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Caffeine: The Good, The Bad and The Ugly

Caffeine swings in and out of favour, is periodically banned from competitive sport, and yet an estimated 1.6 billion cups are drunk worldwide every day. It is the most popular drink across the globe which explains why literally thousands of research studies have been dedicated to deciphering whether caffeine is good or bad for our health.

Here's a short summary of the findings:

Caffeine boosts mood and mental alertness; the 'pick-me-up' before a meeting, or the when you're struggling to hit a deadline. It triggers the release of dopamine which stimulates the pleasure centres in the brain boosting mood. Researchers have found coffee decreases Parkinson’s and Alzheimer's risk due to nervous system stimulation.

Caffeine can boost physical performance. A cup of coffee pre-exercise can increase endurance and therefore training output. Caffeine plays a glycogen sparing role, encouraging the muscles to use fat as fuel when training. It can decrease glycogen use earlier in the session by up to 50%, which has the effect of both saving glycogen for later in the session (increasing endurance), and upping fat burn. When I ran 12 marathons in 12 days I found chocolate covered espresso beans were the winner to give me a push for the last 5km.

Caffeine is a great antioxidant, which is compelling if you spend a lot of your working day in smoggy areas. It has four times the antioxidant levels of green tea. Switch to decaf and you reduce the antioxidant content by 15%.

Further studies have shown caffeine prevents crystallisation of cholesterol, reducing the risk of gallstones. It increases colonic activity, reducing transit time (time digested food hangs around before it is excreted) and thus the risk of colon cancer. It also appears to be protective against liver cancer (the World Cancer Research Forum have cited the evidence as compelling), and theophylline in coffee can protect against asthma.

Caffeine can stimulate the metabolism by up to 10%. However this stimulatory effect is not always positive. The diuretic effects of caffeine coupled with decreased transit time mean that some vitamins and minerals can be poorly absorbed – such as zinc, magnesium, iron, potassium, B vitamins and vitamin C. The effects of these vitamins and minerals are wide ranging within the body, and hence excess caffeine could pose a threat to various other systems. Taking morning vitamins alongside a cup of coffee is a no-go: you'll massively reduce the impact of your supplements. Similarly other medication should not be taken with your morning cuppa.

Excess caffeine can leach calcium from bones, leading to osteoporosis, while chemicals within both coffee and decaf can irritate the lining of the stomach causing digestive disorders, especially when consumed on an empty stomach.

The release of adrenaline and cortisol produced by caffeine can raise blood pressure due to narrowing of the arteries. It can reduce quality of sleep and also interferes with adenosine in the brain, which has a calming effect. If you're frequently feeling stressed out and can’t pinpoint a trigger, caffeine could be contributing.

Weighing up both benefits and potential risks, it seems to me (disclaimer: I love coffee) that moderate coffee consumption is beneficial. The FDA gives coffee ‘GRAS’ status (Generally Recognised as Safe), when consumed within suggested limits. However shop-bought coffees can send you over this 300 mg/day limit in one fell swoop - beware the mega sized cups!

Some final tips:

- If you’re concerned about your caffeine intake (moody, struggling to sleep, jittery...but enough about me) it’s definitely worth limiting your coffee shop trips to one a day, and adding in a couple of decaffs. You may find you're as addicted to the flavour and habit (needing something 'hot wet and brown') as the substance

- You could also try herbal teas or something like dandelion coffee (also hot wet and brown) and experiment with herbals for your afternoon or evening drinks particularly

- OBVIOUSLY you need to be mindful about whatever else is in your cup - syrups, full-fat milk, squirty cream...the 'festive coffees' can easily be 1/3 to 1/2 a day's calories which is fairly horrific. Black is best, but if you like milk give nut or oat milk a whirl for lower sugar/fat and higher protein

- Make sure you are drinking plenty of other fluids to ward off dehydration and gut issues

- If you're wired too late at night stop drinking coffee after 3pm - as a rule!


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