Coffee kills and maims viruses in cells.
Utsunomiya, H, M Ichinose, M Uozaki, K Tsujimoto, H Yamasaki and AH Koyama. 2008. Antiviral activities of coffee extracts in vitro. Food and Chemical Toxicology 46:1919–1924.
Drinking coffee may benefit health by targeting and killing viruses such as herpes and poliovirus. Since coffee is one of the most popular beverages globally, its role in the dietary prevention of disease is of widespread interest. Scientists in Japan tested eight regular and seven instant coffee products by adding weak solutions to cells infected with a herpes virus. The coffee both reduced the virus's ability to spread to other cells and halted their reproduction. With polio, a different type of virus, the extracts stopped viral multiplication. The remarkable antiviral activity of coffee extracts was not solely related to caffeine, and was not dependent on the place where the coffee beans were grown or to the coffee suppliers.
Coffee beans grow on bushes that thrive in the equatorial areas of the world. It is grown in 80 countries and exported by 50 countries. Brazil, Asia, Africa, Mexico and other Central and South America countries produce the majority of the world's raw beans. Hawaii is the only state in the U.S. that produces coffee beans.
The beans' active ingredients, and ultimate flavor, vary from region to region due to weather, soil and other growing conditions. After harvesting, the beans are roasted into specialized varieties that differ in strength and taste. The roasted beans are ground and brewed into the liquid coffee that one-third of the world’s population enjoys every day.
Brewed coffee contains more than 1,000 different chemicals, some known and unknown, including the stimulant caffeine (George et al. 2008). Coffee drinkers would collectively agree that the increased alertness and mood altering powers that caffeine bestows are clearly beneficial.
A recent scientific review by George and colleagues revealed numerous other benefits of drinking coffee including protection against some types of cancer, liver disease and radiation-induced tissue damage (George et al. 2008). The reported benefits of drinking coffee, however, may be countered by its observed links to Parkinson's disease, cardiovascular disease, hypertension and osteoporosis. (Editor's Note, 10/3/2008: The scientific evidence about the link between Parkinson's Disease and coffee is mixed. Epidemiological studies suggest it decreases the risk. (Ross et al. 2000; Sääksjärvi et al. 2008)) Additionally, women trying to conceive and pregnant and nursing women are recommended to avoid coffee.
Coffee is one of the most popular beverages in the world and the United States is the largest consumer. In the US alone, there were 167 million coffee drinkers in 2006, according to the National Coffee Association. Americans spend more than $19 billion on coffee each year.
Viruses are made up of genetic material, either DNA or RNA, which is enveloped by a protective protein coat. These sub-microscopic agents can infect any plant, animal and bacteria but cannot grow or reproduce outside of the host’s cell. Viruses are responsible for many diseases such as the common cold, the flu, chickenpox and cold sores. They are also responsible for more serious diseases, such as AIDS, the avian flu and SARS. Finding that such a common substance as coffee could offer some protection against viruses could lead to novel therapies against viral infections.
Scientists in Japan tested eight regular and seven instant coffee products for their direct antiviral effects as well as the effects on viral growth and reproduction within cell systems.
Coffee beans, coffee grinds or dried coffee products were obtained from manufacturers all over the world. Hot water extracts were made from the coffee grinds or instant coffee powder and were filtered and cooled.
The coffee extract solutions were added 1) directly to viral samples to test for direct inactivation of the viruses or 2) to cell cultures that were infected with either the herpes virus, HSV-1 (strain F), or poliovirus type 1 (Sabin vaccine strain). The highest exposure concentration was one-fifth the dose deemed suitable for drinking.
Coffee extracts killed the herpes virus upon direct contact. When extracts were added to infected cells, the herpes virus was unable to grow and reproduce within cells. The coffee also reduced the likelihood of the virus spreading to other cells.
The coffee stopped viral activity whether it was made from instant powder or was extracted from fresh ground coffee beans.
The same coffee extracts were not able to directly kill the polio virus, but they did stop the virus from reproducing inside of infected cells, which reduced the spread of the infection. Again, it did not matter if the coffee extracts were from instant or ground coffee.
The antiviral activity of coffee extracts was not solely related to caffeine. Decaffeinated instant coffee was as potent as caffeinated instant coffee against both viruses tested.
The antiviral activity of coffee was not dependent on the place where the coffee beans were grown or the suppliers of the coffee grounds. This is surprising since the amount and/or kind of active substances produced in certain plants is often related to the specific place and conditions where the plant grows.
Lattes, Café Americanos or just a plain cup of Joe - whether regular or decaf, African or South American - may do more than just keep us awake. In this study, the Japanese researchers showed that something in coffee extracts is directly and indirectly detrimental to viruses. This is an important finding for both drinkers and nondrinkers alike.
Novel therapies for viral infections could be designed from the ingredients that give coffee extracts their anti-viral properties, once those specific components are identified. This would be the next step to find new, anti-viral drugs.
So, do these findings support your coffee habit? The effect of coffee extracts on viruses is clear, but what this means for a coffee drinker is less so.
Scientists use cell culture systems to better understand how and why substances interact with, and potentially alter, biological systems. Even though the findings from laboratory experiments are not usually directly transferable to humans, they can provide a first step to understanding effects.
It is difficult to determine if drinking 1, 3, 5 or more cups of coffee would be effective against a cold sore caused by a herpes virus in a person. The reason is two-fold: 1) because the actual amount of the substance that gets to the infected cells would be much less than what is actually consumed and 2) cells in culture often do not ‘act’ the same way as cells in an animal. Additional studies using whole animals need to be done in order to gauge the benefits more conclusively.
Not all experts recommend drinking more coffee, or drinking coffee at all. Just recently, McCulloch and colleagues reported on the potential links of coffee with Parkinson’s disease (McCullah et al. 2008). They even point to a potential mechanism for coffee's effects. (Editor's Note, 10/3/2008: The scientific evidence about the link between Parkinson's Disease and coffee is mixed. See above for more.)
It seems for now, the research into health implications of coffee is balanced. For every negative report, such as the article on Parkinson’s disease, there is a positive report touting coffee's benefits to improve a disease state. Quintana and colleagues in Spain have recently shown that the risk of Alzheimer’s disease is less for coffee drinkers than non-coffee drinkers. To summarize the state of science on this topic, George and colleagues at the Central Food Technological Research Institute put forth in their research review article, “Coffee also shows protective or adverse effects on various systems…”
Given the controversy in the scientific literature and the fact that coffee is likely the most consumed beverage in the world, more research is needed to identify which substance or combination of substances, in the coffee extracts is responsible for antiviral properties. Caffeine, a likely suspect, is ruled out since decaffeinated coffee extracts showed the same response as caffeinated ones.
Determining how the extracts work against the virus could be used to develop future treatments. Although such treatments would probably be less enticing than having another cup of coffee, they could be much more targeted and effective against viruses.
For now, we cannot say that drinking those warm, refreshing, energy-enhancing beverages will protect you from viral infections, but wouldn’t it be nice?
Dorea, JG and HM daCosta. 2005. Is coffee a functional food? British Journal of Nutrition 93:773-782.
National Coffee Association 2008. National Coffee Drinking Trends Study.
Ranheim T and B Halvorsen. 2005. Coffee consumption and human health—beneficial or detrimental?—Mechanisms for effects of coffee consumption on different risk factors for cardiovascular disease and type 2 diabetes mellitus. Molecular Nutrition and Food Research 49:274-284.
Ross, GW, RD Abbott, H Petrovitch, DM Morens, A Grandinetti, K-H Tung, CM Tanner, KH Masaki, PL Blanchette, JD Curb, JS Popper and LR White. 2000. Association of coffee and caffeine intake with the risk of Parkinson Disease, Journal of the American Medical Association 283:2674-2679.
Sääksjärvi, K, P Knekt, H Rissanen, MA Laaksonen, A Reunanen and S Männistö. 2008. Prospective study of coffee consumption and risk of Parkinson's disease. European Journal of Clinical Nutrition 62(7):908-15.
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