The Dangers of Coffee

Coffee

Coffee is a popular beverage made from roasted coffee beans, which are the seeds of the coffee plant scientifically known as Coffea arabica. Many individuals consume coffee daily for its stimulating properties, as it enhances alertness, concentration, and reduces fatigue. Additionally, coffee has been associated with the prevention and treatment of various health issues. The coffee plant can grow up to 8 meters tall, features glossy dark green leaves that typically measure between 6 to 20 cm in length and 2.5 to 6 cm in width. While there has been considerable debate over its origin, coffee is currently grown in several tropical regions, including Brazil, Mexico, Colombia, and Ethiopia. It ranks among the most consumed beverages globally, largely due to its caffeine content, along with its enticing flavor and aroma.

Consuming coffee is linked to numerous health benefits, including enhanced alertness, improved cognitive clarity, and potential prevention of conditions such as colorectal cancer, dizziness in the elderly, Parkinson’s disease, gallstones, type 2 diabetes, and liver diseases such as cirrhosis and hepatocellular carcinoma. However, excessive coffee consumption can lead to negative effects, particularly those correlated with high caffeine intake and associated unhealthy behaviors like smoking and lack of physical activity. This article provides a detailed discussion on the adverse effects linked to coffee consumption, backed by scientific evidence.

Disadvantages of Coffee

Daily caffeine consumption of up to 400 mg (approximately 4 cups of coffee) is generally regarded as safe, considering other caffeine sources. Despite the myriad benefits and moderate safety of coffee, excessive intake can lead to various harmful effects, including:

• Increased Risk of Cardiovascular Diseases: Numerous case-control studies suggest that high coffee consumption is linked to a greater risk of coronary artery disease and myocardial infarction. Individuals consuming five or more cups of coffee daily have a 40-60% increased risk of cardiovascular issues compared to non-consumers. Those drinking 600 ml of coffee daily face a threefold higher risk of acute coronary syndrome. On the contrary, many prospective cohort studies found no significant correlation between coffee intake and cardiovascular diseases, and a Norwegian study identified risks only among individuals who consumed nine or more cups daily after a 12-year follow-up.
• Impact on Individuals with Pre-existing Coronary Artery Disease: Limited research explores coffee’s effects on those already diagnosed with coronary artery disease. However, one study indicated that consuming ten or more cups daily increases the risk of sudden cardiac arrest. A separate study involving 1,935 individuals previously afflicted by a myocardial infarction found no link between coffee consumption and mortality over four years.
• Elevated Stroke Risk: A study involving men with hypertension revealed that those consuming at least 700 ml of coffee daily have double the risk of stroke compared to non-consumers. However, some studies do not support a clear relationship between coffee and stroke incidence, indicating further research is necessary.
• Cholesterol Levels: Unfiltered coffee consumption raises total cholesterol, LDL cholesterol, and triglycerides, effects that diminish with filtered coffee.
• Homocysteine Levels: High coffee intake has been shown to elevate blood homocysteine, a marker associated with cardiovascular diseases. Conversely, a six-week cessation from coffee can reduce homocysteine levels by 11% in regular consumers.
• Blood Pressure Effects: Studies demonstrate that acute coffee consumption can elevate blood pressure in both normotensive and hypertensive individuals. A 200-250 mg dose of caffeine can increase systolic blood pressure by 3-14 mmHg and diastolic pressure by 4-13 mmHg.
• Cancer Associations: Preliminary studies have identified connections between coffee consumption and increased risks of certain cancers, such as pancreatic and bladder cancers, but recent, well-designed studies often find no significant links.
• Impact on Calcium Absorption: High coffee intake reduces calcium absorption and increases urinary excretion, leading to potential bone density reduction and increased risk of osteoporosis, though this may not be significant with adequate calcium intake.
• Iron Absorption: Polyphenols in coffee may inhibit iron absorption, particularly non-heme iron. Consumption of coffee close to mealtime can reduce iron absorption significantly.
• Zinc Absorption: Coffee can also reduce zinc absorption, with some studies indicating decreased bioavailability of zinc when coffee is consumed.
• Fertility Concerns: Some research suggests that high caffeine intake may delay the process of conception, particularly in women consuming over 300 mg of caffeine daily.
• Miscarriage Risk: Increased coffee intake has been linked to a higher likelihood of miscarriage in some studies.
• Pregnancy Effects: Consuming 200-400 mg of caffeine daily during pregnancy is associated with lower birth weights and an elevated risk of developmental issues for the fetus.
• Infant Irritability: High caffeine consumption by breastfeeding mothers may lead to increased irritability and sleep disruptions in infants.
• Child Consumption Guidelines: Caffeine intake in children should not exceed 2.5 mg/kg of body weight, with higher amounts leading to irritability and sleep disorders.
• Older Adults Risk: Elderly individuals may experience heightened sensitivity to caffeine, leading to increased drug interactions and additional risks such as osteoporosis.

Side Effects

Moderate coffee consumption is generally safe for most adults; however, excessive intake can lead to several side effects, including arrhythmias, palpitations, insomnia, anxiety, irritability, tremors, headaches, tinnitus, abdominal pain, nausea, vomiting, diarrhea, increased urination, and elevated respiratory rates. Consuming six cups of coffee per day may lead to caffeine addiction, characterized by anxiety and restlessness.

Individuals who have consumed coffee consistently for extended periods may experience withdrawal symptoms, even with minimal daily intake. Symptoms can manifest in those consuming just 100 ml of coffee daily, with withdrawal effects intensifying with increased consumption. These symptoms may include headaches, fatigue, dizziness, irritability, and mood disturbances. Gradual caffeine reduction can alleviate withdrawal symptoms compared to abrupt cessation.

Contraindications for Coffee Consumption

Caution is advised in the following scenarios:

• Pregnancy and Breastfeeding: Consuming up to two cups of coffee (200 mg of caffeine) per day is generally deemed safe during pregnancy, but exceeding this amount can increase risks of miscarriage, preterm labor, and low birth weight. Breastfeeding mothers should limit intake to prevent gastrointestinal irritability and sleep disturbances in infants.
• Children: Caffeine is not considered safe for children due to potentially heightened adverse effects.
• Anxiety Disorders: Coffee consumption may exacerbate anxiety symptoms.
• Bleeding Disorders: Caffeine may worsen certain bleeding issues.
• Heart Conditions: As mentioned, unfiltered coffee may elevate blood lipid levels and homocysteine, increasing cardiovascular risk.
• Diarrhea and IBS: High caffeine intake can worsen diarrhea and irritable bowel syndrome symptoms.
• Glaucoma: Caffeine may elevate intraocular pressure shortly after consumption.
• Hypertension: Caffeine consumption can temporarily raise blood pressure, particularly in hypertensive individuals, although regular consumers might experience reduced effects.
• Osteoporosis: Caffeine can increase calcium loss, making it important for those with osteoporosis not to exceed 300 mg of caffeine daily, compensating for lost calcium through supplements if necessary.

Drug Interactions

Caffeine interacts with numerous medications including:

• It can amplify side effects of stimulants like ephedrine.
• Caffeine may reduce the effectiveness of medications such as adenosine, alendronate, dipyridamole, lithium, and theophylline, and should not be consumed before or after certain medications.
• Some drugs may hinder caffeine metabolism, increasing its levels and potential side effects, including certain antibiotics and alcohol.
• Caffeine can affect the absorption of other medications, necessitating caution with its concurrent use.
• It may enhance the effects of specific medications, especially those that lower blood clotting.