Drinking three cups of coffee a day won't just give you an energy boost, it also could be the sweet spot for keeping your heart healthy, scientists have found.
While drinking too much caffeine may keep you up at night, in moderate amounts it could slash your risk of cardiometabolic diseases such as type 2 diabetes, coronary heart disease and stroke.
Researchers in China revealed drinking approximately 200 to 300 mg caffeine a day — the equivalent to three cups of coffee — was associated with a lower risk of new-onset cardiometabolic multimorbidity (CM), or at least two cardiometabolic diseases.
In fact, the scientists found that those who drink this amount of daily caffeine see their risk reduced by almost half, compared to those who drink less than one coffee cup per day.
The study, published in the Journal of Clinical Endocrinology & Metabolism, arrived at this conclusion using data from the UK Biobank.
The Biobank recruited more than half a million people aged 37-73 years from the UK between 2006 and 2010 and collected a wealth of data.
From these figures researchers excluded individuals who had ambiguous information on how much tea, coffee or caffeine they had.
The participants' heart disease outcomes were identified from self-reported medical conditions, primary care data, linked inpatient hospital data and death registry records linked to the UK Biobank.
Although everyone who drank coffee and caffeine had a lower risk of developing a new cardiometabolic diseases, those that reported drinking about three cups a day had the lowest risk, the study found.
The sweet spot was found to be between 200mg and 300mg of caffeine a day. For context, one mug of instant coffee contains around 100mg, a cup of tea contains about 47mg, while energy drinks can contain 80mg of caffeine in a small 250ml can.
'The findings highlight that promoting moderate amounts of coffee or caffeine intake as a dietary habit to healthy people might have far-reaching benefits for the prevention of CM,' said the study's lead author Chaofu Ke, of the Department of Epidemiology and Biostatistics, School of Public Health at Suzhou Medical College of Soochow University, in Suzhou, China.
However, the study also noted that people who drink more coffee were older, male and more likely to exercise.
They were also more likely to eat less processed meat, but fewer vegetables.
Study authors adjusted for these and multiple other factors in their analysis, including alcohol intake, BMI and kidney function to try and separate the effects of co-founding factors.
To find out why three cups of coffee is the perfect number study authors also looked at 168 participant's blood samples and looked at metabolites — small molecules produced when the body breaks down food.
Researchers found that in 80 of the participants who drank more coffee, their metabolites were significantly different to those who drank far less.
Some of these metabolites are associated with better health and some with worse, Dr Francis Perry Wilson of the Yale School of Medicine told Medscape.
Breaking down the results he explained that it shows coffee, tea, or caffeine intake has a big impact on metabolites of very-low-density lipoprotein (VLDL) — a type of bad cholesterol.
Caffeine appears to lower it, which is good for our health because higher levels can lead to heart disease, suggesting coffee could help protect us from it.
Although drinking caffeine has proven health benefits, some people are more sensitive than others and can experience palpitations. If you experience this the British Heart Foundation suggests you avoid caffeine.
The British Dietetic Association (BDA) advises that most people can safely consume up to 300mg of caffeine a day.
That's because studies have intakes of over 600mg a day to insomnia, nervousness, irritability, increased blood pressure and upset stomachs.
But if you are pregnant you should not consume more than 200mg of caffeine a day, as this could increase the risk of miscarriage or a low birth weight, the NHS warns.
