Coffee and health - the facts, not the froth

Today, it is generally accepted that up to 400 mg a day of caffeine is safe unless you're pregnant, in which case you should limit your intake to 200 mg a day. That's about four mugs of instant or three mugs of brewed coffee - but don't forget to add all your caffeine sources together.

The first ever International Coffee Day brought with it a flurry of requests in the media for me to cover the subject. At first I was amazed at the amount of activity - but then I thought about just how many of us have a vested interest. The British tradition may be for 'a nice cup-o'-tea', but coffee has now become a staple across the world. Today, the UK consumes about 70 million cups of coffee a day (1), and in the USA, about 100 million Americans drink in the region of 350 million cups a day. In fact, about half of all Americans start their day with a cup of coffee, and it's the largest consumer in the world, accounting for one third of worldwide coffee exports. (2)

The origins of coffee are shrouded in mystery. One of the most common stories relates to a goatherd in Eastern Africa (possibly Ethiopia) about 1500 years ago, who noticed his goats bouncing around after eating the berries from a tree. A local monk experimented to see if he could get the same effect on his levels of alertness, and the berries of the coffee tree spread quickly from Abyssinia to Arabia. By the end of the 13th Century, it was drunk across the Arab world, and by the start of the 17th Century had made its way to Europe via Venetian traders.

Some religious bodies dubbed it the 'bitter invention of Satan'. But when they gave some to the Pope to try to enlist his support to have it banned, legend has it that he gave the drink the Papal seal of approval instead. By the mid-17th Century the cafe culture had begun and by the turn of the 18 th Century there were over 3,000 coffee houses in London alone.

Coffee, of course, is not the only source of caffeine in our diets. An average mug of instant coffee contains 100 mg caffeine and a mug of brewed coffee, 140 mg. By comparison, a similar sized mug of tea has about 75 mg caffeine and a regular energy drink up to 80 mg (3).

Today, it is generally accepted that up to 400 mg a day of caffeine is safe unless you're pregnant, in which case you should limit your intake to 200 mg a day (4, 5). That's about four mugs of instant or three mugs of brewed coffee - but don't forget to add all your caffeine sources together.

Coffee is often in the headlines. For instance, there have been all sorts of scare stories about a link between coffee and cancer - but they're just that, scare stories. The World Cancer Research Fund has looked at all the evidence and in its opinion "Most evidence suggests that regular consumption of coffee and/or tea has no significant relationship with the risk of cancer at any site." (6) It has even been linked with a lower risk of colorectal cancer, possibly because of its effect on bile acids (7).

A similar reassuring picture emerges where heart problems are concerned. Don't just take my word for it - the British Heart Foundation, after assessing all the evidence, has concluded that moderate caffeine intake does not increase the risk of high blood pressure, heart disease or abnormal heart rhythms. (8) And a study of 175,000 people shows coffee drinkers actually have lower blood pressure than non-drinkers.(9)

While a couple of years ago, a study about a possible increased risk of type 2 diabetes from coffee drinkers hit the headlines, the reality is very different. The 'bad news' study had just 10 people in it - while other studies involving a total of 525,000 people showed either no link, or a lower risk of type 2 diabetes among coffee drinkers, even when smoking, weight and other lifestyle factors were taken into account.

Every interview I've done this week on coffee has included a question about coffee being a diuretic. In fact, at levels up to 400mg a day it doesn't dehydrate you, and can count towards your daily recommended fluid intake (10).

Finally, there's good news on coffee and dementia. I've found at least a dozen studies suggesting that coffee may protect against cognitive decline, possibly protecting against development of dementia and Alzheimer's in later life.

If you suffer from migrainesoveractive bladder, irritable bowel syndrome or menopausal hot flushes, you may find caffeine makes your symptoms worse.

However, for most other people up to 400 mg a day isn't linked to any significant health harm and may even do you good. This news may not make headlines, but it might bring a smile to your face.


References

1) Allegra Strategies UK Retail Coffee Shop Market Report 2012

2) https://www.realcoffee.co.uk/coffee-encyclopedia/trivia/consumption-facts/

3) Food Standard Agency, Survey of caffeine levels in hot beverages

4) http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678

5) http://webarchive.nationalarchives.gov.uk/20120206100416/http://food.gov.uk/news/newsarchive/2008/nov/caffeinenov08

6) World Cancer Research Fund. Food, Nutrition and the Prevention of Cancer: a Global Perspective. 1997

7) Woolcott CG et al. European Journal of Cancer Prevention 2002; 11: 137-145

8) The British Heart Foundation, http://www.bhf.org.uk/publications/view-publication.aspx?ps=1000767

9) Pannier, B 2013, http:// www.theheart.org/article/1553207.do?utm_medium=email&utm_source=20130619_heartwire&utm_campaign=newsletter

10) British Dietetic Association, www.bda.uk.com

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.