Coffee: The Real Health Verdict — What Science Actually Says

Coffee, if you didn't already know, offers some great health benefits including reduced risk of cardiovascular disease, improved metabolic outcomes by helping regulate glucose reducing type 2 diabetes risk.

Regular coffee consumption has been linked to slower biological ageing, improved cognitive function and reducing the risk of Parkinson's and Alzheimer's. It has been shown to reduce the risk of some types of cancer, particularly liver and endometrial cancer, by protecting DNA and reducing inflammation.

Not everyone has time to read studies, meta-analyses and listen to experts such as Doctors, Professors and coffee experts. That's why we do it and tell you the summarised version here at NutriSavvy.

There does seem to be a consensus on the benefits of drinking coffee but there is some nuance. Not all brewing methods and types of coffee offer the same benefits so you could actually be doing more harm than good, especially for some people with certain conditions.

The good news is that you can significantly reduce the harmful outcomes from drinking the wrong type of coffee and maximise the benefits by drinking the right kind

So, I've already mentioned some of the benefits but not everything is definitive. Some of the benefits such as the reduced risk from some types of cancer haven't yet been proven in human trials. Prior to recent studies there were even indications that it may actually cause some cancers although the more recent studies have not found this to be true.

The Best Types of Coffee to Avoid LDL-Raising Compounds

Unfortunately the diterpenes (mainly cafestol and kahweol) that are the compounds thought to be anti-cancer also raise LDL-C. If you have high cholesterol or have a genetic predisposition that means your cholesterol blood levels are naturally higher then this will just increase your risk.

Key Points

Instant or paper filtered coffee has at least 90% less of the LDL raising compounds diterpenes, mainly cafestol and kahweol.

Unfiltered coffee can raise LDL cholesterol levels by roughly 0.56 to 1.67 mmol/L (10 to 30 milligrams per deciliter) within just a few weeks. That is a significant increase that could pushmany people into high cholesterol territory and increase the associated risk of a heart attack or stroke.

It's not all bad news though. If you choose filtered bean coffee or instant then a significant amount of the LDL raising compounds are removed.

The Health Benefits of Drinking Coffee

The consensus points towards coffee being a beneficial drink and consuming somewhere in the range of 3 to 5 cups of coffee a day is enough to benefit from the positives coffee has to offer. A BMJ umbrella review of 201 meta-analyses cited 3 to 4 cups whilst the European Food Safety Authority (EFSA) deems up to 400 mg caffeine/day, about 4 cups is safe for most adults, and up to 200 mg/day for pregnant or breastfeeding women.

As previously mentioned there are real health risks including raised LDL cholesterol and depending on your dosage and tolerance the effects of the caffeine. Choosing filtered or instant negates most of the risk from the diterpenes found in coffee.

Caffeine is a stimulant in coffee that has been shown to improve performance by an average of 2-7% when engaging in activities that require power such as sprinting or lifting weights.Similar benefits have been found with endurance events with a 2-7% performance boost.

The table above gives you an indication of levels of the compounds found in different types of coffee. The data was gathered from a range of reputable sources and peer reviews. I'd take this as an illustration as there are so many factors that can affect the levels of these compounds including water temperature, brew time, roast type, blends, when and where the beans were grown.

For reference the above table shows CGA levels in various brews of decaf. As you can see levels tend to be slightly lower compared to the equivalent caffeinated brew.

It is important to point out that you should not get too hung up on the granular detail but like with many foods and drinks we consume, use it as a guide. One big takeaway is never rely on a single source for your information, if it's wrong you are at best wasting your time and potentially doing harm. It is the main reason I started NutriSavvy, unless you, like me, are a bit weird and enjoy learning and researching you are not going to get genuine consensus information.

Chlorogenic Acids (CGAs) are a group of compounds that are thought to contribute to many of the health benefits of drinking coffee. As you can see from both the table the levels of CGAs in coffee vary quite a lot depending on raost and coffee type. You can see that drip filtered coffee (generally tastier than instant) contains a good balance of good chemicals and low levels of the LDL raising diterpenes.

The chlorogenic acids found in coffee are thought to be potent antioxidants that reduce oxidative stress, improve glucose metabolism as well as improve insulin sensitivity. It has also been linked with a lower risk of type 2 diabetes.

The risks associated with drinking various brews of coffee including instant are low. You do however have to be mindful of your caffeine intake, especially if you are nursing or pregnant. The other notable risk is from cafestol and kahweol which has been shown to raise LDL-C often referred to as bad cholesterol although it's not really the cholesterol that is bad it's just that the overwhelming evidence indicates that those with high LDL-C levels are at a higher risk of heart disease. To avoid this risk just drink instant coffee or filter your bean coffee.

Coffee consumption is associated with a reduced risk of heart attacks by about 25%. This is supported by epidemiological studies that show coffee drinkers have lower rates of cardiovascular diseases.
James Hoffmann and Professor Tim Spector

CGA may lower blood pressure however the Kozuma study published in PubMed (PMID: 16820341) showed a reduction in blood pressure in both mice and humans but the CGA was extracted from the un-roasted green coffee beans. Roasting reduces the levels of the beneficial compound. A crossover study comparing black (roasted) and green (un-roasted) beans found that the same positive benefits were not achieved.

I couldn't find any further data but the benefits may have come from the much higher CGA levels in green beans and much lower levels of caffeine. Logic would suggest consuming more CGA rich decaffeinated coffee may achieve similar benefits.That's around the recommended 3 to 4 cups a day. The mechanism at work is nitric oxide which relaxes the blood vessels allowing blood to flow more easily reducing pressure.

So there are no direct studies I could find proving this but it sounds like the mechanism should work just the same. If you like coffee the drinking the recommended safe amount, even decaf, there is potential benefit with little to no harm. Caveats do existing to pregnant and nursing mothers and those sensitive to caffeine.

CGA improves blood sugar according to study on chlorogenic acid intake. Doses of CGA at 13.5mg to 1200 mg can reduce fasting blood glucose (FBG), improve glucose tolerance, enable weight loss and prevent weight gain. Another study of 57 women also showed chlorogenic acid extract reduced the blood levels of sugar and an indicator of diabetes (HbA1c) before meals.

Does Adding Milk to Coffee Negate the Health Benefits?

A study on the effect of simultaneous consumption of milk and coffee on chlorogenic acids’ bioavailability in humans indicates that adding milk to your coffee can reduce the bioavailability of CGA in the coffee. Milk proteins, particularly caseins, can bind to CGAs, potentially inhibiting their absorption in the digestive system. This interaction may lead to a decrease in the health benefits associated with CGAs, as they are not fully absorbed and utilized by the body.

Whilst there is no long term data on the impact of adding milk to coffee a 10% reduction was cited in the study by Duarte GS and Farah A, which indicates that milk proteins can bind to CGAs, potentially inhibiting their absorption.

You could negate the impact by drinking some black coffee, if I make ground filter coffee at home I don't use milk. If you are going to that effort over instant then you want to get the best out of the taste. You could also choose a light roast coffee that contains much higher levels of CGA.

How Much Coffee for an Effective CGA Dose?

One study on chlorogenic acid intake guidance suggests doses of 13.5-1200 mg offer the health benefits from drinking coffee but ≥200 mg/day seem to offer more optimal benefits whilst the BMJ umbrella review states 300–500 mg/day (about 3-4 cups) for metabolic benefits in clinical studies. As for safe upper limits there doesn't seem to be enough data to offer any specific numbers, however there's only so much coffee you can drink in one day.

How Much Caffeine is in British Decaf Coffee?

Switching to decaf reduces the amount of caffeine by about 97% according to Wikipedia (based on FDA rules) however a 2006 study found caffeine levels in caffeinated drinks at 1-2% but found levels as high as 20% in some. The UK follows EU regulations that limit decaf coffee to 0.1% for roasted beans and 0.3% for instant coffee so about 2 – 15 mg of caffeine per decaf cup.

Some individuals cannot tolerate caffeine at all, I once spoke to a lady who could not even drink decaf even when most of the caffeine is removed. Everyone is different an some people can tolerate the drinking endless cups whilst others suffer and find it interferes with sleep even at low consumption levels.

Instant coffees available in the UK with the highest anti-oxidant levels.

Most coffee consumed in the UK is instant and drunk at home. About half of the coffee consumed outside the home is ground coffee.

With this in mind, you'd get the best benefit from a light or medium roast, and instant coffee is the preparation of choice due to its convenience.

However, most instant coffee available in British supermarkets is dark roasted, which means significantly lower levels of health-giving polyphenols.

I've dug around, and there isn't much in the way of light or medium roasts—at least not those that explicitly specify the type of roast.

Most instant coffees are dark roasted to mask poor bean quality, maintain as much flavour as possible (since instant coffee loses flavour during processing), and to deliver a product that’s more cost-effective and acceptable to consumers.

Instant coffee still retains about 70 to 80 percent of the polyphenols, although none of the products actually state these levels. These numbers are inferred from studies on a range of instant coffee types.

What we do know is that choosing a light roast (or even a medium) means significantly higher levels of protective CGAs compared to the more commonly available darker roasts.

Arguably, darker roasts offer a more noticeable flavour—but much of the health benefit is lost. Lighter roasts are more delicate, yet they pack a much stronger antioxidant punch.

To give you an idea of what types of coffee have the most polyphenols the table below shows estimated level of CGA's per 100ml. We can only estimate the range as the levels are not specifically implied on the manufacturers labelling.

Instant Coffees in Main UK Supermarkets (Light/Medium Roasts)

These are the products I found that specifically state the roast type, unfortunately the range is very limited but these are available in most of the major UK supermarkets.

I also checked online and Amazon has some light and medium roast instant coffee and they also have a decaf version for when you still need coffee but its the afternoon and you really need to sleep at night.

These are affiliate links so if you do buy you are helping support my coffee habit the work that goes into the NutriSavvy site.

Summary of the Science on Coffee

If you are already a coffee drinker then getting your 2 to 4 cups of coffee a day, caffeinated or decaf, instant or filtered coffee in a light or medium roast will get you the health benefits according to the science.

If you are not a coffee drinker then it is well worth trying considering there are few equivalent foods or drinks that offer the same high levels of polyphenols. Although blueberries contain around 200–400 mg per 100g about the same as a regular mug of light roasted instant coffee.