Drinking coffee can not only help you lose weight, but also reduce the risk of death? But many people don’t drink it right…

We feel sleepy in spring, tired in autumn, and nappy in summer. Spring seems to be particularly sleepy. Whenever we feel drowsy, drinking a cup of coffee to refresh ourselves is the choice of most coffee lovers.

In addition to refreshing the mind, coffee has also been proven to have many benefits:

It can reduce the risk of various cancers, inhibit tumor growth, reduce the risk of Alzheimer's disease and Parkinson's disease, reduce the risk of cardiovascular disease, reduce the risk of gallstones, and reduce the risk of all-cause mortality.

Now, coffee lovers have heard another exciting piece of news!

01

New study confirms drinking coffee can help you lose weight

On March 14, 2023, a study published in the British Medical Journal suggested that high levels of caffeine in the blood may suppress body fat levels and reduce the risk of type 2 diabetes. [1]

Although some previously published studies have found that drinking a cup of coffee with a caffeine content of 70 to 150 mg per day may reduce the risk of type 2 diabetes and cardiovascular disease, these studies are basically observational studies, so it is impossible to determine whether the effect comes from caffeine or other ingredients in coffee drinks, and it is impossible to clarify the causal relationship between caffeine and disease.

This study used a Mendelian randomization approach - because some people metabolize caffeine quickly after drinking coffee, while others metabolize it slowly.

The researchers found genes related to the speed of caffeine metabolism and recruited people with genes that metabolize caffeine slowly to conduct experiments. Because these people metabolize caffeine slowly, the caffeine content in their plasma will be higher, and the researchers use this to assess the impact of caffeine on physical diseases.

The results showed that caffeine content was negatively correlated with body fat percentage and the risk of type 2 diabetes . The higher the caffeine concentration in the blood, the lower the body fat percentage and the lower the risk of type 2 diabetes.

The researchers conducted further causal analysis and found that 43% of the effect of caffeine content on reducing the risk of type 2 diabetes was driven by weight loss.

That is to say, drinking coffee can help you lose weight, and losing weight naturally reduces the risk of developing type 2 diabetes. Researchers speculate that this is because caffeine can promote metabolism, increase fat burning, and reduce appetite.

It is estimated that consuming 100 mg of caffeine per day will increase energy expenditure by about 100 calories, which can help lose weight. However, the researchers also acknowledged that the study has limitations. First, the participants in the experiment were basically Caucasians, which had geographical limitations; second, the Mendelian randomization method used in the study had its own limitations and could not provide particularly conclusive evidence.

02

The pros and cons of drinking coffee

"profit":

In recent years, coffee has become more and more popular among Chinese people. Not only is its unique aroma and flavor fascinating, but its refreshing effect is also deeply relied upon by countless workers and students.

However, the benefits of drinking coffee are not limited to these. In recent years, coffee has been confirmed by researchers around the world to have multiple beneficial effects on health.

1. Drinking coffee may reduce the risk of colorectal cancer and liver cancer

An article published in September 2017 by Harvard Medical School professor Robert Schmerling showed that drinking coffee may reduce the risk of colorectal cancer by 15%, and drinking two cups of coffee a day may reduce the risk of liver cancer by 43%! [2]

2. Drinking coffee may inhibit breast cancer growth

In 2015, researchers from Lund University in the UK published a study in the journal Clinical Cancer Research showing that drinking coffee could inhibit tumor growth and reduce the risk of recurrence in women diagnosed with breast cancer and treated with tamoxifen.[3]

3. Drinking coffee may inhibit the growth of prostate cancer

In 2018, scientists from Kanazawa University and other institutions in Japan published a research report in the journal Prostate, stating that they had discovered for the first time that special compounds in coffee, cafestol and kahweol, may effectively inhibit the growth of prostate cancer. [4]

4. Drinking coffee may reduce the risk of cardiovascular disease

On February 9, 2021, the journal Circulation: Heart Failure published a study led by David Gao, a cardiologist at the University of Colorado Anschutz Medical Campus, which found that higher coffee intake was associated with a lower risk of heart failure. [5]

5. Two compounds in coffee may work together to effectively protect against Parkinson's and other brain degenerative diseases

In September 2022, scientists from Rutgers University in the United States published a research report in the journal Proceedings of the National Academy of Sciences, stating that a fatty acid derivative of the neurotransmitter serotonin in coffee called EHT may work together with caffeine to help fight the occurrence of Parkinson's disease and Lewy body dementia. [6]

6. Drinking coffee may reduce the risk of Alzheimer’s and Parkinson’s disease

In October 2018, scientists from the Krimbil Brain Institute in Canada published a research report in the journal Frontiers in Neuroscience, stating that a compound called phenylindanes produced during the roasting process of coffee may help reduce an individual’s risk of developing Alzheimer’s disease and Parkinson’s disease. [7]

7. Drinking coffee may reduce the risk of all-cause mortality

A study published in the Annals of Internal Medicine in May 2022 by Professor Mao Chen's team from Southern Medical University found that drinking 1.5 to 3.5 cups of coffee a day, whether it is instant coffee, ground coffee or decaffeinated coffee, whether sugar-free or with sugar, can reduce the risk of all-cause mortality by 28 to 31%!

However, the average daily energy intake of people who drank sweetened coffee was 150 kilocalories higher than that of the other groups.[8]

Disadvantages:

In December 2020, a research team from the Centre for Precision Health at the University of South Australia published a study in the journal Clinical Nutrition. They used data from 362,571 UK Biobank participants aged between 37 and 73 years old.

Focusing mainly on the relationship between coffee drinking habits and a series of diseases, the results showed that long-term, heavy (6 cups or more per day) coffee intake can increase the amount of fat in the blood and significantly increase the risk of cardiovascular disease (CVD).

This is exactly the opposite of the effect of drinking small amounts of coffee on lowering blood fat levels and reducing the risk of cardiovascular disease.

Studies have also found that excessive coffee consumption can increase the risk of osteoarthritis, joint disease, and obesity.[9]

03

Tips for drinking coffee

1. No more than 5 cups per day

Although coffee is good, you should not drink too much. So how much coffee should you drink every day?

While other research findings encourage us to drink coffee without worry, the previously mentioned study from the University of South Australia’s Centre for Precision Health reminds us that moderate coffee consumption is the best option for enjoying coffee and maintaining good health.

A team from the Harvard School of Public Health also conducted a large study in which they recruited many subjects who had never smoked. The risk of all-cause mortality decreased by 6%, 8%, 15% and 12% for subjects who drank no more than 1 cup, 1-3 cups, 3-5 cups and more than 5 cups of coffee per day, respectively.

The findings were published in the journal Circulation on November 16, 2015.

Combining the two studies, drinking no more than 5 cups of coffee a day and keeping the average daily caffeine intake below 400 mg seems to be a good choice. However, when drinking so much coffee, you should also pay attention to the sugar intake and try to choose sugar-free coffee.

2. Which type of coffee is better?

There are many types of coffee. How should we choose between instant coffee, freshly ground coffee, and decaffeinated coffee?

A study involving 460,000 people published in the European Journal of Preventive Cardiology by researchers at the University of Melbourne in Australia showed that volunteers who drank decaf coffee and ground coffee had improved multiple heart function parameters and a reduced risk of all-cause mortality.

However, there is insufficient evidence to support that long-term consumption of instant coffee improves cardiovascular health.[10]

The different health effects of different types of coffee may be due to the fact that they undergo different processing and contain different chemical components. For example, although decaffeinated coffee does not contain caffeine, drinking decaffeinated coffee can also help improve cardiovascular health and reduce the risk of death, indicating that other coffee components besides caffeine are also beneficial to health.

The study mentioned earlier by the Center for Precision Health at the University of South Australia suggests that the more unfiltered coffee you drink, the higher your blood lipids and the greater your risk of heart disease.

The researchers remind us to drink less unfiltered coffee, such as French press, Turkish coffee and Greek coffee, and less espresso, such as latte and cappuccino. They believe that filtered coffee and instant coffee are both good choices.

Since instant coffee also contains other food additives, we can make choices based on our actual situation in daily life.

References:

[1]Larsson SC, Woolf B, Gill D. Appraisal of the causal effect of plasma caffeine on adiposity, type 2 diabetes, and cardiovascular disease: two sample mendelian randomisation studyBMJ Medicine 2023;2:doi: 10.1136/bmjmed-2022-000335

[2]Robert H.Shmerling,MD. The latest scoop on the health benefits of coffee.Harvard Health Publishing, 2017

[3]AH Rosendahl, CM Perks, L. Zeng, A. Markkula, M. Simonsson, C. Rose, C. Ingvar, JM Holly, HC Jernstrom. Caffeine and caffeic acid inhibit growth and modify estrogen receptor (ER) and insulin-like growth factor I receptor (IGF-IR) levels in human breast cancer. Clinical Cancer Research, 2015; DOI:10.1158/1078-0432.CCR-14-1748

[4]Hiroaki Iwamoto, Kouji Izumi, Ariunbold Natsagdorj, et al. Coffee diterpenes kahweol acetate and cafestol synergistically inhibit the proliferation and migration of prostate cancer cells, The Prostate (2018). DOI: 10.1002/pros.23753

[5]Laura MS, et al. Association Between Coffee Intake and Incident Heart Failure Risk: A Machine Learning Analysis of the FHS, the ARIC Study, and the CHS. Circulation: Heart Failure (Originally published 9 Feb 2021)

[6]Tae-In Kam et al. Amelioration of pathologic α-synuclein-induced Parkinson's disease by irisin. Proceedings of the National Academy of Sciences, 2022; 119 (36) DOI: 10.1073/pnas.2204835119

[7]Ross S. Mancini, Yanfei Wang, Donald F. Weaver. Phenylindanes in Brewed Coffee Inhibit Amyloid-Beta and Tau Aggregation, Frontiers in Neuroscience (2018). DOI: 10.3389/fnins.2018.00735

[8]Dan Liu,MD et al. Association of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Coffee Consumption With All-Cause and Cause-Specific Mortality. Annals of Internal Medicine. 2022-05-31

[9]Ang Zhou et al, Habitual coffee intake and plasma lipid profile: Evidence from UK Biobank, Clinical Nutrition (2021). DOI: 10.1016/j.clnu.2020.12.042

[10]David Chieng.et al. The impact of coffee subtypes on incident cardiovascular disease, arrhythmias, and mortality: long-term outcomes from the UK Biobank. European Journal of Preventive Cardiology(2022)00,1-10

Produced by | Science Popularization China

Author｜Zeng Xinyue Popular Science Writer

Review | Gao Chao, Associate Researcher, Institute of Nutrition and Health, Chinese Center for Disease Control and Prevention