Foods that harm: coffee

Our major source of caffeine, coffee is the substance millions of North Americans use to stay alert. Many go so far as to say they cannot function properly without that morning cup of java. The following guidelines will walk you through the benefits and drawbacks of consuming coffee on a regular basis.

In addition to caffeine, coffee contains nearly 400 other chemicals, including trace amounts of several vitamins and minerals, tannins and caramelized sugar.

• Coffee is not entirely calorie-free; while a 180 millilitre (six ounce) cup of sugar-free black coffee has only four calories, some specialty coffee drinks have more fat and calories than a rich dessert.
• A cup of whole milk mocha topped with whipped cream is on a par with a hot fudge sundae.
• A dedicated coffee drinker might consider reducing caffeine from other sources — for example, giving up caffeinated soft drinks from the diet.

Coffee is best consumed in moderation. The following are possible hazards linked to coffee:

• Infertility. A number of studies have found that consuming more than 300 milligrams caffeine a day is associated with a delay in conception.
• Heart problems. Caffeine prompts a temporary rise in blood pressure; it can also provoke cardiac arrhythmias in susceptible persons.
• Coffee increases calcium excretion in the urine. To compensate for this loss, heavy coffee drinkers should consume extra ­calcium-rich foods.
• Caffeine withdrawal. Heavy coffee drinkers who stop imbibing coffee abruptly may suffer headaches, irritability and other withdrawal symptoms for a few days. Cut back gradually.
• Cholesterol problems. Cafestol and kahweol, compounds in coffee, can boost cholesterol synthesis by the liver. These are found in highest concentrations in Scandinavian and Turkish coffees, as well as French-press brews.
• Caffeine is a diuretic, meaning it increases the output of urine. This is a concern for men with prostate problems.

Many people drink decaffeinated coffee to escape the insomnia and jittery nerves caused by caffeine. But even decaffeinated coffee has up to five milligrams of caffeine in a 150 millilitre (five ounce) cup. People with sleep problems are better off avoiding coffee.

• Stimulates the central nervous system.
• Can help you stay awake and alert.

• May contribute to difficulty falling asleep and disturbed or reduced sleep.
• Drinking large amounts can cause irritability and jittery nerves.
• Increases excretion of calcium.