National Institutes Of Health Discovers Protective Effects Of CoffeeSeptember 2012
By Kirk Stokel
An exciting new study published in the New England Journal of Medicine suggests that coffee drinking may add years to your life span.1
Evidence is rapidly accumulating about the ability of coffee to reduce vascular disease, slash cancer risk, preserve cognition, and mitigate diabetes/obesity.2
Rich in polyphenols, coffee contains over 1,000 different natural compounds3 that favorably interact within cells.4 Coffee has the proven ability to turn on genes that promote youthful cellular functions.4,5
One coffee compound in particular, chlorogenic acid provides a multitude of these benefits, including impeding after-meal glucose surges that can contribute to obesity and diabetes.6-11
Researchers have found a way to naturally "super charge" coffee and dramatically increase its healthy polyphenol content.12 This means people can obtain more of coffee's unique beneficial compounds while drinking less coffee. For those who can't drink coffee, standardized chlorogenic acid capsules are becoming enormously popular.
Before describing the longevity finding published in the New England Journal of Medicine, we first want to conjecture why coffee drinking still has negative health connotations.
One factor may be early memories of people drinking coffee who simultaneously smoked cigarettes. Smokers are often ravenous coffee drinkers.
Other unhealthy images are those suffering hangovers who use coffee to restore functionality, those suffering sleep deprivation who drink coffee to stay awake, and the hefty "cream and sugar" so many people add to their coffee. These images are hard to delete from our memory banks.
A more current negative health picture is the high-calorie coffee "milkshakes" that contribute to today's obesity epidemic. Certain religions admonish against tobacco, alcohol, and coffee, which implies that coffee drinkers are in the same poor-health category as nicotine addicts and alcoholics. Those who are able to abstain from alcohol addiction often switch to coffee. Finally, some people are sensitive to caffeine and are unable to drink coffee, or suffer heartburn in response to coffee consumption.
If one can dispel these negative images, then coffee drinking may rise to the conscious level of a healthy choice, analogous to green tea drinking.
Coffee Consumption Associated with Lower Risk of Death
Researchers at the National Institutes of Health, in collaboration with AARP (American Association of Retired People), explored coffee drinking habits and their impact on mortality.1 They enrolled 229,119 men and 173,141 women, beginning in 1995 and 1996, when the subjects were 50-71 years old. The subjects completed a thorough questionnaire probing their diet and lifestyle. Anyone with cancer, heart disease, or stroke at the time of enrollment was excluded, leaving basically healthy adults in late middle age.1
The researchers noted each participant's coffee consumption at the beginning of the study. Then they followed them for a total of 13 years, gathering data on a total of 5,148,760 person-years.1 This comprehensive study had massive statistical power.
During the study period, 33,731 men, and 18,784 women died of various causes.1 According to the raw data, the risk of death seemed elevated among coffee drinkers. But coffee drinkers were more likely to smoke cigarettes, markedly affecting the data.
After the researchers adjusted for smoking and other factors, they found a remarkably strong association between coffee drinking and survival.1 In other words, the more coffee the subjects drank; the less likely they were to die. You can see just how powerful this association was by looking at table 1.
That risk reduction applied to what epidemiologists call "all-cause mortality," that is, coffee drinking was associated with a markedly lower risk of dying for any reason at all. A closer look at the data revealed another fascinating fact, one that previous studies had already hinted at.13-15 The survival association with coffee drinking and death applied to the risk of dying from specific diseases, including heart and lung disease, stroke, diabetes, and infections. It even applied to the risk of dying from injuries and accidents.1
The protective effect of coffee drinking was evident whether subjects drank caffeinated or decaffeinated coffee.14
Caffeine, then, was not the protective component of coffee. Let's look at what else coffee contains that might explain its life-saving effects.
Coffee Polyphenols Have Multi-targeted Impact
In addition to caffeine, natural coffee beans contain more than 1,000 different compounds that could affect health and the risk of dying.3 Of those, the polyphenols are the best candidates, for several reasons.
Polyphenols are powerful antioxidants, with all the health benefits that implies. But polyphenols have other, more complex actions, including the surprising ability to modulate gene expression, regulating how much and how often a particular gene is "switched on."16-18 That means that polyphenols regulate many of a cell's most fundamental processes, including signaling that tells cells when to die, when to replicate, when to release or respond to other chemical signals, and so on.17,19
The net effects of this impact on cellular signaling include improvements in tissue repair, immunity, and the body's ability to maintain itself in a steady state, called homeostasis.17,19 Impaired cellular signaling has been implicated in causing cancer, type 2 diabetes, and the risks for heart disease and stroke.20
One polyphenol in particular, chlorogenic acid, is especially abundant in coffee, and is credited with providing many of its beneficial effects. Green coffee beans may possess up to 10% of dry weight chlorogenic acids making coffee the major source of chlorogenic acid in the diet.21 Along with other polyphenols, chlorogenic acid helps drive down the chronic inflammation that's associated with common diseases of aging, such as diabetes and atherosclerosis.6 Chlorogenic acid derivatives in roasted coffee protect cells with high fat content, like brain cells, helping to explain observations that coffee sustains cognition.7
Studies show that other coffee polyphenols beneficially influence the function of liver and fat cells, helping to reduce the impact of obesity and diabetes.8 A reduction in damage to DNA is the likely mechanism by which coffee consumption may lower your risk for cancer.9-11Coffee is the single largest source of those beneficial polyphenols and other antioxidants in our diets.21 On average, Americans who drink coffee consume 3.1 cups of coffee per day.22
But studies of benefits from coffee drinking consistently show that larger amounts, ranging from 4 to as many as 12 cups a day, provide the most protective benefits, reducing the risk of cardiovascular disease, cancer, diabetes, liver disease, and Alzheimer's disease.2,23-35
It's obviously hard to drink that much coffee, and many people develop unpleasant, though not dangerous, side effects, such as heart palpitations and upset stomachs, if they try to consume that much. You will read about a new technique for retaining polyphenol content in both decaffeinated and regular coffee.
Let's now look at the many ways in which high coffee consumption is being linked to reduced risk of specific diseases.
Coffee Benefits Your Brain
"Coffee consumption has been associated with benefits involving cognitive function in aging. For example, in one study of 676 individuals with an average age of about 75 years, coffee consumption was associated with significantly less cognitive decline over a 10-year time period. Furthermore, the least cognitive decline was observed with 3 cups of coffee per day, which was associated with a remarkable 4.3-times smaller level of decline in cognitive function compared with non-consumers of coffee (P<0.001)."36 (See figure 1)
Enriching coffee with polyphenols, especially chlorogenic acid, produces still greater benefits. Such innovative coffees are more neuroprotective even than green coffee, according to laboratory studies. One study showed green coffee increased brain cell survival by an impressive 78% in the face of severe oxidant stress, but a roasted coffee rich in chlorogenic acid derivatives produced a 203% increase in survival.7
A chlorogenic acid-enriched decaffeinated coffee improved mood and attention in a pilot study of 39 healthy older people, compared with standard decaf coffee. A non-decaffeinated roast of similar formulation showed even more powerful effects.37
These benefits are likely to be of special importance in the face of the growing epidemic of Alzheimer's disease and other neurodegenerative conditions. More than 40% of people over 84 will be stricken by Alzheimer's disease, according to recent estimates.38 Moderate levels of daily coffee consumption, 3-5 cups per day, are tied to reduced rates of Alzheimer's disease and other forms of dementia in older adults.35, 39, 40
Of special interest, animal studies now provide evidence that caffeinated coffee consumption (greater than about 5 cups per day in a human), not only protect against brain damage in Alzheimer's disease, but can even reverse some of that damage—in as little as 5 weeks.34
Some insight into how coffee attains its protection against Alzheimer's comes from studies of the "Alzheimer's protein" called Abeta. Caffeine, at levels comparable to 5 cups of coffee daily, reduces levels of the proteins that go into manufacture of Abeta, and lowers levels of Abeta itself in blood and brain tissue.34,41
There is a well-established relationship between high coffee intake and protection from Parkinson's disease as well. People who drink one to four cups of coffee daily experience 47% lower risk of the disease than those who drink none, and those who drink five or more cups have a 60% risk reduction.42