By Dr. Mercola
Tea and coffee are among the most widely consumed beverages in the world. Tea is the most consumed beverage next to water, with 2 billion people drinking it every morning. Eighty-seven percent of millennials also report drinking it regularly.1
In the U.S. nearly 60 percent of adults drink coffee each morning, and 78 percent drink it at least occasionally.2 On the average, coffee drinkers consume about two cups a day.
Both coffee and tea contain caffeine (although there are also decaffeinated varieties), which has been linked to adverse health effects such as elevated blood pressure, gastric upset, and anxiety.
However, both coffee and tea contain other health-promoting ingredients that may outweigh the drawbacks of caffeine.
Among them are beneficial antioxidants and, according to researchers, coffee, because of the volume consumed, not because of its high amount, is the primary source of antioxidants in the American diet.3 The antioxidants may even help neutralize the harsher effects of the caffeine that coffee naturally contains.
Be careful, though, as most all coffee produced is heavily contaminated with pesticides. It's actually one of the most heavily sprayed crops. So, when we speak about the benefits of coffee, let it be understood that we're talking about organic (ideally fair trade), pesticide-free coffee.
Another "con" is that most coffee available today is rancid, packed from ground beans that cannot survive even a week before getting stale. This is because the rate of rancidity increases dramatically once you grind the beans. Hence, much of the bagged coffee you find in your grocery store are already degraded.
All that will give you is the caffeine. It won't provide you with healthy nutritional co-factors. So another basic principle in using coffee for its health benefits is to grind your own coffee beans.
Thirdly, you'll want to make sure it's roasted correctly. It's often the case that foods with the darkest pigments offer the most robust benefits to health, and dark roast coffee, such as French Roast, espresso or Turkish coffee, may be no exception.
One 2011 study4 found that dark roast coffee led to a significant body weight reduction in pre-obese volunteers, whereas light roast did not. Dark roast coffee also produces more of a chemical that helps prevent the production of excess stomach acid, so it may be easier on your stomach.5
Overall, the healthiest form of coffee is organic, freshly ground, and served black, meaning without milk or sugar. Adding dairy may interfere with your body's absorption of beneficial chlorogenic acids, while the added sugar will contribute to insulin resistance, which is at the heart of most chronic disease.
Lastly, 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 may also contain dangerous disinfection byproducts, such as dioxin.
Quality Is Key for Tea as Well
Tea also has its issues. Green tea plants are known to be especially effective at absorbing lead from the soil, which is then taken up into the plants' leaves.
Areas with excessive industrial pollution, such as China (where nearly 90 percent of the world's green tea is produced), may contain substantial amounts of lead.
While the lead in the tea leaves is not thought to leach very effectively into the tea, if you're consuming Matcha green tea (which contains the entire ground tea leaf), it's especially important that it comes from Japan instead of China.
Both black and green teas are also naturally high in fluoride, even if organically grown without pesticides. This is because the plant readily absorbs fluoride thorough its root system, including naturally occurring fluoride in the soil.
So, as with coffee, when selecting tea, opt for organic (to avoid pesticides), grown in a pristine environment (to avoid fluoride, heavy metals, and other toxins from contaminated soil and water). A clean growing environment is essential to producing a pure, high-quality tea.
Heart Healthy Benefits of Coffee
Personally, I don't drink coffee, and can count the number of cups I've had in my lifetime on one hand. I get most of my polyphenols from 3 tablespoons of freshly ground raw cacao nibs a day, which has far more benefits than those detailed here about coffee, due to its superior polyphenol concentration.
But if you do enjoy coffee, you may be pleasantly surprised to find that properly grown, harvested and roasted coffee can actually be very healthy. According to the 2015 edition of Dietary Guidelines for Americans, you can safely consume up to five cups of coffee a day without detrimental effects.6
The recommendation is based on research evaluating the link between coffee and chronic diseases, including cancer, type 2 diabetes, heart disease, Parkinson's, and Alzheimer's.
It used to be said that coffee could increase your blood pressure, at least temporarily. But longer-term studies haven't found a connection, and it's now thought people may develop a tolerance to coffee's hypertensive effects.7
More recent research suggests coffee may actually be quite good for your heart health:
• One meta-analysis8 that included data from 11 studies and nearly 480,000 people found drinking 2 to 6 cups of coffee a day was associated with reduced stroke risk.
The analysis also noted that drinking 1 to 4 cups of coffee a day was associated with a significantly lower risk of coronary heart disease in women, and that coffee consumption is inversely associated with risk of type 2 diabetes9
• Another study10 showed moderate coffee drinking reduces your chances of being hospitalized for heart rhythm problems
• Japanese researchers found drinking a cup of coffee may trigger a 30 percent increase in blood flow in your small blood vessels, which might take some strain off your heart. The effect lasts for about 75 minutes
• Researchers at Beth Israel Deaconess Medical Center and Harvard School of Public Health also found that moderate coffee consumption, defined as two 8-ounce servings a day, may protect against heart failure11
• Research12 has even shown that coffee consumption is inversely associated with premature death. The more coffee drank, the lower the risk of death became, including deaths from heart disease, respiratory disease, stroke, diabetes, and infections
Other Health Benefits of Coffee
Higher coffee consumption is also associated with a significantly lower incidence of Parkinson's disease,13 and caffeine may help control movement in those with Parkinson's disease, according to more recent research.14 Liver cancer and liver disease are also inversely associated with coffee consumption. Interestingly, coffee appears to contain an ingredient that protects against alcoholic cirrhosis.15
According to one study,16 drinking two or more cups of coffee daily may reduce your risk of dying from liver cirrhosis by as much as 66 percent. Italian research17 also found that coffee consumption may reduce your risk of liver cancer by about 40 percent, and if you drink three cups a day, the risk may be reduced by more than half.
Coffee May Boost Athletic Performance
Coffee may also provide specific benefits for athletes. In one recent meta-analysis, 5 of 9 randomized control trials included confirmed the performance-enhancing benefits of coffee. As noted in Medical News Today:18
"Athletes consuming 3 to 7 mg of caffeine through coffee saw an average improvement in endurance performance of 24 percent ... [Lead author Simon Higgins] says: 'This is helpful for athletes because coffee is a naturally occurring compound. There's the potential that getting your caffeine by drinking coffee has similar endurance benefits as taking caffeine pills.'"
In 2011, I interviewed fitness expert Ori Hofmekler about the use of coffee to enhance sports performance, and how caffeine helps you maintain youthful muscle tissue. According to Ori, consumed right before exercise, it can provide a beneficial fitness boost.
Drinking two cups of coffee an hour before training may also reduce post-workout muscle soreness by as much as 48 percent.19 To put this into perspective, studies using naproxen (Aleve) achieved only a 30 percent decrease in post-workout muscle soreness, and aspirin produced a 25 percent decrease.
As for Hofmekler, he recommends having just one cup of coffee or one shot of espresso in the morning, before your workout, and no more thereafter. Because for all its benefits, it can also affect your adrenal glands and increases the excitatory neurotransmitter glutamate, so moderation is still advisable.
One way to moderate your coffee consumption while still reaping the benefits both coffee and tea have to offer is to drink coffee only in the morning, and drinking tea when you want a beverage besides pure water in the afternoon.
The Health Benefits of Tea
While the majority of tea consumed is black tea,20 to maximize the health benefits of your tea drinking habit you may want to consider adding or switching to green tea instead. Green tea is recognized as an abundant source of epigallocatechin-3-gallate (EGCG), a catechin polyphenol, and other antioxidants. One of your healthiest options, and my own personal favorites, is Matcha green tea.
Since it contains the entire ground tea leaf, it can contain over 100 times the EGCG provided from regular brewed green tea. Again, to avoid lead contamination, opt for Japanese-grown Matcha tea rather than those from China. Steamed is also better than roasted or pan-fried varieties.
✓ Heart Health
Green tea improves both blood flow and the ability of your arteries to relax, with research22,23 suggesting a few cups of green tea each day may be helpful for the prevention of arteriosclerosis, cerebral thrombus, heart attack, and stroke.
✓ Type 2 Diabetes
One study24 found people who consume 6 or more cups of green tea daily had a 33 percent lower risk of developing type 2 diabetes than those who consumed less than 1 cup per week.
✓ Weight Loss
There is some evidence that long-term consumption of green tea catechins is beneficial for burning fat and may work with other chemicals to increase levels of fat oxidation and thermogenesis.
✓ Bone Health
Green tea polyphenols combined with a form of vitamin D called alfacalcidol could boost bone structure and strength, according to animal research.25
✓ Vision Health
Catechins in green tea may offer protection against glaucoma and other eye diseases, as research found the compounds travel from your digestive system into the tissues of your eyes. During the study,26 the catechins found in green tea were absorbed into various parts of the eyes anywhere from 30 minutes to 12 hours after rats were given tea.
Green tea components have been shown to downregulate the expression of proteins involved in inflammation, cell signalization, cell motility and angiogenesis, while an association between green tea intake and decreased risk of cancers (including ovarian27 and breast28) have been reported.
Previous research29 has shown that green tea polyphenols act on molecular pathways to shut down the production and spread of tumor cells. They also discourage the growth of the blood vessels that feed the tumors.
Epigallocatechin-3-gallate (EGCG) found in green tea even acts as an antiangiogenic and antitumor agent, and helps modulate tumor cell response to chemotherapy.30
Black Coffee in the Morning, and Green Tea in the Afternoon
While the research suggests you can have upwards of five cups of coffee per day without adverse effects, I believe this may be too much for many, especially with adrenal fatigue being so common. One way to balance the risks and benefits would be to limit your coffee consumption to one or two cups in the morning, and drinking green tea in the afternoon. Also remember that to achieve therapeutic benefits from coffee, it needs to be:
- Organic: Most coffee produced today is heavily contaminated with pesticides. It's actually one of the most heavily sprayed crops grown. So, any coffee you consume should be organic, pesticide-free coffee.
- Fresh whole bean: You'll want to purchase coffee in whole bean form and then grind it yourself to prevent rancidity. Pre-ground coffee may be rancid by the time you drink it.
- Properly dried and roasted: The coffee should smell and taste fresh, not stale. If your coffee does not have a pleasant aroma, it is likely rancid and poor quality. Darker roasts may provide greater health benefits and be easier on your stomach than light roasts.
- Black: Drink your coffee black, without sugar or cream. Add sugar and you'll certainly ruin any of the benefits discussed above by spiking your insulin levels and causing insulin resistance.
One last caveat: Pregnant women are advised to avoid coffee altogether, as caffeine can significantly impact the growing fetus. It is able to freely pass through the placenta, and one 2008 study31 found that just two cups of coffee ingested during pregnancy may be enough to affect fetal heart development and reduce heart function over the entire lifespan of the child.
Since caffeine does not provide any benefits to your baby, only potential hazards, I strongly recommend pregnant women avoid ALL forms of caffeine, including coffee and caffeinated teas.