Health for life

Drinking three to four cups of coffee per day may help to prevent type 2 diabetes according to research highlighted in a session report published by the Institute for Scientific Information on Coffee (ISIC), a not-for-profit organisation devoted to the study and disclosure of science related to coffee and health.

Recent scientific evidence has consistently linked regular, moderate coffee consumption with a possible reduced risk of developing type 2 diabetes. An update of this research and key findings presented during a session at the 2012 World Congress on Prevention of Diabetes and Its Complications (WCPD) is summarized in the report.

The report outlines the epidemiological evidence linking coffee consumption to diabetes prevention, highlighting research that shows three to four cups of coffee per day is associated with an approximate 25 per cent lower risk of developing type 2 diabetes, compared to consuming none or less than two cups per day1. Another study also found an inverse dose dependent response effect with each additional cup of coffee reducing the relative risk by 7-8 per cent2.

Whilst these epidemiological studies suggest an association between moderate coffee consumption and reduced risk of developing diabetes, they are unable to infer a causal effect. As such, clinical intervention trails are required to study the effect in a controlled setting. One prospective randomized controlled trial3, tested glucose and insulin after an oral glucose tolerance test with 12g decaffeinated coffee, 1g chlorogenic acid, 500 mg trigonelline, or placebo. This study demonstrated that chlorogenic acid, and trigonelline reduced early glucose and insulin responses, and contribute to the putative beneficial effect of coffee.

The report notes that the association between coffee consumption a reduced risk of type 2 diabetes could be seen as counter intuitive, as drinking coffee is often linked to unhealthier habits, such as smoking and low levels of physical activity. Furthermore, studies have illustrated that moderate coffee consumption is not associated with an increased risk of hypertension, stroke or coronary heart disease4 ,5, 6. Research with patients with CVD has also shown that moderate coffee consumption is inversely associated with risk of heart failure, with a J-shaped relationship7.

Finally, the report puts forward some of the key mechanistic theories that underlie the possible relationship between coffee consumption and the reduced risk of diabetes. These included the Energy Expenditure Hypothesis, which suggests that the caffeine in coffee stimulates metabolism and increases energy expenditure and the Carbohydrate Metabolic Hypothesis, whereby it is thought that coffee components play a key role by influencing the glucose balance within the body. There is also a subset of theories that suggest coffee contains components that may improve insulin sensitivity though mechanisms such as modulating inflammatory pathways, mediating the oxidative stress of cells, hormonal effects or by reducing iron stores.

Coffee is one of the most extensively researched components in the diet. New studies are regularly being added to the already large body of scientific research, which overall suggests that moderate habitual coffee consumption is not associated with detrimental effects on cardiovascular health

Among recent studies, a new review paper1 highlights that for most healthy people, moderate coffee consumption is unlikely to adversely affect cardiovascular health. Furthermore a new paper2 concluded that higher green tea and coffee consumption is inversely associated with risk of CVD and stroke in the general population.

Considerable research has also been devoted to investigating associations between coffee consumption and key risk factors for cardiovascular disease, such as hypertension (high blood pressure) and elevated cholesterol. Most evidence suggests that regular moderate consumption of caffeinated coffee has no long-term effect on blood pressure and does not increase the risk of hypertension.

A recent study suggests that moderate consumption of paper-filtered coffee may have an unfavourable effect on plasma cholesterol3. The wider body of evidence indicates that the impact of coffee on cholesterol is dependent on the brewing method. Unfiltered coffee raises serum cholesterol levels whereas this is not the case with filter coffee because the cholesterol-raising compounds in coffee are retained in the paper filter.

Throughout 2013 coffee and mortality has been a subject of several scientific research papers, which have produced conflicting results. One study4 found a 21% increase in mortality rate in those drinking more than 28 cups of coffee a week. However recent data from a meta-analysis and systematic review5 assessed 23 studies and concluded that coffee consumption is, in fact, inversely related to the risk of mortality.

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More information about this research is available at http://www.coffeeandhealth.org/coffee-and-health-topics/coffee-consumption-and-cardiovascular-health-2/the-latest-research-on-coffee-and-cardiovascular-health/.

References

1 Rebello S.A. & van Dam R.M. (2013) Coffee Consumption and Cardiovascular Health: Getting to the Heart of the Matter. Current Cardiology Reports, 15:403.

2 Kokubo Y. et al. (2013) The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population: The Japan Public Health Center-Based Study Cohort. Stroke, published online ahead of print.

3 Correa T.A.F. et al. (2013) Paper filtered coffee increases cholesterol and inflammation biomarkers independent of roasting degree. Nutrition, 29(7-8):977-81.

4 Liu J. et al. (2013) Association of coffee consumtpion with all-cause and cardiovascular disease mortality. Mayo Clinic Proceedings, published online ahead of print.

5 Malerba S. et al. (2013) A meta-analysis of prospective studies of coffee consumtpion and mortality for all causes, cancers and cardiovascular disease. European Journal of Epidemiology, 28(7):527-539.

A large new American Cancer Society study adds to increasing evidence that physical activity reduces the risk of breast cancer in postmenopausal women. Researchers say moderate recreational activity was associated with a 14 percent lower risk and high physical activity with a 25 percent lower risk of breast cancer compared to women who were active at the lowest level. The study appears early online in Cancer Epidemiology, Biomarkers, and Prevention.

A large body of evidence shows that women taking part in regular physical activity have an approximately 25 percent lower risk of breast cancer compared to the most inactive. But still unclear are issues such as whether moderate intensity activity, like walking, imparts a benefit in the absence of vigorous exercise. Also unclear is whether the association differs based on tumor features, such as hormone receptor status, or by individual factors such as a womans body mass index (BMI), weight status, and use of postmenopausal hormones. In addition, while prolonged periods of sitting have been associated with the risk of some cancers, the relation between sitting time and postmenopausal breast cancer risk is not well understood.

To learn more, American Cancer Society researchers led by Alpa Patel, Ph.D. compared exercise and breast cancer status in 73,615 postmenopausal women taking part in in the CPS-II Nutrition Cohort, a prospective study of cancer incidence established by the American Cancer Society in 1992. During the 17-year study, 4,760 women in the study were diagnosed with breast cancer.

About one in ten (9.2 percent) women reported no recreational physical activity at the beginning of the study. Among those who were active, the average expenditure was equivalent to 3.5 hours per week of moderately-paced walking. Physically active women engaged primarily in moderate intensity activities, like walking, cycling, aerobics, and dancing rather than vigorous-intensity activities like running, swimming, and tennis. Among all women, 47 percent reported walking as their only recreational activity. Physically active women tended to be leaner, more likely to maintain or lose weight during adulthood, more likely to drink alcohol, and less likely to currently smoke. They were also more likely to use postmenopausal hormone therapy and to have had a mammogram in the past year.

Among those who reported walking as their only activity, those who walked at least seven hours per week had a 14 percent lower risk of breast cancer compared to those who walked three or fewer hours per week. Consistent with most prior studies, the most active women had 25 percent lower risk of breast cancer than the least active. The associations did not differ by hormone receptor status, BMI, weight gain, or postmenopausal hormone use. Also, sitting time was not associated with risk.

"Our results clearly support an association between physical activity and postmenopausal breast cancer, with more vigorous activity having a stronger effect," said Dr. Patel. "Our findings are particularly relevant, as people struggle with conflicting information about how much activity they need to stay healthy. Without any other recreational physical activities, walking on average of at least one hour per day was associated with a modestly lower risk of breast cancer. More strenuous and longer activities lowered the risk even more."

Current guidelines recommend adults get at least two-and-a-half hours per week of moderate-intensity activity, or 75 minutes per week of vigorous-intensity aerobic activity for overall health. But studies indicate less than half of U.S. adult women are active at these minimum levels. "Given that more than 60 percent of women report some daily walking, promoting walking as a healthy leisure-time activity could be an effective strategy for increasing physical activity among postmenopausal women," added Dr. Patel.

Its the time of year when many of us celebrate the holidays with festive foods and drinks, including alcohol. No better time then to ask if it is true, as is widely held, that moderate consumption of alcohol is beneficial to health.

A research team led by an immunologist at the University of California, Riverside now has data that could put the question to rest. The researchers found that moderate alcohol consumption could bolster our immune system, and potentially our ability to fight infections.

The finding, published Dec. 17 in the journal Vaccine, can help lead to a better understanding of how our immune system works. It can also pave the way for potentially new interventions to improve our ability to respond to vaccines and infections, benefiting vulnerable populations, such as the elderly for whom the flu vaccine, for example, has been found to be largely ineffective.

"It has been known for a long time that moderate alcohol consumption is associated with lower mortality," said Ilhem Messaoudi, an associate professor of biomedical sciences in the School of Medicine and the lead author of the research paper. "Our study, conducted on non-human primates, shows for the first time that voluntary moderate alcohol consumption boosts immune responses to vaccination."

Messaoudi did the bulk of the research while she was an assistant professor at the Oregon Health and Science University, where she collaborated with Kathleen Grant, a professor of behavioral neuroscience and a coauthor on the research paper. She joined UC Riverside earlier this year.

To study the impact of alcohol consumption on the immune system, the researchers trained 12 rhesus macaques to self-administer/consume alcohol on their own accord. The team first vaccinated the animals (against small pox) and then allowed them to access either 4 percent ethanol (the experimental group) or calorically matched sugar water (the control group). All the animals also had open access to water as an alternative fluid, as well as food. The researchers then proceeded to monitor the animals daily ethanol consumption for 14 months. The animals were vaccinated one more time, seven months after the experiment began.

The research team found that over nine months of the animals ethanol self-administration, mean daily ethanol intake varied markedly among them.

"Like humans, rhesus macaques showed highly variable drinking behavior," Messaoudi said. "Some animals drank large volumes of ethanol, while others drank in moderation."

The animals voluntary ethanol consumption segregated them into two groups: animals in the first group were those that consumed more alcohol, averaged a blood ethanol concentration (BEC) greater than the legal limit of 0.08 percent and were theore designated heavy drinkers; animals in the second group consumed less alcohol, averaged a BEC of 0.02-0.04 percent and were designated moderate drinkers.

"Prior to consuming alcohol, all the animals showed comparable responses to vaccination," Messaoudi said. "Following exposure to ethanol, however, the animals showed markedly different responses after receiving the booster vaccine."

The researchers found that, as expected based on human epidemiological data, those animals that drank the largest amounts of alcohol showed greatly diminished vaccine responses compared to the control group. In contrast, animals that drank moderate amounts of ethanol displayed enhanced vaccine responses.

"These surprising findings indicate that some of the beneficial effects of moderate amounts of alcohol consumption may be manifested through boosting the bodys immune system," Messaoudi said. "This supports what has been widely believed for some time: moderate ethanol consumption results in a reduction in all causes of mortality, especially cardiovascular disease. As for excessive alcohol consumption, our study shows that it has a significant negative impact on health."

Alcohol abuse kills 25,000 Americans annually and is one of the leading causes of preventable death in the country. Two thirds of U.S. adults consume approximately four drinks a week, considered to be a moderate amount by most consumers.

"If you have a family history of alcohol abuse, or are at risk, or have been an abuser in the past, we are not recommending you go out and drink to improve your immune system!" Messaoudi said. "But for the average person that has, say, a glass of wine with dinner, it does seem, in general, to improve heath, and cardiovascular function in particular, and now we can add the immune system to that list."

The study was carried out under strict accordance with the recommendations outlined in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health, the Office of Animal Welfare and the U.S. Department of Agriculture. The study was also approved by the Oregon National Primate Research Center Institutional Animal Care and Use Committee.

"Next, we plan to harness our observations made in this study to address bigger questions on the immune system, such as how can we boost our immune responses to vaccination, a particular challenge for our elderly," Messaoudi said.

College education and alcohol consumption may be linked to risk for chronic obstructive pulmonary disease (COPD). Researchers from Kaiser Permanente Medical Group in Oakland, California, followed 126,019 people who supplied baseline data from 1978 – 1985 through 2008 with analyses of hospitalizations attributed to COPD (emphysema, chronic bronchitis, or chronic airway obstruction).

Although cigarette smoking, increasing age, and history of respiratory disease/symptoms were powerful predictors of COPD, results also showed that Asian Americans (vs whites) and college graduates (vs no college) were at a moderately lower risk for COPD, as were persons reporting 1 to 2 drinks per day (vs lifelong abstainers).

A Loyola University Chicago Stritch School of Medicine study suggests that omega-3 fish oil might help protect against alcohol-related dementia.

Previous studies have shown that long-term alcohol abuse increases the risk of dementia. The Loyola study found that in the brain cells of rats exposed to high levels of alcohol, a fish oil compound protected against inflammation and cell death.

The study by Michael A. Collins, PhD, and colleagues was reported Sept. 8 at the 14th Congress of the European Society for Biomedical Research on Alcoholism in Warsaw.

An earlier analysis by Collins and Loyola colleague Edward J. Neafsey, PhD, which pooled the results of 143 studies, found that moderate social drinking may reduce the risk of dementia and cognitive impairment. (Moderate drinking is defined as a maximum of two drinks per day for men and 1 drink per day for women.)

It appears that small amounts of alcohol might, in effect, make brain cells more fit. Alcohol in moderate amounts stresses cells and thus toughens them up to cope with major stresses down the road that could cause dementia. But too much alcohol overwhelms the cells, leading to inflammation and cell death.

In the new study, Collins and colleagues exposed cultures of adult rat brain cells to amounts of alcohol equivalent to more than four times the legal limit for driving. These cell cultures were compared with cultures of brain cells exposed to the same high levels of alcohol, plus a compound found in fish oil called omega-3 docosahexaenoic acid (DHA).

Researchers found there was about 90 percent less neuroinflammation and neuronal death in the brain cells exposed to DHA and alcohol than in the cells exposed to alcohol alone.

Further studies are needed to confirm whether fish oil protects against alcohol-related dementia. "Fish oil has the potential of helping preserve brain integrity in abusers," Collins said. "At the very least, it wouldnt hurt them."

But Collins added that best way for an alcohol abuser to protect the brain is, if possible, to quit drinking or cut back to moderate amounts. "We dont want people to think its okay to take a few fish oil capsules and then continue to go on abusing alcohol."

Drinking a couple of glasses of wine each day has generally been considered a good way to promote cardiovascular and brain health. But a new Rutgers University study indicates that there is a fine line between moderate and binge drinking -- a risky behavior that can decrease the making of adult brain cells by as much as 40 percent.

In a study posted online and scheduled to be published in the journal Neuroscience on November 8, lead author Megan Anderson, a graduate student working with Tracey J. Shors, Professor II in Behavioral and Systems Neuroscience in the Department of Psychology, reported that moderate to binge drinking -- drinking less during the week and more on the weekends -- significantly reduces the structural integrity of the adult brain.

"Moderate drinking can become binge drinking without the person realizing it," said Anderson."In the short term there may not be any noticeable motor skills or overall functioning problems, but in the long term this type of behavior could have an adverse effect on learning and memory."

Shors and Anderson worked with postdoctoral fellow Miriam Nokia from the University of Jyvaskyla in Finland to model moderate to heavy drinking in humans using rodents that reached a blood alcohol level of 0.08 percent -- the legal driving limit in the United States and many other countries -- and found that brain cell production was affected negatively.

The researchers discovered that at this level of intoxication in rats -- comparable to about 3-4 drinks for women and five drinks for men -- the number of nerve cells in the hippocampus of the brain were reduced by nearly 40 percent compared to those in the abstinent group of rodents. The hippocampus is a part of the brain where the new neurons are made and is also known to be necessary for some types of new learning.

This level of alcohol intake was not enough to impair the motor skills of either male or female rats or prevent them from associative learning in the short-term. Still, Anderson said, th

is substantial decrease in brain cell numbers over time could have profound effects on the structural plasticity of the adult brain because these new cells communicate with other neurons to regulate brain health.

"If this area of your brain was affected every day over many months and years, eventually you might not be able to learn how to get somewhere new or to learn something new about your life," said Anderson, a graduate fellow in the Department of Neuroscience and Cell Biology. "Its something that you might not even be aware is occurring."

According to the National Institute of Alcohol Abuse and Alcoholism, men who drink 14 drinks a week and women who drink seven are considered at-risk drinkers. Although college students commonly binge drink, according to the institute, 70 percent of binge drinking episodes involved adults age 26 and older.

"This research indicates that social or daily drinking may be more harmful to brain health than what is now believed by the general public," she said.