Archive for February, 2011

RESEARCHER LISTS MORE THAN 4,000 COMPONENTS OF BLOOD CHEMISTRY

Thursday, February 24th, 2011

Edmonton, Alberta - Feb. 24, 2011
After three years of exhaustive analysis led by a University of Alberta researcher, the list of known compounds in human blood has exploded from just a handful to more than 4,000. “Right now a medical doctor analyzing the blood of an ailing patient looks at something like 10 to 20 chemicals,” said U of A biochemist David Wishart. “We’ve identified 4,229 blood chemicals that doctors can potentially look at to diagnose and treat health problems.”

Hannah Gardener, Sc.D.
Dr. David Wishart
University of Alberta
biochemist
Photo: ualberta.ca

Blood chemicals, or metabolites, are routinely analyzed by doctors to diagnose conditions like diabetes and kidney failure. Wishart says the new research opens up the possibility of diagnosing hundreds of other diseases that are characterized by an imbalance in blood chemistry.

Wishart led more than 20 researchers at six different institutions using modern technology to validate past research, and the team also conducted its own lab experiments to break new ground on the content of human blood chemistry.

“This is the most complete chemical characterization of blood ever done,” said Wishart. “We now know the normal values of all the detectable chemicals in blood. Doctors can use these measurements as a reference point for monitoring a patient’s current and even future health.”

Wishart says blood chemicals are the “canary in the coal mine,” for catching the first signs of an oncoming medical problem. “The blood chemistry is the first thing to change when a person is developing a dangerous condition like high cholesterol.”

The database created by Wishart and his team is open access, meaning anyone can log on and find the expanded list of blood chemicals. Wishart says doctors can now tap into the collected wisdom of hundreds of blood research projects done in the past by researchers all over the world. “With this new database doctors can now link a specific abnormality in hundreds of different blood chemicals with a patient’s specific medical problem,” said Wishart.

Wishart believes the adoption of his research will happen slowly, with hospitals incorporating new search protocols and equipment for a few hundred of the more than 4,000 blood-chemistry markers identified by Wishart and his colleagues.

“People have being studying blood for more than 100 years,” said Wishart. “By combining research from the past with our new findings we have moved the science of blood chemistry from a keyhole view of the world to a giant picture window.”

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DIET SODA MAY RAISE ODDS OF VASCULAR EVENTS; SALT LINKED TO STROKE RISK

Thursday, February 10th, 2011

LOS ANGELES,

Study Highlights:
- Drinking diet soda daily is linked to a higher risk of stroke, heart attack and vascular related deaths.

- High salt intake may double the risk of ischemic stroke, independent of sodium’s role in hypertension.

Even if you drink diet soda - instead of the sugar variety - you could still have a much higher risk of vascular events compared to those who don’t drink soda, according to research presented at the American Stroke Association’s International Stroke Conference 2011.

In findings involving 2,564 people in the large, multiethnic Northern Manhattan Study (NOMAS), scientists said people who drank diet soda every day had a 61 percent higher risk of vascular events than those who reported no soda drinking.

Hannah Gardener, Sc.D.
Hannah Gardener, Sc.D.
Epidemiologist
University of Miami
Miller School
of Medicine
Photo: med.miami.edu

“If our results are confirmed with future studies, then it would suggest that diet soda may not be the optimal substitute for sugar sweetened beverages for protection against vascular outcomes,” said Hannah Gardener, Sc.D., lead author and epidemiologist at the University of Miami Miller School of Medicine in Miami, Fla.

In separate research using 2,657 participants also in the Manhattan study, scientists found that high salt intake, independent of the hypertension it causes, was linked to a dramatically increased risk of ischemic strokes (when a blood vessel blockage cuts off blood flow to the brain).

In the study, people who consumed more than 4,000 milligrams (mg) per day of sodium had more than double the risk of stroke compared to those consuming less than 1,500 mg per day.

At the start of both studies, researchers assessed diet by a food frequency questionnaire.

NOMAS is a collaboration of investigators at Columbia University in New York and Miami’s Miller School of Medicine, launched in 1993 to examine stroke incidence and risk factors in a multiethnic urban population. A total of 3,298 participants over 40 years old (average age 69) were enrolled through 2001 and continue to be followed. Sixtythree percent were women, 21 percent were white, 24 percent black and 53 percent Hispanic.

In the soda study, researchers asked subjects at the outset to report how much and what kind of soda they drank. Based on the data, they grouped participants into seven consumption categories: no soda (meaning less than one soda of any kind per month); moderate regular soda only (between one per month and six per week), daily regular soda (at least one per day); moderate diet soda only; daily diet soda only; and two groups of people who drink both types: moderate diet and any regular, and daily diet with any regular.

During an average follow up of 9.3 years, 559 vascular events occurred (including ischemic and hemorrhagic stroke, which is caused by rupture of a weakened blood vessel). Researchers accounted for participants’ age, sex, race or ethnicity, smoking status, exercise, alcohol consumption and daily caloric intake. And even after researchers also accounted for patients’ metabolic syndrome, peripheral vascular disease and heart disease history, the increased risk persisted at a rate 48 percent higher.

In the sodium research, 187 ischemic strokes were reported during 9.7 years of follow-up. Stroke risk, independent of hypertension, increased 16 percent for every 500 mg of sodium consumed a day, the scientists calculated. Those figures included adjustment for age, sex, race/ethnicity, education, alcohol use, exercise, daily caloric intake, smoking status, diabetes, high cholesterol, high blood pressure and previous heart disease.

Only a third of participants met the current U.S. Dietary Guidelines for Americans that recommend daily sodium intake fall below 2,300 mg, or about a teaspoon of salt, Gardener said. Only 12 percent of subjects met the American Heart Association’s recommendations to consume less than 1,500 mg a day. Average intake was 3,031 milligrams.

“The take home message is that high sodium intake is a risk factor for ischemic stroke among people with hypertension as well as among those without hypertension, underscoring the importance of limiting consumption of high sodium foods for stroke prevention,” Gardener said.

Participants’ reporting their dietary behavior is a key limitation of both studies, Gardener said.

In the soda study, investigators also lacked data on types of diet and regular drinks consumed, preventing analysis of whether variations among brands or changes over time in coloring and sweeteners might have played a role.

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WHAT MAKES FRUCTOSE FATTENING? OHSU RESEARCHERS FIND ANSWERS IN THE BRAIN

Wednesday, February 9th, 2011

PORTLAND, Ore.

The dietary concerns of too much fructose is well documented. High fructose corn syrup has become the sweetener most commonly added to processed foods. Many dietary experts believe this increase directly correlates to the nation’s growing obesity epidemic. Now, new research at Oregon Health & Science University demonstrates that the brain - which serves as a master control for body weight - reacts differently to fructose compared with another common sweetener, glucose. The research is published in the online edition of the journal Diabetes, Obesity and Metabolism and will appear in the March print edition.

Jonathan Purnell, MD
Jonathan Purnell, MD
Assistant Professor,
of medicine OHSU School
of Medicine
Photo: ohsu.edu

“We know from animal models that the brain responds uniquely to different nutrients and that these responses can determine how much they eat,” said Jonathan Purnell, M.D., an associate professor of medicine (endocrinology, diabetes and clinical nutrition) in the OHSU School of Medicine.

“With newer technologies such as functional MRI, we can examine how brain activity in humans reacts when exposed to, say, carbohydrates or fats. What we’ve found in this case is that the brain’s response to fructose is very different to the response to glucose, which is less likely to promote weight gain.”

Functional MRI allows researchers to watch brain activity in real time. To conduct the research, nine normal weight human study subjects were imaged as they received an infusion of fructose, glucose or a saline solution. When the resulting brain scans from these three groups were compared, the scientists observed distinct differences.

Brain activity in the hypothalamus, one brain area involved in regulating food intake, was not affected by either fructose or glucose. However, activity in the cortical brain control areas showed the opposite response during infusions of the sugars. Activity in these areas was inhibited when fructose was given but activated during glucose infusion.

This is an important finding because these control brain areas included sites that are thought to be important in determining how we respond to food taste, smells, and pictures, which the American public is bombarded with daily.

“This study provides evidence in humans that fructose and glucose elicits opposite responses in the brain. It supports the animal research that shows similar findings and links fructose with obesity,” added Purnell.

The OHSU Advanced Imaging Research Center, the Oregon Clinical and Translational Research Institute at OHSU, the NIH Roadmap for Medical Research, the USDA-ARS Project, the Diabetes Action Research and Education Foundation, and the National Center for Research Resources, a component of the National Institutes of Health, funded this research.

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NEW EXPLANATION FOR HEART HEALTHY BENEFITS OF CHOCOLATE

Monday, February 7th, 2011

WASHINGTON

In time for the chocolate giving and chocolate noshing fest on Valentine’s Day, scientists are reporting discovery of how this treat boosts the body’s production of high density lipoprotein cholesterol (HDL) - the “good” form of cholesterol that protects against heart disease. Just as those boxes of chocolates get hearts throbbing and mouths watering, polyphenols in chocolate rev up the activity of certain proteins, including proteins that attach to the genetic material DNA in ways that boost HDL levels. Their report appears in the Journal of Agricultural and Food Chemistry, one of 39 peer-reviewed scientific journals published by the American Chemical Society.

Midori Natsume, Ph.D., and colleagues note that studies have shown that cocoa, the main ingredient in chocolate, appears to reduce the risk of heart disease by boosting levels of HDL, or “good” cholesterol, and decreasing levels of low-density lipoprotein (LDL), or “bad” cholesterol. Credit for those heart-healthy effects goes to a cadre of antioxidant compounds in cocoa called polyphenols, which are particularly abundant in dark chocolate. Until now, however, nobody knew exactly how the polyphenols in cocoa orchestrated those beneficial effects.

The scientists analyzed the effects of cocoa polyphenols on cholesterol using cultures of human liver and intestinal cells. They focused on the production of apolipoprotein A1 (ApoA1), a protein that is the major component of “good” cholesterol, and apolipoprotein B (ApoB), the main component of “bad” cholesterol. It turns out that cocoa polyphenols increased ApoA1 levels and decreased ApoB levels in both the liver and intestine. Further, the scientists discovered that the polyphenols seem to work by enhancing the activity of so-called sterol regulatory element binding proteins (SREBPs). SREBPs attach to the genetic material DNA and activate genes that boost ApoA1 levels, increasing “good” cholesterol. The scientists also found that polyphenols appear to increase the activity of LDL receptors, proteins that help lower “bad” cholesterol levels.

Other recent research on the health benefits chocolate published in ACS journals:

* New evidence that dark chocolate helps ease emotional stress

* Study finds that people are programmed to love chocolate

* Natural ACE inhibitors in chocolate, wine and tea may help lower blood pressure

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ROASTING COFFEE BEANS A DARK BROWWN PRODUCES VALUED ANTIOXIDANTS:UBC FOOD SCIENTISTS

Wednesday, February 2nd, 2011

Vancouver, British Columbia

Food scientists at the University of British Columbia have been able to pinpoint more of the complex chemistry behind coffee’s much touted antioxidant benefits, tracing valuable compounds to the roasting process. Lead author Ami Ya Zheng Liu and co author Prof. David Kitts found that the prevailing antioxidants present in dark roasted coffee brew extracts result from the green beans being browned under high temperatures.

Their findings will appear in a forthcoming issue of Food Research International.

Liu and Kitts analyzed the complex mixture of chemical compounds produced during the bean’s browning process, called the “Maillard reaction.” The term refers to the work by French chemist Louis-Camille Maillard who in the 1900s looked at how heat affects the carbohydrates, sugars and proteins in food, such as when grilling steaks or toasting bread.

Antioxidants aid in removing free radicals, the end products of metabolism which have been linked to the aging process.

“Previous studies suggested that antioxidants in coffee could be traced to caffeine or the chlorogenic acid found in green coffee beans, but our results clearly show that the Maillard reaction is the main source of antioxidants,” says Liu, an MSc student in the Faculty of Land and Food Systems (LFS).

“We found, for example, that coffee beans lose 90 per cent of their chlorogenic acid during the roasting process,” says Kitts, LFS food science professor and director of the Food, Nutrition and Health program.

The UBC study sheds light on an area of research that has yielded largely inconsistent findings. While some scientists report increased antioxidant activity in coffee made from dark roasted beans, others found a decrease. Yet other theories insist that medium roast coffees yield the highest level of antioxidant activity.

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