Posts Tagged "caffeine"

There’s been a lot of controversy about caffeine-spiked energy drinks in recent years following a spate of deaths and overdoses related to the beverages. In one of the most heartbreaking cases, 14-year-old Anais Fournier of Maryland died after consuming two 24-ounce cans of an energy drink. Food and Drug Administration has been studying such cases to try to determine if there’s a causal link and, if so, what to do about it. Makers of energy drinks, meanwhile, have insisted that the beverages are safe and that some of the cases of bad reactions may have been due to pre-existing conditions that the individuals in question had.

In an effort to get more information about exactly happens in your body after you consume one of the drinks, Mayo Clinic researcher Anna Svatikova and her colleagues recruited 25 volunteers.

All were young adults age 18 or older, nonsmokers, free of known disease, and not taking medications. They were asked to drink a 16-ounce can of a Rockstar energy drink and a placebo — with the same taste, texture, color and nutritional contents but without the caffeine and other stimulants — within five minutes on two separate days.

The energy drink had the following stimulants: 240 mg of caffeine, 2,000 mg of taurine and extracts of guarana seed, ginseng root and milk thistle.

Researchers took numerous measurements first before they drank and 30 minutes after. With the placebo, there was very little change. With the energy drink, however, many of the changes were marked:

-Systolic blood pressure (the top number) – 6.2 percent increase

-Diastolic blood pressure (the bottom number) – 6.8 percent increase

-Average blood pressure – 6.4 percent increase

-Heart rate – none

-Caffeine in blood – increase from undetectable to 3.4 micrograms/mL

-Norepinephrine level (the stress hormone, which can give you the shakes when you have too much caffeine) in blood – increase from 150 pg/mL to 250 pg/ML

Writing in JAMA, the researchers said that these changes may predispose those who drink a single drink to increased cardiovascular risk.

Source: The Washington Post

Drinking caffeinated beverages may be associated with a lower likelihood of erectile dysfunction (ED), according to study findings presented at the American Urological Association 2014 annual meeting. Lopez, et al., University of Texas Medical School, Houston, and colleagues analyzed data from 3,724 men aged 20 years and older who participated in the National Health and Nutrition Examination Survey (2001-2004), a cross-sectional survey of the general U.S. population. The researchers looked at 24-hour dietary recall to estimate intake of caffeine and caffeinated beverages. Overall, men in the 3rd quintile of total caffeine intake (85-170 mg/day) and the 4th quintile (171-303 mg/day) were less likely to report ED compared with men in the first (reference) quintile (0-7 mg/day).

Among overweight and obese men and those with hypertension, the researchers found a significantly decreased likelihood of reported ED among men in the 2nd, 3rd, 4th, and 5th quintiles compared with the reference quartile, after adjusting for multiple variables. The authors concluded that total caffeine intake equivalent to about 2-3 cups of coffee (250-375 mg/day) is associated with a significantly lower likelihood to report ED. The team noted that their study is strengthened by the use of a large representative sample of men in the U.S. and validated dietary recall methodology from NHANES. As NHANES is a cross-sectional study, they cannot infer causality or suggest a clinical practice change, the researchers pointed out.

Source: Renal And Urology News

A new, large-scale study has identified six new genetic variants associated with habitual coffee drinking. The genome-wide meta-analysis, led by Harvard School of Public Health and Brigham and Women’s Hospital researchers, helps explain why a given amount of coffee or caffeine has different effects on different people and provides a genetic basis for future research exploring the links between coffee and health.

“Coffee and caffeine have been linked to beneficial and adverse health effects. Our findings may allow us to identify subgroups of people most likely to benefit from increasing or decreasing coffee consumption for optimal health,” said Marilyn Cornelis, research associate in the Department of Nutrition at Harvard School of Public Health and lead author of the study.

Genetics have long been suspected of contributing to individual differences in response to coffee and caffeine. However, pinpointing the specific genetic variants has been challenging.

The researchers, part of the Coffee and Caffeine Genetics Consortium, conducted a genome-wide meta-analysis of more than 120,000 regular coffee drinkers of European and African American ancestry. They identified two variants that mapped to genes involved in caffeine metabolism, POR and ABCG2 (two others, AHR and CYP1A2 had been identified previously). Two variants were identified near genes BDNF and SLC6A4 that potentially influence the rewarding effects of caffeine. Two others—near GCKR and MLXIPL, genes involved in glucose and lipid metabolism—had not previously been linked to the metabolism or neurological effects of coffee.

The findings suggest that people naturally modulate their coffee intake to experience the optimal effects exerted by caffeine and that the strongest genetic factors linked to increased coffee intake likely work by directly increasing caffeine metabolism.

“The new candidate genes are not the ones we have focused on in the past, so this is an important step forward in coffee research,” said Cornelis.

“Like previous genetic analyses of smoking and alcohol consumption, this research serves as an example of how genetics can influence some types of habitual behavior,” said Daniel Chasman, associate professor at Brigham and Women’s Hospital and the study’s senior author.

Source: (Harvard School of Public Health)