Coffee consumption has been reported to decrease oxidative damage in peripheral white blood cells (WBC). However, effects on the level of spontaneous DNA strand breaks, a well established marker of health risk, have not been specifically reported yet. We analyzed the impact of consuming a dark roast coffee blend on the level of spontaneous DNA strand breaks.
Your DNA gets damaged in a variety of ways, and when your DNA repair mechanisms can’t fix it or don’t fix it correctly – you get mutations and improper protein function (because your cell is accessing corrupted data). This can lead to constantly active growth signals or inactive anti-growth signals, both of which will lead to cancer. On the flip side, DNA can be mutated into overall lack of function, which leads to cellular aging – effectively organism aging.
What they did in this experiment was measure in peripheral white blood cells for a single type of DNA damage, the strand break. As the name implies, a strand break is when one or both strands of a molecule of DNA break apart. This is a nasty type of damage – a double strand break can cause chromosomal translocations, which is where two different chunks of broken DNA are put together to potentially result in improper genetic function. For example, the “always active” switch of a tumor suppressor gene may be fused to a gene coding for a protein that promotes cell proliferation, which will promote cancer. If a single strand break occurs, improper repair of the strand can lead to new mutation on its own.
The study findings indicate that those who drank 750 ml (~3 cups) of coffee per day experienced 27% fewer strand breaks in white blood cells than those who only drank water, controlling for diet and body weight. Why did they look at white blood cells? Leukemia, literally meaning “white blood,” is cancer of the white blood cells.
Would decaffeinated coffee has the same effects?
According to this study, that caffeine is not the significant DNA damage-preventing chemical in coffee. But that’s only one study. Still…
Current evidence suggests that coffee consumption is associated with a reduced risk of liver, kidney, and to a lesser extent, pre-menopausal breast and colorectal cancers, while it is unrelated to prostate, pancreas and ovary cancers. Coffee drinking may still help reduce death due to liver cancer. But they aren’t quite sure what the reason for coffee being good – it’s not solely caffeine, so they’re wondering if it’s a combination of caffeine and other things in coffee.