Polyphenols: What are their benefits, where can you get them, and how can you get more from your coffee?

Over the last 6 months, I’ve been busy researching the depths of the science on polyphenols and their many health benefits. I’ve also been feverishly testing the polyphenol content of Exhale coffee brewed in different ways, something I’ve wanted to do for years. I learned so much that I didn’t quite know what to do with all of the information.

Then last month I was interviewed on The Doctor’s Kitchen podcast which helped me organise my thoughts. The plan was to share the highlights in our last email newsletter before our summer break, but it got so long that I just had to turn it into a blog! But if you'd rather, you can have a listen to or watch the podcast here.

I genuinely believe that if you read this blog, and follow the blueprint laid out in it, then you’re giving yourself the best shot at harnessing the immense healing power of the everyday foods we all have at our fingertips. Your dependence on expensive supplements will all but vanish. And you will feel superhuman again!

I’ll start with a quote I read online:

“A lack of polyphenols isn’t associated with specific side effects. But they’re regarded as “lifespan essentials” for their potential to reduce your risk of chronic diseases.”

 And how do they do this?

“Studies show that polyphenols are powerful antioxidants. In this role, they prevent or reverse damage in your cells caused by aging, the environment, and your lifestyle. Over time, this damage is linked to an increased risk of many chronic diseases.”

The benefits of polyphenols that are supported by science.

Thousands of studies have been published on polyphenols, here are the findings of a handful of recent ones:

• “Higher intake of polyphenols associated with lower inflammation measured using blood markers - CRP and fibrinogen” (1)
• 50% lower risk of dementia for higher consumers of polyphenols (2)
• 47% lower incidence of cardiovascular events (3)
• “An overall inverse association between polyphenol intake and CV risk events and mortality, as well as, between polyphenols and other outcomes of health status” (4)
• “Phenolic acids, a group of polyphenols mainly found in tea and coffee, had a strong inverse association with Type 2 Diabetes” (5)
• “Total dietary polyphenol intake was associated with lower SBP (serum blood pressure) among overweight and obese individuals (Blood Pressure)” (6)
• 20% lower all-cause mortality risk and a 40% lower cardiovascular mortality risk. (7)
• A diet rich in polyphenols slows down the biological aging process (8)
• Polyphenol consumption reduced GC (gastric cancer) risk by 29% (9)

The benefits weren’t just in adults with one study finding “A significant negative association between one unit increase in dietary polyphenol intake and risk of ADHD. We found that the increased dietary intake of polyphenols is associated with a lower risk of ADHD in preschool and school children.” (10)

There are of course loads more studies out there but I’ll stop there, but I think it’s safe to assume the research supports a broad range of benefits from higher intakes of polyphenols!

How much polyphenols do we need to consume to get these benefits?

Quantities very in every study, but in general it seems the average daily consumption is around 500mg to 900mg of polyphenols. The scale of benefits listed above seem to be achieved by consuming around 1g to 2g of polyphenols per day (1,000mg to 2,000mg) depending on the benefit.

Therefore, I think if we all aim to get 2 grams of polyphenols a day from our diets, we’ll be giving ourselves the best shot of living life to the full for many decades to come.

How much does coffee provide?

Coffee’s main polyphenols are chlorogenic acids (CGA) a group of phenolic acids. Coffee is packed full of them and in it’s unroasted state, CGAs make up 7 or 8% of coffee’s total weight!

Studies show the quantity of CGAs in coffee is massively variable with one study testing 104 espressos and finding they contained between 6mg (that was Starbucks, sorry guys) and 188mg of CGA in them (11). Needless to say, if you’re unknowingly drinking a coffee on the lower end (or even mid-range) of that you’re not doing much to help meet your 2,000mg daily polyphenol target!

I’m proud to share that just 1 cup of Exhale coffee provides between 350-415mg of CGA, double even the best in their list!

If you drink our recommended two cups of regular coffee and one cup of decaf (or three decaf) a day, which science clearly shows is the optimal amount to achieve the maximum health benefits from coffee (read more in our article), then you’re easily hitting 1 gram of polyphenols and so 50% of your daily target from Exhale coffee alone!

READ: How much coffee should you drink for maximum health benefits?

Can you get all your polyphenols from coffee alone? 

Technically, you could easily hit your quota by just drinking coffee, however, it’s recommended that you get your polyphenols from a variety of different sources as different polyphenols are more associated with different specific health outcomes. There is also research that clearly demonstrates that combining polyphenols means they work synergistically together to enhance the benefits of each other. Something I'm going to call 'polyphenol pairing'! But more on that in another blog (I have some exciting plans here...).

Do all polyphenols have health benefits?

Well, no actually. There are over 8,000 different polyphenols known, some aren’t very bioavailable at all (12) (meaning they aren’t easily usable by the body) and some just don’t seem to have any science-backed benefits (7) (possibly because they’re not bioavailable). So while we should aim for a variety of polyphenols in our diets, it’s a good idea to go after certain types.

How does coffee compare as a polyphenol source to the others?

Science-backed benefits

In 2023 a study (7) followed 12,161 Spanish people over 12.5 years and they tested 23 different subgroups of polyphenols. They found that only 7 subgroups of polyphenols showed benefits and the rest weren’t associated with any benefit at all. Those that were beneficial had a 20% reduced risk of all-cause mortality (death from any cause) and a 40% reduced risk of cardiovascular mortality. The good news for coffee drinkers is that coffee contains CGAs in significant quantities, which was in one of the 7 beneficial subgroups. Coffee also contains two of the other subgroups in small quantities.

Bioavailable

In 2021 a review published in Nutrients (12) ranked the bioavailability of the 7 classes of polyphenols and the class which CGAs are in (phenolic acids) was ranked as the most bioavailable of all! This means they are the type most easily digested and used by our bodies. It’s known that around a third of CGAs are directly absorbed as they pass through our small intestines and the remaining is broken down by our friendly gut microbes further along and we then benefit from the compounds they are broken down into. So as with many foods, a healthy gut helps you gain the maximum benefit from your coffee polyphenols.

Zero calories

Bioavailability, tick, science-backed benefits, tick, but how else does coffee compare?

Probably the biggest realisation I made was that coffee has a major advantage over other polyphenol sources… it has zero calories! Most other sources contain either sugars or fats so to get the equivalent 1 gram of polyphenols from consuming them you’d need to also consume a ton of sugar or fats as well. Not with coffee! There’s even decaf for those who can’t tolerate the caffeine in coffee. Ace.

On a side, if you’re someone who fasts, since coffee has no calories, it doesn’t break your fast. So it’s an incredible way of getting the benefits of polyphenols while you fast.

What other foods should you consume to hit your 2 grams per day target?

The foods that come up time and time again as either having bioavailable polyphenols or being associated with health benefits are the classics.

Here is my own personal blueprint for achieving 2 grams (2,000mg) of polyphenols a day from my diet and so reaping their many health benefits:

• 1,000mg – Three cups of coffee: 2 Exhale House Roast and 1 Exhale Decaf
• 250mg – 20-30g of dark chocolate
• 350mg – A big handful of mixed berries
• 100mg – 5 or 6 olives and 2-3 tablespoons of Extra Virgin Olive Oil (EVOO)
• 100mg – Cooking with mixed spices and herbs in any meal I can
• 200mg – A handful of mixed nuts and seeds

Total = 2,000mg

The above are all rough numbers, it’s not an exact science (unless you drink lab tested Exhale coffee of course!) but if you try to do all of those, every day, as well as adding dark leafy greens, and a variety of other fruits and vegetables into your diet, you’re onto a winner.

Choosing the best non-coffee polyphenols

With Exhale Healthy Coffee, we’ve done the testing for you so you know what you’re getting. But unfortunately, with other foods it’s more of an educated guessing game.

Perhaps one day we will see polyphenol content on the back of packs alongside calories, carbs and fats?! But until then, here are a few handy pointers:

Chocolate – Always go for dark chocolate, 20g contains something like 250mg vs just 35mg in milk chocolate.

Extra Virgin Olive Oil – This is incredibly healthy, but it’s overhyped as a good source of polyphenols. Even Bryan Johnson’s high polyphenol EVOO contains only 400mg in an entire bottle (13) which you can get from just one cup of Exhale coffee... for just 60p vs £35 for a bottle of his EVOO. You get more polyphenols from eating olives themselves so I eat 4 or 5 olives every day (but do use EVOO liberally for other reasons).

Red wine – This is a great source of polyphenols including an especially good one called Resveratrol which has a ton of science supporting its benefits. However it also contains alcohol which you may not want to drink on a daily basis! The good news is that red grapes contain more resveratrol, especially in their skin, so eating a few of those a day will tick the resveratrol box nicely. White wine (and so grapes) does contain some, but one cup of red wine has around 200mg of polyphenols vs 30mg in white wine so I assume it’s a similar relationship between red and green grapes too.

Spices and herbs – These are incredibly high in polyphenols, but of course you only have fairly small quantities of them. I have fun cooking with them in most meals. For example, I fry eggs for breakfast every day by sizzling freshly chopped ginger, garlic and turmeric root in butter, then adding whatever mix of spices and/or herbs I fancy that day.

As well as being a fun way to flavour your food and a great source of polyphenols, Dr Rupy recorded a cracking podcast recently on the many other benefits of spices. The bit on using them for wounds genuinely blew my mind.

LISTEN: The Doctor's Kitchen Podcast - #253 Sensational Spices and Healing Herbs with Simon Mills

How to brew coffee to maximise the levels of polyphenols

Here we go, the bit you’ve all been waiting for!

At Exhale we’ve done all we can to provide you with a coffee with the maximum possible quantity of CGAs (polyphenols) in. This is through our meticulous sourcing and roasting process. But I’m afraid the final hurdle is yours to jump, by brewing our beans in a way that extracts as much of these polyphenols as possible. 

Read about our entire process on the Our Process page of our website. 

Over the last month I've done a ton of testing comparing different brew methods and different ways of using them. Here are some conclusions I was able to draw:

Weight

The weight of the coffee used makes a big difference. Before you shout ‘No sh*t Sherlock’ hear me out...

Initially, I was shocked to find a double espresso, for example, extracted a total of 410mg vs just 350mg from a small cafetiere. But upon further analysis, I realised I brewed the espresso using 20g of coffee vs 17g for a cafetiere. This actually made a cafetiere slightly more efficient, extracting 20.9mg/g vs 20.5mg/g for espresso. However, with such a small difference, for all intents and purposes they’re basically the same if you brew using the same amount of coffee.

Volume of water

The volume of water makes a difference. Unfortunately for AeroPress drinkers, no matter how long I let it steep for, it just didn’t extract quite as much as other methods. One AeroPress still extracted a whopping 330mg, but even though I used 17g, and used a fine grind size, the maximum I could extract was 330mg, so 6% less than the equivalent amount of coffee in a cafetiere. I put this down to the fact that it only can fit 150ml of water in and AeroPress so I concluded you would need a brew method with little more water to extract any more. I look forward testing that in the coming months.

But fear not AeroPress users, even at 330mg you’re still getting loads of polyphenols… and you could always brew it with 18g or 19g of coffee instead of 17g!

Side note: Espresso, of course, uses much less water, and my double espresso in the test was 45ml (extracted from 20g in 25 seconds), but it extracts using pressure instead of just steep time. An AeroPress also uses pressure but only a relatively tiny amount of around 0.5 bar extra (so 1.5 bar total) vs 9 bar for espresso.

Steep time

The amount of time coffee needs to be in contact with hot water isn’t actually that long.

I brewed a cafetiere and tested after 3 minutes steep time, 5 minutes and 7 minutes and they all produced exactly the same amount - 350mg for 17g of coffee.

So by 3 minutes (and potentially even less) we now know that it has extracted the maximum amount possible (for a cafetiere) and letting it steep any longer will only effect it’s taste and body. But, I still recommend 5 minutes as I think it tastes better that way.

Paper vs steel filter

My testing showed that a paper filter doesn’t remove the CGAs from coffee. It removes some other healthy compounds in coffee called cafestol and kahweol, read more about that in our blog ‘Is it time to ditch the paper filters’. But when I tested medium ground coffee brewed using an AeroPress with a paper and a steel filter they contained the same amount of CGAs in them.

However, there was one big difference. When using a steel filter, either in a dripper or AeroPress, because of it’s wider mesh, you need to use a finer grind size… and this makes a huge difference.

Grind Size

Brewing coffee using a steel dripper, with 280ml of hot water and 17g of fine ground coffee, and a steep time of 2.5 minutes, yielded 415mg of CGAs.

Brewing coffee using a cafetiere, also with 280ml of hot water and 17g but of medium ground coffee, could only extract a maximum of 350mg of CGAs… no matter how long I let it steep for.

But why?

It took a while to get my head around this, but I concluded it was because of the grind size. It made that much of a difference.

It’s usually recommended to use a coarse grind size in a cafetiere but for years I’ve advised to use a medium grind instead. This is because I had a theory that the greater surface area of medium ground coffee would make the extraction of polyphenols more efficient and so you would end up with more in your brew.

My results above were using medium ground coffee in a cafetiere, I can only imagine what the result would have been with coarse ground coffee (I’ll test that too soon!).

The problem with a cafetiere is that if you use too fine a grind size the plunger won’t work and you’ll get a gritty cup of coffee. However with a steel dripper you have to use a fine ground coffee in order to get the best tasting cup of coffee. So in this case, the requirements for the best taste and the healthiest cup are beautifully aligned!

My theory is that in a cafetiere, the CGAs buried deep inside the medium ground coffee grinds are impossible to reach and extract so they remain locked away no matter how much time, water or heat you apply. This is why you can access more CGAs from fine ground coffee. My next phase of testing is to see how far I can push this – some methods such as the Turkish method use coffee ground so fine it’s like a powder! Watch this space…

Final thoughts

I have lots more testing planned, including other brew methods like a Moka Pot and Cold Brewed coffee. I also want to test more obscure methods like the Turkish Method. And I plan on testing our other coffees, and differing lengths of time after roasting and grinding.

But in the meantime here are a few final conclusions:

It seems a steel dripper, using fine ground coffee, produces the healthiest cup of coffee! It extracted 24mg of CGAs per 1 gram of coffee used so was the most efficient.

A cafetiere extracted 21mg/g, a double espresso 20mg/g and an AeroPress 19mg/g. Cold Brew left for 16 hours extracted just 17mg/g but we usually recommend 24 hours steep time so that could be more, watch this space.

But, and this is a big BUT, if you prefer using something else other than a steel dripper:

• You’re still getting a TON of polyphenols from your coffee if you drink Exhale however you brew it. Let’s keep things in perspective!
• You can just brew it slightly stronger, adding 1-2 grams more coffee, to achieve the same, or bigger, an effect.
• If you really are concerned about getting a little less polyphenols from your cafetiere, just use it as an excuse to eat a couple of cubes of dark chocolate while drinking it!

The steel dripper does have some drawbacks in that it’s a faff if making more than one cup of coffee, and you have to carefully make sure the water doesn’t pass through it too quickly, see our ‘Complete Guide to Brewing Healthier Coffee’ for our full instructions.

It’s sod’s law that just as I crown the steel dripper, our manufacturer stopped making them! But fear not, I’m in talks with a factory direct about manufacturing more, as well as using the above intel to invent two entirely new coffee brewers aimed at brewing the healthiest possible coffee ever in the easiest, most delicious, fool proof way. Don’t worry, I’ve got your backs!

If you want to read more on this topic, Dr Rupy has written an awesome blog on his The Doctor's Kitchen website, or you can listen to my interview on his podcast or watch the full episode on YouTube.

Happy brewing, hope you found this blog useful, let me know your thoughts in the comments below.

Al x

Exhale CEO and co-founder

 

(1) https://www.sciencedirect.com/science/article/abs/pii/S0022316624002827?via%3Dihub
(2) https://pubmed.ncbi.nlm.nih.gov/29703769/
(3) https://pubmed.ncbi.nlm.nih.gov/30459074/
(4) https://pubmed.ncbi.nlm.nih.gov/31208133/
(5) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7234961/
(6) https://pubmed.ncbi.nlm.nih.gov/38012598/
(7) https://pubmed.ncbi.nlm.nih.gov/37290979/
(8) https://pubmed.ncbi.nlm.nih.gov/34067821/
(9) https://pubmed.ncbi.nlm.nih.gov/36497359/
(10) https://pubmed.ncbi.nlm.nih.gov/36474220/
(11) https://pubmed.ncbi.nlm.nih.gov/25014672/
(12) https://pubmed.ncbi.nlm.nih.gov/33477894/
(13) https://blueprint.bryanjohnson.com/products/extra-virgin-olive-oil-x1