Category Archives: Fruit and Nuts

Fruit Helps Prevent Diabetes Type 2

November 14th is designated as World Diabetes Day, and in recognition of this our posts this week will review topics related to diabetes. Today’s post will examine the role of fruit in the diet, and subsequent development of diabetes.

Statistics from the World Health Organization regarding diabetes are quite startling. Well over 400 million adults worldwide suffer from diabetes. Global prevalence of diabetes is over 8%. Diabetes is estimated to be the 7th leading cause of death worldwide.

Researchers from the Harvard School of Public Health tackled the question of whether certain types of fruits are associated with the risk of type 2 diabetes. Data from the Nurse’s Health Study, the Nurses Health Study II, and the Health Professionals Follow-Up Study was used for their research.

The participants were queried about their intake of individual fruits- apricots, peaches or plums; apples or pears; bananas, blueberries, cantelope, grapes or raisins; grapefruit; oranges; and strawberries. Participants were also questioned about fruit juices, including apple, grapefruit, and orange. The questionnaires were given at baseline, and then every two years in follow-up.

The results of the study were interesting. Total whole fruit intake was associated with a lower risk of diabetes. In particular, greater consumption of apples, bananas, blueberries, grapes and grapefruit were significantly associated with a decreased risk of diabetes. Conversely, increased fruit juice consumption was associated with an increased risk of diabetes, and switching from fruit juice to whole fruit in general led to a lower risk of diabetes. Even more interesting was the fact that the glycemic index alone did not seem to account for the association with Type 2 diabetes. 

Proper diet and regular exercise are two of the most important components of diabetes treatment. It appears incorporating fruit into the diet may be a strategy for prevention of diabetes as well.

“Fruit is definitely on the maintenance diet. It’s on the lifestyle diet.”– Robert Atkins

(Source- BMJ 2013; 347:15001)

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.

Extra-Virgin Olive Oil and Nuts for Prevention of Cardiovascular Disease

In our third and final post in recognition of National Olive Oil Month, today’s article will review research on primary prevention of cardiovascular disease using a Mediterranean-style diet.

The Mediterranean Diet loosely defined is inspired by the eating habits of those countries who surround the Mediterranean Sea, including Spain, Italy and Greece. This diet emphasizes high consumption of fruits and vegetables, as well as olive oil. There is more emphasis on fresh fish and less emphasis on red meats. Moderate wine consumption is also considered to be a component.

A group of researchers affiliated with the PREDIMED Study in Spain designed a study to examine the effects of a Mediterranean-style diet on the primary prevention of cardiovascular disease in a group considered to be at high cardiovascular risk.

Enrollees did not have a history of cardiovascular disease at the time of enrollment. The enrollees did have either type 2 diabetes, or at least 3 of the major risk factors of family history of premature coronary heart disease, high LDL, hypertension, low HDL, obese or overweight, or smoking.

Participants were randomly assigned to one of three groups- a Mediterranean diet supplemented with extra-virgin olive oil, a second group which followed a Mediterranean diet supplemented by nuts, or a third control group which was instructed to follow a low fat diet. Those in the extra-virgin oil group were instructed to consume at least four tablespoons of oil each day. Those in the nut-supplemented group received 30 grams of mixed nuts each day (almonds, hazelnuts, walnuts). Participants adherence to each assigned diet was assessed by a food questionnaire. Subjects were followed on average for nearly 5 years. Primary end point was death from cardiovascular causes, heart attack, or stroke.

The researchers discovered that the Mediterranean-style diet, when either supplemented with extra-virgin olive oil or nuts, was associated with a lower risk of major cardiovascular events over a period of 5 years, then was the low-fat control diet. In addition, among those who more closely adhered to the Mediterranean diet the cardiovascular benefit was greater.

Important points to consider regarding this study include- enrolled high risk subjects without a history of cardiovascular disease, and examined primary (not secondary) prevention. Also, these diets were not calorie restricted. Primary prevention is especially important, as that is what a lot of folks are concerned about.

This study leads to the veritable mountain of research showing that a proper diet can help or in this case prevent significant health issues. Perhaps give this some thought with the next trip to the grocery store or fast-food drive through window.

“Knowledge is the food of the soul.”–  Plato

(Source- New England Journal of Medicine 2018; 378)

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.

 

 

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.

 

An Orange a Week May Prevent Macular Degeneration

February is AMD/Low Vision Awareness Month, and in recognition of this our post today will examine the effects of dietary flavonoids on age-related macular degeneration (AMD).

Age-related macular degeneration is one of the leading causes of vision loss in the US. It is estimated that approximately 1.75 million Americans age 40 and older suffer with macular degeneration. The World Health Organization ranks AMD as the third leading cause of blindness worldwide, after cataracts and glaucoma. AMD is characterized by the loss of the central field of vision. Risk factors for AMD include advanced age, smoking, high blood pressure, and a diet low in fruits and vegetables. Family history is also a factor.

Foods that are considered to be good sources of flavonoids include apples, blueberries, brocoli, cabbage and chocolate (make that dark chocolate) and tea. In turn, flavonoids can be sub-divided into six classes including anthocyanins, flavan-3-ols, flavanones, flavones, flavonols, and isoflavones.

A research group in Australia examined the association of dietary intake of flavonoids and the subsequent development of age-related macular degeneration. Over 2800 subjects were enrolled at baseline, and over 2000 were followed up to 15 years. Dietary information was collected via a 145-item self-administered food frequency questionnaire. The sum of the flavonoid compound for each food was computed. Enrollees in the study were invited to follow-up at 5 years, 10 years and finally 15 years.

The researchers found a protective and significant association between the total flavonoids intake, and in addition the total flavonol and total flavanone intake, and AMD prevalence. Interestingly, those participants who consumed at least one serving of oranges a week but less than one serving each day had reduced odds of 92% of the development of late AMD, compared to those who did not consume any oranges.

Given the commonality of AMD, incorporating some simple dietary choices into your daily regimen seems like an easy intervention. In particular, finding time to eat an orange or two a week could be very beneficial.

“Orange is the happiest color”.  Frank Sinatra

(Source- American Journal of Clinical Nutrition 2018; 108)

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.

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.

 

Bluberries1

 

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)

 

Walnut Oil Lowers Cholesterol in Diabetics

May 17th is National Walnut Day, and in recognition of this today’s post will review recently published research on walnut oil.

A group of researchers in Iran designed a study to examine the effects of walnut oil on lipids in a group of patients with Type 2 diabetes. Compared to other tree nuts such as almonds, cashews, hazelnuts and pecans, walnuts are particularly high in essential fatty acids, such as linoleic acid and alpha-linolenic acid. Because of favorable nutritional qualities such as this walnuts have been the subject of research in regards to potential health benefits. China is the largest producer of walnuts in the world, while the U.S. is the largest exporter of walnuts.

The researchers completed a double-blind, randomized placebo-controlled trial, enrolling 45 diabetic patients in the walnut oil group, and another 45 patients in the placebo group. Those in the walnut oil group ingested four capsules of walnut oil three times each day. Those in the placebo group ingested similar capsules which contained simply water.

Labs were drawn at the start of the study and again at the conclusion after three months. The primary outcome measure was change in total cholesterol, triglycerides, LDL (“bad cholesterol”) and HDL (“good cholesterol”).

After 90 days researchers found that the participants in the walnut oil group had a significant decrease in total cholesterol, triglycerides and LDL. There was also a trend towards higher HDL. The walnut oil preparation was well tolerated, with no significant side effects. 

Walnuts may be part of a low-risk diet strategy for primary prevention in a high risk population of diabetic patients.

 (Source- Nutrition&Diabetes (2017) 7, 259)

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.

 

More Reasons to Eat Blueberries- Part Two

Bluberries1

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. 

Walnuts. Good for the Brain.

Walnuts3

“The brain is wider than the sky”.

Emily Dickinson

This is the third in a series of three blog posts detailing recent research on walnuts, in honor of National Walnut Day. This post will look at research from UCLA, which examined the association between walnut consumption and cognitive function in adults.

In particular, the researchers looked at data from the National Health and Nutrition Examination Survey (NHANES). The NHANES was designed to be a representative sample of the U.S. population, ages 20 to 90.

A group of participants who ate walnuts and other nuts were compared to a group who did not eat nuts. Adults ages 20-59 completed the simple reaction time test, the simple digit learning test, and the symbol digit substitution test. Adults ages 60 and over were administered the story recall test or the digital symbol substitution test.

Results from the study showed that walnut consumption had a positive association with cognitive functions in both the 20-59 year old participants, as well as those ages 60 and older.

This interesting study adds to the growing  body of evidence in support of the health benefits of walnuts.

(Source- Journal of Nutrition and Health Aging, Volume 19, Number 3, 2015)

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.