London, Nov 23: Moderate coffee drinking is safe and three to four cups a day may have some health benefits, a study in the British Medical Journal (BMJ) showed. The University of Southampton researchers collected data on the impact of coffee on all aspects of the human body, taking into account more than 200 studies - most of which were observational, the BBC reported on Thursday. Compared with non-coffee drinkers, those who drank about three cups of coffee a day appeared to reduce their risk of getting heart problems or dying from them, according to the study. The strongest benefits of coffee consumption were seen in reduced risks of liver disease, including cancer. But Paul Roderick, co-author of the study, from the faculty of medicine at the University of Southampton, said the review could not say if coffee intake had made the difference. "Factors such as age, whether people smoked or not and how much exercise they took could all have had an effect," the BBC quoted Roderick as saying. "There is a balance of risks in life, and the benefits of moderate consumption of coffee seem to outweigh the risks," he said. However, the UK'S National Health Services recommends pregnant women have no more than 200mg of caffeine a day - two mugs of instant coffee - because too much can increase the risk of miscarriage. The researchers say coffee drinkers should stick to "healthy coffees" - which avoid extra sugar, milk or cream, or a fatty snack on the side.