What are the side effects of drinking coffee? What happens if you drink too much coffee? which brand of instant coffee tastes good?

Professional coffee knowledge exchange more coffee bean information please follow the coffee workshop (Wechat official account cafe_style)

The advantages and disadvantages of drinking coffee

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 efficacy is even higher than that of similar 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 broke 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.)

The benefits of drinking coffee:

What are the recommended scientific and 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 thermogenic effect (thermogenesis), which helps to increase metabolic rate by 3-11%.

Another study found that caffeine helps dieters maintain weight, and the underlying mechanism is that drinking coffee increases energy consumption and reduces calorie intake (which may have an appetite-suppressing effect). If you can combine coffee with exercise, you can achieve a better fat-burning weight loss effect (compared with exercise alone) Note 4

Three kinds of slimming health food for reducing body fat

two. Reduce the risk of liver cancer

Liver cancer is a common cancer of digestive organs, ranking fifth and eighth respectively in the list of cancers in men and women, especially hepatocellular carcinoma, accounting for about 80%.

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 literature analysis (meta-analysis, including 16 observational studies of liver cancer population) found that subjects with coffee drinking habits reduced the risk of hepatocellular carcinoma (Hepatocellular Carcinoma) by an average of about 40%. Note 1

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, the literature integration analysis on dose-response analysis also pointed out (meta-analysis, including 18 demographic studies) that drinking one cup of coffee a day reduced the risk of liver cancer by 15% (but was not significantly associated with the risk of biliary cancer). Note 2

* conclusion: demographic observation studies have found that people with coffee drinking habits can help 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 35% at 90.

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 coffee drinking 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 least intake) note 26

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.

Three health foods that reduce the risk of dementia (the first most common)

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. Note 2

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 reduced the risk of progression to liver fibrosis by 30% in patients who already had non-alcoholic fatty liver disease. Note 1

Three kinds of health food beneficial to fatty liver (the first is very common)

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.

Many studies have 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, those 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.

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 have the effects of lowering blood sugar and improving insulin concentration (found in oral glucose tolerance test) note 8

Three kinds of health food beneficial to diabetes

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 after years of validation, moderate coffee drinking is still 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.

Four kinds of health food which are beneficial to cardiovascular disease

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%. Note 13

Other observations also found that people who drank 3-4 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. Epinephrine is 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 bloodstream as energy.

Combined with the above two effects, it was mentioned in an exercise test integration analysis (Meta-analysis/ includes 40 double-blind trials) that caffeine can improve exercise performance, and the average score can be improved by 12.3% (especially for endurance exercises) Note 16

Coffee beans

The disadvantages of drinking coffee?

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.

Drinking coffee may increase blood pressure by 3-4 mm/Hg. For those who have coffee drinking habits, these effects will gradually disappear (due to the development of tolerance).

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