Can coffee prevent cancer?
There's good news on the horizon for coffee lovers, with research suggesting that it can reduce the risk of developing endometrial cancer by up to 25 per cent.
Originating in the lining of the uterus, endometrial cancer is one of the most common invasive gynaecological cancers.
In the US, where the research was conducted, the National Cancer Institute estimated that more than 46,000 new cases of the cancer would be seen in 2011 and 8000 people would die of the disease.
High levels of oestrogen and insulin are associated with an increased risk of the disease but researchers involved in the Nurses' Health Study from the Department of Nutrition at the Harvard School of Public Health have discovered that high-coffee-consuming women have lower levels of these hormones, compared with those who drink little or no coffee.
"This is an observational study - coffee intake is self-selected, not randomised - so our study cannot prove causal relationship between coffee and endometrial cancer risk, but we found an inverse association between coffee and endometrial cancer risk," reported study author Youjin Je, doctoral student at the Harvard School of Public Health.
"Four or more cups of coffee may contribute to lower risk of endometrial cancer by lowering levels of oestrogen and insulin which are related to endometrial carcinogenesis due to increased cell proliferation and reduced cell death."
To obtain their results researchers followed 67,470 women aged 34 to 59 from 1980 to 2006 and asked that they report every four years how frequently, on average, they consumed coffee over the previous year.
They then calculated cumulative average coffee intake to represent long-term consumption patterns for the individual subjects and found that those consuming four cups per day on average were 25 per cent less likely to develop the cancer.
And it's not just the caffeine that helps decrease the risk, with participants who drank two or more cups of decaffeinated coffee per day seeing a 22 per cent decrease.
Though Je points out that the data is less stable due to the low incidence of frequent use of decaf coffee and that both the caffeine and coffee itself is thought to work together to produce maximum benefits.
"We found an inverse association with two or more cups of decaf per day, although the link was less robust, and we did not find any association with caffeine containing tea consumption," she said.
"Thus, the benefit of coffee is likely linked to several bioactive compounds in coffee that act as antioxidants, reduce inflammation, and regulate insulin. Caffeine also seems to be partly responsible for the risk reduction by increasing oestrogen metabolism."
But before you run down to the coffee cart to order a full-cream double shot with two sugars be warned that a high intake of sugars and fats can counteract the proposed benefits of consumption.
"Based on scientific evidence, substantial amounts of sugar or cream can contribute to weight gain and insulin resistance, which is related to increased risk of endometrial cancer," said Je.
"Thus, women who typically added lots of sugar and cream to coffee may not have any benefits from coffee drinking against endometrial cancer."
Though consuming four cups of coffee each day is not advised for pregnant women, those controlling their blood pressure or with a sensitivity to caffeinated beverages, scientists say that it is perfectly safe for the rest of the population.
In addition to the reduced risk of endometrial cancer laboratory testing has found that coffee has strong antioxidant properties that protect cells, protein and DNA against oxidative damage by directly neutralising reactive oxidants or by modulating gene expression contributing to oxidative stress.
Which, in layman's terms, means that coffee has the potential to prevent a number of chronic diseases.
Research over the past few years suggests that coffee consumption may protect against type 2 diabetes, Parkinson's disease, cirrhosis of the liver, depression in women and other cancers - including aggressive prostate cancer.
However, the aforementioned groups who need to monitor or reduce their caffeine intake aren't entirely out of the loop with study authors recommending they drink decaf to get at least some of the benefits of coffee components.
"It's not at the stage where we would recommend women who don't drink coffee to start drinking," said Je.
"More large prospective studies should be done to further clarify the role of coffee among different subgroups. But, yes, women consuming coffee should feel reassurance that coffee in general is not a harmful substance, and may even offer some health benefits."
Sydney Morning Herald