Cancer Fighting Effects of Coffee

• Evidence of Benefit
• Nutritional Content
• Adding Coffee to Your Diet

With billions of cups consumed every day worldwide, coffee (made from Coffea arabica or Coffea robusta) is one of the most popular drinks in the world, despite its humble beginnings. According to legend, it is believed to have been discovered by an astute goat-herder in Ethiopia between 600 and 850 AD who noticed that the goats became livelier after eating the bright-red berries containing the coffee beans. He experimented by eating the berries himself and sharing them with local monks, where they all noticed increased alertness, one of the natural stimulant effects of the caffeine in coffee beans. However, coffee as the beverage we know today (made from boiling coffee beans in water) was invented by Arab traders a few hundred years later in 1000 AD, when the beans also began to be roasted before brewing. ^(i.162-164)

Modern science has studied coffee extensively, and caffeine from coffee is used in pharmaceutical drugs. Some studies have associated it with a number of health risks — many of which were later refuted or modified because they failed to account for health risk factors (e.g., smoking) that at the time were linked to coffee consumption. Today some medical experts indicate that drinking too much unfiltered coffee may mildly raise cholesterol, and more than two cups a day can increase risk of heart disease for people with the genetic predisposition to metabolize caffeine slowly. On the other hand, recent studies have also shown that moderate consumption of 2-3 cups of coffee has a number of health benefits, including decreased risks of adult-onset diabetes, Parkinson's disease, and some types of cancer. ^{(i.162, 164-167)}

It should be cautioned that some experts warn that excessive consumption of coffee may lead to increased risk of bladder cancer. Heavy consumption (in terms of bladder cancer) appears to be five or more cups of coffee a day. However, based on a review of multiple population studies, other researchers note that although some studies do suggest an increased risk of bladder cancer associated with habitually drinking lots of coffee, no study has shown a measurable dose-response relationship (which would more directly indicate that the it was the coffee that caused or helped cause cases of bladder cancer). Still, as in all things dietary, moderation seems to be a wise choice for good health. ^(i.167)

Specific Effects of Coffee on Cancer

So what's in coffee that can help prevent cancer? According to researchers from Harvard in the United States, it may be the same ingredient that keeps you alert — caffeine, a natural plant alkaloid that offers a protective effect against developing certain types of cancer. In one small clinical trial, participants who drank coffee (brewed with either paper or metallic filters) had significantly less DNA damage (a precursor to cancer development) and follow-up studies suggest that coffee stimulates production of the body's own detoxifying antioxidant enzymes. ^(i.168-170)

Brain Cancer

In an ongoing prospective investigation involving multiple European countries and thousands of men and women, a 10-year analysis of coffee consumption showed that drinking about a ½-cup of coffee or more a day correlated to lower risk of glioma brain cancer. This corroborated results of 3 prospective studies done in the United States which found a strong association of lower glioma cancer risk with coffee and tea consumption. The benefit appears to be stronger in men than in women. ^(i.171)

Research indicates that besides antioxidant protection, certain natural terpenoid compounds in coffee may also contribute to a lower risk of brain cancer. These coffee terpenoids increase DNA-repair activity in the brain by MGMT proteins, which are believed to help protect against glioma brain cancer. The inference of MGMT's protective activity is further reinforced by studies showing that genetic changes in the MGMT protein are associated with higher risk of developing glioma. In addition to MGMT support, lab studies indicate caffeine inhibits certain types of cell receptor activity associated with invasive growth of glioblastomas. ^(i.171)

Breast Cancer

According to a study comparing coffee consumption and lifestyle factors between women within same age group, drinking coffee may help reduce the risk of certain types of breast cancer. The results showed that after adjusting for other health and lifestyle factors, women who drank coffee had lower incidences of the type of breast cancer that is insensitive to estrogen and progesterone hormones (and doesn't respond to hormone therapies) compared to their non-coffee-drinking counterparts. German researchers also conducted a study that showed a similar trend, albeit with a weaker relationship. The difference may have been caused by the types of coffee used or method of preparation. ^(i.172-173)

Endometrial Cancer

A recent prospective study conducted at 40 clinical centers around the United States examined coffee intake and rates of endometrial cancer found in 45,696 postmenopausal women (who completed both the initial study and follow-up) over an average 7.5 years. Analysis of results showed that drinking at least 2 cups of coffee a day was associated with a lower risk of endometrial cancer in women suffering from obesity — the group most at risk from the disease. ^(i.174)

Drinking regular coffee did not appear to confer any benefit of reduced endometrial cancer risk for other groups of women in this study — a finding that does not match other prospective studies done in Denmark and Japan, where coffee consumption was associated with 25% and 62% overall lower risk, respectively. However, the Denmark study did find the beneficial effect of coffee was strongest in those with higher BMIs. There was a slight correlation between drinking decaffeinated coffee and lower risk of endometrial cancer, but the results were inconsistent across different weight groups. ^(i.174)

Estrogen levels, obesity, and diabetes are known risk factors of endometrial cancer, while coffee and caffeine have been shown to help regulate the hormones associated with these conditions. These effects may help explain the mechanisms behind coffee's association with lower risk of endometrial cancer. Other phytochemicals in coffee, such as chlorogenic acids, can help improve glucose metabolism. The antioxidant and anti-estrogenic properties of coffee polyphenols may also contribute to coffee's apparent cancer-preventive effect in obese postmenopausal women. ^(i.174)

Liver Cancer

Analysis of many case and prospective population studies have found that coffee may help to protect against cancer of the liver. Coffee consumption appears to significantly reduce the risk of liver cancer — with some meta-analysis suggesting as high as 43% lower risk for coffee-drinkers compared to non-drinkers. This protection was even found amongst those people who had liver disease. ^{(i.165, 167)}

Researchers suggest that the polyphenols in coffee may help regulate iron levels in the liver. The combination of protection from damage caused by excess iron in the liver and coffee's known ability to inhibit certain liver enzymes that contribute to cirrhosis (a leading risk factor for liver cancer) could explain the cancer-preventive effect of the popular beverage. ^(i.167)

Pancreatic Cancer

Although coffee consumption has been associated in the past as a possible risk factor for pancreatic cancer, subsequent studies in the past 30 years now suggest the reverse is true. Meta-analysis of many case-control and prospective population studies involving close to ¾ of a million people indicates that drinking coffee could very well decrease the risk of developing pancreatic cancer. The researchers indicate that each cup of coffee consumed, up to 6 cups a day, was linked to a 4% reduction in risk for the disease. ^(i.175)

Lab experiments indicate that caffeine may help prevent carcinogenesis. Other research (both lab and animal) suggest that polyphenols such as cafestol, kahweol, chlorogenic acid, and caffeic acid may also be good chemoprevention against pancreatic cancer by inhibiting DNA damage and mutations and reducing the toxicity of carcinogens. ^(i.175)

Prostate Cancer

Results of a 22-year prospective study of the rates of prostate cancer amongst almost 48,000 men showed a strong association between coffee consumption and decreased risk of lethal prostate cancer. Interestingly this association was found even with those who drank decaffeinated coffee. This indicates that the cancer-preventive effect of coffee for prostate cancer may not be due to the caffeine content of coffee. The study's researchers suggest that the bioactive polyphenols in coffee (such as phenolic acids) could help regulate hormones involved in prostate cancer. ^(i.176)

Skin Cancer

Results from a recent prospective population study involving over 110,000 adults indicate that drinking coffee may prevent the development of basal cell carcinoma (BCC), which is the most common type of skin cancer. According to the over-20 year study, women consuming more than three cups daily showed a 18-20% lower risk compared to those who drank the least amount of caffeinated coffee, while men who drank the same amount of coffee had their risks lowered by 9-13%. Caffeine seemed to be the main cause for the effect, since no change in rates of BCC was noted in people drinking decaffeinated coffee. ^(i.168)

Three types of skin cancer were studied in the research: melanoma, squamous cell carcinoma and basal cell carcinoma. Caffeinated coffee appeared to have a protective effect on basal cell carcinoma only, and researchers suggest that the caffeine may help get rid of precancerous skin cells before they can progress to cancerous lesions. ^(i.168)

Nutritional Content

Coffee has no cholesterol or saturated fat, and a serving of an 8-ounce cup of black, unsweetened coffee contains only two calories. It has mild anti-inflammatory properties and high antioxidant content. Coffee also contains small amounts of the following vitamins and minerals: ^{(i.54, 162, 176)}

• Calcium
• Choline
• Folate
• Magnesium
• Manganese
• Niacin
• Pantothenic acid
• Potassium
• Riboflavin
• Thiamine
• Vitamin A
• Vitamin B6
• Vitamin C
• Vitamin K

In addition to these vitamins and minerals, coffee beans also contain a number of beneficial, cancer-fighting flavonoid and non-flavonoid phytonutrients: ^{(i.99, 156, 167, 178-182)}

• Caffeic acid and ferulic acids. Hydroxycinnamic-type phenolic acids exhibit antioxidant behavior. When combined with flavonols such as hydroxycinnamic acids, they can help shield against UV-B radiation. Studies suggest caffeic acid may protect against the development of colon cancer.
• Caffeoylquinic acids. Although the green (non-roasted) C. arabica coffee bean contains the highest amounts of these chlorogenic acids, even roasted and brewed coffee is particularly rich in these potent antioxidant derivatives of caffeic acids.
• Lignans. Coffee has high levels of these compounds that convert into mildly estrogenic substances such as enterolactone and enterodiol in the intestines. Easily absorbed into the bloodstream, studies show that coffee intake is associated with higher blood levels of enterolactone. Lignans have both antioxidant and anti-estrogenic properties which studies suggest could lower the risk of diabetes, a known risk factor for cancer.
• Cafestol and kahweol. Terpenoids in coffee that stimulate enzymes in the liver which help get rid of toxic carcinogens and also induce DNA repair activity.
• Vinylguaiacol and ethylguaiacol. These volatile phenols are mostly created upon roasting the coffee bean and exhibit potent antioxidant activity similar to vitamin E.

Adding Coffee to Your Diet

Besides the obvious cup of coffee, cappuccino, or latte, you can also try adding coffee to chili and stews. It is also used as a flavoring in candy, ice cream, liqueurs, and malted beverages. ^(i.164)

The latest coffee craze is cold brew. It's less acidic-tasting than hot-brewed coffee, and can be kept in the refrigerator without becoming bitter. According to the nutritionist interviewed by the gourmet cooking site Epicurious, cold brew coffee still contains the caffeine and antioxidants found in fresh hot coffee.

How to Make Cold Brew Coffee

Cold brew coffee may sound exotic but it is easy to make. Starting with a 12-ounce (or larger) glass jar with a lid, simply stir 6 cups of cold water into 4 cups of coarsely ground coffee beans. Let the coffee steep 24 hours in the fridge and strain through a cheesecloth into another glass jar and voilà! — you've made a cold-brew coffee concentrate. Dilute some of the concentrate with an equal amount of water, milk, cream, or even almond or coconut milk and add some ice for a delicious glass of cold brew iced coffee.