Is coffee bad? Effect of decaffeinated, reheated or with milk

Excess coffee can cause irritation, aggression and anxiety , in addition to facilitating the appearance of headaches and muscle pain in people who are already predisposed to these manifestations.

In the composition of the drink, there are substances such as caffeine, minerals, amino acids, lipids, vitamins of the B complex and sugars.

The presence of caffeine, for example, can impair sleep and lead to addiction.

Among the harms of excessive fluid intake is also the loss of mineral salts, caused by the diuretic action of the drink.

Drinking too much coffee also causes other damage to the health of organs, such as the skin and stomach.

At the same time, if consumed moderately , it is believed that coffee can act in the prevention of some types of cancer (breast and prostate, for example).

Read more: Drinking coffee can slow the progression of prostate cancer

Some phenolic acids present in the drink increase good cholesterol (HDL) and help to reduce liver fats.


What is the recommended daily amount?

According to the World Health Organization (WHO), a healthy adult should drink between 150mL and 250mL of coffee per day . This equates to a minimum of 3 and a maximum of 5 50ml cups of the drink throughout the day.

It is recommended to have breakfast in the morning and in the afternoon, with intervals of at least an hour between one cup and another. It is also advised not to drink the drink before going to sleep.

Pregnant women, children, women who are taking contraceptive treatment and people who have insomnia or stomach problems should avoid taking it.

Is drinking too much coffee bad? What are the effects on the body?

Coffee contains caffeine, which acts on the body for up to 6 hours after ingestion. Therefore, consumption should be reduced or avoided before going to sleep.

It is also common for people to experience stomach upset and heartburn after ingesting large amounts, especially on an empty stomach. This is due to the acidic residue from the digestion of coffee.

Coffee can have positive or negative effects. It all depends on the amount in which it is consumed.


Coffee helps to eliminate other fluids from the body. This, on the one hand, is bad because a dehydrated body reflects on dry or older looking skin and hair.

If the drink is consumed in excess, it can stimulate the appearance of pimples and warts and cause skin irritations.

But on the other hand, when taken moderately, coffee can help prevent skin cancer.

Cellulite can also be reduced by this drink, which facilitates weight loss by making the skin firmer. Creams that are based on coffee can help in these processes.


The drink can help protect the heart because it contains polyphenols. These substances help to improve the lining of veins and arteries, and stimulate the production of platelets in the blood.

Bad cholesterol (LDL) decreases and good cholesterol (HDL) increases when drinking the correct amount of coffee. Thus, heart problems also tend to be alleviated or avoided.

But coffee, if taken in larger doses than recommended, can speed up the heart and cause tachycardia, facilitating heart attacks and heart attacks.

Nervous system

Coffee improves the ability to concentrate and the state of alertness, that is, after drinking it, we tend to remain more attentive, focused and willing.

Therefore, excess of the substance can alter sleep and lead to insomnia. This product in excess releases high doses of adrenaline and cortisol, leaving the consumer more tense and anxious.

Irritation, nervousness and aggression are also consequences of excess caffeine in the body.

In contrast, when consumed in moderate doses, coffee relieves headaches due to caffeine. Therefore, it is used in some medications for these complications.

Studies at Harvard University, conducted with rats, indicate that the liquid may also help prevent Alzheimer’s. Similar research on humans is being budgeted and planned for the coming years.


Coffee is not recommended for people with gastritis and other diseases in the digestive system.

That’s because the drink irritates the lining of the stomach. If this irritation is not treated, the person may develop sores on this organ.

In people who do not have any stomach complications, coffee should still be consumed in moderation, since excessive consumption is one of the risk factors for such diseases.


The liver benefits from coffee. The drink helps prevent and treat liver disease.

In addition to medications, drinking a few cups of coffee a day may be the medical recommendation to treat diseases such as Hepatitis C and Cirrhosis .

This is because the drink can help speed up the metabolism and, therefore, participate in the burning of fats, including those that are present in the liver (hepatic steatosis).

Can I have reheated coffee?

Reheated coffee can be bad for your health in the short term. It is common for people to report headaches and tummy, heartburn, nausea and dizziness after drinking the heated drink again.

This is because of the chemical oxidation process of the drink.

In the oxidation of coffee, the liquid comes into contact with the oxygen gas, changing the aroma and flavor and inhibiting its properties.

This process does not take long to begin, so it is recommended to drink coffee as soon as it is ready.

The oxidation of coffee can also happen if the drink stays all day in thermoses that are not well sealed.

This chemical process occurs regardless of the form of preparation (strained, dripped, filtered, etc.).

Is too hot coffee bad?

A cup or not. But often, yes.

The problem with drinking very hot coffee is exactly the temperature.

This is because very hot liquids can, over time, cause sores in parts of the digestive system (such as the esophagus). These wounds can become inflamed and cause major complications.

The International Agency for Research on Cancer (IARC) defends that the frequent consumption of very hot coffee (or any liquid), is related to the development of esophageal cancer.

Therefore, other drinks such as teas and chimarrão should also not be consumed at high temperatures.

The World Health Organization (WHO) recommends that liquids, in general, should be consumed at a maximum temperature of 65 ºC.   

Is coffee with milk bad for your health?

In general, no. If there are no restrictions, moderate consumption does not affect health. Milk can also ease some discomfort caused by pure coffee, reducing its acidity. Remembering that, in excess, there may also be side symptoms.

However, for those who use coffee with milk as a source of calcium, it is important to pay attention to the proportions.

About 30mL of milk is enough to reduce the effects of caffeine, for example. However, if more coffee is added, the benefits of milk are canceled out.

Even without doing harm, coffee can prevent the absorption of some substances in the drink, such as calcium and iron.

Therefore, for milk to serve as a source of nutrients, the drink must be mixed in equivalent quantities (half coffee, half milk) or give priority to milk.

If consumed correctly, this mixture can bring advantages such as relieving headaches and preventing diseases.

What is the difference between regular and decaffeinated coffee?

Decaffeinated coffee contains up to 97% less caffeine in its composition, compared to traditional coffee. This value varies according to the brand and type of preparation of the coffee bean. The product can be indicated for people sensitive to caffeine, but who like the drink.

Unlike other types, the decaffeinated version is treated from the coffee plantation so that, in its final state, it does not contain caffeine.

Decaffeinated coffee is also consumed by people who have problems with insomnia, anxiety and hyperactivity, as it contains a reduced amount of the stimulant (caffeine).

Read more: Caffeinated drinks can improve performance in sports

Coffee is a popular drink in Brazil and is present in the daily lives of most people.

In general, coffee consumption is not harmful to health as long as it is done sparingly.

In fact, if it is ingested in the correct amount, that daily cup of coffee can come with benefits for the heart and brain.

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