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Adjusting the clocks to summer time on the last Sunday in March increases the risk of myocardial infarction in the following week. In return, putting the clocks back in the autumn reduces the risk, albeit to a lesser extent, according to research in the New England Journal of Medicine. (Credit: iStockphoto/Karen Roach)

Karolinska Institutet, via AlphaGalileo, November 2, 2008 — Adjusting the clocks to summer time on the last Sunday in March increases the risk of myocardial infarction in the following week. In return, putting the clocks back in the autumn reduces the risk, albeit to a lesser extent. This according to a new Swedish study.

Scientists at Karolinska Institutet have examined how the incidence of myocardial infarction in Sweden has changed with the summer and winter clock-shifts since 1987. Their results show that the number of heart attacks, on average, increases by about five per cent during the first week of summer time.

“There’s a small increase in risk for the individual, especially during the first three days of the new week,” says Dr Imre Janszky, one of the researchers behind the study. “The disruption in the chronobiological rhythms, the loss of one hour’s sleep and the resulting sleep disturbance are the probable causes.”
The team also observed that the readjustment back to winter time on the last Sunday in October, which gives us an extra hour’s sleep, is followed by a reduction in the risk of heart attack on the Monday. The reduction for the whole week is, however, less than the increase related to the summer adjustment.
According to the scientists, the study provides a conceivable explanation for why myocardial infarction is most common on Mondays, as demonstrated by previous research.

“It’s always been thought that it’s mainly due to an increase in stress ahead of the new working week,” says Dr Janszky. “But perhaps it’s also got something to do with the sleep disruption caused by the change in diurnal rhythm at the weekend.”
Even though the increase and decrease in risk are relatively small for the individual, the team believes that the study can improve our understanding of how disruptions to diurnal rhythms impact on our health.

“Roughly 1.5 billion people are subjected to these clock-shifts every year, but it’s hard to make any generalised statement about how many heart attacks they can cause,” adds Dr Rickard Ljung, another member of the research team.

Publication

Janszky I, Ljung R. Shifts to and from Daylight Saving Time and Incidence of Myocardial Infarction. New England Journal of Medicine, 30 October 2008, 359;18:1966-68

California Institute of Technology, October 31, 2008 — Brain-imaging studies reveal that voting decisions are more associated with the brain’s response to negative aspects of a politician’s appearance than to positive ones, says a team of researchers from the California Institute of Technology (Caltech), Scripps College, Princeton University, and the University of Iowa. This appears to be particularly true when voters have little or no information about a politician aside from their physical appearance.
Deciding whom to trust, whom to fear, and indeed for whom to vote in an election depends, in part, on quick, implicit judgments about people’s faces. Although this general finding has been scientifically documented, the detailed mechanisms have remained obscure. To probe how a politician’s appearance might influence voting decisions, Michael Spezio, an assistant professor of psychology at Scripps College and visiting associate at Caltech, and Antonio Rangel, an associate professor of economics at Caltech, examined brain activation in subjects looking at the faces of real politicians.

Using a functional magnetic resonance imaging (fMRI) scanner at the Caltech Brain Imaging Center, the researchers obtained high-resolution images of brain activation as volunteers made decisions about politicians based solely on their pictures.
The researchers conducted two independent studies using different groups of volunteers viewing the images of different politicians. Volunteers were shown pairs of photos, each with a politician coupled with their opponent in a real election in 2002, 2004, or 2006. Importantly, none of the study subjects were familiar with the politicians whose images they viewed.

In some experiments, the volunteers had to make character-trait judgments about the politicians–for example, which of the two politicians in the pair looked more competent to hold congressional office, or which looked more likely to physically threaten the volunteer. In other experiments, volunteers were asked to cast their vote for one politician in the pair; once again, their decisions were based only on the politicians’ appearances.

The results correlated with actual election outcomes. For example, politicians who were thought to look the most physically threatening in the experiment were more likely to have actually lost their elections in real life. The correlation held true even when volunteers saw the politicians’ pictures for less than one tenth of a second.

Importantly, the pictures of politicians who lost elections, both in the lab and in the real world, were associated with greater activation in key brain areas known to be important for processing emotion. This was true when volunteers simply voted and also when they closely examined the politicians’ pictures for character traits. The studies suggest that negative evaluations based only on a politician’s appearance have some effect on real election outcomes–and, specifically, may influence which candidate will lose an election. This influence appears to be more uniform than the influence exerted by positive evaluations based on appearance.

This finding fits with prior studies in cognitive neuroscience as well as in political theory.

“The results from our two studies suggest that intangibles like a candidate’s appearance may work preferentially, or more uniformly, via negative motives, and by means of brain processing contributing to such negative evaluations,” says Michael Spezio, the lead author on the study.

“It’s important to note that the brain region most closely associated with seeing pictures of election losers, known as the insula, is known to be important in processing both negative and positive emotional evaluations. Its increased activation in response to the appearance of election losers is consistent with its association with negative emotional evaluations in several domains, including the sight of someone who looks disgusted or untrustworthy,” Spezio says.

“Candidates try to evoke emotional reactions when they campaign for office, and this research gives us a new perspective on how much emotions might matter, and how they might matter, in terms of how voters view candidates,” says study coauthor R. Michael Alvarez, a professor of political science at Caltech and codirector of the Caltech/MIT Voting Technology Project.

One surprise in the study is that negative evaluations, such as the perception that a candidate is threatening, influence election loss significantly more than positive evaluations like attractiveness influence election success.

“While these findings are certainly very provocative, it is important to note their limitations,” says study senior author Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology at Caltech, and director of the Caltech Brain Imaging Center.

In particular, Adolphs says, the observed effects, while statistically significant, were rather small. “There is no doubt that many, many sources of information come into play when we make important and complex decisions, such as will happen in the upcoming elections. We are not claiming that how the candidates look is all there is to the story of how voters make up their minds–or that this is even the biggest part of the story. However, we do think it has some effect–and, moreover, that this effect may be largest when voters know little else about a candidate.”

Adds Spezio, “Given the size of the effects we see, we are likely detecting the influence of voters who have little or no information about a candidate’s views or life story, for example, or who choose not to pay attention to that information. Our finding is consistent with literature showing that humans prioritize negative information about outgroups”–groups of individuals who are perceived to not belong to one’s own group, as defined by characteristics such as profession, age, gender, social community, and shared values, but to an outside group. “A voter who knows nothing about a candidate will likely put that candidate into a default outgroup position. From there, negative attributions are expected to get the primary weight in decisionmaking. And that is precisely what we see,” he says.
“Earlier behavioral studies showed that rapid, effortless inferences from facial appearance predict the outcomes of political elections,” says study coauthor Alex Todorov, an assistant professor of psychology and public affairs at Princeton University. In 2005, Todorov published the first study to show that voter decisions are significantly associated with character-trait judgments that are based entirely on the visual appearance of political candidates.
“However,” Todorov adds, “these studies did not show how these inferential processes could play out at the level of individual voters. Two types of evidence will be critical to delineate the causal effects of appearance on electoral success: work by political scientists studying real voting decisions and work by cognitive neuroscientists studying the proximal mechanisms of the effects of inferences on decisions. The fMRI studies are an important step in the latter direction.”

The work was supported by the Gordon and Betty Moore Foundation, the National Science Foundation, and the National Institutes of Health.

Journal reference:

Spezio et al. A neural basis for the effect of candidate appearance on election outcomes. Social Cognitive and Affective Neuroscience, 2008; DOI: 10.1093/scan/nsn040

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Grape intake lowered blood pressure and signs of heart muscle damage, and improved heart function in lab rats. (Credit: iStockphoto)

University of Michigan Health System, October 31, 2008 — Could eating grapes help fight high blood pressure related to a salty diet? And could grapes calm other factors that are also related to heart diseases such as heart failure? A new University of Michigan Cardiovascular Center study suggests so.
The new study gives tantalizing clues to the potential of grapes in reducing cardiovascular risk. The effect is thought to be due to the high level of phytochemicals – naturally occurring antioxidants – that grapes contain.

The study was performed in laboratory rats. The researchers noted that while these study results are extremely encouraging, more research needs to be done.

The researchers studied the effect of regular table grapes (a blend of green, red, and black grapes) that were mixed into the rat diet in a powdered form, as part of either a high- or low-salt diet. They performed many comparisons between the rats consuming the test diet and the control rats receiving no grape powder — including some that received a mild dose of a common blood-pressure drug. All the rats were from a research breed that develops high blood pressure when fed a salty diet.

In all, after 18 weeks, the rats that received the grape-enriched diet powder had lower blood pressure, better heart function, reduced inflammation throughout their bodies, and fewer signs of heart muscle damage than the rats that ate the same salty diet but didn’t receive grapes. The rats that received the blood-pressure medicine, hydrazine, along with a salty diet also had lower blood pressure, but their hearts were not protected from damage as they were in the grape-fed group.

Says Mitchell Seymour, M.S., who led the research as part of his doctoral work in nutrition science at Michigan State University, “These findings support our theory that something within the grapes themselves has a direct impact on cardiovascular risk, beyond the simple blood pressure-lowering impact that we already know can come from a diet rich in fruits and vegetables.” Seymour manages the U-M Cardioprotection Research Laboratory, which is headed by U-M heart surgeon Steven Bolling, M.D.

Bolling, who is a professor of cardiac surgery at the U-M Medical School, notes that the animals in the study were in a similar situation to millions of Americans, who have high blood pressure related to diet, and who develop heart failure over time because of prolonged hypertension.

“The inevitable downhill sequence to hypertension and heart failure was changed by the addition of grape powder to a high-salt diet,” he says.

“Although there are many natural compounds in the grape powder itself that may have an effect, the things that we think are having an effect against the hypertension may be the flavanoids – either by direct antioxidant effects, by indirect effects on cell function, or both. These flavanoids are rich in all parts of the grape – skin, flesh and seed, all of which were in our powder.” Bolling explains.

Such naturally occurring chemicals have already been shown in other research, including previous U-M studies, to reduce other potentially harmful molecular and cellular activity in the body.

Although the current study was supported in part by the California Table Grape Commission, which also supplied the grape powder, the authors note that the commission played no role in the study’s design, conduct, analysis or the preparation of the journal article for publication. Seymour also receives funding from the National Heart, Lung and Blood Institute, part of the National Institutes of Health, through a National Research Service Award.

“Though it’s true that your mom told you to eat all your fruits and your vegetables, and that we are learning a lot about what fruits, including grapes, can do in this particular model of hypertension and heart failure, we would not directly tell patients to throw all their pills away and just eat grapes,” says Bolling.

However, research on grapes and other fruits containing high levels of antioxidant phytochemicals continues to show promise. So does research on the impact of red wine on heart health, though that issue is also far from settled.

The U-M team notes that a clinical research on grapes may be a possibility in the future, but is not currently planned.
In the meantime, Bolling says, people who want to lower their blood pressure, reduce the risk of heart failure, or help their weakened hearts retain as much pumping power as possible should follow tried-and-true advice: Cut down on the amount of salt you get through your food and drink.

“There is, as we now know, a great variability, perhaps genetic even, in sensitivity to salt and causing hypertension,” he says. “Some people are very sensitive to salt intake, some are only moderately so, and there are perhaps some people who are salt resistant. But in general we say stay away from excess salt.”

He notes that the popular DASH diet, which is low in salt and high in fruits and vegetables, has been proven to reduce mild high blood pressure without medication. The dose of whole table grape powder that was consumed in the study was roughly equivalent to a person eating nine human-sized servings of grapes a day. Currently, five to nine servings of fruits and vegetables are recommended as part of the DASH diet.

The rats in the study were from a strain called Dahl rats, which have been specially bred to all be susceptible to salt-induced hypertension. This allowed the researchers to look at a uniform sample of rats that would be affected in the same way by their diet, so that the effects of the salt level, grape powder and hydrazine could be seen clearly.

Each group of 12 rats was fed the same weight of food each day, with powdered grapes making up 3 percent of the diet (by weight) for rats that received grapes as part of either a low-salt or high-salt diet. The rats that received hydrazine were fed it through their water supply in a dose that has been previously shown to be effective in reducing blood pressure.
The rats in the high-salt grape and high-salt hydrazine groups did develop high blood pressure over time, but they had lower systolic blood pressures than the high-salt rats that did not receive grapes.

The researchers also measured the distortion of the heart size, weight and function that occurred over time – characteristics of heart failure – and found that the high-salt grape group had less of a change than the high-salt hydrazine group. Parameters related to the diastolic blood pressure – an important factor in human heart failure — and to the heart’s relaxation during the diastolic phase also changed in just the high-salt grape group. Finally, the grape-fed rats had improved cardiac output, or more blood pumped per unit of time.
The researchers also looked for signs of inflammation, oxidative damage and other molecular indicators of cardiac stress. Again, the rats that received the high-salt grape diet had lower levels of these markers than rats that received the high-salt diet with hydrazine – and even the low-salt grape-eating rats had lower levels than the rats that received a low-salt diet alone.
In all, the researchers say, the study demonstrates that a grape-enriched diet can have broad effects on the development of hypertension and the risk factors that go along with it. Whether the effect can be replicated in humans, they say, remains to be seen.

Journal reference:

E. M. Seymour, Andrew A. M. Singer, Maurice R. Bennink, Rushi V. Parikh, Ara Kirakosyan, Peter B. Kaufman and Steven F. Bolling. Chronic Intake of a Phytochemical-Enriched Diet Reduces Cardiac Fibrosis and Diastolic Dysfunction Caused by Prolonged Salt-Sensitive Hypertension. Journal of Gerontology: Biological Sciences, Vol. 63A, No. 10, October 2008 [link]

ScienceDaily, November 1, 2008 — A growing body of research data suggests that consuming foods rich in polyphenols from grapes, including red wine, helps reduce the risk of heart disease, according to a review article in the November issue of Nutrition Research.

“Consumption of grape and grape extracts and/or grape products such as red wine may be beneficial in preventing the development of chronic degenerative diseases such as cardiovascular disease,” write Wayne R. Leifert, Ph.D., and Mahinda Y. Abeywardena, Ph.D., of Commonwealth Scientific and Industrial Research Organisation in Adelaide, Australia.

The authors review the accumulating evidence that grape polyphenols work in many different ways to prevent cardiovascular and other “inflammatory-mediated” diseases. Polyphenols are natural antioxidants found in grapes and some other plant foods. Their types and actions vary, depending on where in the grape they are found. Grape seeds, grape skin, and grape juice contain several types of polyphenols, including resveratrol, phenolic acids, anthocyanins, and flavonoids.
Through their antioxidant effects, grape polyphenols help to slow or prevent cell damage caused by oxidation. Polyphenols decrease oxidation of low-density lipoprotein cholesterol (“bad” cholesterol)—a key step in the development of atherosclerosis (hardening of the arteries). Grape polyphenols also have other protective effects on the heart and blood vessels, including actions to reduce blood clotting, abnormal heart rhythms, and blood vessel narrowing. It’s not yet clear exactly how these benefits of polyphenols occur, although there is evidence of effects on cellular signaling and on the actions of certain genes. The wide range of health-promoting effects suggests that several different, possibly interrelated mechanisms may be involved.

So far, most of the evidence on grape polyphenols comes from laboratory experiments and animal studies. However, a few studies support the disease-preventing benefits of grapes in humans. Studies in patients treated with grape seed extracts have shown improvements in blood flow and cholesterol levels. In other studies, drinking Concord grape juice has improved measures of blood flow in patients with coronary artery disease and lowered blood pressure in patients with hypertension.
Studies investigating the lower rates of heart disease in France—the so-called “French paradox”—first raised the possibility that red wine might have health benefits. The subsequent research reviewed by Drs. Leifert and Abeywardena helps build the case that grapes and grape products might be a useful part of strategies to lower the high rate of death from cardiovascular disease.
At a time of growing interest in the use of “functional foods and nutraceuticals” to promote heart health, grapes and grape polyphenols are “attractive candidates” for use in such supplements, Drs. Leifert and Abeywardena believe. “Therefore,” they conclude, “supplementation with grape seed, grape skin or red wine products may be a useful adjunct to consider for a dietary approach in the prevention of cardiovascular diseases, although additional research is required to support such a strategy.”