Coffee and Your Health

[David Baxter PhD]

Drink Coffee for a Longer Life?
Berkeley Wellness
October 5, 2017

Coffee drinkers have modestly lower mortality rates than people who don’t drink coffee, two recent studies in the Annals of Internal Medicine have found.

One study followed more than 450,000 adults from 10 European countries for an average of 16 years and found that coffee was associated with a 12 percent reduction in all-cause mortality rates in men and a 7 percent reduction in women, with higher intakes linked to greater benefits.

The second study followed 185,000 U.S. adults, also for 16 years, and linked one daily cup of coffee to a 12 percent reduction in mortality rates—and two or more cups to an 18 percent reduction—across multiple ethnic groups (except native Hawaiians, possibly because of their small number).

Both studies found similar trends for regular and decaf coffee.

Previous research has linked coffee consumption to a reduced risk of many disorders, from diabetes and colon cancer to cardiovascular, liver, and Parkinson’s disease.

Although the two new studies controlled for smoking and many other factors, such observational research can only establish associations, not causation. Thus, the accompanying editorial concluded that “Recommending coffee intake to reduce mortality or prevent chronic disease would be premature. However, it is increasingly evident that moderate coffee intake up to 3 to 5 cups per day or caffeine intake up to 400 milligrams a day is not associated with adverse health effects in adults and can be incorporated into a healthy diet.”

For more about the potential health benefits of coffee, see Coffee and Your Health.

 

[David Baxter PhD]

Coffee & Your Health: What the Research Says
Berkeley Wellness
August 06, 2013

Not too long ago, coffee drinking was considered a bad habit and many people avoided it for health reasons. But now, as with chocolate and wine, the pendulum has swung so far in the other direction that we have to remind readers that moderation is still a good idea.

Coffee, the world?s most popular beverage after water and tea, used to be blamed for everything from high blood pressure and high cholesterol (and thus heart disease) to pancreatic cancer, fibrocystic breasts and bone loss. But early research linking coffee or caffeine to health problems has almost always been refuted by better studies. In recent years, most research has suggested that coffee actually has health benefits.

How can coffee be healthful?
Like all plant foods, coffee beans contain many naturally occurring chemicals?more than 1,000 have been identified so far, many formed during the roasting process. Some are potentially harmful for coffee drinkers, while others are potentially healthful, according to lab studies. Many of the beneficial substances are polyphenols that are antioxidants; these contribute to the bitter and acidic taste of the beverage. In fact, coffee is the No.1 source of antioxidants in the U.S. and many other countries, largely because we drink so much of it.

For most people, coffee means caffeine, which is one of the most studied substances in food. Caffeine is a natural pesticide that helps protect coffee plants from predators. Brewed coffee typically contains anywhere from 60 to 120 milligrams of caffeine in six ounces. Caffeine is a mild psychoactive substance that stimulates the central nervous system. Thus, it improves reaction time, mental acuity, alertness and mood; wards off drowsiness; and helps people wake up and feel better in the morning. So it?s no surprise that a recent Australian study of long-distance truck drivers, published in BMJ, found that caffeine greatly reduced the risk of crashes.

What?s more, caffeine is classified as an ?ergogenic aid? because it can improve some aspects of athletic performance. It also enhances the analgesic effect of pain relievers, which is why it?s in some over-the-counter formulations.

Coffee's potential health benefits
Every month or two another study on coffee comes out. Most research has focused on regular coffee, but some has included decaf. Here?s a sampling of recent findings:

Diabetes. Research, including two large studies in the American Journal of Clinical Nutrition in 2012 and 2013, has fairly consistently linked long-term coffee consumption (regular or decaf) to a reduced risk of type 2 diabetes. Some of coffee?s polyphenols may enhance insulin sensitivity and slow the release of glucose into the bloodstream. Most studies on people who already have diabetes have not found a benefit from coffee, however.

Heart disease. Compounds in coffee have positive and negative effects on coronary risk. Overall, coffee does not affect the risk of heart attacks (or strokes), according to a large German study last year as well as previous research. One way coffee may be good for the heart is by reducing the risk of diabetes. One way it can be bad is if it is unfiltered and raises blood cholesterol.

Blood pressure and stroke. There has long been a concern about caffeine?s effect on blood pressure. However, a 2011 review of studies concluded that it?s okay for people with controlled hypertension to drink caffeinated coffee. The studies on the acute effects found that in people with hypertension who had abstained from caffeine for 9 to 48 hours, two cups of coffee raised blood pressure (7 points, on average) for up to three hours. But in studies lasting two weeks, daily coffee intake did not increase blood pressure, probably because tolerance to caffeine develops in about a week. And longer observational studies in the review found no link between habitual coffee consumption and the risk of cardiovascular disease.

Even better news, a Swedish analysis published in the American Journal of Epidemiology in 2011 found that moderate coffee consumption was associated with a modest reduction in stroke risk. Other studies have also shown this.

Colon cancer. An analysis from the large NIH-AARP Diet and Health Study last year found that people who drank at least four cups of coffee (regular or decaf) a day were 15 percent less likely to develop colon cancer than nondrinkers. Previous studies have been inconsistent; different coffee types and methods of preparation may have different effects on cancer risk.

Prostate cancer. A British study published in the Nutrition Journallast year found a reduced risk of aggressive prostate cancer in coffee drinkers, though the overall risk for prostate cancer was not affected. That confirms the conclusions of a large 2011 study in the Journal of the National Cancer Institute, which found that men who regularly consumed the most coffee (including decaf) had a 60 percent lower risk of advanced or lethal prostate cancer than nondrinkers. Even drinking one to three cups per day was linked to a 30 percent lower risk. This potential benefit is ?biologically plausible,? according to the Harvard researchers, since coffee improves blood sugar control, has antiinflammatory and antioxidant effects and affects sex hormone levels, all of which play a role in prostate cancer progression.

Endometrial cancer. In 2011 two large studies of women linked coffee to a decreased risk of endometrial cancer. This was especially true of obese women, who are at increased risk for the disease.

Parkinson?s disease. Many observational studies have suggested that coffee helps protect against Parkinson?s, according to a review paper in Experimental Neurobiology last year. It noted that caffeine appears to have neuroprotective effects, though this may depend on a genetic variable involved in caffeine metabolism.

Depression. Women who drank two to three cups of regular coffee a day over a 10-year period were 15 percent less likely to develop depression than those who drank little or no coffee, according to a 2011 analysis from the Nurses? Health Study. The authors theorized that coffee can positively affect serotonin and other brain chemicals.

Cognitive decline. In a study in the Journal of Alzheimer?s Disease in 2011, older women (but not men) who drank coffee had a reduced rate of cognitive decline over an eight-year period. Another paper in the same journal last year linked higher levels of caffeine in the blood to reduced progression from mild cognitive impairment to dementia in people over 65.

Liver disease. Several recent studies suggest that regular coffee may protect against the development or progression of non-alcoholic fatty liver disease.

Life expectancy. People who drank at least two cups of coffee (regular or decaf) a day were 10 to 15 percent less likely to die over a 14-year period than nondrinkers, according to a large study in the New England Journal of Medicine in 2012. Smoking and other factors that influence health and longevity were taken into account. Reductions were seen in deaths from diabetes, heart and respiratory disease, strokes, infections and accidents.

Bottom line: There?s no health reason to deprive yourself of coffee if you like the lift it gives and the sociability it affords, unless it affects you adversely. On the other hand, we can?t recommend that anyone start drinking coffee for its potential benefits, since most are still too uncertain. Notably, all the long-term studies have been observational, so they do not prove cause and effect. Keep in mind that tea also contains an array of potentially beneficial compounds and has been linked to many health benefits.

 

[David Baxter PhD]

Nervous About Coffee's Effects?
Berkley Wellness
August 06, 2013

It's easy to see why some people would worry about coffee. First of all, because caffeine is a stimulant, it can cause jitters and insomnia. It can boost heart rate temporarily, which is why people with certain heart problems are sometimes advised to avoid it. Coffee, regular or decaf, can also cause stomach upset and heartburn.

Moreover, the effects of coffee and caffeine can vary from person to person, depending on genetic and other factors. For instance, caffeine's transient effect on blood pressure and heart rate depends largely on whether you are used to caffeine or not. For most people, any such boost isn't a danger. However, in people with multiple cardiac risk factors who rarely consume it, caffeine may increase the risk of a heart attack during the hour or two after drinking coffee.

The stimulant effects vary as well. In fact, a 2010 British study suggested that caffeine isn't stimulating for people who drink coffee regularly. For them, caffeinated beverages merely counter the effects of caffeine withdrawal (such as headaches and a decreased ability to pay attention) and only help restore or maintain a normal state of alertness. In contrast, infrequent coffee drinkers get more of a stimulant effect from the caffeine. The more caffeine you consume regularly, the more you build up a tolerance for it.

Coffee's effects also depend on the amount of caffeine and other compounds in it. This, in turn, depends on the type of bean, how the beans were processed, and how the beverage is prepared. For instance, it has long been known that large quantities of unfiltered coffee?notably espresso or that made in a French press, regular or decaf?can boost blood cholesterol. The likely culprits are cafestol and kahweol, which are diterpenes in the coffee's oil that are trapped in paper filters. (Interestingly, though, these compounds have anti-cancer properties.) If you have undesirable cholesterol levels and regularly drink large quantities of unfiltered coffee, try cutting down or switching to filtered coffee. Single-serving coffee pods, by the way, contain a filter.

Note for pregnant women: Some research suggests that high doses of caffeine raise the risk of miscarriage and birth defects. While the evidence for this is not consistent, to be safe, pregnant women should drink no more than one or two cups a day.

 

[David Baxter PhD]

Types of Coffee
Berkley Wellness
February 29, 2016

There are two principal botanical varieties of coffee grown: Coffea arabica and Coffea robusta. Robusta is a hardier, more economically attractive plant that can be grown at lower altitudes. It also produces a lower quality bean. All top-quality coffees come from arabica plants, while robusta beans are used in so-called ?commercial? coffees, which are sold as instant or pre-ground in cans. Cans of coffee may also be more likely to be cut with fillers such as ground leaves, grains, or parchment.

The coffee bean
Arabica, or ?specialty,? coffee beans are labeled according to one or more of several criteria. First, some beans are known only by the country of origin, but most are further pinpointed by a regional name. For example, Ethiopian Harrar is grown near the city of Harrar in Ethiopia. Sometimes the origin name will be the port through which the beans are exported, such as Mocha, which is exported through the Yemenese port of Mocha.

Other coffees are known not by regional names, but only by their countries and grades. Unfortunately, grading systems are complicated, not at all standardized, and usually designed to confuse. As a basic guideline, grade names that imply high altitude, hardness or density of beans, and ?washing? are all desirable.

Another clue to getting around in a coffee store is knowing the difference between ?straight? coffees and ?blends.? A straight Mexican Altura Coatepec, for example, should be nothing but beans of that grade (altura) from that region (Coatepec) in that country (Mexico). Blended coffees, on the other hand, can be a number of different bean types mixed together and are usually labeled as ?blends? or ?styles.? Often a blend will be the proprietary blend of the specialty store or the roaster. Beans are usually blended to create a better, more balanced, coffee (like the classic blend of Mocha-Java, for instance). Sometimes, unfortunately, the coffees are blended to save the merchant money: Thus, a Hawaiian Kona Blend coffee may have a very small percentage of Kona beans and a high percentage of another, cheaper bean.

The coffee roast
An important factor to consider in buying coffee is its roast. The coffee bean has no coffee taste at all until it has been roasted. The roasting process brings out the coffee essence, more or less, depending on the length of roasting time. Most straight coffees sold in this country are roasted to a medium-brown roast. Darker roasts?like French and Espresso?are also available, but the coffee beans thus roasted are almost always blends, since most coffee dealers believe that the dark roast obscures the individual flavor characteristics of straight coffees and feel that a blend is just as good.

• Full city roasted coffee: This is not a roast name that you will see in stores, but it is a term that roasters use and it is the roast most common in urban America. The bean is medium-dark brown with a dry surface.
• Viennese roasted coffee: This roast is somewhere between full city and French. It is often a blend of two roasts, usually dark and medium in a ratio of 1 to 2.
• French roasted coffee: The bean is the color of semisweet chocolate with an oily surface. French roast coffee with chicory added becomes New Orleans-style coffee.
• Italian or Espresso roasted coffee: The bean is almost black and is very oily. This is the heaviest, most bittersweet of all roasts.