did show improvements in HDL (“good cholesterol”), endothelial function, and systemic arterial stiffness. It was estimated that a 13% reduction in future cardiovascular events was possible in the one cup per day group.

This is an important study, with one of the longer study periods (six months) completed to date. The study population had significant health issues, including metabolic syndrome and was older. Although the intervention did not change the insulin resistance numbers, it is possible that the study intervention was simply not long enough.

Metabolic syndrome is a cluster of conditions including elevated blood pressure, excessive fat around the waist, elevated triglyceride levels, and decreased HDL. Individuals with metabolic syndrome are at higher risk for heart attack and stroke, and metabolic syndrome is thought to be a precursor for Diabetes Mellitus Type 2.

Here is a well-designed study showing the benefits of a simple dietary intervention on metabolic syndrome. Next time you are considering something for dessert or a snack, put the cake, cookies and ice cream away and reach for blueberries instead. And buy local if possible, and support our farmers and propagators.

“There are eyes, to be sure, that give no more admission into the man than blueberries.”-    Ralph Waldo Emerson

(Source- American Journal of Clinical Nutrition 2019; 109)

This blog is a review of published medical and scientific literature, and should only be used for informational purposes. It does not constitute medical or health advice, nor does it create a physician-patient relationship with anyone. Discuss any health concerns with your personal physician.

 

Blueberries- Good For Your Brain?

July is National Blueberry Month and in recognition of this today’s post will examine research related to the benefits of blueberry supplementation in children.

 

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A group of researchers affiliated with the University of Reading in the United Kingdom designed a study to examine the potential benefits of blueberry supplementation in children. The researchers took a group of 7-10 year olds and administered a drink containing either 15 or 30 grams of freeze-dried wild blueberries, or a placebo drink. The researchers did their best to conceal from the participants the real blueberry drink from the placebo drink, using opaque cups and straws.

Children in the study were administered a variety of tests of cognitive performance, including the Auditory Verbal Learning Task, Modified Flanker Task, and Picture Matching Task tests.

Results of the study showed that wild blueberry supplementation led to significant improvement in cognition. The 30 gram supplemented group showed the best improvement in their performance compared to baseline, while the 15 gram supplemented group also showed improvement, but not as substantial as the 30 gram group.

Eating healthy blueberries seems a simple and low risk way to possibly improve cognitive performance, and celebrate National Blueberry Month at the same time.

 

This blog is a review of medical and scientific literature, and should only be used for informational purposes. It does not constitute medical or health advice, nor does it create a physician-patient relationship with anyone. Discuss any health concerns with your personal physician.

(Source- European Journal of Nutrition, October 5, 2015)

 

More Reasons to Eat Blueberries- Part Two

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Metabolic syndrome is a growing problem, not only in the U.S., but worldwide. Some of the components of metabolic syndrome include increased abdominal fat, high blood pressure, high triglycerides associated with low HDL (“good cholesterol”), and impaired glucose tolerance. Some of you may be familiar with the term “insulin resistance” in the context of metabolic syndrome.

As metabolic syndrome may be a precursor to the development of diabetes there is considerable on-going research on this topic. A study performed at the University of Oklahoma and Oklahoma State University examined the effect of blueberry intake on obese men and women with metabolic syndrome. In particular, cardiovascular risk factors were examined.

Forty-eight participants were randomized to either a blueberry group or control group. Those in the blueberry group consumed a freeze-dried blueberry beverage twice a day, while the control group drank an equivalent amount of water.

Over the eight week course of the study the blood pressure in the blueberry group dropped 6% (systolic) and 4% (diastolic). Biomarkers of oxidative stress were also decreased in the blueberry group. Oxidized LDL dropped 28%, while combined serum malondialdehyde and hydroxynonenal concentrations dropped 17%. Both the decreases in blood pressure and oxidative stress biomarkers were substantially larger in the blueberry group than the control (water) group.

Interestingly this study shows a similar drop in blood pressure to the blueberry study we previously reviewed. This is simply more evidence of the beneficial effects of blueberries on cardiovascular health, in a particularly high-risk population.

This blog is a review of medical and scientific literature, and should only be used for informational purposes. It does not constitute medical or health advice, nor does it create a physician-patient relationship with anyone. Discuss any health concerns with your personal physician.

(Source- The Journal of Nutrition, July 21, 2010)

Blood Pressure Creeping Up? Think Blue(berries)

“When any lagged behind, the cry of “blueberries” was most effectual to bring them up.”
Henry David Thoreau

Bluberries1Blueberry

July is National Blueberries Month and in honor of this delectable fruit today’s post will examine research on the health benefits of blueberries.

Recent research indicates that daily consumption of blueberry powder lowered both blood pressure and arterial stiffness in a group of post-menopausal women, who were either in pre-hypertension or the earliest stages of hypertension. A research group primarily from Florida State University followed 48 women through the 8 week study. Women were allocated to a blueberry powder group (equivalent to one cup of fresh blueberries per day) or a placebo powder group.

Subjects in both groups were asked to continue their usual diet and exercise regimens (or lack thereof). After 8 weeks of daily blueberry powder the women were found to have a mean reduction of 5.1% in systolic blood pressure, and 6.3% in diastolic blood pressure, while the placebo powder group had no change.

What’s important about this study is that it shows the potential benefits of a simple dietary intervention, eating blueberries, on lowering blood pressure. It would be interesting to know if eating actual blueberries rather than the powder, would offer more blood pressure benefit, or whether eating more than just a cup of blueberries would offer additional benefit. Also, is this blood pressure lowering effect of blueberries extended to the general population?

(Source: Journal of the Academy of Nutrition and Dietetics, March 2015, Volume 115, Number 3)

This blog is a review of medical and scientific literature, and should only be used for informational purposes. It does not constitute medical or health advice, nor does it create a physician-patient relationship with anyone. Discuss any health concerns with your personal physician.