You’ll be pleased to know that many of the foods and beverages you love aren’t just “okay” as an occasional indulgence, they’re good for you! Let’s start with coffee and tea… and I invite you to read my articles related to wine, beer and chocolate.

Coffee is made from the roasted and ground seeds of various tropical trees or shrubs of the genus Coffea.

An Arab legend tells of a goatherd who made a drink from berries that grew on strange bushes, and after drinking it he experienced extraordinary lucidity and alertness. The bushes are said to have been planted by the descendants of the Queen of Sheba, who came from Ethiopia, where Coffea arabica originates.

To date, nearly 20,000 scientific studies have been conducted on coffee or caffeine. Here, in a nutshell, are the results: Drinking coffee in moderation is not only not a health threat, it can actually be a blessing. It is harmless even during pregnancy and children are no more sensitive to caffeine than adults.

The average American consumes about 200 milligrams of caffeine a day, roughly the equivalent of two cups of coffee (a figure that, of course, includes non-drinkers). “Moderate” consumption is generally defined as 300 mg daily: two to five cups of coffee or four to eight cups of hot tea, depending on the size of the cup.

What has more caffeine, coffee or tea? It depends. We have pound for pound basis, tea has more. But because less tea is required to make a cup of tea, a cup of coffee typically has about twice as much caffeine. There are also significant variations in the variety of coffee or tea and the preparation method used. Dark roasted coffees may contain less caffeine than lighter roasted beans; Arabica beans tend to be less caffeinated and milder in flavor than robusta.

“Decaffeinated” coffee and tea contain about 5 mg per cup.

Caffeine is a central nervous system stimulant. While people vary in their sensitivity to caffeine, some generalizations apply. Caffeine can increase the speed of rapid information processing, alertness, energy, stamina, motivation, and concentration. All of this has major implications, especially for night shift workers and drivers, as well as anyone who wants to stay productive at work after lunch. This alertness-enhancing effect may also relieve discomfort associated with the common cold. (Now, that’s good news for those of us who prefer coffee but feel compelled to switch to an herbal tea when we start feeling a sore throat or stuffy nose!)

Caffeine relieves headaches by constricting blood vessels in the brain, which in turn reduces cranial pressure. So it’s no surprise that it’s an active ingredient in headache pain relievers.

Some studies have linked caffeine consumption with decreased levels of depression and anxiety.

Caffeine has long been known to help asthmatics, many of whom have found that regular coffee consumption has a moderating effect on attacks. That’s no surprise either, thanks to the ingredient theophylline, a prescription medication for the symptomatic relief of bronchial asthma.

Higher caffeine intake is associated with a significantly lower incidence of Parkinson’s disease. That’s because caffeine consumption reduces the amount of dopamine depletion, one of the hallmarks of Parkinson’s.

Last but not least, caffeine stimulates the metabolism.

Aside from the caffeine, coffee has a complex chemical composition. A characteristic of many plants is the abundance of compounds with antioxidant properties, and coffee is no exception. Flavonoids are particularly widespread in plants and are also important in protecting against diseases.

Antioxidants reduce the risk of cancer and prevent good cholesterol (HDL) from turning into bad cholesterol (LDL), a cause of heart disease. Antioxidants neutralize the effect of “free radicals,” highly reactive molecules that travel through the body and cause chemical chain reactions that can damage cells by binding to extra electrons. Free radicals have also been implicated in stroke, cancer, and the aging process. There are substances with antioxidant activity that are generated in the roasting process.

Coffee is a good dietary source of potassium. That makes coffee a good choice as a diuretic; Potassium loss is an undesirable side effect of most diuretics. Coffee can reduce the risk of liver cirrhosis.

The tea is made from the leaves of a shrub of the genus Camellia.

The Chinese first collected tea leaves in the wild and have cultivated the tea plant since at least AD 350. The court of Charles II of England in the 17th century established tea as a fashionable drink for the elite.

The cooking, fermentation and/or oxidation that is done to the leaves determines if the tea will be green, black or oolong.

Tea is a source of vitamins A and B6, thiamine, and riboflavin; nicotinic, pantothenic, ascorbic and folic acids; manganese, potassium and fluoride.

Flavonoids are found in all types of tea; green tea has the highest concentration. The tea is being studied for its benefits in improving immune function, lowering LDL and increasing HDL levels, lowering blood pressure, thinning the blood, reducing the risk of heart attack, stroke, and cancer, increasing longevity, helping digestion and promote dental health.

There is convincing evidence of a protective effect of both coffee and tea against colorectal cancer, the second leading cause of cancer-related deaths in the United States. High coffee consumption decreases the excretion of bile acids, which are suspected to be carcinogenic to the colon. Due to its diuretic properties, caffeine may help reduce the risk of bladder cancer.

Higher intake of coffee and tea, both regular and decaffeinated, was associated with a lower risk of kidney stone formation, much more so than water. (A slight advantage was found for caffeinated coffee over decaf.) Interestingly, higher consumption of apple and grapefruit juice was correlated with a higher risk of stone formation.

A study has found that people who drink coffee are less likely to suffer from heart disease than tea drinkers. However, this may not be a direct cause-and-effect relationship: possibly people who choose to drink coffee have more youthful/healthy lifestyles in other ways.

Science has debunked the dark myths that caffeine contributes to breast cancer, bladder cancer, ulcers, indigestion, and osteoporosis.

Is there a reason not to consume caffeine? In some patients, caffeine is associated with temporary increases in blood pressure, so people with high blood pressure may be advised to avoid caffeine during times of high stress.

Also, people who are more sensitive to caffeine may not be able to drink coffee or tea at the end of the day because the caffeine delays the onset of sleep. Worse yet, some people may not realize that they are not as rested the next day as they should be, and therefore may be more prone to fatigue-related accidents.

Is it possible to become addicted to caffeine? Coffee drinkers do not exhibit the behaviors that define addiction: severe withdrawal symptoms, tolerance, the need to consume the addictive substance at all costs, and anti-social behavior, including delinquency. Neither coffee nor other caffeine-containing products are classified by drug addiction experts as addictive.

However, quitting caffeine suddenly can be unpleasant. The most common withdrawal symptoms include headaches, fatigue, drowsiness, irritability, depression, and flu-like feelings. Weaning yourself off gradually, say over a week, should minimize discomfort.

So drink up, without the guilt.