Caffeine is naturally produced by a variety of different plants and acts as a pesticide to protect the plant or seeds against insects. It is a compound known as a xanthine alkaloid (methylxanthine) that acts as a stimulant in the human body. The most commonly consumed sources of caffeine are Coffee, Tea (Top Ten Teas), and Cocoa (Cacao) although other sources like Yerba Mate, Kola Nut, and Guarana are also gaining popularity and becoming mainstream. Caffeine is also commonly added to carbonated drinks and energy Drinks and due to caffeine's health benefits, it's added to some medications for cold and headache relief.

Caffeine & Your Health: Benefits & Concerns

Caffeine As A Stimulant

Caffeine acts as a central nervous system stimulant and offers health benefits to those who feel low in energy or suffer from brain fog. This stimulating effect allows caffeine to help reduce fatigue and improve mental alertness. Caffeine is the most commonly used psychoactive substance worldwide. It is estimated that 90% of adults in North America consume caffeine daily. The stimulant effects of caffeine also result in an increased heart rate, relaxation of smooth muscle, and increased stomach acid secretion.

Caffeine's Diuretic Properties

When not used daily, caffeine has a diuretic effect, which means that it increases the shedding of water from the kidneys and thus increases urination. Rather than providing benefits, this is where caffeine may cause health concerns. Due to this diuretic effect, caffeine also reduces the water content of the body, which can lead to dehydration. The flushing caused by this diuretic effect can cause a reduction in calcium and other important electrolytes in the body. This is why caffeine consumption can increase the risk of Osteoporosis. Those who use caffeine regularly and develop tolerance generally no longer get this diuretic effect.

Asthma & Caffeine

Traditionally, a cup of coffee was used to help treat mild asthma attacks in children. Due to its ability to relax smooth muscle, caffeine can act as a bronchodilator in people with asthma. Caffeine is very similar in structure to theophylline, another methylxanthine commonly used to treat asthma. Recent research has found that caffeine can be used in place of theophylline when necessary for bronchodilation in asthmatics.

Energy Metabolism

Professional athletes will often use small to moderate doses of caffeine to help improve their athletic performance. A health benefit of caffeine is it helps to mobilize fat from the muscle and increase blood epinephrine levels. These effects allow the muscles to mobilize and use fat for energy, which spares muscle glycogen. This allows for better results with endurance exercise, by giving longer acting energy. The dosing for this effect is very specific, as excess can quickly become detrimental to athletic performance, by throwing off coordination and balance. The metabolic effects of caffeine may also allow it to help prevent the development of Type II Diabetes. Unfortunately, once diabetes is already present, caffeine’s effects are detrimental and can worsen blood sugar control.

Cellular Protective Effects of Caffeine

Some preliminary studies show caffeine as having a benefit on healthy cell growth. Far more research is required before we can draw conclusions in this area. Interestingly, caffeine intake has been associated with a reduced risk of developing Parkinson’s Disease, probably because of its stimulatory effects altering dopamine secretion.

Caffeine and Constipation

Because of its diuretic effects, caffeine can cause dehydration, a condition that can greatly worsen constipation over time. This seems counter-intuitive to the many people who drink coffee to promote a bowel movement in the morning. This direct effect is likely due to the relaxation of smooth muscle caused by caffeine. In general, it is a good idea to find other ways to promote bowel movements, rather than relying on a stimulant like caffeine.

Caffeine Toxicity

Although caffeine does offer health benefits, the side effects of caffeine exposure depend on the dose. At typical doses, it can cause insomnia, nervousness, restlessness, gastritis, nausea, increased heart rate, high blood pressure, and increased urination. Often people will complain of muscle tremors known as the “caffeine jitters” after ingesting excess caffeine.

Larger doses can cause headaches, anxiety, agitation, ringing in the ears, stomach cramps, sensory disturbances, vomiting, rapid breathing, tremors, delirium, irregular heartbeat, and even convulsions. Fatal overdoses by ingestion are rare because the irritation of the gastric lining caused by caffeine generally results in vomiting of excess amounts. This irritation is also why caffeine intake is associated with an increased risk of developing Ulcers. Prolonged use of caffeine has also been shown to be associated with an increased risk of developing several health conditions such as High Blood Pressure, and Cardiovascular disease.

Addiction, Tolerance, and Withdrawal of Caffeine

The regular consumption of caffeine can lead to addiction and tolerance. When one has developed a tolerance to something, this means they must consume greater and greater amounts of a substance to maintain the same level of stimulation. Caffeine users report that the stimulation they receive from a cup of coffee decreases with daily use leading to greater amounts of caffeine being used and a higher physical dependency on the chemical. Stopping caffeine intake leads to withdrawal symptoms which can include: headaches, poor concentration, stomach pain, irritability, insomnia and joint aches. Nicotine, found in cigarettes, increases the destruction of caffeine in the bloodstream which reduces the effects of the caffeine. Often, smokers will be heavier consumers of caffeinated products for this reason.

Benefits of Decaf

To produce beverages like coffee and tea without the caffeine content, manufacturers came up with ways to remove the caffeine. Originally, this was done using solvents like benzene, chloroform, trichloroethylene, and dichloromethane. Due to the toxic nature of these chemicals and their environmental impact, other methods have since been created. 

The two most common, and more natural means of decaffeinating are water extraction and supercritical carbon dioxide extraction. In both cases the caffeine is extracted, leaving the coffee bean intact. The caffeine that is removed is then used in the manufacturing of caffeinated energy drinks and carbonated beverages.

Appropriate Doses of Caffeine & Side Effects

The amount of caffeine required to have a stimulatory effect varies by body size and degree of tolerance. One cup (250ml) of brewed coffee contains between 95-200mg of caffeine. It is recommended that pregnant women not exceed 2 cups of coffee daily, which is effectively a dose of 190-400mg of caffeine per day. Health Canada recommends a daily caffeine intake of no more than 400mg daily for healthy adults, which is the equivalent of about three cups of brewed coffee. In children, this amount is significantly lower, with the recommended dose falling between 40 and 85mg of caffeine daily depending on body weight.