Coffee, friend or foe?
Photo by Siobhan Calder
I’m afraid there is no easy answer to the above question and it is likely to fluctuate throughout our lives. At points, sitting firmly within best friend territory and at other times, it may be your worst enemy (a see-saw relationship a bit like that flaky friend at school). Why? Because it’s so dependent upon not only your baseline caffeine tolerance, but also what else you are experiencing within your life e.g. stress, anxiety, sleep issues, trying to conceive (TTC), menopause etc.
Understanding a little more about coffee’s pros and cons is key in making the right decision for your health & wellbeing.
Let’s start with the pros..
First things first, the joys coffee can bring…it’s a ritualistic process; the smell, the taste, the anticipation. Some of my best memories involve hunting down the best coffee spots, whatever country we are in. Luckily, I have a serious appreciation for it, even if I didn’t, my Antipodean man would drag me on his constant quest for the perfect cup. Stumptown, Blue Bottle, basically everywhere in Australia & NZ, our old London favs Story, Birdhouse and Monmouth – I salute you all. Those old sleepless, palpitation-filled nights following one too many Espresso Martinis, I think I even salute you too.
There were associations* between consumption and a lower risk of several specific cancers, neurological (e.g. Alzheimer’s), metabolic (e.g. diabetes type 2, metabolic syndrome) & liver conditions (1). *remember, this is an association and not causal, so sadly it doesn’t mean drink a bucket of coffee and reduction of said disease is guaranteed, other factors may be at play.
These potential health benefits are likely to result from:
Antioxidants: Coffee is high in antioxidants (antioxidants are helpful molecules that fight free-radical damage in the body). In fact, studies found that coffee contributes more antioxidants to the Western diet than fruit and vegetables (!) (2,3). Pretty.Crazy. I’d always advocate getting a colourful rainbow & variety of plant foods in the diet to increase antioxidant intakes vs upping your coffee intake.
Polyphenols & our gut bacteria: Human trials have found moderate coffee consumption (3 cups/day) can positively impact gut bacteria (4), potentially due to its polyphenol content (these are micronutrients we get from plant foods loaded with potential health benefits). Remember, good gut health (i.e. happy & balanced gut bacteria) is critical for good physical & mental health.
So, what’s the best type of coffee?: Interestingly, studies have found that the polyphenol content and antioxidant activity are dependant both the coffee’s origin and the degree of roasting. A study found longer roasting times = greater break-down of polyphenols, so, the highest polyphenol concentrations were found in lightly roasted coffee. Simple? Sadly, not. As they also found with increasing degrees of roasting the antioxidant activity increased, with strongly roasted coffee having higher activity than lightly roasted coffee. However, overall from a nutritional standpoint, the researchers concluded that the most favoured coffees were those lightly or medium roasted (5).
Now, let’s flip over to the cons…
Your unique metabolism: Research shows genetic variation can impact our response, So, don’t fear, if you feel like you can’t tolerate it and everyone else is enjoying their flat whites or espresso martinis; you’re not alone & it could be within your genes. One of the key genes dictating this is called CYP1A2, this gene contains instructions for an enzyme that breaks down 95% of the caffeine you consume. So, different variants of this gene mean we could be ‘slow or fast metabolisers’ of caffeine. Slower metabolisers tend to have a lower tolerance and can experienced increased negative impacts of caffeine, including caffeine-induced anxiety (6).
Sleep: Caffeine impacts the body fairly quickly, reaching a peak level in the blood within 30-60 minutes. Yet, it’s half-life (time taken for the body to eliminate one-half of the caffeine consumed) is on average 5 hours. But this depends on many factors including age, weight, medication, genetics, and liver health. It can range from 1.5 to 9.5 hours. This is important to consider when reviewing that afternoon coffee’s impact on our sleep! If you’re feeling tired and worn down, be mindful that coffee may exaggerate these symptoms. It might be worth trying to limit if after midday to try to ensure it is cleared the system for sleep.
Dependency: Do you reply on that morning coffee to wake you up? How do you feel if you cut it out? Caffeine withdrawal does exist, even when consuming fairly low doses (e.g. 100mg/d, that’s just 1 daily latte or flat white). The symptoms include headache, fatigue, depressed mood, irritability, and decreased happiness. Symptoms generally increase in severity with increased daily dose. Onset is typically 12-24 hours after abstinence and can peak at 20-51 hours (7). So, if you’re trying to reduce your intake, know these will pass and there are things you can do to ease symptoms. If you just cannot imagine getting through the day without coffee, perhaps it’s time to uncover factors that could be contributing to those slumps in energy.
Hormone balance: Some studies have found coffee consumption can increase our cortisol levels (ak.a. our stress hormone) in the evening (8). Cortisol has a natural pattern throughout the day, decreasing in the evening, preparing us for sleep. High cortisol in the evening can leave us feeling ‘tired but wired’. Irregularities in our cortisol balance tends to tip off the delicate balance of our other hormones too. Key to consider in blood sugar regulation, or hormonal conditions such as PCOS.
Adrenaline & nervous energy: Caffeine causes a release of adrenaline. Therefore coffee intakes have been found to amplify the increases in blood pressure and heart rate that are associated with higher levels of self-reported stress during the day, this indicates it can exaggerate our sympathetic nervous system response (like a foot on the accelerator) and increase stress reactivity (9). If we’ve got a hectic day at home or work, rushing from event-to-event, it can be so easy to rely on another coffee to keep us going; but it’s really important to consider this effect. The coffee can just exacerbate our stress response, leaving us feeling further on edge & potentially hindering performance.
Nutrient absorption: Caffeine does have the potential to negatively impact our health if not consumed in moderation. It can cause depletion of key nutrients such as vitamin B6 (deficiency can cause mood changes, tiredness & low energy), alongside interfering with the absorption of minerals such as calcium, iron and magnesium (10). Another reason why moderation (<3cups/d) is key, or reviewing if it’s friend or foe at different periods within your life is key (e.g. unwell, infections, high stress etc).
Chemicals: coffee is said to be one of the most heavily sprayed crops when it comes to chemicals - think insecticides, herbicides, pesticides etc. Buying organic ensures that you avoid exposure to these harmful chemicals, as well as supporting often socially and environmentally progressive cooperatives. It’s not only what it is sprayed with, but if not dried or stored properly coffee can become the perfect growth medium for moulds and yeast. Mycotoxins are toxins formed by yeast and moulds, which can pose a 'serious risk to human health', and regular coffee consumption (particularly in high quantities) can contribute to exposure. Good manufacturing practices and hygiene standards during coffee production is strongly recommended to reduce the risk of contamination in coffee. This is why I always recommend purchasing your coffee from a trusted brand. My favourite in the UK, is Exhale. They have strict procedures in place for processing, transport, Organic standards, and testing any coffee they sell for mycotoxins, yeasts, mould, pesticides, and heavy metals. They don’t only focus on ensuring the coffee is free from the “bad stuff” but also that it is higher in the “good stuff”; testing for antioxidants and vitamins. If you fancy trying their coffee, get £10 off using this link or the code ALEXANDRAMARIE. (I am an affiliate, but only because I totally agree with their values, know they are credible from the lab testing they conduct and certificates they share).
Photo by Siobhan Calder
HOW MUCH COFFEE IS TOO MUCH?
A very umbrella review of 201 meta-analyses (a meta-analysis statistically reviews evidence from other studies) of observational research concluded coffee consumption is generally safe within usual levels of intake. Guidelines recommend 400mg caffeine / day or less. That’s around 3 cups of coffee. Remember caffeine also comes from (although to a lesser extent) cola, energy drinks, black tea, green tea and chocolate…so they will all add to that total. However, I think given many people benefit from less than this.
does coffee impact fertility?
There is no simple answer. For the men - a systematic review (which pools data from numerous studies) found semen parameters where not significantly impacted by caffeine intake. However, male coffee drinking was associated with prolonged time to pregnancy in some, but not all, studies. And caffeine intake was associated with some markers of DNA damage in sperm (11) (remember, association isn’t causation). Some studies also suggest lower IVF success rates with men drinking 3+cups/day vs those who consumed >1 cup/day.
For women, as mentioned in the cons it can impact hormonal balance, cortisol and blood sugar. There isn’t enough evidence to say for certain if caffeine can cause fertility problems, however, some evidence suggests high consumers (4-6+ cups/day) were associated with higher miscarriage rates, and lower ART (e.g. IVF) success rates.
Remember in pregnancy, no more than 200mg/day of total caffeine is recommended. That’s covered in a single espresso shot from some take away retailers. This helpful article lists how much caffeine you’re likely getting from different chains, which can really differ.
what about decaf?
A couple of points to remember when opting for decaf.
It doesn’t remove 100% of the caffeine, so check levels that could remain.
Opt for water-processed decaf coffee, also known as Swiss-Water process. More of the caffeine tends to be removed and it also uses just water instead of chemicals. Another shout-out to Exhale for their naturally-processed decaf, which I love.
Photo by Siobhan Calder
to sum up…
Remember coffee contains beneficial compounds, which can vary depending on origin and roast. Research has found there are potential associated health benefits with consumption. However, it also has some disadvantages. It is completely personal, based not only on your lifestyle but also genetics. If you’ve got a lot on, are feeling stressed, jittery, anxious, or struggling with sleep; it could be wise to trial reducing your coffee consumption, particularly restricting caffeine post-lunch given the time it may take for your body to excrete the caffeine. Remember, withdrawal effects may be felt, but these will pass.
some golden coffee rules
Try to enjoy your coffee after your food in the morning. This may help buffer the effect, and help protect those adrenals.
Minimise coffee after midday. If you find it impacts the quality of your sleep, you could be a slower metaboliser of coffee. Stopping intake after midday can help ensure caffeine’s effects have diminished by bedtime.
If you’re feeling particularly anxious, perhaps take a break and opt for an alternative (check out an upcoming post on matcha, yes it contains caffeine but has a secret little substance that can buffer the caffeine jitters). Or opt for caffeine-free alternatives.
If you’re TTC, potentially look to reduce or eliminate caffeine consumption. And, keep within guidelines when pregnant.
If you’re opting for take-away, pretty please do not drink through the plastic lids. Read more about this here.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482951/