What you need to know about coffee and Health

Coffee. Morning Brown. Many of us love it. Some of us fear it. It’s one of the mostly commonly consumed beverages on the planet, therefore any health effects are on a population scale.

Coffee has connotations with negative health. “I really need to cut down on my coffee” or “ I decided to quit coffee” are frequent statements heard from patients. Often the reasoning behind this is not clear, but I suspect general messaging within social media, the ‘addictive’ nature of caffeine (and subsequent ‘need’ to detox), or additives such as sugar/milk and contribution to weight may play a role.

We often just perceive coffee as the elixir for focus and revival. Unable to function until we have that first (or second) brew of the day. If only we could claim it on tax as a work-related expense. It’s also a fantastic excuse for a social catchup, as evidenced by the thriving cafe culture on Newcastle’s streets.

• But what are the health benefits or consequences?
• How many cups of coffee per day are recommended by health experts? The answer may surprise you..

Where does coffee come from?

Did you know that coffee originates from a cherry? Wild!

There are many different types of coffee, but the most common brews include Arabica and Robusta from regions including Africa, Asia-Oceania and South America.

Coffee can be a functional beverage.

It is much more than a brown coloured drink that contains caffeine. It also contains a wide range of nutrients including riboflavin (vitamin B2), niacin (vitamin B3), magnesium, potassium, and over 1000 bioactive compounds.The bioactives have names that sound like planets in a Star wars movie, such astrigonelline, melanoidins, diterpenes, chlorogenic acids just to name a few. These have antioxidant and anti-inflammatory effects in the body.

The specific health benefits depend on the combination of both nutrients and bioactives to deliver a more ‘functional’ beverage. These components can reduce the risk of chronic diseases including diabetes, cancer and hypertension. The fact that health benefits remain regardless of caffeination status (caffeinated vs decaffeinated) highlights the importance of these compounds.

Coffee types can vary widely

Summarising the benefits of coffee is complicated by many variations including bean type, growing region, growing practices, caffeination, roast level (dark, light) and brew type (filtered, unfiltered, instant). Arabica and Robusta contain 5-10% less caffeine than those from Asia-Oceania and South America. Existing evidence is not strong enough to indicate the optimal coffee type, however we know there is minimal difference between caffeination status (except lower risk of pancreatitis with decaf) and minimal difference between roasting type. To further complicate the matter, there are further variations in absorption, depending an individual’s genotype (genetic makeup) and microbiome (balance of bacteria in our lower gut).

What is the existing evidence for health?

In 2017, researchers undertook a review  of over 200 studies investigating coffee and  health outcomes) which was published in the British Medical Journal (see end of article for reference).  The findings showed that 3-4 cups of coffee a day was associated with a lower risk of some health conditions, particularly heart disease and specific cancers. However, further research was recommended to understand whether the associations are causal. This Importantly, outside of pregnancy, existing evidence suggests that it could be tested as an intervention without significant risk of causing harm. Women at increased risk of fracture should possibly be excluded.tudies suggest that people who include 3 cups per day vs none have a 17% lower risk of all cause mortality (death). Isn’t that awesome?!

The table below summarises the broad associations between coffee consumption and disease type, and the level of consumption for the lowest risk

Health Domain	Effect	Amount (no. cups for lowest risk)
Heart	lowers the risk of hypertension, CVD, CHD, stroke, heart failure and all-cause mortality.	3 cups per day
Diabetes	6% lower risk at 1 cup.30% lower risk high vs low.	2-3 cups per day
Cancer	lower risk of liver, endometrial, oral/pharyngeal, oesophageal and colorectal. 18% overall lower risk high vs low.	1-6 cups
Bone Health	lower risk of osteoporotic fractures in men	3 cups
Kidney Disease	lowers risk of kidney disease (13-14%) and kidney stones (8.7% per cup) and gout (57%)	Per cup
Liver/Pancreas	lowers risk of chronic liver disease, liver cancer and pancreatitis	‘High’ (no. cups unclear)
Emerging
Mental Health	24% lower risk of depression	3-4 cups.
Alzheimers	27% lower risk with higher doses though other studies have not found a difference for all cause dementia, cognitive decline or impairment.	3-5 cups.
Weight	lower BMI, waist circumference	Further research needed
Gut Health	increases in Bifidobacterium (a healthy gut bacteria). Improved GI effects post abdominal surgeries.	Further research needed

The study also indicated the ten strongest protective associations, when comparing any level of coffee consumption versus nil consumption. This means that the chance of developing certain diseases issues occurring was lower for people that drink coffee versus none drinkers. These diseases from highest to lowest: Liver cirrhosis (39% lower incidence), chronic liver disease (38%), Parkinsons disease (36%), liver cancer (34%), non-alcoholic fatty liver disease (27%), chronic kidney disease (29%), liver fibrosis (27%), Alzheimers disease (27%), urinary incontinence 25%), colorectal cancer (17%).

When to be cautious about coffee consumption.

Whilst the benefits of coffee are promising, it must be highlighted that some people will not benefit from drinking it. Individuals with a high sensitivity to caffeine may experience digestive issues, anxiety and compromised sleep. Children and teenagers should limit caffeine consumption (from all sources) and women who are pregnant, breastfeeding or at increased risk of fracture are also advised to either avoid or limit caffeine from coffee and other sources. Current caffeine guidelines are shown below and women at increased risk of fracture are advised to limit their intake to around 400mg per day.
https://www.foodstandards.gov.au/consumer/generalissues/PublishingImages/Caffeine_infographic.jpg

Mythbusting

There are several common misconceptions about coffee and health, as highlighted below:

Myth	Fact
#1  Coffee is addictive	Whilst dependence and withdrawal can occur in some people, no long term effects have been established.
#2 Coffee is dehydrating	Caffeine only has a small diuretic effect that is outweighed by the fluid consumed by coffee. Only at larger amounts may the diuretic effect apply. Decaffeinated coffee will not dehydrate you.
#3 Coffee improves sports performance	It is the caffeine itself rather than just coffee. Coffee will still be effective, by acting as an ergogenic aid and reducing perception of effort, but this may also be achieved via other forms of caffeine.
#4 Coffee should be avoided in pregnancy	It can be included but guidelines recommend no more than 200mg/day of caffeine.
#5 Instant coffee has additives and is higher in caffeine	The opposite is true – instant contains 100% dehydrated coffee beans and lower caffeine.
#6 Dark roast has more caffeine	Roasting does not affect caffeine levels.

How many per day?

So what did the umbrella review indicate as the optimal number of cups per day? 3-4 cups per day – unless contraindicated (during childhood/adolescence, pregnancy, breastfeeding and for women at higher risk of bone fracture).  This is not to say that you need to increase your consumption from existing levels and further quality research in the future will provide a clearer picture, but that the existing evidence suggests a protective benefit for health due to the nutritional and bioactive components in coffee. So pour another brew!

Written by: Rowan one of our dietitians

References:

Poole et al. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ. 2017; 359: j5024. https://www.bmj.com/content/359/bmj.j5024

Liu Q-P, Wu YF, Cheng HY, et al. Habitual coffee consumption and risk of cognitive decline/dementia: A systematic review and metaanalysis of prospective cohort studies. Nutrition 2016;32:628-36. doi:10.1016/j.nut.2015.11.015

Yu X, Bao Z, Zou J, Dong J. Coffee consumption and risk of cancers: a meta-analysis of cohort studies. BMC Cancer 2011;11:96. doi:10.1186/1471-2407-11-96

Lee DR, Lee J, Rota M, et al. Coffee consumption and risk of fractures: a systematic review and dose-response meta-analysis. Bone 2014;63:20-8. doi:10.1016/j.bone.2014.02.007

Nutrition Research Australia https://nraus.com/