Coffee heart and blood vessels


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Is it advisable to drink coffee when you have a ‘heart condition’? Does drinking
coffee have any influence on the occurrence and development of cardiovascular
disease? People used to think so. But what is the current advice? Heavy coffee
drinkers are quite often also heavy smokers. For instance, in one of the first
studies in this field the relationship between drinking coffee and cardiovascular
disease could be wholly attributed to the fact that coffee drinkers had been
smoking more (Katan, 1994). More recent studies, have adjusted for ‘other’
factors that could influence the results.

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Coffee heart and blood vessels

  1. 1. coffee vessels heart and blood
  2. 2. ColophonPublishersCoffee and Health Information BureauDesign and printingStimio Consultants, Drukwerk & Design bv, TielCopyright© november 2007, Coffee and Health Information Bureau, AmsterdamAvailabilityThe brochure ‘Coffee, heart and blood vessels’ can be ordered free of chargefrom Coffee and Health Information Bureau. You can also register here for thedigital newsletter. This free Dutch newsletter is aimed at health care profes-sionals and keeps you informed about the most recent scientific informationconcerning coffee and health and appears four to five times a year.Coffee and Health Information Bureau(Voorlichtingsbureau voor Koffie en Gezondheid)Postbus 161, 2280 AD RijswijkTel: +31 (0)70 - 336 51 63Fax: +31 (0)70 - 336 51 67E-mail: info@koffieengezondheid.nlWebsite:
  3. 3. IntroductionIs it advisable to drink coffee when you have a ‘heart condition’? Does drinkingcoffee have any influence on the occurrence and development of cardiovasculardisease? People used to think so. But what is the current advice? Heavy coffeedrinkers are quite often also heavy smokers. For instance, in one of the firststudies in this field the relationship between drinking coffee and cardiovasculardisease could be wholly attributed to the fact that coffee drinkers had beensmoking more (Katan, 1994). More recent studies, have adjusted for ‘other’factors that could influence the results.This does not mean there are no further questions about coffee and heartconditions and the risk factors for cardiovascular disease (blood pressure andcholesterol). Coffee is consumed by 8 out of 10 Dutch people every day andtotal annual consumption of coffee per head of the population amounts to 144litres (VNKT, 2006). Research on the effects of coffee and heart health continuesto be an important field of scientific investigation.In the last few decades there has been significant scientific research into therelationship between coffee and health, including drinking coffee and riskfactors for cardiovascular disease. This brochure is aimed at health care profes-sionals and provides a summary of the results of innumerable scientific studies.The questions were formulated in collaboration with the Dutch Working Groupfor Cardiology Dieticians. You can read more about the influence of coffee onheart conditions in chapter 1. Chapter 2 describes the relationship betweencoffee and cholesterol and chapter 3 gives more information about coffee andblood pressure.The Coffee and Health Information Bureau (Voorlichtingsbureau voor Koffie enGezondheid) sought assistance from three scientists who carry out research inthis field. Dr. Marianne Gelijnse (nutritional epidemiologist, Human NutritionDepartment, Wageningen University) and Dr. Cuno Uiterwaal (MD, clinicalepidemiologist, Julius Centre, Utrecht University Medical Centre) assisted in Coffee, heart and blood vessels | 3
  4. 4. answering the questions about heart (chapter 1) and blood pressure (chapter 3). Dr. Mark Boekschoten (medical biologist, Department of Human Nutrition, Wageningen University) contributed to the substantive coordination of chapter 2, on coffee and cholesterol. Some topics do not yet have an unequivocal answer, because the amount of research in that area is currently insufficient. We continue to follow scientific developments. If you have any questions or comments about this brochure, please let us know. Coffee and Health Information Bureau (Voorlichtingsbureau voor Koffie en Gezondheid) Literature Katan MB, Koffie, cholesterol en coronaire hartziekten. Hart Bulletin, 1994; 25:119-123. Vereniging van Nederlandse Koffiebranders en Theepakkers (VNKT), Jaarverslag 2006.4 |
  5. 5. 1 Coffee and cardiovascular disease1 Is there a relationship between coffee consumption and the risk of cardiovascular disease?Analysis of several extensive cohort studies (see shaded text on page 35) doesnot show a relationship between coffee consumption and the risk of cardiovas-cular disease (Grobbee, 1990; Woodward, 1999; Willett, 1996; Lopez-Garcia,2006; Frost-Andersen, 2006). Furthermore, there is no evidence of a linkbetween coffee consumption and disease prognosis after myocardial infarction(Mukamal, 2004).A meta-analysis in 2006 did not indicate that coffee consumption results in ahigher risk of developing cardiovascular disease. Despite a significant associa-tion between high consumption of coffee and coronary heart disease (CHD)reported in case-control studies, no significant association between daily coffeeconsumption and CHD emerged from long-term follow-up prospective cohortstudies (Sofi, 2006).In some studies, coffee appears to protect against the risk of cardiovasculardisease (Woodward, 1999; Hammar, 2003; Frost-Andersen, 2006). In 2006,a study among more than 41,000 women showed that coffee drinkers hada lower risk of death attributable to cardiovascular disease. It was suggestedthat consumption of coffee, a major source of dietary antioxidants, may inhibitinflammation and thereby reduce the risk of cardiovascular and other inflamma-tory diseases in post menopausal women (Frost-Andersen, 2006). Coffee, heart and blood vessels | 5
  6. 6. Preventive effect of coffee on type 2 diabetes Type 2 diabetes is a strong risk factor for cardiovascular disease. The inverse relationship between coffee consumption and type 2 diabetes was first de- scribed in 2002 (Van Dam, 2002). This Dutch epidemiological study among more than 17,000 men and women showed that people who drank seven or more cups of coffee a day were 50% less likely to develop type 2 diabetes than people who drank two cups of coffee or less. A 2005 meta-analysis also indicated a link between coffee consumption and a substantially lower risk of developing type 2 diabetes (Van Dam, 2005). More recent studies confirm this inverse relationship. Moreover these studies show that this effect occurs with decaffeinated coffee as well. Furthermore, a recent Finnish study investigating almost 4,000 people with type 2 diabetes indicated a reduced risk of cardiovas- cular mortality in the case of those who drank three or more cups of coffee a day (Bidel, 2006). 2 Is there a relationship between coffee consumption and the risk of heart failure? Little is known about coffee consumption in relation to the risk of heart failure. A Swedish study examined risk factors for heart failure in a long-term follow- up among almost 7,500 men. Risk factors for the occurrence of heart failure included increasing age, family history of myocardial infarction, diabetes, chest pain, smoking, high coffee consumption, excessive alcohol, high BMI and hypertension (Wilhelmsen, 2001). Epidemiological data from the Framingham study indicate that hypertension has the highest impact on heart failure and is responsible for about 39% of heart failure in men and 59% in women. After adjustment for age and other factors, hypertension increases the risk of heart6 |
  7. 7. failure by a factor of 2 in men and a factor 3 in women. Diabetes increasesthe risk of heart failure by a factor of 2 to 8, more so in women than in men(Kannel, 2000). This study did not investigate the relationship between coffeeand heart failure. However, coffee is associated with a decreased risk of diabetesand a lower risk of cardiovascular mortality in the case of people with diabetes(see shaded text on page 6).As we have insufficient scientific data at present, no clear pronouncement canbe made on coffee consumption in relation to the risk of heart failure.3 Can you still drink coffee if you suffer from heart failure?A 2006 study investigated the effect of caffeine on the stamina of patients withheart failure (Notarius, 2006). Ten patients were infused intravenously with 4mg of caffeine per kg bodyweight or a placebo. With caffeine, patients wereable to exercise longer at peak effort. However, this study is much too limited tobe able to derive any recommendation from it.4 Does coffee affect the incidence of cardiac arrhythmia?A large Danish prospective cohort study among nearly 48,000 people investi-gated the relationship between daily caffeine consumption from various foodsand the incidence of arrhythmia. The study could not find any relationship bet-ween arrhythmia and caffeine, not even in the case of high concentrations (997mg/day, equivalent to approximately 10 cups of coffee a day (Frost, 2005)). Coffee, heart and blood vessels | 7
  8. 8. 5 Can you drink coffee if you suffer from cardiac arrhythmia? An eight year long prospective cohort study among nearly 129,000 Americans over a period of 8 years did not show any relationship between coffee con- sumption and cardiac arrhythmia mortality (Klatsky, 1993). Intervention studies with caffeine in amounts of up to 450 mg/day (comparable to 5 small cups of coffee a day) showed no relationship with the nature or frequency of cardiac arrhythmia, either in healthy people or in heart patients (Myers, 1991; Nawrot, 2003). Conversely, caffeine restriction was found not to have any effect on pa- tients with ventricular tachyarrhythmia (fast and abnormal heart rate) (Newby, 1996). Caffeine content of beverages Beverage (serving size) Average caffeine content in mg Filtered coffee (150 ml) 85 Instant coffee (150 ml) 65 Espresso (50 ml) 65 Cappuccino (150 ml) 65 Coffee from coffee pods (150 ml) 85 Decaffeinated coffee (150 ml) 3 Tea (125 ml) 30 Cola (180 ml) 18 Energy drink (250 ml) 75 Iced tea (180 ml) 16 Chocolate milk (250 ml) 5 (Source: |
  9. 9. 6 Can coffee influence homocysteine levels of blood?Intervention studies show that high coffee consumption (6 - 10 cups of coffeea day) increases total plasma homocysteine (tHCys) (Grubben, 2000; Urgert,2000) and that tHCys decreases if regular coffee consumers stop drinking coffee(Christensen, 2001). However, a study based on 5 cups of espresso a day didnot show a significant effect on tHCys (Esposito, 2003), possibly because of thesmaller volume. Caffeine is suggested as being partly responsible for the effectof coffee on tHCys (Verhoef, 2002), but the presence of chlorogenic acid incoffee can also contribute to the effect on homocysteine (Olthof, 2001). Severalfactors influence plasma homocysteine levels, such as intake of folic acid andvitamin B12, age, gender, heredity, smoking, hypertension and physical activity(Refsum, 2006). However, it is still unclear whether reducing high homocysteinelevels will lead to a lower risk of cardiovascular disease. No causal relationshiphas been established between high tHCys and cardiovascular disease (Higdon,2006). A high homocysteine level can also be an indication of a low vitaminstatus and/or an unhealthy lifestyle (Verhoef, 2004). Coffee, heart and blood vessels | 9
  10. 10. 7 Can someone with angina pectoris carry on drinking coffee? Various large cohort studies show that there is no relationship between cof- fee consumption and cardiovascular diseases (see question 1). Little research has been undertaken into the effect of caffeine consumption on patients with angina pectoris. A Dutch study (Riksen, 2006) tested the effect of caffeine on so-called preconditioning in an experimental model involving healthy volun- teers (see shaded text on page 11). In an experimental model, healthy patients received a single intravenous injection of caffeine (4 mg/kg body weight) in the forearm. Caffeine was found to have an adverse impact on the protective effect of preconditioning. However, the researcher states that the results of this experimental study cannot be extrapolated to daily coffee consumption. It is not possible to give advice on this until further research among patients has estab- lished whether a high plasma caffeine concentration at the moment a heart attack takes place will worsen the course of events (Riksen, 2007). Normally, people drink their coffee in the course of the day, so that the caffeine is absorbed via the gastrointestinal tract over a longer period of time and the physiological effect would not be the same as that seen when a single dose of caffeine is injected into the blood stream. Furthermore, the effect of coffee is not always the same as that of caffeine (see question 8).10 |
  11. 11. Angina pectoris and preconditioningA heart attack will not be as serious when people have just had an angina pec-toris attack. In the case of angina pectoris so-called preconditioning occurs. Fora moment, the heart muscle receives insufficient oxygen. This makes the heartmuscle more tolerant of a longer period of oxygen shortage, such as occurs inthe case of myocardial infarction. Adenosine, which occurs naturally in the body,plays an important part in preconditioning. Caffeine is a so-called adenosine-antagonist and can block the effect of adenosine. The preconditioningmechanism does not reduce the occurrence of cardiovascular disease, but oncea myocardial infarction has occurred it can limit its seriousness.8 Do the effects of coffee and caffeine differ?Caffeine is without doubt the most examined substance in coffee. The effects ofpure caffeine are regularly translated directly to coffee, but this does not alwaysprove justified. Pure caffeine (in tablet form) for example is found to be capableof increasing the blood pressure, while this hardly occurs if at all in the case ofthe same quantity of caffeine via coffee (Noordzij, 2005; see chapter 3.)Coffee contains much more than just caffeine. For instance it contains potas-sium and magnesium, which may be capable of counteracting the blood-pressure-increasing effect of caffeine. Coffee is also a good source of anti-oxidants (polyphenols such as chlorogenic acids). Coffee, heart and blood vessels | 11
  12. 12. Caffeine After consumption, caffeine (1,3,7-trimethylxanthine) is absorbed rapidly and achieves its peak value approximately 1 to 1.5 hours after consumption. Its physi- cal half-life (time needed by the body to process half of the caffeine intake) varies from 3 to 7 hours and is affected by many factors such as gender, age, smoking and pregnancy. The most important effect of caffeine is stimulation of the central nervous system, which results among other things in increased alertness and countering sleepiness. An overview of published studies reveals that no relation- ship can be demonstrated between moderate caffeine consumption (400 mg daily) and the occurrence of cardiovascular disease) (Nawrot, 2003).12 |
  13. 13. 9 Can people with cardiovascular disease consume coffee normally?Most studies show that there are no indications that moderate consumptionof coffee (approximately 4 - 5 cups a day) increases the risk of cardiovasculardisease related to healthy people. A number of studies have examined whethercaffeine consumption or abstinence from caffeine consumption affect the bloodpressure of people with hypertension (see chapter 3) or in the case of patientswith cardiac arrhythmia. To date there are no indications for advising peoplewith cardiac arrhythmia against drinking coffee (see question 5). Nonetheless,individuals concerned with the possible effects of coffee in relation to cardiovas-cular disease, should seek the advice of their medical practitioner.10 Is decaffeinated coffee a better choice than ordinary coffee in the case of cardiovascular disease?In relation to hypertension or cardiac arrhythmia there are no indications tosuggest that individuals should avoid drinking caffeinated coffee in moderation(4-5 cups a day). If the individual prefers not to consume caffeine, decaffeinatedcoffee is a good alternative. Coffee, heart and blood vessels | 13
  14. 14. Literature Bidel S e.a., Coffee consumption and risk of total and cardiovascular mortality among patients with diabetes type 2. Diabetologia, 2006; 49(11):2618-2626. Christensen B e.a., Abstention from fi ltered coffee reduces the concentrations of plasma homocysteine and serum cholesterol-a randomized controlled trial. Am J Clin Nutr, 2001; 74(3):302-307. Esposito F e.a., Moderate coffee consumption increases plasma glutathione but not homocysteine in healthy subjects. Aliment Pharmacol Ther, 2003; 17:595-601. Frost L and Vestergaard P, Caffeine and risk of atrial fi brillation or fl utter: the Danish Diet, Cancer, and Health Study. Am J Clin Nutr, 2005; 81(3):578-582. Frost Andersen L e.a., Consumption of coffee is associated with reduced risk of death attributed to inflammatory and cardiovascular diseases in the Iowa Women’s Health Study. Am J Clin Nutr, 2006; 83:1039-1046. Grobbee DE, e.a., Coffee, caffeine, and cardiovascular disease in men. New Eng J Med, 1990; 323:1026-1032. Grubben MJ e.a., Unfi ltered coffee increases plasma homocysteine concentrations in healthy volun- teers: a randomized trial. Am J Clin Nutr, 2000; 71:448-484. Hammar N e.a., Association of boiled and fi ltered coffee with incidence of fi rst nonfatal myocardial infarction: the SHEEP and the VHEEP study. J Intern Med, 2003; 253(6):653-659. Higdon JV and Frei B., Coffee and Health: A Review of Recent Human Research. Crit Rev Food Sci Nutr, 2006; 46:101-123. Kannel WB, Incidence and epidemiology of heart failure. Heart Fail Rev 2000; 5(2):167-173. Klatsky AL, e.a., Coffee, tea, and mortality. Ann Epid, 1993; 3:375-381. Lopez-Garcia E e.a., Coffee consumption and coronary heart disease in man and women: a prospective cohort study. Circulation, 2006; 113(17):2045-2053. Mukamal KJ e.a., Caffeinated coffee consumption and mortality after acute myocardial infarction. AmHeart J, 2004; 147:999-1004. Myers MG, Caffeine and cardiac arrhythmias. Ann Intern Med, 1991; 114(2):147-150. Nawrot P e.a., Effects of caffeine on human health. Food Addit Contam, 2003; 20(1):1-30. Newby DE e.a., Caffeine restriction has no role in the management of patients with symptomatic idiopathic ventricular premature beats. Heart, 1996; 76(4):355-357.14 |
  15. 15. Noordzij M e.a., Blood pressure response to chronic intake of coffee and caffeine: a meta-analysis ofrandomized controlled trials. J Hypert, 2005; 23:921-928.Notarius CF e.a., Caffeine prolongs exercise duration in heart failure. J Card Fail, 2006; 12(3):220-226.Olthof MR e.a., Consumption of high doses of chlorogenic acid, present in coffee, or of black tea incre-ases plasma total homocysteine concentrations in humans. Am J Clin Nutr, 2001; 73:532-538.Refsum H e.a., The Hordaland Homocysteine Study: a community-based study of homocysteine, itsdeterminants, and associations with disease. J Nutr, 2006; 136(6 suppl):1731S-1740S.Riksen NP e.a., Caffeine Prevents Protection in Two Human Models of Ischemic Preconditioning.J AmColl Cardiol, 2006; 48:700-707.Riksen NP, Nieuwsbrief Koffi e en Gezondheid april 2007 (www.koffi F e.a., Coffee consumption and risk of coronary heart disease: A meta-analysis. Nutr Met CardiovDis, 2006; 17(3):209-223.Urgert R e.a., Heavy coffee consumption and plasma homocysteine: a randomized controlled trial inhealthy volunteers. Am J Clin Nutr, 2000; 72:1107-1110.Van Dam R and Feskens E, Coffee consumption and risk of type 2 diabetes mellitus. The Lancet, 2002;360(9344):1477-1478.Van Dam R and Hu F, Coffee consumption and risk of type 2 diabetes: a systematic review. JAMA, 2005;294:97-104.Verhoef P e.a., Contribution of caffeine to the homocysteine-raising effect of coffee: a randomizedcontrolled trial in humans. Am J Clin Nutr, 2002; 76:1244-1248.Verhoef P and Katan MB, A healthy lifestyle lowers homocysteine, but should we care? Editorial AmJ Clin Nutr, 2004; 79:713-714.Wilhelmsen L e.a., Heart failure in the general population of men-morbidity, risk factors and prognosis.J Intern Med, 2001; 249(3):253-261.Willett WC e.a., Coffee consumption and coronary heart disease in women. A ten-year follow-up.JAMA, 1996; 275(6):458-462.Woodward M and Tunstall-Pedoe H, Coffee and tea consumption in the Scottish Heart Health Studyfollow up: confl icting relations with coronary risk factors, coronary disease, and all cause mortality.J Epid Comm Health, 1999; 53:481-487. Coffee, heart and blood vessels | 15
  16. 16. 16 |
  17. 17. 2 Coffee and the serum cholesterol level1 Does coffee affect the blood serum cholesterol level?That depends on the brewing method used for making coffee. Unfiltered coffeecan increase the serum cholesterol level, while filtered coffee does not have thiseffect (Boekschoten, 2003, 2006; Urgert, 1996a; Urgert, 1996b). The increasein cholesterol is attributable to the diterpenes cafestol and kahweol, two fat-soluble substances that are naturally present in coffee oil. The effect of cafestol,in particular, on serum cholesterol levels has been demonstrated (Urgert, 1997).Only in the case of certain coffee brewing methods the diterpenes do permeatethe brewed coffee. Scandinavian-type boiled coffee, French press (Cafetièreor plunger) coffee, Greek coffee and Turkish coffee for instance contain thesesubstances in higher concentrations. In the case of filtered coffee and coffeemade with coffee pods, the most common methods of brewing coffee inthe Netherlands, cafestol and kahweol are retained by the filter. These coffeestherefore have no cholesterol-raising effect (Ahola, 1991; Dusseldorp, 1991;Boekschoten, 2006). Instant coffee and vending-machine coffee based on liquidcoffee concentrate also contain hardly any diterpenes and have a neglible effecton serum lipids (Urgert, 1997; Sara Lee/DE, 1998). Coffee, heart and blood vessels | 17
  18. 18. 2 Do different brewing methods affect the levels of the diterpenes cafestol and kahweol in the coffee? The diterpenes, cafestol and kahweol naturally present in coffee oil increase se- rum cholesterol levels (see question 1 in this chapter). Whether these diterpenes permeate the coffee brew and to what extent depends on the brewing method. Boiled coffee, coffee that is prepared by boiling ground coffee in water and pou- ring the brew without filtering it, contains the diterpenes, cafestol and kahweol in higher concentrations. The amounts of diterpenes in boiled coffee vary from 3.0 to 10.9 mg of cafestol and 3.9 to 10.7 mg of kahweol per cup (Urgert, 1995; Boekschoten, 2006). Consuming large amounts of boiled coffee will in- crease the serum cholesterol level. French press coffee, Greek coffee and Turkish coffee also contain comparable amounts of cafestol and kahweol (Urgert, 1995). In the case of filtered coffee and coffee made with coffee pods, the diterpenes are retained in the paper filter. Both these coffees contain an average of 0.1 mg cafestol and 0.1 mg kahweol per cup (Urgert, 1995; Boekschoten 2006). The ef- fect of this on the serum cholesterol content is therefore negligible. Instant cof- fee and vending-machine coffee based on liquid coffee concentrate also contain negligible amounts of cafestol and kahweol. These substances are virtually fully removed during the production process (Sara Lee/DE, 1998). In the case of espresso coffee and coffee from vending machines in which the coffee is freshly brewed, these types of coffee may contain cafestol and kahweol. The ultimate quantity and the effect on serum cholesterol content depends on a combination of factors, such as the type of machine, the type and quantity of coffee, the type of filter used and the number of cups consumed daily.18 |
  19. 19. 3 How substantial is the effect of cafestol on the cholesterol content?Based on intervention studies (see shaded text on page 35) an estimate hasbeen made that, daily intake of 10 mg of cafestol for a period of 4 weeks, willresult in an increase of 0.13 mmol/l in the total cholesterol level of the blood(Weusten van der Wouw, 1994). However, in the case of long-term consump-tion the increase in serum cholesterol level becomes less, which may point topartial adaptation by the body to the effects of diterpenes (Urgert, 1996b).Consumption of a litre per day of very strong coffee brewed in a Cafetière(plunger or French press) (38 mg of cafestol and 33 mg of kahweol) for a periodof six months resulted after 12 weeks in a maximum increase in serum choles-terol of 0.52 mmol/l. Thereafter the cholesterol level declined again and aftersix months the total increase was still 0.30 mmol/l compared with the startingvalues. Shorter-term studies can result in overestimation of the effect (Urgert,1997).How much kahweol contributes to raising serum cholesterol is not fully un-derstood, since no studies have been carried out with pure kahweol. Whatis known, however, is that a mixture of cafestol and kahweol has a slightlystronger effect than cafestol on its own (Urgert, 1997). Moreover the effectof the diterpenes is reversible. After cessation of consumption of cafestol andkahweol serum cholesterol levels return to their starting values (Urgert, 1996a).The table on page 20 shows the various brewing methods, the cafestol and kah-weol levels of the associated brews and the estimated serum cholesterol increasein the case of consumption of 5 cups of coffee a day (after Urgert, 1996a). Coffee, heart and blood vessels | 19
  20. 20. Coffee type / brewing Cafestol Kahweol Theoretical¹ increase in method in mg/cup in mg/cup serum cholesterol in the case of daily consumption of 5 cups (mmol/l) Filtered coffee 0.1 0.1 <0.01 Instant (soluble) coffee 0.2 0.2 0.01 Espresso 1.5 1.8 0.10 Boiled coffee 3.0 3.9 0.19 French press coffee 3.5 4.4 0.23 Turkish/Greek coffee 3.9 3.9 0.25 ¹Theoretical increase based on the estimation that 10 mg of cafestol causes the serum cholesterol level to increase by 0.13 mmol/l.20 |
  21. 21. 4 Do regular and decaffeinated coffee have different effects on the blood cholesterol level?This is highly improbable. There is no difference in the concentration of diter-penes between comparable caffeinated coffee and decaffeinated coffee (Urgert,1996a). Studies with decaffeinated filtered coffee show no effect on serumcholesterol content (Dusseldorp, 1990; Urgert, 1997). In the case of abstinencefrom caffeine for a period of 9 weeks, randomised research among 69 healthyyoung Dutch people also shows no effect on serum lipid contents (Bak, 1989).5 Does limitation of coffee have a cholesterol-lowering effect?This depends once again entirely on the coffee brewing method (see questions1 and 2). Filtered coffee does not have a cholesterol-raising effect (see question1). However, if a lot of unfiltered coffee is drunk, switching from unfiltered tofiltered coffee results in a clear fall in serum cholesterol levels. This is the case inScandinavian countries, where traditionally a large amount of boiled coffee waspreviously consumed (Pietinen, 1996).Intervention studies have also revealed that the effect of diterpenes is reversible.If consumption is ceased, the serum cholesterol values return to their startinglevels (Urgert, 1996a). Coffee, heart and blood vessels | 21
  22. 22. 6 What other factors affect the cholesterol content and to what extent is this comparable with cafestol? The amount of cholesterol in the blood is strongly related to the consumption of saturated fatty acids and trans fatty acids. Smoking and excess body weight also increase the risk of raising serum cholesterol. Moderate drinking of alcohol and regular physical activity in fact can reduce risk of raised serum cholesterol because these factors increase the content of the protective HDL cholesterol. Ideally preventive interventions should focus simultaneously on several factors which cause an unfavourable cholesterol level, such as excessive intake of satu- rated fat, trans fatty acids, smoking, physical inactivity and excess weight (www. A review from 2006 provides an overview of the LDL-cholesterol reducing effect of various nutritional measures (Devaraj, 2006). The following reductions are achievable: • 8-10% in the case of consuming maximum 7 energy % saturated fat • 6-10% in the case of consuming phytosterols/stanols up to 2 grams daily • 5-8% in the case of losing 4.5 kilos in weight • 3-5% in the case of consuming a maximum of 200 mg cholesterol per day • -5% in the case of 5 to 10 grams higher daily consumption of (soluble) 3 dietary fibre Based on theoretically estimated increases in serum cholesterol on the basis of the cafestol contents of various brews (see table on page 20), switching from 5 cups of filtered coffee to 5 cups of espresso can be expected to increase the cholesterol level by approximately 2% (Urgert, 1996b).22 |
  23. 23. Spread of cholesterol measurementsAn individual’s cholesterol level can vary substantially, on average by 0.35mmol/l (Smith, 1993; Cooper, 1988). For someone with a normal cholesterollevel this amounts to some 7%. In order to be able to determine whether thereis an increase or a fall in cholesterol, it is necessary to measure the cholesterollevel several times. This applies particularly in the case of patients with a slightlyraised cholesterol level.7 Are positive effects of kahweol and cafestol also known?In epidemiological studies it has been suggested that consumption of coffeeis associated with a lower risk of certain forms of cancer (Giovannucci, 2000;Tavani, 2000). In various studies diterpenes have been found to have inflamma-tion-inhibiting and anti-carcinogenic properties and possibly to provide pro-tection against certain forms of cancer (Cavin, 2002; Huber, 2004; Kim, 2004;Lee, 2007). In vitro studies and animal studies suggest that a potential anti-carcinogenic effects can be explained by the induction of detoxification in theliver and intestine by cafestol and kahweol. However, there is no direct proof ofan anti-carcinogenic effect of cafestol or kahweol in people (Ricketts, 2007). Coffee, heart and blood vessels | 23
  24. 24. 8 May someone with a raised cholesterol level continue to drink coffee? People with a raised cholesterol level may choose to continue to drink coffee with negligible amounts of cafestol, such as filtered coffee and coffee made with coffee pods; or up to 2-3 cups of espresso coffee consumed over the course of the day (Urgert, 1996a). In view of the cholesterol-raising effect of consuming boiled coffee, Turkish or Greek coffee or Cafetière (French press) coffee, people with a raised serum cho- lesterol levels are advised to limit coffee from these methods of brewing coffee.24 |
  25. 25. Coffee, heart and blood vessels | 25
  26. 26. Literature Ahola I e.a., The hypercholesterolaemic factor in boiled coffee is retained by a paper fi lter. J Intern Med, 1991; 230:293-297. Bak AA and Grobbee DE. The effect of serum cholesterol levels of coffee brewed by fi ltering or boiling. N Eng J Med, 1989; 321:1432-1437. Boekschoten MV e.a., Reproducibility of the serum lipid response to coffee oil in healthy volunteers. Nutr J, 2003; 2(1):8. Boekschoten MV e a., Verwaarloosbare hoeveelheden cholesterolverhogende diterpenen in koffie gezet met de koffiepadmethode bij vergelijking met ongefi lterde koffi e. Ned Tijdschr Geneeskd, 2006; 52:2873-2875. Cavin C e.a., Cafestol and kahweol, two coffee specifi c diterpenes with antiocarcionogenic activity. Food Chem Toxicol, 2002; 40(8):1155-1163. Cooper GR e.a., Standardization of lipid, lipoprotein, and apolipoprotein measurements. Clin Chem,1988; 34(8):B95-B105. Devaraj S e.a., The role of dietary supplementation with plant sterols and stanols in the prevention of cardiovascular disease. Nutr Rev, 2006; 64:348-352. Dusseldorp M van e.a., Effect of decaffeinated versus regular coffee on serum lipoproteins. A 12 week double blind trial. Am J Epidem, 1990; 132(1):33-40. Dusseldorp M van e.a., Cholesterol-raising factor from boiled coffee does not pass a paper fi lter. Arthe- rios Thromb, 1991; 11:586-593. Giovannucci E, Meta-analysis of Coffee Consumption and Risk of Colorectal Cancer. Am J Epidemiol, 1998; 147(11):1043-1052. Huber W e.a., Potential chemoprospective effect of the coffee components kahweol and cafestol pal- mirates via modifi cation of hepatic N-acetyltransferase and glutathione-S-transferase activities. Environ Mol Mutagen, 2004; 44(4):265-276. Kim JY e.a., Suppressive effects of the kahweol and cafestol on cyclooxygenase-2 expression in macro- phages. FEBS Letters, 2004; 569:321-326. Lee KJ e.a., Hepatoprotective and antioxidant effects of coffee diterpenes kahweol and cafestol on carbon tetrachloride-induced liver damage in mice. Food. Chem. Toxicol., 2007: doi:10.1016/j. fct.2007.05.010. Pietinen P e.a., Changes in diet in Finland from 1972 to 1992: impact on coronary heart disease risk. Prev Med, 1996; 25:243-250.26 |
  27. 27. Ricketts, ML e.a., The Cholesterol-Raising Factor from Coffee Beans, Cafestol, as an Agonist Ligand forthe Farnesoid and Pragnane X Receptors. Mol Endocrinol, 2007; 21:1603-1616.Sara Lee/Douwe Egberts, intern rapport, 1998.Smith SJ e.a., Biological variability in concentrations of serum lipids: sources of variation among resultsfrom published studies and composite predicted values. Clin Chem, 1993; 39(6):1012-1022.Tavani A, Coffee and cancer: a review of epidemiological studies, 1990-1999. Eur J Canc Prev, 2000;9(4):241-256.Urgert R e.a., Levels of the Cholesterol-Elevating Diterpenes Cafestol and Kahweol in Various CoffeeBrews. J Agric Food Chem, 1995; 43:2167-2172.Urgert R and Katan MB, The cholesterol-raising factor from coffee beans. J R Soc Med, 1996a;89(11):618-623.Urgert R e.a., Comparison of effect of cafetiere and fi ltered coffee on serum concentrations of liveraminotransferases and lipids: six month randomised controlled trial. Br Med J, 1996b; 313:1362-1366.Urgert R and Katan MB, The cholesterol-raising factor from coffee beans. Annu Rev Nutr, 1997; 17:305-324.Weusten van der Wouw PME e.a., Identity of the cholesterol-raising factor from boiled coffee and itseffects on liver function enzymes. J Lip Res, 1994; 35:721-733. Coffee, heart and blood vessels | 27
  28. 28. 28 |
  29. 29. 3 Coffee and blood pressure1 Does coffee affect blood pressure?Regular consumption of coffee has either very little or no effect on blood pres-sure in the case of people with normal blood pressure (Myers, 1991; Stamler,1997; Jee, 1999; Geleijnse, 2004; Noordzij, 2005; Winkelmayer, 2005; Uiter-waal, 2007).There is, however, a difference between the short-term effect and the effect inthe longer term. Shortly after consumption, drinking coffee slightly increasesblood pressure, the effect being comparable with the effect on blood pressureof holding a conversation (Nurminen, 1999). This type of acute effect resultsfrom the caffeine, and the blood pressure falls again within a few hours to itsstarting level. In addition, tolerance appears to occur in terms of the effect ofcaffeine (Casiglia, 1992; Jee, 1997). Studies relating to a longer term effect indi-cate that coffee has negligible if any impact on blood pressure (Geleijnse, 2004;Noordzij, 2005; Winkelmayer, 2005; Uiterwaal, 2007). Coffee, heart and blood vessels | 29
  30. 30. 2 How substantial is the acute effect of coffee on blood pressure? A meta-analysis in 2005 comprising 16 intervention studies (see shaded text on page 35) of the effect of coffee or caffeine on blood pressure, gave different results for coffee and caffeine. Coffee (average 725 ml per day (approximately 5 cups)) resulted in an increase of 1.2 mg Hg in systolic blood pressure and 0.5 mg Hg in diastolic blood pressure (Noordzij, 2005). A comparable amount of caffeine administered in tablet form resulted in increases of 4.2 and 2.4 mg Hg in systolic and diastolic blood pressure respectively. Why pure caffeine raises blood pressure and caffeinated coffee has negligible if any such effect is not fully understood. It is possible that the effect of caffeine when consumed in cof- fee is negated by other components in coffee, such as potassium, magnesium and polyphenols. 3 Is there a relationship between drinking coffee and the risk of hypertension? Various studies show that coffee has no specific effect on the risk of hyperten- sion (Klag, 2002; Geleijnse 2004; Winkelmayer, 2005, Uiterwaal, 2007). In the Dutch cohort study carried out by Uiterwaal et al on almost 3,000 men and al- most 3,400 women without hypertension, the long-term effects of drinking cof- fee on the risk of hypertension (systolic pressure 140 mmHg) were examined. Even after correction for other factors, the group that never drank coffee was found to have a lower risk of hypertension than people who consumed small amounts of coffee (1 - 3 cups a day) (Uiterwaal, 2007). However, the group of non-coffee drinkers was small and it is possible that not drinking coffee is linked with a different and more healthy lifestyle which could not be entirely corrected for. A striking result was that women who drank a lot of coffee (6 cups a day)30 |
  31. 31. had a lower risk of hypertension. A comparable result was also found in the caseof the Nurses’ Health Study of more than 155,000 women without hyperten-sion, who were monitored over a period of 12 years (Winkelmayer, 2005).Consumption of more than 6 cups of coffee a day was found to have a slightlyprotective effect on the risk of hypertension. Cola on the other hand was foundto be related to an increased risk of hypertension.4 What are the results of limiting coffee in the case of hypertension?Research in people with hypertension shows that withholding coffee has no ef-fect on the blood pressure of hypertensive patients (MacDonald, 1991; Nurmi-nen, 1998). Blood pressure was also not further increased as a result of drinkingcoffee in the case of people with moderate hypertension.Known risk factors that play a major role in the case of hypertension are obesity,physical inactivity, high salt intake and low potassium intake (Geleijnse, 2004).5 Is decaffeinated coffee better in the case of hypertension?There are no indications for advising against moderate consumption of caffein-ated coffee (4 to 5 cups a day) for people with hypertension (see question 4).If people prefer not to consume caffeine, decaffeinated coffee is an alternativechoice. Coffee, heart and blood vessels | 31
  32. 32. 6 What advice regarding coffee consumption can be given to people with hypertension? There are no indications for advising against coffee consumption for individuals with hypertension. At this moment most research suggests that regular intake of caffeinated coffee does not increase the risk of hypertension. Sensitive to caffeine? Caffeine has a mildly stimulating effect on the central nervous system. This ex- presses itself in the form of heightened alertness and concentration and a redu- ced feeling of fatigue. In the case of people who are sensitive to caffeine, it can also cause restlessness, trembling or increased time taken to fall asleep. Caffeine sensitive individuals are advised to limit the quantity of caffeine to an amount at which the individual experiences minimal effects from caffeine. These people may also choose for example to drink decaffeinated coffee. Women who are pregnant or breast-feeding are advised to limit their daily intake of caffeine to a maximum of 300 mg. In some countries e.g. the UK, the upper recommended limit is 200mg. Tea, cola, energy drinks, drinking chocolate and some painkillers are also sources of caffeine intake (see table on page 8).32 |
  33. 33. Coffee, heart and blood vessels | 33
  34. 34. Literature Casiglia E e.a., Haemodynamic effects of coffee and purifi ed caffeine in normal volunteers: a placebo- controlled clinical study. J Hum Hypertens, 1992; 6(2):95-99. Geleijnse JM e.a., Impact of dietary and lifestyle factors on the prevalence of hypertension in Western populations. Eur J Pub Health, 2004;14:235-239. Jee SH e.a., The effect of coffee on blood pressure, a meta analyses of controlled clinical trials. Can J Cardiol 1997; 13(Suppl B):36B. Jee SH e.a., The effect of chronic coffee drinking on blood pressure: a meta-analysis of controlled clini- cal trials. Hypertension, 1999; 33(2):647-52. Klag MJ e.a., Coffee intake and the risk of hypertension: the Johns Hopkins precursors study. Arch Intern Med, 2002; 162(6):657-62. MacDonald TM e.a., Caffeine restriction: effect on mild hypertension. Br Med J, 1991; 303:1235-1238. Myers MG en Reeves RA, The effect of caffeine on daytime ambulatory blood pressure. Am J Hypert, 1991; 4:427-431. Noordzij M e.a., Blood pressure response to chronic intake of coffee and caffeine: a meta-analysis of randomized controlled trials. J Hypert, 2005; 23:921-928. Nurminen ML e.a., Dietary factors in the pathogenesis and treatment of hypertension. Ann Med, 1998; 30(2):143-150. Nurminen ML e.a., Coffee, caffeine and blood pressure: a critical review: Euro J Clin Nutr, 1999; 53:831-839. Stamler J e.a., Relation of Relation of body mass and alcohol, nutrient, fi ber, and caffeine intakes to blood pressure in the special intervention and usual care groups in the Multiple Risk Factor Intervention Trial. Am J Clin Nut, 1997; 65(suppl):338-65. Uiterwaal C e.a., Coffee intake and incidence of hypertension, Am J Clin Nutr, 2007; 85:718-723. Winkelmayer WC e.a., Habitual Caffeine Intake and the Risk of Hypertension in Women. JAMA, 2005; 294:2330-2335.34 |
  35. 35. Study of coffee and healthEvery type of research has its own evidential value and limitations. Most of thestudies reported in this brochure can be differentiated into:1. Meta-analysis: A literature study of various studies (intervention studies, cohort studies and/or patient control studies) of the relationship between coffee consumption behaviour and a biomarker or (medical) condition, with the aim of obtaining a more precise outcome.2. Intervention study: In the case of this type the effect of the substance to be investigated on a group of people is measured and compared with a control group, which is not given the substance. Intervention studies in the area of coffee research are usually relatively short and the group size is limited.3. Cohort study (prospective): In this brochure in the case of this type of study large groups of people have been monitored (prospectively) over a longer period. In this context at the start of the study differences in coffee con- sumption between people who have and have not developed a (medical) condition during the study are examined. The pattern of coffee consump- tion of the participants has therefore not been influenced by the condition.4. Patient-control study: In the case of this type of study the differences in coffee consumption patterns are investigated in groups of people who have and have not developed the (medical) condition. In this case therefore questions are asked after the event about previous coffee consumption behaviour. A disadvantage of this type of study may be that the coffee consumption pattern of the people who have that condition has been modified or is assessed differently than in the case of people who do not have the condition. Coffee, heart and blood vessels | 35
  36. 36. coffee vessels heart and blood KO F F I E E N G E Z O N D H E I D