The efficacy and side effects of black coffee the advantages and disadvantages of coffee

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Coffee, which was discovered thousands of years ago, is popular all over the world because of its special flavor and refreshing effect. it is the most flavor and health-preserving drink in the world.

Because coffee beans are rich in plant antioxidants, their antioxidant effects are even higher than those of cocoa, green tea and black tea. a study in the Journal of Nutrition also pointed out that coffee is the largest source of antioxidants in the adult diet. as a result, many people are surprised by their glasses.

When it comes to drinking coffee, most of the impressions are limited to refreshing, and in the past it was always considered to be irritating and easy to rely on, so it made many people both love and fear.

However, according to a number of epidemiological observations, drinking moderate amount of coffee is indeed beneficial to health and can reduce the incidence of many diseases (such as brain and cardiovascular disease, diabetes, liver disease, etc.)

What's the advantage of drinking coffee?

What are the recommended scientific empirical benefits of drinking coffee?

one. Promote metabolism, help burn fat, help lose weight

In the past, people only had to worry about not having enough to eat and become skinny, but now due to changes in lifestyle and excessive refinement of diet, the obesity rate remains high, and the overweight population has almost surpassed the slim population.

Losing weight is a journey that most people (especially women) have experienced, but most of the time they move forward aimlessly, and because of their different physiological structures, women have to undertake the important task of reproducing the next generation. therefore, it is easier to store fat, which helps to maintain body temperature and provide energy sources, so it is more difficult to maintain standard weight than men.

Several studies have found that caffeine in coffee can affect energy balance and increase heat production, which helps to increase the metabolic rate by 3-11%.

Another study found that caffeine helps dieters maintain weight. The underlying mechanism is that drinking coffee can increase energy consumption and reduce calorie intake (can have the effect of suppressing appetite, while combining coffee drinking with exercise can achieve better fat-burning weight loss effect (compared with exercise alone).

Slimming health food with body-lowering fat

two. Reduce the risk of liver cancer

Liver cancer is a common cancer of digestive organs, ranking fifth and eighth in the list of cancers in men and women, especially hepatocellular carcinoma (HCC).

Among the causes of hepatocellular carcinoma, 70% to 90% of patients have a history of chronic liver disease or liver cirrhosis. the main risk factors include viral hepatitis, alcoholic liver disease or non-alcoholic fatty liver. other obesity, diabetes, hereditary diseases and foods contaminated with aflatoxins

A comprehensive analysis of the literature shows that people who drink coffee can reduce the risk of hepatocellular carcinoma (Hepatocellular Carcinoma) by an average of 40%.

The same study also found that the hepatoprotective effects of coffee were consistent in any ethnic group or subgroup (such as gender, alcoholism, hepatitis or liver history).

In addition, a comprehensive analysis of the literature on dose-response analysis also showed that drinking 1 cup of coffee a day reduced the risk of liver cancer by 15% (but not significantly associated with the risk of biliary tract cancer).

Conclusion: demographic observation study found that people who had the habit of drinking coffee helped to reduce the risk of liver cancer.

three. Dementia (Alzheimer's disease)

Dementia is one of the diseases most feared by the elderly, of which Alzheimer's disease is the most, accounting for 70% of all cases. The prevalence rate has increased from 1% after 60 to 90 years old.

Alzheimer's disease is a neurodegenerative disease with initial symptoms including loss of memory and direction, impaired judgment, decision-making and language disorders, and even various mental symptoms in the middle and later stage. such as depression, apathy, anxiety, agitation, delusions, hallucinations, etc., making it difficult for the patients' families to take care of them.

An integrated analysis (Meta-analysis, including 11 prospective studies (prospective study) with a sample size of 29115) found that although drinking coffee did not significantly improve cognitive decline and dementia index, subgroup analysis found that it helped to reduce the risk of Alzheimer's disease (alzheimer disease) by 27% (those with the highest intake compared to those with the lowest intake).

The underlying mechanism is related to the fact that the ingredients in coffee can inhibit adenylate receptor antagonist (Adenosine Receptor Antagonists), so it can slow down the nervous system damage caused by the accumulation of type B amyloid plaque (beta-amyloid), but it remains to be confirmed by more verification.

four. Coffee and nonalcoholic fatty liver disease (Non-alcoholic Fatty Liver Disease)

Nonalcoholic fatty liver disease, an ectopic fatty liver disease (ectopic fat), is the most common liver disease in western countries, affecting about one in three people and usually asymptomatic (but non-specific symptoms have been reported including fatigue and right upper abdominal discomfort).

Fatty liver means abnormal accumulation of fat in liver cells (obesity and diabetes are the main causes). Depending on the degree, the progression of the disease can be divided from steatosis, steatohepatitis, fibrosis and even liver cirrhosis, and the most serious complication is hepatocellular carcinoma.

A systematic literature review and integrated analysis (Meta-analysis, including 5 studies) found that regular coffee drinkers contributed to a 29% reduction in the incidence of nonalcoholic fatty liver disease. In addition, drinking coffee can reduce the risk of progression to liver fibrosis by 30% in patients who already have non-alcoholic fatty liver.

five. Reduce the incidence of type 2 diabetes

Diabetes is one of the fastest growing diseases in the world, resulting from obesity, lack of exercise and poor eating habits. According to the World Health Organization, 9% of the world's people over the age of 18 suffer from diabetes. If blood sugar is out of control for a long time, it will cause irreversible symptoms such as blindness, amputation and kidney failure.

In many studies, it has been found that there is an inverse relationship between coffee drinking and the incidence of diabetes. The incidence of high intake is much lower than that of non-intake, and each cup of coffee can reduce the relative risk by about 7%.

In a large systematic review (Systematic Review) of 193000 men and women, people who drank 6 cups of coffee a day reduced their risk of diabetes by 35%, while those who drank 4-6 cups reduced their risk of diabetes by 28% (compared to those who drank less than 2 cups).

In addition, the Generation study (Cohort Study) (including 41934 men and 84276 women) also observed that men and women who consumed more than 6 cups of coffee a day reduced the incidence of type 2 diabetes by 54% and 29%, respectively (compared with non-drinkers).

The underlying mechanism is believed to be related to chlorogenic acid-Chlorogenic Acid and trigonelline-Trigonelline in coffee beans, both of which have been found to reduce blood sugar and improve insulin concentration (found in oral glucose tolerance test)

six. Reduce the incidence of cardiovascular disease

Cardiovascular disease is a health killer second only to cancer, especially for the elderly, with the characteristics of high morbidity, high mortality and high disability rate.

Clinically, it is also found that about 80% of cardiovascular diseases are caused by arteriosclerosis and vascular obstruction, which are not only prone to coronary heart disease, but also to heart failure, stroke and lameness (vascular obstruction of lower extremities).

In several early studies, it was suggested that coffee drinking may increase the risk of coronary heart disease (coronary heart disease), but it has been confirmed over the years that moderate coffee consumption is good for cardiovascular health.

In a large Finnish / Finnish study (including 59490 people for 19.2 years), it was found that women who consumed one to two cups of coffee a day reduced their risk of heart failure by 27% (compared to non-drinkers).

Another large observation of diabetics also found that drinking coffee reduced all-cause mortality (all-cause mortality) and the risk of dying from cardiovascular disease by 30 per cent.

seven. Reduce the incidence of stroke

Stroke is mainly divided into hemorrhagic and ischemic vascular lesions, because the brain is one of the most oxygen-consuming organs in the human body (10 times that of the heart). Once the cerebral vessels block or bleed when transporting oxygen or energy, the nerve cells are prone to injury. if the blood flow of the cerebral artery is interrupted for less than 30 seconds, the damaged cells may recover, and if interrupted for more than 5 minutes or even hours, the nerve cells will almost be destroyed. Therefore, it is very important to maintain the normal function of cerebral vessels.

One observation found that coffee drinkers may help reduce the risk of hemorrhagic stroke (Cerebral Hemorrhage) by 36%.

Other observations also found that people who drank 3 to 4 cups of coffee a day reduced their risk of dying from stroke by 23% (compared with those who drank less than 2 cups), while those who drank 5 to 6 cups decreased by as much as 36%.

eight. Improve sports performance

Whether you are a professional athlete or just an occasional sports person, improving sports performance through various scientific methods can not only give people a greater sense of achievement, but also enhance the motivation to continue.

In the study, it was found that caffeine can increase epinephrine in the blood, a hormone that is usually secreted in large quantities in the face of reactions such as fighting or flight, so that the body can cope with a large amount of physical exertion.

In addition, caffeine can also promote the release of fatty acids by adipocytes and enter the blood as energy.

Combining the above two effects, it is mentioned in a sports test integration analysis that caffeine can improve exercise performance, and the average score can be increased by 12.3% (especially in endurance exercises).

What are the side effects of drinking coffee? (disadvantages)

Most of the coffee-related side effects are related to excessive caffeine intake in the short term. Common adverse reactions include palpitation, rapid heartbeat, insomnia, anxiety, restlessness, tremor, headache, abdominal pain, nausea, vomiting, diarrhea, polyuria and so on. Abnormally high doses of caffeine can also lead to hypokalemia (hypokalemia).

Long-term coffee drinkers who suddenly stop or reduce the number of cups may develop caffeine withdrawal disorder (caffeine withdrawal). Common symptoms include headache, tiredness, irritability, difficulty concentrating, depression and so on.

Coffee drinking may increase blood pressure by 3-4 mm/Hg. For those who have coffee drinking habits, these effects will gradually disappear.

However, some studies have also pointed out that the emergence of tolerance is not complete, especially for some ethnic groups (such as hypertensive patients, overweight people, the elderly), it may have a strong effect on increasing blood pressure, so we should pay attention to avoid excessive caffeine intake.

Safety precautions (taboo)

Some drugs interfere with caffeine metabolism in the liver and may increase caffeine-related side effects (e.g. gastric acid inhibitor / Tagamet, antiaddict / Antabuseestrogens, antifungal agent / Diflucan, antipsychotic drug / Luvox, antiarrhythmic drug / Mexitil, antifungal agent / Lamisil)

For people with insufficient calcium intake, coffee intake (more than 4 cups, containing about 330 mg of caffeine) may increase the risk of osteoporosis

Excessive caffeine intake during pregnancy (more than 300 mg per day) may increase the risk of miscarriage (miscarriage) and fetal weight loss, but so far, the results are still inconsistent, but for caution, it is best to reduce your intake during pregnancy (no more than one cup).