Three cups of coffee each day may be the magic number to reduce calcium deposits in the heart. Drinking much more than three cups doesn’t seem to boost the effect and may even hurt your heart health, according to researchers from the University of Sao Paulo who studied more than 4,400 coffee drinkers. Almost all of those in the study consumed caffeinated coffee. Coffee drinkers who had larger amounts of coffee had lower Coronary Artery Calcium (CAC) readings. Those who had more than three cups a day tended to have the lowest CAC scores, researchers found.

Scientists remained unsure whether it is the caffeine or the antioxidant properties in coffee that lowered calcium deposits on the aorta in the heart. “Coffee is a complex mixture of minerals and various components,” said Andreia Miranda, the study’s author.

Other scientists say decaffeinated coffee has the same impact as regular coffee in delivering health benefits. That belief leads the researchers to conclude that antioxidant plant compounds—not caffeine—may help lower blood pressure at healthy levels. Coffee’s antioxidants may also hold an amino acid found in red meats (homocysteine) at healthy levels, they say.

Previous studies indicate coffee reduces the risk of developing cardiovascular disease by 15 per cent and cuts the chance of a cardiovascular death by 19 per cent. The beverage also lowers the risk of developing liver cancer by 34 per cent and bowel cancer by 17 per cent.

These findings come a research team that reviewed the combined results of 201 published studies on coffee consumption. The team, which included experts from the University of Edinburgh, noted the large number of compounds that could make an impact on health. They said: “Roasted coffee is a complex mixture of over 1,000 bioactive compounds, some with potentially therapeutic antioxidant, anti-inflammatory, antifibrotic, or anticancer effects.”

They noted, however, that coffee seems to increase the risk of leukemia, lymphoma and lung cancer.

The Sao Paulo scientists did not indicate that drinking more than three cups of coffee each day would further reduce coronary calcification. “We have not tested the limit of cups of coffee for which there was a protection,” Ms. Miranda said. “Other studies have already shown that excessive consumption of this beverage may not bring health benefits.”

The new study from the University of Sao Paulo was published in the Journal of Journal of the American Heart Association.