Coffee is good for health, but not everyone is suitable for it

Science has proven that coffee is a beverage that offers numerous health benefits for humans. However, it is not a drink suitable for everyone.

According to Hanoi Heart Hospital, coffee is generally good for health. However, it also comes with some undesirable side effects, including:

Premature graying of hair: This is an indirect effect. It is well-known that a deficiency or decrease in melanin (the pigment) in hair can lead to graying. While there are no formal studies indicating that coffee reduces melanin in hair, coffee is one of the potential causes of insomnia.

Anxiety, stress, insomnia, fatigue, postpartum conditions, and aging can trigger a chain reaction affecting melanocyte activity and disrupting melanin synthesis, which determines the natural color of hair. The cause of graying hair is the aging of the body, which causes melanocytes to gradually produce less melanin pigment.

Coffee increases the risk of stomach ulcers.

Causes diarrhea.
Caffeine in coffee can stimulate the nervous system, leading to insomnia for some users.

Another important note is that not everyone is suitable for coffee consumption. According to doctors, the following individuals should limit or avoid coffee:

People with stomach issues: For some individuals, exposure to chlorogenic acid in coffee (especially on an empty stomach) can irritate the stomach lining. This irritation can lead to symptoms such as abdominal pain, heartburn, hiccups, nausea, and vomiting. Coffee also increases the risk of stomach ulcers or exacerbates existing stomach conditions.
People with pancreatitis (as it may worsen the condition): Consuming large amounts of coffee can raise insulin levels in the blood, disrupting the body’s balance and adversely affecting the pancreas.
People with musculoskeletal disorders: High coffee consumption can increase the risk of osteoporosis or brittle bones, as it may accelerate bone loss.
Children and adolescents.
Women during menstruation.
People with Irritable Bowel Syndrome (IBS): Angel Planells, a nutrition expert and former president of the Washington State Academy, states: “Caffeine can increase bowel motility, including the likelihood of diarrhea – a primary symptom of IBS.”
People with glaucoma: Nutrition expert Angel Planells notes: “The intraocular pressure increases for those with glaucoma when consuming coffee. Therefore, patients should limit or avoid it.” According to Mount Sinai research, high caffeine intake increases the risk of glaucoma in individuals predisposed to the condition.
People with overactive bladder: One side effect of coffee on the bladder is increased urination frequency. This is because caffeine can alter bladder activity, affecting both the frequency and volume of urination. Nutrition expert Sue Heikkinen mentions: “If you don’t regularly consume coffee, your body may be more sensitive to it.”

Heart patients should limit caffeine intake. (Photo: Shutterstock).

People with heart disease: Nutrition expert Kelli McGrane states: “Caffeine from coffee can temporarily raise blood pressure and heart rate.” Those with heart conditions should consult their doctor or health expert regarding safe coffee consumption levels. A study published in the American Journal of Clinical Nutrition concluded that there is a potential for a sudden spike in blood pressure shortly after consuming caffeine. However, there is insufficient evidence to suggest any long-term effects on blood pressure or heart health.
People with sleep disorders: According to recommendations from the Sleep Foundation, it is advisable to avoid caffeine at least 6 hours before bedtime to maintain sleep quality. A study from the Journal of Clinical Sleep Medicine found that consuming caffeine 6 hours prior to sleep can disrupt sleep patterns. These findings are based on a level of 400 milligrams of caffeine, equivalent to about 4 cups of coffee. Although you may not consume that much caffeine in the afternoon, it clearly has a significant impact on sleep.
People with high anxiety levels: Nutrition expert Kelli McGrane mentions: “Caffeine is a stimulant that can exacerbate anxiety in some individuals. If you frequently feel anxious or panicked, you may want to consider avoiding or reducing caffeine intake.” Research from the Psychiatric General Hospital indicates that high caffeine consumption (about 5 cups of coffee per day) can trigger panic attacks in those with anxiety disorders.
Excessive coffee drinking can lead to osteoporosis. In fact, if you consume a small amount of coffee after a hearty breakfast around 10 AM, there are typically no issues. However, drinking large amounts of coffee daily, especially in the late afternoon or evening, can lead to health problems.

Coffee contains high levels of caffeine, which is associated with osteoporosis. According to a study published in the Journal of Orthopaedic Surgery and Research in 2006, caffeine may hinder the effectiveness of bone cells (cells involved in forming new bone).

“Caffeine also affects calcium absorption in the intestines and accelerates calcium excretion, potentially leading to bone loss. Calcium is essential for maintaining strong bones,” states Julia Thomson, a specialized nurse at the National Osteoporosis Society. Therefore, she advises limiting coffee consumption to no more than 3 cups per day and suggests adding milk, as coffee with milk can help counteract the calcium-depleting effects of caffeine.

So, how much coffee is reasonable for an average person to consume each day?

Doctors recommend that you should not exceed 4 cups of coffee per day (approximately 400 mg) to avoid undesirable side effects such as anxiety or stimulation.

Avoid drinking coffee immediately after waking up and on an empty stomach.

Vietnamese people often have a habit of drinking coffee every morning. However, please note that you should avoid drinking coffee immediately after waking up and on an empty stomach. Coffee beans contain acidic components that can irritate the stomach and intestinal lining. Drinking coffee on an empty stomach can cause the stomach to increase acid secretion, leading to diarrhea and irritable bowel syndrome.

Another note is that individuals with heart disease can consume coffee at a permissible level of about 170 mg per day, as caffeine increases the sensitivity of the nervous system, activating the cardiovascular system.

Many people wonder if coffee aids in weight loss. Doctors suggest that if you want to lose weight, you should drink black coffee without adding sugar or milk, as these will increase the calorie intake, preventing weight loss.

Coffee is safe for pregnant women. However, pregnant women should only consume 1-2 small cups a day, as excessive intake can lead to insomnia, nervous system issues, digestive disorders, and may affect the fetus.

Additionally, caffeine in coffee stimulates gastric secretion, which may lead to heartburn, stomach cramps, and reflux in some individuals.