Every day, billions of people consume some coffee. Whether it is to go through your night shift or starting your day, coffee is part of our every day life making it one of the most used ingredient in the world. The caffeine contained in regular coffee is often avoided for its negative effects on sleep and anxiety. However, numerous studies have reported on various health benefits.
Caffeine: what it is and dosage
Caffeine is a natural stimulant commonly found in tea, coffee, and cacao plants. It works by stimulating the brain and central nervous system, helping you stay alert and prevent the onset of tiredness. It increases mental and physical performance and it is generally safe to use under controlled dosages. Once consumed, caffeine is quickly absorbed from the gut into the bloodstream. From there, it travels to the liver and is broken down into compounds that can affect the function of various organs. It stimulates the brain by blocking the effects of the neurotransmitter adenosine. However the major risk with caffeine supplements, foods and drinks is the excessive dosage that can cause unhealthy side effects such as:
- Makes hard to fall asleep
- Makes the heart beat faster often accompanied by uneven heart rhythm
- Raises blood pressure
- Can cause headaches
The FDA and the European Food Safety Authority set a limit of 400 mg per day of caffeine for safe use in non-pregnant adults, which is about four to five cups of coffee. Other reports on lower dosages of 100-200 mg per day a safe dosage. Health Canada noted 100-400 mg per day as safe as long as 200 mg per single dose is not exceeded..
Common source of caffeine
Caffeine is a naturally occurring compound that belongs to the a group of substances called methylxanthies. It is found in coffee, tea, chocolate, botanical supplements, nonprescription drugs, and drinks. The following list reports typical values of caffeine expected in 240 mL of some popular beverages:
- Espresso: 240–720 mg
- Coffee: 102–200 mg
- Yerba mate: 65–130 mg
- Energy drinks: 50–160 mg
- Brewed tea: 40–120 mg
- Soft drinks: 20–40 mg
- Decaffeinated coffee: 3–12 mg
- Cocoa beverage: 2–7 mg
- Chocolate milk: 2–7 mg
Caffeine: the goods
Caffeine has several desirable effects including
- May improve mood and brain function. Caffeine has the ability to block the brain-signaling molecule adenosine. This causes a relative increase in other signaling molecules, such as dopamine and norepinephrine (Ref).This change in brain messaging is thought to benefit your mood and brain function.
- May boost metabolism and fat burning. Because of its ability to stimulate the central nervous system, caffeine may increase metabolism by up to 11% and fat burning by up to 13% (Ref, Ref). Some studies reported that caffeine can be beneficial for athletic performance, especially endurance athletes, by decreasing glycogen utilization and increase fat oxidation. In other words, caffeine may increase the use of fat as fuel.
- May protect against heart disease and diabetes. Despite what you may have heard, caffeine doesn’t raise the risk of heart disease (Ref, Ref).In fact, evidence shows a 16–18% lower risk of heart disease in men and women who drink between 1–4 cups of coffee daily (providing approximately 100–400 mg of caffeine) (Ref).One thing to keep in mind is that caffeine may slightly raise blood pressure in some people. However, this effect is generally small (3–4 mmHg) and tends to fade for most individuals when they consume coffee regularly (Ref).
- Weight-loss aid. Due to the combination effects of caffeine has on the body, it is also used as weight loss aid. Caffeine has thermogenic effects resulting in increasing the calorie expenditure rate and promote the use of fatty acids for energy. The mild diuretic effect might help in reduce water retention.
Caffeine: the bads
Despite the great benefits of caffeine, some side effect can occur and should be taken into account.
- Calcium depletion. Immediately after drinking a cup of coffee, the caffeine will increase the amount of calcium excreted by the body. Each 150 milligrams of coffee results in a corresponding loss of five milligrams of calcium. Over time, this can reduce bone mass and increase the risk of hip fractures. Caffeine also prevents Vitamin D receptors from absorbing Vitamin D.
- Diuretic effects. Although the mild diuretic effect might help in reduce water retention, proper hydration should be maintained throughout the day to avoid dehydration.
- Vitamin absorption. Caffeine has a mild diuretic effect, which leads to an increase in urination. As a result, water-soluble vitamins, such as B-vitamins and vitamin C can be depleted due to fluid loss. When you sip a cup of coffee alongside an orange as a morning snack, you are risking the caffeine from the coffee preventing proper absorption of the orange’s vitamin C content. Research also demonstrated that the higher the level of caffeine, the more it interfered with vitamin D absorption (ref). Caffeine can also interfere with the absorption of calcium. A cup of coffee can slightly reduce calcium absorption in the body and increase its loss in urine due to its diuretic effect (ref). Further research concluded that drinking a cup of coffee or tea with a hamburger meal reduced iron absorption by 39% and 64% (ref).
Instead of drinking caffeinated drinks with snacks, meals and your multivitamin supplements, wait at least half an hour before and after before enjoy your coffee or tea.