By Dr. Mercola
Coffee was long regarded by many as a guilty pleasure, a beverage the majority of US adults consumed despite its effect on their health – not because of it. But it turns out coffee, a natural drink that's been widely enjoyed since ancient times, may be quite good for you.
Some of the latest research – a large-scale study published in the journal Circulation – even suggests drinking coffee may enhance your longevity.1 It's sure to be welcome news for the 61 percent of Americans who drink coffee daily,2 but there are some considerations you should know.
Coffee Drinkers Have a 15 Percent Lower Risk of Dying Early
In a study that followed more than 200,000 people for up to 30 years, researchers collected data on participants' diet and behavior, including coffee drinking.
Among non-smokers, those who drank one cup of coffee a day had a six percent reduced risk of death compared to those who drank no coffee. Drinking one to three cups a day lowered death risk by eight percent while three to five cups daily resulted in a 15 percent lower risk.
Further, drinking coffee was associated with a lower risk of death from a number of causes, including heart disease, stroke, diabetes, neurological diseases (such as Parkinson's), and suicide. According to the researchers:3
"Higher consumption of total coffee, caffeinated coffee, and decaffeinated coffee was associated with lower risk of total mortality."
While the study doesn't prove coffee is the reason for the health benefits seen in the study, the association is strong. There are more than 1,000 different chemicals in coffee, and researchers are only beginning to tease out how the synergy between them might benefit your health.
In this study, the researchers suggested beneficial compounds in coffee such as chlorogenic acid, lignans, quinides, trigonelline, and magnesium may have anti-inflammatory effects and reduce insulin resistance, both of which could be responsible for the lowered premature death risk seen among coffee drinkers.
Past research published in the New England Journal of Medicine also found that coffee consumption is inversely associated with premature death.
The more coffee participants drank, the lower their risk of death became, including deaths from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections.4
How Much Coffee Is Beneficial? How Much Is Too Much?
There does appear to be a "Goldilock's zone" when it comes to coffee. In the featured study, benefits increased up to five cups a day, but then seemed to taper off.
Among those who drank more than five cups a day, a 12 percent lower death risk was still seen, but this was lower than the 15 percent lower risk seen with three to five daily cups.
In its recommendations for the 2015 edition of Dietary Guidelines for Americans, a government advisory committee, for the first time, said Americans could safely consume up to five cups of coffee a day, or approximately 400 milligrams (mg) of caffeine, with no detrimental effects.5
How big is a "cup?" When referring to a "cup" of coffee most research considers it to be five to eight ounces with about 100 mg of caffeine. In contrast, a small cup at many coffee houses starts at 12 ounces while a large cup may hold 20 to 24 ounces.
Accumulating Evidence Shows Coffee May Lower Your Risk of Chronic Disease
If you enjoy a good cup of Joe, there's likely good reason to keep up your habit, assuming you don't overdo it, of course. From your heart to your brain and even your risk of cancer, moderate coffee consumption appears to be highly protective.
- Heart Health: Moderate coffee consumption (three to five cups a day) was associated with less calcium buildup in the arteries.6
- Type 2 Diabetes: Drinking six cups of coffee daily may lower your risk of type 2 diabetes by 33 percent, according to a systematic review and meta-analysis by the American Diabetes Association.7
- Melanoma and Non-Melanoma Skin Cancer: Drinking four cups of caffeinated coffee daily might reduce your risk of melanoma, the most dangerous form of skin cancer.8 According to researchers:
"[C]offee constituents suppress UVB-induced skin carcinogenesis, induce cell apoptosis, protect against oxidative stress and DNA damage, reduce inflammation in epidermal cells, and inhibit changes in DNA methylation."9
In separate research, women who consumed more than three cups of coffee a day had a significantly lower risk of basal cell carcinoma (non-melanoma skin cancer) than those who consumed less than one cup per month.10
- Multiple Sclerosis and Parkinson's: Drinking four to six cups of coffee a day is associated with a lower risk of multiple sclerosis, as is drinking a high amount of coffee over five to 10 years.
According to researchers, "Caffeine has neuroprotective properties and seems to suppress the production of proinflammatory cytokines."11 Higher coffee and caffeine intake are also associated with a lower risk of Parkinson's disease.12
- Dementia: Caffeine promotes production of the neurotransmitters serotonin, dopamine, and noradrenaline, and triggers the release of brain-derived neurotrophic factor (BDNF), which activates brain stem cells to convert into new neurons, thereby improving your brain health.
Among people with mild cognitive impairment (MCI), those with higher blood levels of caffeine (due to coffee consumption) were less likely to progress to full-blown dementia.13
"Caffeine/coffee intake is associated with a reduced risk of dementia or delayed onset, particularly for those who already have MCI," the researchers said.
Does the Type of Coffee Matter?
Yes! Coffee beans are one of the most heavily pesticide-sprayed crops. So, you should select only coffee beans that are certified organic.
Whenever possible, purchase sustainable "shade-grown" coffee as well to help prevent the continued destruction of our tropical rain forests and the birds and other species that inhabit them.
There are many who say shade-grown coffee tastes better as well. In addition, you'll want to purchase whole-bean coffee that smells and tastes fresh, not stale; if your coffee does not have a pleasant aroma, it is likely rancid.
Grind it yourself to prevent rancidity, as pre-ground coffee may be rancid by the time you get it home.
If you use a "drip" coffee maker, be sure to use non-bleached filters. The bright white ones are chlorine-bleached, and some of this chlorine will leach from the filter during the brewing process. Bleached filters are also notoriously full of dangerous disinfection byproducts, such as dioxin.
If you are dousing your cup of Joe in creamer, non-dairy creamer, sugar, and other sweeteners and flavorings, you are missing out on the therapeutic benefits and potentially harming your health. The natural blend of polyphenol antioxidants are part of what makes coffee so healthy.
However, some research suggests that adding dairy to your coffee may interfere with your body's absorption of beneficial chlorogenic acids.14 Meanwhile, if you add sugar to your coffee you'll spike your insulin levels, which contributes to insulin resistance.
If you're interested in the health benefits, drink your coffee black, without sugar, non-dairy creamer or cream, or flavorings. If you really can't stand your coffee black, you could try adding non-dairy alternatives like coconut milk or a natural sweetener like stevia.
Light Roast or Dark Roast, Which Is Healthier?
You probably choose your roast based on flavor, but there might be compelling health differences too. Darker roasts typically contain less caffeine than lighter roasts due to the prolonged heat breaking down more of the caffeine molecules. (Bean species also differ widely in their naturally occurring concentrations of caffeine.)
Dark roast coffee, such as French or Italian Roast, or roasts used to make espresso or Turkish coffee, are typically higher in neuroprotective agents than green (unroasted) coffees. One study in Molecular Nutrition & Food Research found that dark roast coffee restored blood levels of the antioxidants vitamin E and glutathione more effectively than light roast coffee.15
The dark roast also led to a significant body weight reduction in pre-obese volunteers, whereas the lighter roast did not. Other studies have shown that dark roast coffee produces more of a chemical called N-methylpyridinium, which helps prevent your stomach from producing excess acid, so darker roast coffee may be easier on your stomach than lighter roast coffee.16
That said, the process of roasting will also produce acrylamide — a toxic byproduct created when you expose a food to high heat. Acrylamide has been associated with an increased cancer risk. From the perspective of limiting your exposure to this toxin, a light roast would seem to be preferable, but at least one study suggested the content of acrylamide in coffee reaches a peak early in the roasting process and "levels of acrylamide in the fully roasted product are a small fraction of the peak reached earlier."17
Lighter roasts may therefore have higher levels of acrylamide than darker roasts. Coffee made with higher levels of Robusta beans (compared to Arabica beans, which naturally have about half the caffeine content of Robusta beans) also appear to have higher acrylamide levels.18 Former National Coffee Association president Robert Nelson said in Roast magazine:19
"For coffee, the issue of acrylamide arises in the roasting process. As coffee beans are roasted, natural sugars and moisture enable the desirable browning process, which chemically creates some acrylamide. The exact mechanisms of acrylamide's formation in coffee may involve asparagine and other possible pathways. However, the highest level of the compound occurs at a roasting level too light for consumer preferences, after which it begins to degrade significantly during further roasting.
Completed roasting leaves only a fraction of the original acrylamide levels in the bean. Moreover, there's very little acrylamide left in brewed coffee as it is consumed."
I don't claim to have the definitive answer here, but the evidence supporting dark roast for higher antioxidant content is quite compelling... and it seems light roasts may have higher levels of acrylamide than dark roasts. The level of acrylamide in brewed coffee will be significantly less than what is found in the bean, however – and instant coffee appears to have more acrylamide than non-instant. HealWithFood.org compiled the following chart that shows acrylamide levels in various coffee brands:20
Average acrylamide levels in selected coffees (in parts per billion, or ppb)
Brand Not instant Instant Dark Roast Regular Roast Brewed Folgers 314 458 237 346 10 Maxwell House 215 218 201 223 6 Chock full o'Nuts 201 NA 191 212 NA Starbucks 149 NA 132 158 9 Hills Bros. 135 NA NA 135 NA Yuban 51 NA NA 51 NA Café Bustelo 142 NA 138 NA 6 Medaglia d'Oro 168 NA 164 NA 6 Taster's Choice 272 353 NA NA 7 Nescafé NA 471 NA NA 6 7-Eleven NA NA NA NA 6
The average amounts of acrylamide in the chart above have been calculated by HealWithFood.org based on data released by the FDA. The FDA has cautioned that the acrylamide values it has reported for various foods and drinks are exploratory and only cover a limited number of food categories, products, and brands. In addition, they do not generally address unit-to-unit variation or lot-to-lot variation.
Who Shouldn't Drink Coffee?
Many people may benefit from a few cups of black, organic coffee daily, but there are always exceptions to the "rule." For instance, I strongly recommend pregnant women avoid ALL forms of caffeine. Research has shown that ingesting caffeine during pregnancy can result in a wide range of problems for your baby, including:
- Increased risk of miscarriage
- Low birth weight
- Birth defects such as cleft palate
- Increased risk of Sudden Infant Death Syndrome (SIDS)
- Decreased cardiac function and heart damage
Others who might want to avoid coffee, at least the caffeinated varieties, are those who are especially sensitive to the effects of caffeine. If you're one of those people who can't sleep if you drink even a sip of coffee in the afternoon, you're probably one of them. As explained by Newsweek:21
"… [C]affeine's effects on the body are not the same for everyone. Caffeine is metabolized by the enzyme CYP1A2, and the body's ability to produce this enzyme is controlled by the CYP1A2 gene. Some people are genetically predisposed to producing less of this enzyme, while others produce more than average.
Those who produce more of it are rapid caffeine metabolizers, which means they're not very sensitive to caffeine. That's your friend who guzzles a double latte at 11 p.m. and then an hour later says she's ready for bed — while you'd like nothing better than to talk all night."
Finally, if you're like me and don't enjoy the taste of coffee, there's no need to start drinking it just for the potential health benefits. You can find plenty of beneficial plant compounds in other foods and beverages, including tea and vegetables, so there's no need to feel that you're missing out.