Ripe fruit is preferred. Why does an apple a day keep the doctor away, if the apple is ripe? It happens because chlorophyll breakdown in ripening apples and pears produces highly active antioxidants, says a recent study. The disappearance of the color green and the simultaneous appearance of other bright colors are also signs of ripening fruit.
In this 2007 study, a team led by Bernhard Kräutler at the University of Innsbruck (Austria) determined that the breakdown of chlorophyll in ripening apples and pears produces the same decomposition products as those in brightly colored leaves. Picture bright autumn leaves, for example. What makes them turn from green to orange or red for a time? And why is that ripe, bright color so healthy when it's in ripe fruit?
As the researchers report in the journal Angewandte Chemie, these colorless decomposition products, called nonfluorescing chlorophyll catabolytes (NCC), are highly active antioxidants—making them potentially very healthy, according to the study, "Colorless Tetrapyrrolic Chlorophyll Catabolites in Ripening Fruit Are Effective Antioxidants," published in the journal Angewandte Chemie International Edition 2007, 46, No. 45, 8699–8702. The author is Bernhard Kräutler, Universität Innsbruck (Austria).
The beautifully colored leaves of fall are a sign of leaf senescence, the programmed cell death in plants. This process causes the disappearance of chlorophyll, which is what gives leaves their green color
For a long time, no one really knew just what happens to the chlorophyll in this process. In recent years, Kräutler and his team, working with the Zurich botanists Philippe Matile and Stefan Hörtensteiner, have been able to identify the first decomposition products: colorless, polar NCCs that contain four pyrrole rings—like chlorophyll and heme.
A few years ago the Innsbruck researchers examined the peels of apples and pears. Unripe fruits are green because of their chlorphyll. In ripe fruits, NCCs have replaced the chlorophyll, especially in the peel and the flesh immediately below it.
The brightly-colored peels of apples and pears
These catabolytes are the same for apples and pears, and are also the same as those found in the leaves of the fruit trees. “There is clearly one biochemical pathway for chlorophyll decomposition in leaf senescence and fruit ripening,” concludes Kräutler, according to the November 6, 2007 news release, "Ripe fruit preferred."
When chlorophyll is released from its protein complexes in the decomposition process, it has a phototoxic effect: When irradiated with light, it absorbs energy and can transfer it to other substances. For example, it can transform oxygen into a highly reactive, destructive form. As the researchers were able to demonstrate, the NCCs have an opposite effect: They are powerful antioxidants and can thus play an important physiological role for the plant.
Absorbing the light and turning it to antioxidant energy to be transfered to other substances
When chlorophyll is released from protein complexes it has a phototoxic effect. But when irradiated with light, it absorbs the energy and can transfer it to other substances. And NCCs are powerful antioxidants.
It then became apparent that NCCs are components of the diets of humans and other higher animals, and that they could thus also play a role in their systems. Other previously identified important antioxidants in the peels of fruits include the flavonoids. Thus, the saying, “an apple a day keeps the doctor away” seems to be true, according to Kräutler.
Think dried fruit has too much sugar and will raise your blood glucose levels too high? Snacking on raisins significantly reduces overall post-meal blood sugar levels, says a recent study
Research that debuted at the American Diabetes Association's 72nd Annual Scientific Session in 2012 suggested that eating raisins three times a day may significantly lower postprandial (post-meal) glucose levels when compared to common alternative snacks of equal caloric value. Lead researcher, Harold Bays, MD, medical director and president of L-MARC, conducted the study at the Louisville Metabolic and Atherosclerosis Center (L-MARC). Harold Bays, MD is medical director and president of L-MARC.
The study's participants were 46 men and women who had not previously been diagnosed with diabetes mellitus, but who had mild elevations in glucose levels. Participants were randomly assigned to snack on raisins or pre-packaged commercial snacks that did not contain raisins or other fruits or vegetables, three times a day for 12 weeks.
- Compared to control snacks, raisins significantly decreased mean post-meal glucose levels by 16 percent
- Compared to baseline within group paired analysis, raisins significantly reduced mean hemoglobin A1c by 0.12 percent
- Consumption of the control snacks in the study did not significantly reduce mean post-meal glucose or hemoglobin A1c
"Compared to the snacking control group, the group consuming raisins had a significant statistical reduction in their after-liquid meal blood sugar levels among study participants who had mean baseline fasting glucose levels between 90 and 100 mg/dl.," said Dr. Bays, according to the June 21, 2012 news release, New study: Snacking on raisins significantly reduces overall post-meal blood sugar levels. "This favorable glucose effect of raisins was further supported by the statistically significant reduction in hemoglobin A1c (a standard test for overall blood sugar control in diabetes mellitus) in the within group comparison to baseline. The within group comparisons from baseline with snacks did not demonstrate a reduction in hemoglobin A1c."
The study was funded by the California Raisin Marketing Board through a grant to the L-MARC Research Center in Louisville, Kentucky.
"Raisins have a relatively low glycemic index and contain fiber and antioxidants, all factors which contribute to blood sugar control," said James Painter, Ph.D., R.D., and nutrition research advisor for the California Raisin Marketing Board, according to the news release. "Decreasing blood sugar and maintaining normal hemoglobin A1c levels is important because it can prevent long-term damage to the heart and circulatory system."
This research is part of a two-part study by L-MARC that looked at raisins and possible impacts to blood pressure and blood sugar levels. The first part of the study announced at the American College of Cardiology's 61st Annual Scientific Session suggests eating raisins three times a day may significantly lower blood pressure among individuals with slightly higher than normal blood pressure, otherwise known as prehypertension. You also may wish to check out the website of the American College of Cardiology.
Snacking on raisins may offer a heart-healthy way to lower blood pressure
A small randomized controlled trial is first to put this potassium-rich fruit to the test, says the March 25, 2012 news release, "Snacking on raisins may offer a heart-healthy way to lower blood pressure." If you have slightly higher than normal blood pressure – known as prehypertension – consider eating a handful of raisins, the news release explains. (But what if you're elderly with high blood pressure?)
New data suggest that, among individuals with mild increases in blood pressure, the routine consumption of raisins (three times a day) may significantly lower blood pressure, especially when compared to eating other common snacks, according to research presented in 2012 at the American College of Cardiology's 61st Annual Scientific Session. The Scientific Session, the premier cardiovascular medical meeting, brings cardiovascular professionals together to further advances in the field.
Even though raisins are popularly cited to lower blood pressure on various websites and are known to have intrinsic properties that could benefit heart and vascular health, researchers believe this is the first controlled study to scientifically support raisins' blood pressure-lowering effects compared to alternative snacks
"It is often stated as a known fact that raisins lower blood pressure. But we could not find much objective evidence in the medical literature to support such a claim," said Harold Bays, MD, according to the March 25, 2012 news release, "Snacking on raisins may offer a heart-healthy way to lower blood pressure."
Bays is medical director and president of Louisville Metabolic and Atherosclerosis Research Center (L-MARC) and the study's lead investigator. "However, our study suggests if you have a choice between eating raisins or other snacks like crackers and chocolate chip cookies, you may be better off snacking on raisins at least with respect to blood pressure."
In this investigation, Dr. Bays and his team conducted a randomized controlled clinical trial to compare the blood pressure effect of eating raisins versus other snacks in 46 men and women with prehypertension. Participants were randomly assigned to snack on raisins or prepackaged commercial snacks that did not contain raisins, other fruits or vegetables but had the same number of calories per serving three times a day for 12 weeks. The study controlled for individual differences in nutrition and physical activity.
Data analyses found that compared to other snacks, raisins significantly reduced systolic blood pressure at weeks 4, 8, and 12, ranging from -4.8 to -7.2% or -6.0 to -10.2 mmHg (p values <0.05). Within group analysis demonstrated that raisins significantly reduced mean diastolic blood pressure at all study visits, with changes ranging from -2.4 to - 5.2 mmHg (p values < 0.05). Pre-packaged snacks (including crackers and cookies) did not significantly reduce systolic or diastolic blood pressure at any study visit.
"Overall, these findings support what many people intrinsically believe: that natural foods often have greater health benefits than processed foods," Dr. Bays said, according to the news release. The study did not identify how raisins lower blood pressure.
Raisins are high in potassium, and have fiber, polyphenols, phenolic acid, tannins and antioxidants
"Raisins are packed with potassium, which is known to lower blood pressure," Dr. Bays said, according to the news release. "They are also a good source of antioxidant dietary fiber that may favorably alter the biochemistry of blood vessels, causing them to be less stiff, which in turn, may reduce blood pressure."
Although this study was not designed or powered to evaluate for outcomes benefits, other studies support that in patients with prehypertension, mild lowering of blood pressure with medications may have clinical benefits in reducing cardiovascular events. According to the Centers for Disease Control and Prevention, nearly one in three (28 percent) American adults have prehypertension – defined as a systolic pressure from 120 to 139 millimeters of mercury (mm Hg) or a diastolic pressure from 80 to 89 mm Hg.
This study's findings help validate some current nutritional recommendations. For example, 60 raisins – about a handful – contain 1 gram of fiber and 212 milligrams of potassium, which are both recommended in the Dietary Approaches to Stop Hypertension (DASH) diet
Dr. Bays cautions that this was a single site study; larger trials are needed to confirm the blood pressure-regulating effect of raisins. Nonetheless, he says work in this area is particularly exciting because applying similar scientific methods to natural products, as required for drug development, provides consumers with objective data about which foods may or may not benefit heart health.
This study was funded by the California Raisin Marketing Board through a grant to L-MARC Research Center. Dr. Bays presented the study "Raisins And Blood Pressure: A Randomized, Controlled Trial" on Sunday, March 25, 2012 at the American College of Cardiology's 61st Annual Scientific Session.
The Scientific Session, the premier cardiovascular medical meeting, brings cardiovascular professionals together to further advances in the field. For more information on raisins and summaries of the California Raisins' nutrition research, visit the California Raisin Marketing Board website.
About the California Raisin Marketing Board: A State Marketing Order in 1998 created the California Raisin Marketing Board and it is 100-percent grower funded. Its mission is to support and promote the increased use of California-grown raisins and sponsor crop production, nutrition and market research. For more information about the California Raisin Marketing Board, visit its website.
Prunes may help bone density says another study
More people need to find out about the extraordinarily positive effect that dried plums have on bone density. Most people know prunes are dried plums, but how many know that prunes may put a stop to bone loss? No bones about it: Eating dried plums helps prevent fractures and osteoporosis, says a recent Florida State University study. When it comes to improving bone health in postmenopausal women — and people of all ages, actually — a Florida State University researcher has found a simple, proactive solution to help prevent fractures and osteoporosis: eating dried plums.
"Over my career, I have tested numerous fruits, including figs, dates, strawberries and raisins, and none of them come anywhere close to having the effect on bone density that dried plums, or prunes, have," said Bahram H. Arjmandi, according to the August 17, 2011news release, "No bones about it: Eating dried plums helps prevent fractures and osteoporosis." Florida State University's Margaret A. Sitton Professor and chairman of the Department of Nutrition, Food and Exercise Sciences in the Florida State University College of Human Sciences explained, according to the news release that "All fruits and vegetables have a positive effect on nutrition, but in terms of bone health, this particular food is exceptional."
Arjmandi and a group of researchers from Florida State and Oklahoma State University tested two groups of postmenopausal women. Over a 12-month period, the first group, consisting of 55 women, was instructed to consume 100 grams of dried plums (about 10 prunes) each day, while the second — a comparative control group of 45 women — was told to consume 100 grams of dried apples. All of the study's participants also received daily doses of calcium (500 milligrams) and vitamin D (400 international units).
The group that consumed dried plums had significantly higher bone mineral density in the ulna (one of two long bones in the forearm) and spine, in comparison with the group that ate dried apples
This, according to Arjmandi, was due in part to the ability of dried plums to suppress the rate of bone resorption, or the breakdown of bone, which tends to exceed the rate of new bone growth as people age. The group's research, "Comparative Effects of Dried Plum and Dried Apple on Bone in Post Menopausal Women," is published in the British Journal of Nutrition.
Arjmandi conducted the research with his graduate students Shirin Hooshmand, Sheau C. Chai and Raz L. Saadat of the College of Human Sciences; Dr. Kenneth Brummel-Smith, Florida State's Charlotte Edwards Maguire Professor and chairman of the Department of Geriatrics in the College of Medicine; and Oklahoma State University statistics Professor Mark E. Payton.
In the United States, about 8 million women have osteoporosis because of the sudden cessation of ovarian hormone production at the onset of menopause: What's more, about 2 million men also have osteoporosis
"In the first five to seven postmenopausal years, women are at risk of losing bone at a rate of 3 to 5 percent per year," Arjmandi said, according to the news release. "However, osteoporosis is not exclusive to women and, indeed, around the age of 65, men start losing bone with the same rapidity as women." Arjmandi encourages people who are interested in maintaining or improving their bone health to take note of the extraordinarily positive effect that dried plums have on bone density.
"Don't wait until you get a fracture or you are diagnosed with osteoporosis and have to have prescribed medicine," Arjmandi said in the news release. "Do something meaningful and practical beforehand. People could start eating two to three dried plums per day and increase gradually to perhaps six to 10 per day. Prunes can be eaten in all forms and can be included in a variety of recipes."
The U.S. Department of Agriculture funded Arjmandi's research. The California Dried Plum Board provided the dried plums for the study, as well as some funding to measure markers of oxidative stress.
Plums, peaches, and nectarines also are studied for their effects to prevent or help those with diabetes, metabolic syndrome, and breast cancer in other studies
Peaches, plums, nectarines give obesity, diabetes slim chance, says a recent study from Texas A&M AgriLife. Do your children or other family members show signs of metabolic syndrome? Peaches, plums and nectarines have bioactive compounds that can potentially fight-off obesity-related diabetes and cardiovascular disease, according to new studies by Texas A&M AgriLife. Researchers presented the study back in August 2013, at the American Chemical Society. But research on the health benefits of peaches continues with new studies.
In the 2012 study, researchers showed that the compounds in stone fruits could be a weapon against "metabolic syndrome," in which obesity and inflammation lead to serious health issues, according to Dr. Luis Cisneros-Zevallos, AgriLife Research food scientist.
"In recent years obesity has become a major concern in society due to the health problems associated to it," said Cisneros-Zevallos, according to the June 18, 2012 news release, "Peaches, plums, nectarines give obesity, diabetes slim chance." Cisneros-Zevallos also is an associate professor at Texas A&M University. "In the U.S., statistics show that around 30 percent of the population is overweight or obese, and these cases are increasing every year in alarming numbers."
While he acknowledged that lifestyle, genetic predisposition and diet play a major role in one's tendency toward obesity, the major concern about obesity is the associated disease known as metabolic syndrome
"Our studies have shown that stone fruits – peaches, plums and nectarines – have bioactive compounds that can potentially fight the syndrome," Cisneros-Zevallos said, according to the news release, Peaches, plums, nectarines give obesity, diabetes slim chance. "Our work indicates that phenolic compounds present in these fruits have anti-obesity, anti-inflammatory and anti-diabetic properties in different cell lines and may also reduce the oxidation of bad cholesterol LDL which is associated to cardiovascular disease."
What is unique to these fruits, he said, is that their mixture of the bioactive compounds work simultaneously within the different components of the disease. "Our work shows that the four major phenolic groups – anthocyanins, clorogenic acids, quercetin derivatives and catechins – work on different cells – fat cells, macrophages and vascular endothelial cells," he explained in the news release.
"They modulate different expressions of genes and proteins depending on the type of compound. However, at the same time, all of them are working simultaneously in different fronts against the components of the disease, including obesity, inflammation, diabetes and cardiovascular disease," he said, according to the news release.
Cisneros-Zevallos said this is believed to be the first time that "bioactive compounds of a fruit have been shown to potentially work in different fronts against a disease"
"Each of these stone fruits contain similar phenolic groups but in differing proportions so all of them are a good source of health promoting compounds and may complement each other," he said in the news release, adding that his team plans to continue studying the role of each type of compound on the molecular mechanisms and confirm the work with mice studies.
The studies on the health benefits of stone fruit are funded by the California Tree Fruit Agreement, The California Plum Board, the California Grape and Tree Fruit League and the Texas Department of Agriculture. The Cisneros-Zevallos lab team in this study included Freddy Ibanez, Paula Castillo, Paula Simons and Dr. Congmei Cao.
Can two to three peaches a day keep certain cancers away?
Can this type of 'diet' obtain similar effects in humans as it did in mice? Texas researchers found that peaches inhibit breast cancer metastasis in mice, says new study, "Polyphenolics from peach (Prunus persica var. Rich Lady) inhibit tumor growth and metastasis of MDA-MB-435 breast cancer cells in vivo," published March 20, 2014 in the Journal of Nutritional Biochemistry. Lab tests at Texas Texas A&M AgriLife Research have shown that treatments with peach extract inhibit breast cancer metastasis in mice.
AgriLife Research scientists say that the mixture of phenolic compounds present in the peach extract are responsible for the inhibition of metastasis, according to the study. "Cancer cells were implanted under the skin of mice with an aggressive type of breast cancer cells, the MDA-MB-435, and what we saw was an inhibition of a marker gene in the lungs after a few weeks indicating an inhibition of metastasis when the mice were consuming the peach extract," said Dr. Luis Cisneros-Zevallos, according to a March 25, 2014 news release, "Texas researcher: Peaches inhibit breast cancer metastasis in mice."
Cisneros-Zevallos is a food scientist for AgriLife Research in College Station. "Furthermore, after determining the dose necessary to see the effects in mice, it was calculated that for humans it would be equivalent to consuming two to three peaches per day."
Peach and plum polyphenols selectively killed aggressive breast cancer cells and not the normal ones in the new study
This is very important because it can be translated into something that is also beneficial for people, he added, according to the news release. This work builds upon previous work at AgriLife Research released a few years ago, which showed that peach and plum polyphenols selectively killed aggressive breast cancer cells and not the normal ones, Cisneros-Zavallos said, according to the news release.
The previous work as well as the present one was conducted by Cisneros-Zevallos, Dr. David Byrne, both with AgriLife Research; Dr. Weston Porter, Texas A&M University department of veterinary physiology and pharmacology; and then-graduate student Giuliana Noratto, who is now on the faculty at Washington State University.
In the western hemisphere, breast cancer is the most common malignant disease for women, he said in the news release. In the U.S. last year, the American Cancer Society estimated about 232,340 new cases of invasive breast cancer among women. Most of the complications and high mortality associated with breast cancer are due to metastasis, Cisneros-Zevallos pointed out.
"The importance of our findings are very relevant, because it shows in vivo the effect that natural compounds, in this case the phenolic compounds in peach, have against breast cancer and metastasis. It gives opportunity to include in the diet an additional tool to prevent and fight this terrible disease that affects so many people," he said, according to the news release.
Most peach fruit share similar polyphenolic compounds but might differ in content
Researchers conducted the study using the peach variety Rich Lady. However, according to Cisneros-Zevallos, most peach fruit share similar polyphenolic compounds but might differ in content. The study also determined that the underlying mechanism by which peach polyphenols are inhibiting metastasis would be by targeting and modulating the gene expression of metalloproteinases.
"In general, peach fruit has chemical compounds that are responsible for killing cancer cells while not affecting normal cells as we reported previously, and now we are seeing that this mixture of compounds can inhibit metastasis," said Cisneros-Zevallos, according to the news release. "We are enthusiastic about the idea that perhaps by consuming only two to three peaches a day we can obtain similar effects in humans. However, this will have to be the next step in the study for its confirmation."
Cisneros-Zevallos continues testing these extracts and compounds in different types of cancer as well as in diabetes studies in vitro and in vivo to understand the molecular mechanisms involved. The work documenting the health benefits of stone fruit has been supported by the Vegetable and Fruit Improvement Center at Texas A&M, the U.S. Department of Agriculture and the California Tree Fruit Agreement.