Nutritional News
Mushrooms offer heart health fibres | Mushrooms As Good An Antioxidant Source As More Colorful Veggies |
Antioxidant supplements - myth or misunderstood? | The supplements - bird flu debate: selenium |
Scientists Identify Cell-Killing Molecular Switch Activated by Free Radicals and Oxidative Stress |
Study could spell opportunity for fruit and vegetable ingredients |
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Mushrooms As Good An Antioxidant Source As More Colorful Veggies
6/26/2006
Source: Penn State
Portabella and crimini mushrooms rank with carrots, green beans, red peppers and broccoli as good sources of dietary antioxidants, Penn State researchers say.
Dr. N. Joy Dubost, who recently earned her doctorate in food science at Penn State, measured the activity of two antioxidants, polyphenols and ergothioneine, present in mushrooms, using the ORAC assay and HPLC instrumentation, as part of her dissertation research. She found that portabella mushrooms had an ORAC value of 9.7 micromoles of trolox equivalents per gram and criminis had an ORAC value of 9.5. Data available from other researchers shows carrots and green beans have an ORAC value of 5; red pepper 10; and broccoli 12.
The ORAC assay, the most well known test of antioxidant capacity, focuses on the peroxyl radical, the most predominate in the human body. Free radicals, such as the peroxyl radical, are thought to play a role in the aging process and in many diseases, including cancer, Alzheimer's and atherosclerosis. Epidemiological studies have shown that those who eat the most fruits and vegetables rich in antioxidants have lower incidence of these diseases.
Dubost detailed her results in a paper, Quantification of Polyphenols and Ergothioneine in Cultivated Mushrooms and Correlation to Total Antioxidant Capacity Using the ORAC and HORAC Assays, presented Monday, June 26, at the Institute of Food Technologists meeting in Orlando, Fl. Her co-author is her dissertation adviser, Dr. Robert Beelman, professor of food science.
Dubost explains that assays are a first step toward determining how effective a food is in providing protection against oxidative damage. Anti-oxidants inhibit increased rates of oxidation, which can damage proteins, lipids carbohydrates and DNA.
She adds, "The ORAC assay does not tell what happens in the human body but this assay is currently under investigation as to how it can predict physiological activity."
The Penn State study showed that the anti-oxidant effect of mushrooms is due primarily to the presence of polyphenols. Dubost and Beelman had earlier identified mushrooms as an abundant source of the anti-oxidant, ergothionene.
Dubost notes, "Evidence suggests that erogothioneine is biologically very important and, even though the assay used does not show it contributes to total antioxidant activity in the mushrooms, it may significantly contribute antioxidant activity in the body."
The ORAC values found in the latest study indicate that mushrooms are potent anti-oxidant sources. The research revealed that, of the mushrooms tested, portabella mushrooms and crimini mushrooms have the highest ORAC values. Criminis, which are brown, are otherwise similar to the popular white button mushroom, the one mostly commonly consumed in the U.S. The white button mushroom has an ORAC value of 6.9, above tomato, green pepper, pumpkin, zucchini, carrot, and green beans.
Dubost says, "You don't have to eat only the vegetables with the highest anti-oxidant capacity to benefit. If you eat a variety of mushrooms along with a variety of other vegetables, you'll be getting a variety of antioxidants."
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Antioxidant supplements - myth or misunderstood?
(7/8/06, Stephen Daniells, Source: NutraIngredients.com).
News Archives
07/08/2006 - Coverage of the New Scientist article questioning the benefits of antioxidant supplements has generated a flurry of feedback from industry and health care practioners, in agreement with and disputing the arguments.
The New Scientist article was written by Dr Lisa Melton from the London-based registered charity, the Novartis Foundation, and investigated the apparent disagreement between the vast body of epidemiological studies and randomized clinical trials (RCTs) for the prevention of diseases by antioxidants.
While the epidemiological evidence linking dietary antioxidant intake and reduce incidence of risks of a range of disease is strong, when such antioxidants have been extracted, purified, or synthesised and put into supplements, the results, according to the randomized clinical trials (RCTs), do not produce the same benefits, and may even be harmful.
NutraIngredients invited comment from readers, and the responses were a mixed bag, with many feeling that the role of antioxidants is not myth, merely misunderstood.
The feedback picked up the use of the drug model for RCTs, described by Dr Andrew Shao, from the supplement industry trade association the Council for Responsible Nutrition, as perhaps “not be the best approach to assess the health benefits of antioxidants (or other nutrients for that matter).”
Indeed, Neil E. Levin, CCN, DANLA from NOW Foods, said: “It is telling that much of the criticism of antioxidants comes from science that is testing single nutrients, using a drug model. But knowledgeable antioxidant researchers are aware that this is a 'family' of nutrients that can synergistically 'recharge' each other, making single nutrient studies fairly irrelevant as to the holistic interaction of these substances in vivo.”
Mr Grant Weidler of Weidler Associates, Texas, questioned why researchers do not use whole extracts, instead of isolated compounds.
“I agree that anytime you isolate one specific ingredient from a whole food, you're already biasing negatively, the likelihood of a positive result. Take for instance that most studies done on vitamin E have used isolated alpha tocopherol, whereas in a nature, it is composed of four tocopherols and four tocotrienols,” said Weidler.
Dr Shao also raised the point that most of the large-scale, high-profile RCTs have focused on diseased populations.
“These trials do not test the question of whether, for example, vitamin E supplementation can reduce the risk of a heart attack in the general healthy population. Instead, they are testing the question of whether vitamin E + statins + beta-blockers + diuretics, etc can reduce the risk of a second heart attack in very sick patients. These are two very different questions,”
he said.
Jerry Hall from Balanced LifeStyles agreed: “The supplements formulation, binders, whole food extracts, etc, would all play in the efficacy, the absorption of the nutrient. Secondly, as mentioned, the population used in the study surely would result in a negative result. And third, when vitamins are combined with drugs, both the drugs and the vitamins efficacy can be compromised.”
Dr Melton said in her article that: “Whatever is behind the health benefits of a diet rich in fruits and vegetables, you cannot reproduce it by taking purified extracts or vitamin supplements.”
Dr Adriana Descalzo from the Centro de Agroindustrias, INTA, Castelar in Buenos Aires said that she was in complete agreement with Dr Melton's views: “It is clear that cellular mechanisms select the natural isomers to be incorporated into the tissues, and the quality of vitamins and polyphenols found on their natural sources present more efficacy as active biomolecules.”
Richard LeFebvre, Sweetwater Natural Products, said that Dr Melton's point was well-made: When isolated compounds are extracted and refined or synthesized it stands to reason they will not behave the same as in nature. That said, I believe there are extractions that are done in such a way as to concentrate natural compounds increasing their activity and efficacy.
“There are many epidemiological studies that have shown this to be true and Dr Melton ignores a large body of science when she claims there is no proof. I refer her to Dr Masquelier's work at the University of Bordeaux on oligomeric proanthocyanidins (OPC) as just one example of a clinically proven efficacious antioxidant,” he said.
Ademola Okubena, from Hains Herbal/Health Forever Products, felt that the New Scientist article had missed the point: “I can agree with the statement made by Dr Melton that normal benefits of eating fruits and vegetables that contain antioxidant cannot be reproduced by consuming purified extracts and vitamin supplements, but the point is not reproducing the effect of the benefits or replacing naturally good foods, but to supplement them and provide additional benefits by the proven and efficacious vitamins and supplements.”
Taking a similar line, Wisconsin-based James R Bowman, a classically trained MD physician with advanced training and daily clinical experience as an ND (naturopath) and nutritionist, said he agreed with stance that supplements are secondary to eating fresh, healthy food.
However Dr Bowman said: “I completely disagree with the 'findings and conclusions' of this article… I have practiced for 30 years, and have the experience and training to absolutely refute every false allegation stated in this article which is short sighted, misleading, poorly researched, and incomplete in its data and context.”
The completeness of Dr Melton's article was also questioned by Levin, who pointed out that the majority of the negativity in her article was based on quotes from Barry Halliwell from the National University of Singapore.
“Much of the negativity about antioxidants in the article comes from a single scientist in Singapore and does not accurately express the state of the science on the topic.
“Unfortunately, this article in New Scientist uses old science that has been virtually repudiated and has not included a fair representation of the whole body of science in which antioxidants do have documented benefits for problems associated with aging,” said Levin.
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The supplements - bird flu debate: selenium
(2/27/06, Source: NutraIngredients.com)
27/02/2006 - Following last week’s claims and counter claims that dietary supplements may offer protection from avian flu, Stephen Daniells looks into statements that selenium supplements may offer protection.
Many novel virus have been found in selenium deficient populations, with experts suggesting that relatively harmless viruses can mutate into deadly versions on passing through a selenium deficient host.
This has led some to propose that selenium supplements may offer some kind of protection from the world's newest threat – avian flu.
Consumers seem to be taking notice of such reports, with some companies reporting increased sales in light of increased press coverage.
Rita Stoffaneller, senior nutritionist and registrations manager with Wassen International Ltd who offer a range of selenium products, told NutraIngredients.com: “Consumers are increasingly aware of the role of selenium and immune protection. Recent press articles have generated a sales increase of more than 60% across the range in the UK in the last 2 weeks.”
The link between selenium and immune system health is backed up by a growing body of science.
Researchers from the University of North Carolina, and the US Department of Agriculture reported that selenium deficient mice infected with a mild strain of influenza developed severe lung infections. When the researchers recovered the virus from the mice, they found an increased number of viral mutations, “resulting in a more virulent phenotype.” (Trends in Microbiology, 2004, Vol. 12, pp. 417-423).
“Wide-spread nutritional deficiencies occur in many developing countries, which are frequently the site of emergence of new viral diseases as well as old viral diseases with new pathogenic properties,” wrote the researcher.
The increased occurrence of mutated viruses in selenium-deficient individuals has been linked to the antioxidant nature of the mineral. Selenium is included into about 25 selenoproteins, five of which are powerful antioxidant enzymes.
If the host's antioxidant defences are weakened, then the virus is exposed to greater oxidative stress, and thus a greater chance of viral mutations.
Not only have low selenium levels been linked to higher virus mutations, but also to a reduction in the efficiency of the immune system. Selenium deficiency has been linked to reduced T-lymphocyte activity and reduced antibody production.
Dr Margaret Rayman of the Centre of Food Safety and Nutrition at Surrey University has published several articles on the immune boosting activities of selenium (Proceedings of the Nutrition Society, 2002, Vol. 61,pp. 203-215).
“Taking a selenium supplement may make a difference to a person with low selenium status and may help them deal more quickly and effectively with a viral infection. This could reduce their chances of becoming seriously ill,” said Rayman.
It would be incorrect and irresponsible to suggest that increasing the selenium intake of populations will eradicate the threat of H5N1. However, like vitamin C and zinc, the mineral could boost the body's natural defences, a view shared by Wassens.
The US Council for Responsible Nutrition recently warned consumers to be wary of supplements being touted as offering protection from avian flu.
In a statement issued in November, the CRN said: "We do not believe that any dietary supplements have been specifically shown to prevent or treat avian ‘flu."
Judy Blatman, VP communications for CRN told NutraIngredients-USA.com at that time: "We believe that responsible supplement companies will not take advantage of consumers' fears about avian flu and try and market a product as a remedy for it."
European selenium levels have been falling since the EU imposed levies on wheat imports from the US, where soil selenium levels are high. As a result, average intake of selenium in the UK has fallen from 60 to 34 micrograms per day.
The European recommended daily intake (RDI) is 65 micrograms.
The current market for selenium supplements in Europe is estimated to be worth around €40 million.
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Scientists Identify Cell-Killing Molecular Switch Activated by Free Radicals and Oxidative Stress. The Molecular Pathway May Contribute to Stroke, Neurodegenerative Diseases, Heart Disease, Diabetes, and the Aging Process
(6/1/06, Source: Harvard Medical School News Release).
BOSTON-June 1, 2006-Just as humans undergo daily stress, so do our individual cells. The cellular variety, called oxidative stress, is caused by the build-up of free radicals, which over time inflict damage linked to aging and age related diseases such as Alzheimer's. Researchers at Harvard Medical School (HMS) have now defined a molecular signaling pathway by which oxidative stress triggers cell death, a finding that could pave the way for new drug targets and diagnostic strategies for age-related diseases. The findings are reported in the June 2 issue of Cell.
"A common molecular denominator in aging and many age-related diseases is oxidative stress," says the studies lead author Azad Bonni, MD, PhD, HMS associate professor of pathology. The skin of a bitten apple will brown because of its exposure to air, and in some ways that is a good metaphor for the damage that oxidative stress is causing to neurons and other types of cells over time.
Humans and other organisms depend on oxygen to produce the energy required for cells to carry out their normal functions. A cell's engine, the mitochondria, converts oxygen into energy. But this process also leaves a kind of exhaust product known as free radicals. When free radicals are not destroyed by antioxidants, they create oxidative stress. As the body ages, it produces more and more free radicals and its own antioxidants are unable to fight this process, which results in the generation of highly reactive oxygen molecules that inflict cellular damage by reacting with biomolecules including DNA, proteins, and lipids. A lifetime of oxidative stress leads to general cellular deterioration associated with aging and degenerative diseases.
How the oxidative-stress signals trigger these profound effects in cells has remained unclear. But Bonni and his research team -- Maria Lehtinen, a graduate student in the HMS program in neuroscience, and Zengqiang Yuan, PhD, an HMS research fellow in pathology -- in collaboration with Keith Blackwell, MD, PhD, HMS associate professor of pathology, have now defined how a molecular chain-of-events links oxidative-stress signals to cell death in brain neurons.
In the course of investigating the mechanisms of cell death in neurons from rat brain, the team focused their attention on the function of a protein called MST, which had been previously implicated in cell death. They found that exposure of brain neurons to oxidative-stress signals stimulates the activity of MST, and once activated, MST instructs neurons to die. The researchers also found a tight link between MST and another family of molecules called FOXO proteins. FOXO proteins turn on genes in the nucleus, the command center of the cell. Once stimulated by oxidative stress, MST acts in its capacity as an enzyme to modify and thereby activate the FOXO proteins, instructing the FOXO proteins to move from the periphery of the cell into the nucleus of neurons. Once in the nucleus, the FOXO proteins were found to turn on genes that commit neurons to programmed death.
The discovery of the MST-FOXO biochemical switch mechanism fills a gap in our understanding of how oxidative stress elicits biological responses in neurons, and may include besides cell death, neuronal dysfunction and neuronal recovery. Since oxidative stress in neurons and other cells in the body contribute to tissue damage in a variety of disorders, including stroke, ischemic heart disease, neurodegenerative diseases, and diabetes, identification of the MST-FOXO switch mechanism could provide potential new targets for the diagnosis and treatment of many common age-associated diseases.
The study was funded by the National Institutes of Health; National Science Foundation; Albert J. Ryan Foundation; Lefler Foundation; and the Myra Reinhard Family Foundation.
Contact:
John Lacey, Harvard Medical School, 617-432-0442 (public_affairs@hms.harvard.edu)
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Study could spell opportunity for fruit and vegetable ingredients
(9/5/06, Clarisse Douaud). 9/5/2006 -
As the gap between the recommended and actual amounts of fruit and vegetables Americans consume increases, there may be more room for ingredients made from the powder or extract versions of these foods.
The US Department of Agriculture recently boosted its recommendations for fruit and vegetable consumption in its new MyPyramid food guide. But a study published in this month's issue of the Journal of the American Dietetic Association simultaneously found most of the population hasn't even been able to keep up with the previous, less stringent guidelines.
The odds of consumers meeting the new standard for nutrient intake through eating fresh vegetables alone consequently look even bleaker and could create an opportunity for formulators to market such ingredients and bridge this gap.
The study, conducted by researchers at the USDA and the National Cancer Institute, found in 1999 to 2000, just 40 percent of the American population met the then current recommendations to eat an average of five or more servings of fruits and vegetables per day. The figures were as low as ten percent among girls ages four to eight, and as high as 60 percent among men ages 51 to 70.
Ingredients makers insist fruit and vegetable-based nutraceuticals are not meant to replace a well-balanced intake of the real thing, but rather to compliment their diet.
On the basis of nutritionists recommending more fruits and vegetables, companies like PL Thomas have launched fruit and vegetable based ingredients ranging from apple, to artichoke, to onion to salad extracts. On its web site, the New Jersey-based ingredient distributor explains its “food origin ingredients” can be “used in a variety of formulations to provide supplemental servings of traditional foods”.
Pure Fruit Technologies has banked on tempting consumers with a thirst for a quick nutrient fix with its “fruitaceutical” beverages. The Utah-based manufacturer calls the drinks “nutritional juice supplements”.
The company claims the juices have been big sellers, with production of flagship product, mangosteen fruit based supplement, Mango-xan growing from 6,500 bottles a month in 2004 to 52,000 bottles a month in 2005.
If the USDA succeeds in generating a sense of urgency regarding eating more fruits and vegetables, not only could formulators who sell fruit and vegetable extracts stand to benefit, more innovation surrounding the issue could take place.
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The researchers conclude with a call to action:
“Nutrition and other health-care professionals must help consumers realize that for everyone over age 3 years, the new recommendations for fruit and vegetable intake are greater, and in many cases much greater, than the familiar five servings per day.”
Formulators could perhaps compensate for some of the lack of darker-colored yet healthier vegetables in the US diet. The study found Americans on average eat less than a third of the recommended amounts of dark green and orange vegetables. These vegetables tend to richer in beneficial nutrients such as antioxidants.
The new MyPyramid recommendations are 2 to 6 ½ cups per day of fruits and vegetables. The researchers reported that adequate intakes of fruits and vegetables ranged from a low of 0.7 percent of boys age 14 to 18 years, whose combined recommendation is five cups, to a high of 48 percent of children age 2 to 3, whose combined recommendation is one cup. Among women age 51 to 70 years, only 17 percent met their combined recommendation. Among all other sex-age groups, fewer than 11 percent met their goals.
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Mushrooms offer heart health fibres | Mushrooms As Good An Antioxidant Source As More Colorful Veggies |
Antioxidant supplements - myth or misunderstood? | The supplements - bird flu debate: selenium |
Scientists Identify Cell-Killing Molecular Switch Activated by Free Radicals and Oxidative Stress |
Study could spell opportunity for fruit and vegetable ingredients |
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