Java lovers appear to enjoy a variety of health benefits, including a reduced risk of developing Alzheimer’s or Parkinson’s disease. Now a team of Canadian researchers reports that they have figured out what it is about coffee that is helpful (Frontiers in Neuroscience, Oct. 12, 2018). Hint: it’s not the caffeine.

The Coffee Study:

The scientists tested three instant coffee extracts: light and dark roast with caffeine and dark roast without caffeine. (They used Starbucks Via Instant.) They also tested six different components of the brew. The tests were conducted on purified beta-amyloid and tau, complex brain proteins that lead to neurological problems when they aggregate to form plaques and tangles.

What these laboratory tests revealed is that dark roast coffee, both regular and decaf, slows the agglomeration of both amyloid and tau more than light roast does. In the testing of the separate coffee constituents, caffeine had no effect. However, a compound called phenylindane strongly inhibited the aggregation of both tau and amyloid. Roasting the beans longer for a dark color and more intense flavor creates more phenylindane.

These are laboratory findings, and we don’t yet know how much neurological protection people might from drinking dark roast coffee on a regular basis. But it does seem that you shouldn’t fear that your morning cup of joe will harm your brain, regardless of whether you prefer decaf or high-test. Presumably, though, it makes sense to choose dark roast rather than light.

Caffeine Is Okay for People with Heart Failure:

Sometimes people are told that they must give up on coffee because of their medical condition. This may be prudent advice in some cases; for example, certain people develop heartburn when they drink coffee. For years, cardiologists have warned their heart failure patients to avoid coffee. That’s because they worried that caffeine would trigger irregular heart rhythms.

High-Dose Caffeine Vs. No Caffeine:

A randomized placebo-controlled study found that this is unlikely (JAMA Internal Medicine, Dec. 2016). The researchers included 51 patients with chronic heart failure and gave them five doses of caffeine or placebo over the course of five hours. Each dose was accompanied by a small cup of decaf coffee. This resulted in a total dose of 500 mg caffeine or 0 mg caffeine for those who got the placebo. (For comparison, 20 ounces of coffee from Starbucks has between 340 and 475 mg, depending on the blend.)

After a week of wash-out, the exercise was repeated; patients who had gotten placebo were given caffeine and vice versa. During both sessions, patients had continuous electrocardiographic monitoring.

The Results:

There were no significant differences between the groups with respect to any type of arrhythmia. The exercise stress tests also revealed no differences. The volunteers in this study did experience some rhythm disturbances, but these were equally common whether they were taking caffeine or placebo.

Based on these results, the investigators conclude,

“To date, there is no solid evidence to support the common recommendation to limit moderate caffeine consumption in patients at risk for arrhythmias.”

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