Contraindications to coffee and 8 side effects — who exactly should not drink it

How we learned from of the last article , coffee has many proven beneficial properties: from improving overall performance to preventing cardiovascular diseases and oncology.

However, if there are contraindications, as well as abuse, undesirable reactions may develop. There may be deviations from the digestive, cardiovascular and nervous systems.

In addition, there are certain groups of people who are not allowed to drink coffee at all.

List of main contraindications

There are contraindications in which coffee should be limited or completely excluded. The main ones include:

  1. Pregnancy (the maximum allowable dose is 2 cups, it is better to refuse altogether).
  2. Breastfeeding.
  3. Any sleep disorders.
  4. Mental disorders ( neuroses , obsessive-compulsive syndrome, panic attacks, etc.).
  5. Diseases of the stomach and duodenum. This group includes: acute gastritis, exacerbation of chronic gastritis, peptic ulcer disease.
  6. GERB.
  7. Uncontrolled hypertension and symptomatic arterial hypertension.
  8. Smoking (the dose of caffeine should be reduced at least 2 times, it is recommended to give up either coffee or smoking).
  9. Glaucoma.
  10. Taking oral contraceptives and fluvoxamine (an antidepressant). These drugs slow down the metabolism of caffeine in the body.
  11. Iron deficiency anemia.
  12. Diseases liver with a decrease in the functional activity of the organ (cirrhosis).

During pregnancy caffeine is able to penetrate the fetoplacental barrier and cause the development of biological effects in the fetus, which poses a high danger to the life of the unborn child. It is recommended to completely abandon coffee or significantly limit its consumption to 200 mg of caffeine (2 cups) per day.

When breastfeeding coffee is strictly contraindicated, as large doses of caffeine penetrate into breast milk and even accumulate in it.

For children  coffee is also contraindicated. Due to the immaturity of most of the child's body systems, the drink can cause harm (delayed growth and development, early development of cardiovascular diseases). The minimum age threshold for a teenager is 13-15 years old.

For the elderly, in the absence of serious diseases from the cardiovascular system (uncontrolled hypertension, coronary heart disease, myocardial infarction or stroke in the anamnesis), it is allowed and even useful to drink coffee (1-2 cups a day). It helps to increase life expectancy, is good for the brain and prevents the appearance of extremely common degenerative brain diseases (Pick's disease, Alzheimer's, Parkinson's).

There are enough pathological conditions and diseases in which coffee can cause significant harm to the human body. If in doubt, consult a doctor.

8 side effects

Of course, coffee is an extremely healthy drink, but it is not without drawbacks. Most studies show that when taking in moderate volumes , there are no side effects. But excessive consumption in large quantities can lead to negative effects.

8 of the most basic side effects of coffee are discussed below.

1. Anxiety and irritability

According to American scientists , coffee blocks receptors for adenosine, a substance that increases general fatigue. It also accelerates the secretion of adrenaline several times, a substance that increases the activity of all body systems, promotes the development of anxiety and increased alertness.

With high doses of caffeine, the production of adrenaline becomes excessive, which provokes the appearance of pronounced anxiety, nervousness, and panic attacks.

Experts from the UK claim that similar effects are usually observed at a dose of more than 1000 mg (about 6-8 cups), however, in some caffeine-sensitive people they can manifest themselves at any volume.

According to accumulated scientific evidence, low and moderate doses of coffee contribute to cheerfulness and Performance improvement , but excessive ones cause anxiety, anxiety and irritability.

2. Sleep disturbance

One of the main qualities of coffee is an increase in physical and mental activity , fighting the desire to sleep. However, such an effect can cause significant disturbances in the structure and duration of sleep, which leads to physical exhaustion of the body.

Australian Studies demonstrate that excessive caffeine consumption increases the amount of time needed to fall asleep, makes sleep shallow and reduces overall sleep duration.

At the same time installed that the permissible doses of caffeine do not affect sleep, there is not even a bad effect on people suffering from insomnia due to other causes.

Recommended drink coffee at least 5-6 hours before the expected start of sleep. During this period of time, most of the caffeine is metabolized in the liver and is almost completely eliminated from the body. It is absolutely impossible to drink coffee at night before going to bed, regardless of the amount.

Late coffee intake contributes to the development of insomnia. In order to improve sleep, it is recommended to take it at least 5-6 hours before going to bed.

3. Digestive disorders

Caffeine activates the motor activity of the smooth muscles of the digestive tract, which leads to faster movement of food particles. The effect is mainly based on increased production of gastrin, a hormonal substance produced by the gastric mucosa.

This feature can lead to the development of a large number of symptomatic disorders and diseases of the digestive system.

Dutch scientists proved that coffee causes gastro-esophageal reflux (reflux of stomach contents into the esophagus), which is manifested by a feeling of heartburn or pain behind the sternum. The drink also stimulates contraction of the gallbladder , as a result, the breakdown of fats in the small intestine is accelerated.

Also proven that coffee stimulates the motor activity of the colon, which can be manifested by stool disorders such as diarrhea. This property is like claim scientists, it may be useful in the treatment of constipation and atony of the large intestine due to various organic and functional causes.

The effect of coffee on the incidence of gastritis and peptic ulcer of the stomach and duodenum deserves special attention.

Caffeine causes increased secretion of hydrochloric acid and gastrin, destroys the protective bicarbonate barrier on the mucous membrane, which, theoretically, should irritate the gastric mucosa and cause ulcerative and erosive defects. However, such a fact has not yet been proven. In one of the major Japanese studies (more than 8,000 units of observation) was not revealed there is no relationship between coffee consumption and the development of peptic ulcer disease.

To reduce the likelihood of negative effects of coffee on the stomach, it should not be drunk in the morning on an empty stomach, especially if you prefer a strong drink.

Coffee accelerates intestinal motor activity and can lead to a number of dyspeptic disorders. If any symptoms appear from the gastrointestinal tract, you should limit the intake of the drink or completely abandon it.

4. Destruction of muscle fibers

Rhabdomyolysis is a dangerous pathological condition in which muscle destruction occurs, and the products of their decay enter the systemic bloodstream and cause the development of acute renal failure (it can be fatal in the absence of medical care).

The most common causes of destruction of muscle fibers are traumatic injuries, infectious diseases, exposure to narcotic substances, as well as insect and snake poisons. Unfortunately, more and more cases of this condition are being registered against the background of coffee abuse.

According to statistics, there are an increasing number of cases of emergency treatment due to rhabdomyolysis caused by caffeine consumption (in the form of coffee or energy drinks).

The question regarding the dose of caffeine that can lead to the described complication remains controversial. For example, American doctors recorded the use of 24 grams of caffeine (a suicidal attempt), and Taiwanese - 565 milligrams (in order to increase mental activity).

Coffee can cause muscle breakdown (rhabdomyolysis) when taken excessively. To avoid this, it is recommended not to take more than 250 mg of caffeine per day.

5. Dependence

French scientists claim that caffeine causes the development of addiction, which has certain differences from that found against the background of drug use (cocaine, amphetamine) and other psychoactive substances.

The more a person consumes coffee, the more pronounced Caffeine addiction . The severity of dependence is also affected  affects the multiplicity of reception.

Some scientists even advise include such a condition in the list of psychiatric diseases.

Coffee causes addiction. Abrupt withdrawal from it can lead to withdrawal symptoms in people who take the drink on a regular basis.

6. The development of cardiovascular diseases

Data regarding effects of coffee on the heart and blood vessels are contradictory.

Caffeine contributes to an increase in blood pressure, however slightly (by 3-4 mmHg).  According to Italian scientists , with regular intake, there is no increase in blood pressure at all.

Many major studies also failed to prove an increase in cardiovascular diseases (for example, coronary heart disease) when drinking coffee.

Japanese scientists even fixed reducing the likelihood of stroke by 20% when taking 2 to 4 cups of drink per day.

However, there are many scientific papers showing the reverse dynamics. Dutch scientists proved that coffee increases the risk of coronary heart disease and hypertension. The effect is long-term and is observed with excessively frequent intake.

The described features should be taken into account by persons suffering from hypertension and symptomatic arterial hypertension, in which even a slight increase in blood pressure increases the likelihood of stroke or myocardial infarction several times.

Separately, it should be mark polymorphism of the enzyme CYP1A2 in the liver, which is responsible for the utilization of caffeine in the human body. In some individuals, there is a deficiency or defect of this enzyme, and therefore caffeine is metabolized more slowly (up to 56 hours, instead of 5-6), which leads to a longer effect on the human body. Drinking coffee against the background of this condition increases the risk of myocardial infarction by 60%, and also contributes to the development of type II diabetes mellitus.

Caffeine, in exceptional cases, contributes to an increase in blood pressure and the risk of cardiovascular diseases. With a burdened cardiological background, coffee intake should be approached carefully.

7. The development of fatigue

Any products containing caffeine (coffee, tea) increase mental and physical activity. Upon discontinuation of their intake, the reverse dynamics is observed: the development of fatigue and "energy exhaustion" of the body.

In one of the major reviews of scientific literature  is described that people who abuse coffee and energy drinks experience a feeling of fatigue and drowsiness the next day.

Coffee takes the body to a higher level of activity, to which a person gets used and gradually cannot do without a new dose of caffeine .

Excessive coffee consumption can lead to fatigue, which is usually observed the next day.

8. Diuretic effect

Increased urination is one of the most common side effects of coffee.

According to research data, caffeine leads to an increase in diuresis, but this effect is weakly expressed.

The dose of caffeine, which can increase the volume of urine formation and excretion, is 4.4 mg per kilogram of body weight.

Coffee helps to increase diuresis, which can be dangerous for patients with edematous syndrome.

Daily rate

For adult women and men, a dose equal to 400 milligrams is considered safe pure caffeine per day. In terms of teaspoons: 6 – for instant coffee , 4 – for natural. The described volume corresponds to about 4 cups of coffee.

A dose equal to 10 grams is considered dangerous for human life, and 1 gram is undesirable. In no case should you consume the described volumes, otherwise you will not avoid negative effects on the body and serious complications.

About that, which kind of coffee is healthier , see in a separate article.

The maximum allowable dose of caffeine per day is 400 milligrams (approximately 4 cups).

Conclusion

Thus, in reasonable quantities, coffee is safe for human health. If abused, side effects may occur: from banal fatigue and increased irritability to death (myocardial infarction, acute renal failure, etc.).

It is also important to consider the list of diseases and conditions in which coffee is contraindicated. It should not be taken against the background of pregnancy and breastfeeding, as well as for persons under 13-14 years of age.