Love your coffee? Here’s another reason to pour yourself a cup. A recently published study should the consumption of a dark roasted coffee brew (500ml) daily for one month resulted in a 23 percent reduction in DNA damage to white blood cells compared to baseline levels. The protective feature of coffee is thought to be the polyphenols that are found in coffee. These bioactive ingredients (such as caffeic acid, catechol, hydroxyhydroquinone, trigonelline and the alkylpyridinium compounds) have been studied for their antioxidant and anti-inflammatory properties. They are able to mop up reactive oxidative stress (ROS) molecules that are the byproduct of metabolism. Obviously a small amount of ROS is necessary, however too much can overwhelm our anti-inflammatory and antioxidant system, causing increased inflammation and the reduction in the ability for these pathways to function, causing DNA damage.
DNA damage accelerates ageing and is the underlying cause of the growth of carcinogenic cells in the body. It leads to telomere shortening – telomeres are like small caps on the end of your DNA chromosomes, protecting them from damage, and are used as a biomarker for ageing. The study was a randomised controlled trial; therefore, it is able to establish causation (unlike a lot of nutrition research, which is largely observational in nature).It is consistent with other studies that show a reduction in DNA damage after even short term exposure (such as this study, where healthy volunteers showed a reduction in damage after only 2h of drinking coffee). The current research was conducted in both healthy men and women, and the 500ml of coffee per day equated to around 372mg caffeine daily – equal to around four cups of espresso. That sounds like a lot of coffee (and it is!) however this is consistent with other observational and clinical trial research that has shown a reduction in cardiovascular disease risk, cancer incidence and all-cause mortality for people who habitually consume around 4-5 cups of coffee per day. This latest study adds to a body of knowledge regarding the health benefits of coffee. The polyphenols mentioned above help protect us from type 2 diabetes, stroke and cardiovascular disease, with improvements being seen in glucose and insulin metabolism (important for blood sugar control), blood pressure and markers of inflammation in the body.
I’ve talked before on the health benefits we see in coffee, and though this is great news for coffee drinkers, let’s not forget there is a fairly substantial proportion of people who are sensitive to the caffeine in the coffee and can’t tolerate its stimulant effects. Caffeine is metabolised in the liver, with the CYP1A2 enzyme responsible for detoxifying most of the caffeine. Our ability to produce this enzyme is coded by our genes, and there is variation as to how active this is for each individual. Those that have an active gene are able to metabolise caffeine efficiently, therefore the stimulating effects of caffeine are mild and short-acting. This may affect their enjoyment of caffeine and clearly their ability to tolerate it. The opposite is also true – someone with reduced activity of the gene will metabolise caffeine more slowly and its effects will be longer lasting and more noticeable. You can find out your genetic ability to tolerate caffeine through a Fitgenes DNA test(PM me for more information). In addition to the genetic differences, environmental elements also influence our ability to tolerate caffeine. Even if you are a fast metaboliser, stress and lack of sleep can impact on caffeine’s effects – ramping up cortisol levels and with it anxiety and blood sugar dysregulation. Three coffees a day when on holiday and in a relaxed state may not be a problem, however when a work deadline is looming and you’ve been running on little more than petrol fumes rather than sleep, it is a different story.
With the present research, as the health benefits are from polyphenols present in the coffee, rather than the caffeine, the reduction in DNA damage may well be seen in decaffeinated coffee too, with previous research finding benefits with regards to type 2 diabetes and liver damage when consuming both decaffeinated and caffeinated coffee. has found health benefits from drinking this. However, without clinical trials to confirm this, at this stage it is unknown.