News To Empower You

By Dace L. Trence, MD, FACE

Caffeine: Good for you or not?

Are you reaching for your morning cup of coffee, or perhaps your second? You’re not alone. More than half of American adults drink some form of coffee each day, according to the National Coffee Association. But is it good for you…or not?

This ongoing controversy has had quite a bit of attention recently following reports in two major medical journals, the New England Journal of Medicine and Circulation.

In one report, researchers from the National Cancer Institute reported results from data that included 400,000 adults ages 50 to 71. Those who drank three or more cups of coffee per day had a lower risk of death than non-coffee drinkers. For men who drank one cup of coffee daily, risk went down 6 percent, for two or three cups about 10 percent, for four or five cups daily about 12 percent, and for six or more cups of coffee per day a 10 percent reduction.

For women, one cup daily resulted in a 5 percent decreased risk, for two to three cups 13 percent, for four to five cups 16 percent, and for six or more cups, 15 percent. Decreased risks were seen in mortality from several conditions, including heart disease, diseases related to lung function, stroke, injuries and accidents, and diabetes and infections, but not for deaths due to cancer.

In another study that included 208,000 men and women, the results showed that those who drank 1.1 to three cups of coffee per day had a 9 percent lower risk of dying than non-drinkers, while those downing 3.1 to five cups per day had a 7 percent lower risk of dying. Those who drank more than five cups per day had a 2 percent increase in their risk of dying.

Because many people who drink a lot of coffee also smoke, researchers did a further analysis, taking smoking out of the observed results. The resulting data were even more surprising. If study participants who were smokers ingested 1.1 to three cups per day, they had an 8 percent drop in mortality, and if they drank 3.1 to five cups per day, they had a 15 percent lower risk of death. Those drinking five or more cups had a 12 percent drop in mortality.

Although these associations seem wonderful for coffee lovers, they really are not hard science. All of these results were based on data from food recall diaries that the study participants were asked to complete, which aren’t always accurate. (Think about how well you remember what you had for yesterday’s lunch.) At best, these results suggest that drinking coffee is not necessarily bad for one’s health.

So what’s in coffee that was suggested as being health beneficial? Not caffeine. People who drank caffeinated or decaffeinated coffee had similar health results, which suggests there is some other component in the coffee that is potentially beneficial. Some experts have suggested that there are anti-inflammatory substances in coffee (antioxidants among them) that counteract the inflammation process believed to be associated with so many chronic diseases, diabetes among them.

Other studies have found that coffee reduces the risk of certain medical conditions, including stroke, depression, dementia and some cancers, such as colon cancer — a finding that was not supported by the above studies, as cancer occurrence was no different between coffee drinkers and non-drinkers.

If you’re reaching for another cup of Joe, consider the downsides of excess coffee consumption — feeling like you just ran up 10 flights of stairs with your heart pounding and your fingers shaking so badly that your computer keys feel like jelly. There are many reasons to be cautious with coffee intake: caffeine can raise blood pressure and also may raise blood cholesterol. Difficulty falling asleep, irritability, an upset stomach, and a fast heartbeat can also be associated with too much caffeine intake. The amount of caffeine that will result in these undesirable side effects varies from person to person and their sensitivity to caffeine’s effects, including how strong the brew is made.

Take-home message:

Armed with these study results, coffee drinkers can enjoy coffee in moderation and be more reassured about the impact on their health.

Blood pressure: what is too high?

It’s not difficult to find information about blood pressure in the news lately: Suggestions abound about the appropriate targeted pressure standards – 130/80... or 140/90…or maybe something else. Much of the renewed interest in ideal blood pressure targets has been generated by reports about the results from the recent SPRINT (Systolic Blood Pressure Intervention Trial) study, a clinical trial sponsored by the National Institutes of Health (NIH).

High blood pressure is a very common health problem and a disease risk factor, including coronary heart disease, stroke, heart failure, chronic kidney disease and decline in cognitive function. Previous studies have suggested a progressive increase in this risk associated with blood pressure even above 115/75 (measured as mmHg). Prior research has shown that decreasing an elevated systolic (referring to the top number) blood pressure does lower the risk of complications. However, the best systolic blood pressure to reduce blood pressure-related disease risk remains unclear. And the benefit of treating to a systolic blood pressure well below 140 mmHg has not been proven in a large, definitive clinical trial.

Among the research studies was SPRINT, a multicenter, randomized, controlled trial that compared treating systolic blood pressure. One group received care for a systolic measure of less than 140 mmHg, the current standard target for control, and the other group received more aggressive treatment, with a goal systolic pressure of less than 120 mmHg. Study participants had to be age 50 or older with an average baseline systolic blood pressure equal or greater than 130 mmHg.

Study participants also had to have evidence of having cardiovascular disease, chronic kidney disease, a 10-year Framingham cardiovascular disease risk score of equal or greater than 15 percent (a calculation that, based on a number of heart disease risk factors, would translate to a risk of a 15 percent or more chance of developing heart disease in the next 10 years) or age equal to or greater than 75 years. Outcomes tracked were myocardial infarction (heart attack), acute coronary syndrome (new onset of chest pain due to coronary disease), stroke, heart failure, or cardiovascular disease death. Other outcomes focused on included death from any cause, a decrease in kidney function or development of kidney failure, dementia, decline in cognitive function and evidence of stroke-like disease.

The study was stopped earlier than planned (at around 3 ½ years after launch) as results so strongly favored the lower systolic blood pressure. At one year, the achieved average systolic blood pressure was 121.4 mmHg in the intensive-treatment group and 136.2 mmHg in the standard-treatment group. Death from any cause was significantly lower in the intensive-treatment group, and there was a 25 percent lower relative risk of the primary tracked disease outcomes mentioned above. The intensive-treatment group had lower rates of several other important outcomes, including heart failure, death from cardiovascular causes and death from any cause.

But there was a cost to intensive blood pressure control. Fainting was more common among the intensive-treatment group than among those in the standard-treatment group. There was no difference between the two groups in falls resulting in injury. However, there was a higher rate of kidney injury and kidney failure in the intensive-treatment group. These treatment side effects need to be considered when you discuss treatment with your doctor, as well as your personal benefits versus risks. People with diabetes were excluded from SPRINT, which is being debated among experts, as previous studies focused exclusively on persons with diabetes suggested a different blood pressure target, and whether having diabetes suggests a different blood pressure target than not having diabetes.

Take-home message:

To recap, lower blood pressure is better, but can come with significant side effects. And if you have diabetes, the jury is still out.

Dr. Dace Trence, FACE, is Director of the Diabetes Care Center and Professor of Medicine at the University of Washington Medical Center in Seattle. She is also the University of Washington Endocrine Fellowship Program Director and Director of Endocrine Days, a medical education program for endocrinologists practicing in the Pacific Northwest. She is on the American College of Endocrinology Board of Trustees and chairs the CME Committee and is also chair of the AACE Publications Committee.