HealthAssist Blog

Do you like coffee? I do, it’s taste and aroma make my mornings so much better!

However, coffee is not usually considered as a healthy food. It has a long history of being blamed for many ills. But some recent research indicates that coffee may not be so bad after all. So which is it - good or bad for your health?

I decided to do my own little research and noted 10 benefits and 11 potential health risks of coffee drinking. Here is what I have found:

1 Antioxidant content

Coffee is a rich source of antioxidants like chlorogenic acid[6] and melanoidins. Melanoidins from roasted coffee show strong antioxidative effects depending on the way the coffee is treated [7-8]

Researchers[4] found that a typical serving of coffee contains more antioxidants than typical servings of grape juice, blueberries, raspberries and oranges.

2 Diabetes

Coffee consumption is potentially protective against the development of type 2 diabetes. A prospective cohort study[9] as part of the US Nurses Health Study found that moderate consumption of both caffeinated and decaffeinated coffee may lower the risk of type 2 diabetes in younger and middle aged women. The finding that higher consumption of decaffeinated coffee was associated with a lower risk of type 2 diabetes suggests that the protective effect could not be attributed exclusively to caffeine, but rather that it should be explained by other components, most probably chlorogenic acid and various antioxidants.

Prospective study[10] based on an oral glucose test confirmed striking protective effect of caffeinated coffee against incident type 2 diabetes (in both with impaired glucose and those with normal).

3 Parkinson’s disease

There is strong evidence that regular coffee consumption reduces the risk of Parkinson’s disease. A number of studies[11-13] have demonstrated that people who drink coffee on a regular basis are significantly less likely to develop Parkinson’s.

4 Liver cirrhosis

Coffee drinking may protect against liver cirrhosis, especially alcoholic cirrhosis[14].

5 Gallstones

There is some evidence that coffee drinking may be protective against gallstone formation in men and women[15-16].

6 Kidney stones

Coffee consumption lowers the risk of kidney stones formation[17-18].

7 Gout

Hyperuricemia (high level of uric acid in the blood) can contribute to both gout and kidney stone formation. Coffee drinking may decrease the serum uric acid level and lower the risk of gout in men [19].

8 Work performance

Caffeine is a well-known stimulant. Many studies[20-22] demonstrate the beneficial effects of caffeine in coffee on alertness, attentiveness, and wakefulness. The cup of coffee can increase information processing.

9 Asthma

There is some evidence[5] that coffee may help manage asthma and even control attacks when medication is unavailable. Caffeine in coffee is related to theophylline, an old asthma medication. Caffeine can open airways and improve asthma symptoms.

10 Alzheimer’s disease

Several studies[39] comparing moderate coffee drinkers (about 2 cups a day) with light coffee drinkers (less than one cup a day) found that those who drank more coffee were significantly less likely to develop Alzheimer’s disease later in life.

These were benefits of coffee drinking. Now let’s look at the potential health risks associated with coffee. Coffee, particularly in large doses, can cause several problems for susceptible individuals:

1 Heart disease

The relation between coffee consumption and risk of cardiovascular disease has been examined in many studies, but the results remain controversial. Most prospective cohort studies have not found coffee consumption to be associated with significantly increased cardiovascular disease risk[23-24]. The strongest evidence for the suggestion that coffee is associated with increased risk of coronary heart disease comes from the case control studies[25].
Coffee is a complex mixture of compounds that may have either beneficial or harmful effects on the cardiovascular system. On one hand, diterpenes cafestol and kahweol present in unfiltered coffee and caffeine each appear to increase risk of coronary heart disease. High quality studies (randomized controlled trials)[26-27] have confirmed the cholesterol-raising effect of diterpenes, which may contribute to the risk of coronary heart disease. On the other hand, a lower risk of heart disease among moderate coffee drinkers might be due to antioxidants found in coffee.
Besides that, coffee consumption is also associated with an increase of plasma homocysteine, a risk factor for coronary heart disease[28-29].

To get an idea of where the confusion comes from, consider two recent studies. A study of 128,000 men and women showed no increase in the risk of heart disease from drinking filtered coffee. The findings of the study - which published in May 2006 in the journal Circulation - indicated that it didn’t matter how much coffee participants drank. Another study of 4,000 coffee drinkers published in March 2006 in the Journal of the American Medical Association found that two or more cups of coffee a day can increase the risk of heart disease in people with a specific - and fairly common - genetic mutation that slows the breakdown of caffeine in the body. The design of a study can have some effect on the interpretation of results, which may be another reason for the different conclusions. Overall, given the research reviewed it would be reasonable to conclude that coffee poses little or no threat to healthy adults.

Interestingly, the researchers did find that people who drank more coffee were more likely to be smokers, drink more alcohol, drink less tea, take vitamin supplements, or exercise regularly, all of which have been linked to increased risks of heart problems.

2 Increased cholesterol levels

Heavy consumption of boiled coffee elevates blood total and LDL cholesterol levels[30]. Unfiltered coffee is a significant source of cafestol and kahweol, which are diterpenes responsible for cholesterol-raising effects of coffee[26-27]. Diterpenes are extracted by hot water but are retained by a paper filter. This explains why filtered coffee does not affect cholesterol, whereas Scandinavian boiled, cafetiere, and Turkish coffees do.

3 Damage to arteries

Coffee negatively affects the blood vessel tone and function (increases arterial stiffness and wave reflections)[31].

Greek researchers recently proposed that caffeine increased aortic stiffness and, subsequently, the risk of heart disease

4 Heart rhythm disturbances

There is only little experimental evidence that caffeine causes cardiac arrhythmias[32-33].

5 Blood pressure

Although coffee consumption is not a significant risk factor for hypertension, it produces unfavourable effects on blood pressure[34-35]. No doubt caffeine is responsible for blood pressure increase. However, there is some evidence, that when caffeine is ingested from coffee, it has a small effect on blood pressure. People prone to hypertension may be more susceptible to coffee blood pressure elevating effects. Recent Italian study[36] found that coffee drinking can slightly increase the risk for development of sustained hypertension in persons with elevated blood pressure.

6 Osteoporosis (bone loss)

Coffee intake may induce an extra urinary excretion of calcium. Heavy coffee consumption (4 cups=600 ml or more) can modestly increase the risk of osteoporosis, especially in women with a low calcium intake[37-38]

7 Disrupted sleep, nervousness and anxiety

Excess caffeine can overstimulate the central nervous system. High amounts of caffeine produce negative effect on sleep onset and sleep quality[20]. However, there are large individual differences in the effects of caffeine on sleep. Many people consume coffee during the evening and have no problems falling asleep. Some people find that the mild stimulation of caffeine consumed shortly before a bed time delays the time to fall asleep.

8 Heartburn

Some people suffer from heartburn after drinking coffee. Coffee promotes gastro-oesophageal reflux, but is not associated with dyspepsia.

9 Dehydration

The caffeine in coffee is a mild diuretic and can increase the volume of urine excreted. However, this effect can be easily counteracted by the drinking extra glass of water.

10 Coffee & Pregnancy: A Bad Mix (raises miscarriage risk)

The effects of coffee during pregnancy is extensively researched - and the results of the various studies into the effects of caffeine and coffee on pregnant women, fertility and the development of the growing baby are contradictory.

Drinking a couple of cups of coffee a day has long been considered safe during pregnancy, but a new study[1] finds that even this modest amount of caffeine could double a woman’s risk of miscarriage.

A team led by Dr. De-Kun Li, a researcher at Kaiser Permanente in Oakland, Calif., conducted one of the first studies to take into account morning sickness. They concluded that a daily habit of drinking 200 milligrams of caffeine - the amount typically found in just two cups of coffee - significantly increases the risk of miscarriage.

While research results have been mixed, the American College of Obstetricians and Gynecologists recommends that pregnant women consume no more than 1 to 2 cups of coffee per day.

11 Rheumatoid arthritis

Decaffeinated coffee may increase the risk of rheumatoid arthritis[2]. Researchers speculate that rather than the presence or absence of caffeine being the culprit, there may be something in the way decaffeinated coffee is processed that triggers an arthritic response, perhaps industrial solvents.

Interestingly, the study linking decaffeinated coffee and rheumatoid arthritis suggests that, “Women who drink more than three cups of tea a day are much less likely to develop the disease than those who don’t drink tea”.

Another study[3] found that people who drank four or more cups of coffee a day had twice the risk of developing rheumatoid arthritis, compared with those who drank less coffee.

Dr. Maarku Heliovaara of the National Public Health Institute in Helsinki and colleagues looked at data from nearly 19,000 healthy men and women who entered a study in the early 1970s and were followed for 15 years. Coffee drinkers were at higher risk of developing rheumatoid factor-associated rheumatoid arthritis.

It is not clear why coffee might be associated with rheumatoid factor. Most people in the study drank boiled coffee, a practice no longer common in Finland. It is possible that some ingredient in coffee that is associated with rheumatoid factor is removed by the filtration, according to the researchers.

The key is quantity and quality. For those consuming moderate amounts of coffee (3-4 cups/day providing 300-400 mg/d of caffeine), there is little evidence of health risks and some evidence of health benefits. However, some people, including persons with hypertension, osteoporosis, heart disease, pregnant women, children, adolescents, and elderly may be more vulnerable to the adverse effects of coffee.

At least, coffee is far less toxic and more healthier than the sugar-laden drinks like soda.

What’s your conclusion? Does the benefit outweigh the negative effects?

Sources & References

• 1. Weng X, Odouli R, Li DK. Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study. Am J Obstet Gynecol. 2008 Mar;198(3):279.e1-8. Epub 2008 Jan 25. PubMed
• 2. Mikuls TR, Cerhan JR, Criswell LA, Merlino L, Mudano AS, Burma M, Folsom AR, Saag KG. Coffee, tea, and caffeine consumption and risk of rheumatoid arthritis: results from the Iowa Women’s Health Study. Arthritis Rheum. 2002 Jan;46(1):83-91. PubMed
• 3. Heliovaara M, Aho K, Knekt P, Impivaara O, Reunanen A, Aromaa A. Coffee consumption, rheumatoid factor, and the risk of rheumatoid arthritis. Ann Rheum Dis. 2000 Aug;59(8):631-5. PubMed
• 4. Bente L Halvorsen, Monica H Carlsen, Katherine M Phillips, Siv K B?hn, Kari Holte, David R Jacobs, Jr and Rune Blomhoff. Content of redox-active compounds (ie, antioxidants) in foods consumed in the United States. American Journal of Clinical Nutrition, Vol. 84, No. 1, 95-135, July 2006
• 5. Pagano R, Negri E, Decarli A, La Vecchia C. Coffee drinking and prevalence of bronchial asthma. Chest. 1988 Aug;94(2):386-9. PubMed
• 6. Daglia M, Racchi M, Papetti A, Lanni C, Govoni S, Gazzani G. In vitro and ex vivo antihydroxyl radical activity of green and roasted coffee. J Agric Food Chem. 2004 Mar 24;52(6):1700-4. PubMed
• 7. del Castillo MD, Ames JM, Gordon MH. Effect of roasting on the antioxidant activity of coffee brews. J Agric Food Chem. 2002 Jun 19;50(13):3698-703. PubMed
• 8. Borrelli RC, Visconti A, Mennella C, Anese M, Fogliano V. Chemical characterization and antioxidant properties of coffee melanoidins. J Agric Food Chem. 2002 Oct 23;50(22):6527-33. PubMed
• 9. van Dam RM, Willett WC, Manson JE, Hu FB. Coffee, caffeine, and risk of type 2 diabetes: a prospective cohort study in younger and middle-aged U.S. women. Diabetes Care. 2006 Feb;29(2):398-403. PubMed
• 10. Smith B, Wingard DL, Smith TC, Kritz-Silverstein D, Barrett-Connor E. Does coffee consumption reduce the risk of type 2 diabetes in individuals with impaired glucose? Diabetes Care. 2006 Nov;29(11):2385-90. PubMed
• 11. Saaksjarvi K, Knekt P, Rissanen H, Laaksonen MA, Reunanen A, Mannisto S. Prospective study of coffee consumption and risk of Parkinson’s disease. Eur J Clin Nutr. 2007 May 16. PubMed
• 12. Hu G, Bidel S, Jousilahti P, Antikainen R, Tuomilehto J. Coffee and tea consumption and the risk of Parkinson’s disease. Mov Disord. 2007 Aug 21. PubMed
• 13. Hernan MA, Takkouche B, Caaman~o-Isorna F, Gestal-Otero JJ. A meta-analysis of coffee drinking, cigarette smoking, and the risk of Parkinson’s disease. Ann Neurol. 2002 Sep;52(3):276-84. PubMed
• 14. Klatsky AL, Morton C, Udaltsova N, Friedman GD. Coffee, cirrhosis, and transaminase enzymes. Arch Intern Med. 2006 Jun 12;166(11):1190-5. PubMed
• 15. Leitzmann MF, Stampfer MJ, Willett WC, Spiegelman D, Colditz GA, Giovannucci EL. Coffee intake is associated with lower risk of symptomatic gallstone disease in women. Gastroenterology. 2002 Dec;123(6):1823-30. PubMed
• 16. Leitzmann MF, Willett WC, Rimm EB, Stampfer MJ, Spiegelman D, Colditz GA, Giovannucci E. A prospective study of coffee consumption and the risk of symptomatic gallstone disease in men. JAMA. 1999 Jun 9;281(22):2106-12. PubMed
• 17. Curhan GC, Willett WC, Speizer FE, Stampfer MJ. Beverage use and risk for kidney stones in women. Ann Intern Med. 1998 Apr 1;128(7):534-40. PubMed
• 18. Shuster J, Finlayson B, Scheaffer RL, Sierakowski R, Zoltek J, Dzegede S. Primary liquid intake and urinary stone disease. J Chronic Dis. 1985;38(11):907-14. PubMed
• 19. Choi HK, Willett W, Curhan G. Coffee consumption and risk of incident gout in men: a prospective study. Arthritis Rheum. 2007 Jun;56(6):2049-55. PubMed
• 20. Hindmarch I, Rigney U, Stanley N, Quinlan P, Rycroft J, Lane J. A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. Psychopharmacology (Berl). 2000 Apr;149(3):203-16. PubMed
• 21. Smith AP, Brockman P, Flynn R, Maben A, Thomas M. Investigation of the effects of coffee on alertness and performance during the day and night. Neuropsychobiology. 1993;27(4):217-23. PubMed
• 22. Philip P, Taillard J, Moore N, Delord S, Valtat C, Sagaspe P, Bioulac B. The effects of coffee and napping on nighttime highway driving: a randomized trial. Ann Intern Med. 2006 Jun 6;144(11):785-91. PubMed
• 23. Lopez-Garcia E, van Dam RM, Willett WC, Rimm EB, Manson JE, Stampfer MJ, Rexrode KM, Hu FB. Coffee consumption and coronary heart disease in men and women: a prospective cohort study. Circulation. 2006 May 2;113(17):2045-53. Epub 2006 Apr 24. PubMed
• 24. Sofi F, Conti AA, Gori AM, Eliana Luisi ML, Casini A, Abbate R, Gensini GF. Coffee consumption and risk of coronary heart disease: a meta-analysis. Nutr Metab Cardiovasc Dis. 2007 Mar;17(3):209-23. Epub 2006 Dec 5. PubMed
• 25. Tofler OB, Foy S, Ng K, Hickey G, Burke V. Coffee and coronary heart disease. Heart Lung Circ. 2001;10(3):116-20. PubMed
• 26. Urgert R, Essed N, van der Weg G, Kosmeijer-Schuil TG, Katan MB. Separate effects of the coffee diterpenes cafestol and kahweol on serum lipids and liver aminotransferases. Am J Clin Nutr. 1997 Feb;65(2):519-24. PubMed
• 27. \van Tol A, Urgert R, de Jong-Caesar R, van Gent T, Scheek LM, de Roos B, Katan MB. The cholesterol-raising diterpenes from coffee beans increase serum lipid transfer protein activity levels in humans. Atherosclerosis. 1997 Jul 25;132(2):251-4. PubMed
• 28. Strandhagen E, Landaas S, Thelle DS. Folic acid supplement decreases the homocysteine increasing effect of filtered coffee. A randomised placebo-controlled study. Eur J Clin Nutr. 2003 Nov;57(11):1411-7. PubMed
• 29. Verhoef P, Pasman WJ, Van Vliet T, Urgert R, Katan MB. Contribution of caffeine to the homocysteine-raising effect of coffee: a randomized controlled trial in humans. Am J Clin Nutr. 2002 Dec;76(6):1244-8. PubMed
• 30. Urgert R, Weusten-van der Wouw MP, Hovenier R, Lund-Larsen PG, Katan MB. Chronic consumers of boiled coffee have elevated serum levels of lipoprotein(a). J Intern Med. 1996 Dec;240(6):367-71. PubMed
• 31. Vlachopoulos C, Panagiotakos D, Ioakeimidis N, Dima I, Stefanadis C. Chronic coffee consumption has a detrimental effect on aortic stiffness and wave reflections. Am J Clin Nutr. 2005 Jun;81(6):1307-12. PubMed
• 32. Myers MG. Caffeine and cardiac arrhythmias. Ann Intern Med. 1991 Jan 15;114(2):147-50. PubMed
• 33. Myers MG, Harris L. High dose caffeine and ventricular arrhythmias. Can J Cardiol. 1990 Apr;6(3):95-8. PubMed
• 34. Klag MJ, Wang NY, Meoni LA, Brancati FL, Cooper LA, Liang KY, Young JH, Ford DE. Coffee intake and risk of hypertension: the Johns Hopkins precursors study. Arch Intern Med. 2002 Mar 25;162(6):657-62. PubMed
• 35. Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake and the risk of hypertension in women. JAMA. 2005 Nov 9;294(18):2330-5. PubMed
• 36. Palatini P, Dorigatti F, Santonastaso M, Cozzio S, Biasion T, Garavelli G, Pessina AC, Mos L. Association between coffee consumption and risk of hypertension. PubMed
• 37. Hallstrom H, Wolk A, Glynn A, Michaelsson K. Coffee, tea and caffeine consumption in relation to osteoporotic fracture risk in a cohort of Swedish women. Osteoporos Int. 2006;17(7):1055-64. Epub 2006 May 4. PubMed
• 38. Hasling C, Sondergaard K, Charles P, Mosekilde L. Calcium metabolism in postmenopausal osteoporotic women is determined by dietary calcium and coffee intake. J Nutr. 1992 May;122(5):1119-26. PubMed
• 39. Barranco Quintana JL, Allam MF, Serrano Del Castillo A, Ferna’ndez-Crehuet Navajas R. Alzheimer’s disease and coffee: a quantitative review. Neurol Res. 2007 Jan;29(1):91-5. PubMed