French Press Coffee (Cafetiere Coffee) and LDL Cholesterol

Drinking Unfiltered CoffeeRaises LDL Cholesterol

Numerous studies have found that drinking coffee which is not filtered by a paper filterincreases LDL cholesterol levels by 10% or more. LDL is the so-called “bad cholesterol” and an increase of 10% substantially increases one’s risk of heart attack and stroke.

The cause of this increase in LDL was found to be the presence of the lipids (also called diterpenes)cafestol and kahweol in unfiltered coffee. Dr. Arild C. Rustan of the Department of Pharmacology, University of Oslo identified these two lipids as“the most potent cholesterol-raising components known”.

At one time these lipids were believed to be present only in Scandinavian boiled coffee in which coffee grounds are boiled for five to ten minutes. However many later studies foundthat they are also present in ordinary French Press brew, and metal-filtered drip brew.

FOLLOWING THE SCIENCE NEWS ITEM BELOW, ARE EXCERPTS FROM SOME OF OVER THIRTY MEDICAL STUDIES THAT WE REVIEWED ON THIS SUBJECT.

UNLIKE THE CONTROVERSY OVER CAFFEINE, THERE IS VERY LITTLE ARGUMENT OVER THIS ISSUE OF LDL CHOLESTEROL AND UNFILTERED COFFEE. THE GREAT MAJORITY OF THESE STUDIES ARE CONCORDANT.

From:

Science News November 30, 1996

Many coffee aficionados eschew the filtered brew, arguing that filters remove some of a bean’s savory flavor. What filtering really does -- besides screening out gritty grounds -- is eliminate coffee’s oils, rich in alcohols known as diterpenes. Two of these alcohols, cafestol and kahweol, can elicit a number of unhealthy changes in the blood of regular coffee drinkers.

The newest diterpene effect to be identified -- an increase in blood levels of an enzyme that is normally associated with damage to liver cells -- emerged in a 6-month long Dutch trial with healthy, coffee-loving volunteers.

Rob Urgert and his colleagues at WageningenAgriculturalUniversity in the Netherlands recruited 46 men and women to participate in the experiment. All of the volunteers received a locally popular blend of coffee and strict instructions on how to brew two batches of it each day.

Urgert’s group directed half the men and women to pour boiling water through 33 grams of ground beans sitting in a cone-shaped filter until the dripping brew filled a half-liter jar.

The remaining volunteers were told to pour their boiling water and ground beans together into a French press -- also known as cafetière -- coffee maker. The top of this type of pot is fitted with a large plunger. The volunteers were told to stir the mix and then to let the grounds steep for 2 to 5 minutes before they pushed the plunger down. (This effectively stops the brewing and traps any floating grounds so that they won’t enter the cup.) The coffee was then decanted into another bottle.

The participants, all healthy and between the ages 19 and 69, were told to drink almost a liter of the coffee daily for 24 weeks. Every 2 to 4 weeks, the scientists brought the volunteers in for blood tests that measured concentrations of cholesterol, triglycerides, and a host of liver enzymes.

A report of the study, published in today’s British Medical Journal, shows that men and women who drank the filtered coffee exhibited no changes over the course of the trial in any of the assayed blood constituents. Previous studies by Urgert’s group had shown that such a filter effectively removes all of the coffee-oil’s diterpenes. Those who drank coffee made by the French press method, however, displayed a host of undesirable changes.

For instance, levels of one liver enzyme (alanine aminotransferase) nearly doubled early in the trial. This enzyme serves as a marker of potential stress to the liver, Urgert explains. "If there is some change in liver cell integrity, the concentration of these enzymes in the blood can rise."

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The Dutch nutrition scientists also observed a sharp, transitory 26 percent rise in serum triglyceride levels among the men and women drinking French-pressed coffee. Like the liver-enzyme changes, however, the triglycerides fell as the study progressed. By the end of 24 weeks, their concentrations had already returned to levels recorded before the start of the study.

Of far greater concern, Urgert believes, were increases of between 9 and 14 percent in the concentrations of low-density-lipoprotein (LDL) cholesterol -- the so-called bad cholesterol -- in volunteers drinking the pressed brew. An increase this large in LDLs, a risk factor for heart disease, might over a lifetime elevate an individual’s chance of developing coronary disease by up to 20 percent, he notes. Also observed in several shorter studies by this group, this potent elevation in LDL concentrations shows no sign of attenuating with time.

"These diterpenes are amazingly predictable," Urgert observes. "If you knew how much you gave to the Dutch volunteers, you could almost exactly predict their change in LDL cholesterol."

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References:

Urgert, R., et al. 1996. Comparison of effect of cafetière and filtered coffee on serum concentrations of liver aminotransferases and lipids: Six month randomized controlled trial. British Medical Journal 313(Nov. 30):8.

Urgert, R., et al. 1995. Levels of the cholesterol-elevating diterpenes cafestol and kahweol in various coffee brews. Journal of Agricultural and Food Chemistry 43(August):2167.

Levels of the Cholesterol-Elevating Diterpenes Cafestol and Kahweol in Various Coffee BrewsJournal of Agricultural Food Chemistry; 1995;43(8) pp 2167 - 2172

by Rob Urgert, Guido van der Weg, Truus G. Kosmeijer-Schuil, Peter van de Bovenkamp, Robert Hovenier, and Martijn B. Katan - Department of Human Nutrition, AgriculturalUniversity, Wageningen, The Netherlands.

This study listed the levels of these lipids in grams per cup of brew. A “cup” was defined as five ounces for the Scandinavian or French press brews or the average amount of a single espresso serving from a sample of ten different Italian espresso houses.

Brewing Method / Cafestol / Kahweol
Scandinavian boiled / 3.0mg / 3.9mg
French press / 3.5mg / 4.4mg
Italian espresso / 1.5mg / 1.8mg
Drip – Gold Filtered / 2.5mg / Not given
Drip – Paper filtered / 0.1mg / Not given

Note that French press coffee has even higher levels of cafestol and kahweol than Scandinavian boiled coffee.

A single Italian espresso has about half as much cafestol and kahweol as a cup of Scandinavian boiled coffee. Thus the common double espresso would have about the same levels as a cup of boiled coffee. The brew strength of espresso varies more widely than other coffee drinks. Most other studies found lower levels of these lipids than the figures listed above which were measured in espresso brewed by ten different Italian coffee houses.

Thisstudy and those cited below, allfound that paper filtering reduced thelipidsto negligible levels and eliminatesthe cholesterol-elevating effect. This was confirmed both by laboratory analysis of the brew and clinical trials on human subjects.

Please note that “Cafetiere Coffee” in some studies below is simply another term for French Press coffee.

Cholesterol-raising factor from boiled coffee does not pass a paper filter

M van Dusseldorp, MB Katan, T van Vliet, PN Demacker and AF Stalenhoef
Department of Medicine, University of Nijmegen, The Netherlands.

Previous studies have indicated that consumption of boiled coffee raisestotal and low density lipoprotein (LDL) cholesterol, whereas drip-filteredcoffee does not. We have tested the effect on serum lipids of consumedcoffee that was first boiled and then filtered through commercial papercoffee filters. Sixty-four healthy volunteers consumed six cups per day ofthis boiled and filtered coffee for 17 days. Then, they were randomlydivided into three groups, which, for the next 79 days, received eitherunfiltered boiled coffee (lipid content, 1.0 g/l), boiled and filteredcoffee (0.02 g lipid/l), or no coffee.

Serum total cholesterol levels roseby 0.42 mmol/l (16 mg/dl; 95% confidence interval [CI], 0.14-0.71), LDLcholesterol levels by 0.41 mmol/l (16 mg/dl; 95% CI, 0.16-0.66), andapolipoprotein B levels by 8.6 mg/dl (95% CI, 3.8-13.4) in those whoconsumed boiled coffee relative to those who consumed boiled and filteredcoffee. Responses of triglycerides, high density lipoprotein cholesterol,and apolipoprotein A-I did not differ significantly among these groups.

Nosignificant effects on serum lipid levels were found in the boiled andfiltered coffee-consuming group compared with those who drank no coffee. Insubjects who drank boiled coffee, serum campesterol level, an indicator ofcholesterol absorption, remained constant. The serum lathosterol level, anindicator of cholesterol synthesis, increased by 11% (p less than 0.05),but the lathosterol to cholesterol ratio did not change. We propose thatpaper filters of the type used for drip-filtered coffee retain the lipidpresent in boiled coffee and in that way remove the hypercholesterolemicfactor.

Comparison of effect of cafetiere and filtered coffee on serum concentrations of liver aminotransferases and lipids: six month randomised controlled trial

Rob Urgert, nutrition researcher,a Saskia Meyboom, dietitian,a Marjan Kuilman, nutrition researcher,a Henny Rexwinkel, nutrition researcher,a Maud N Vissers, nutrition researcher,a Mariska Klerk, nutrition researcher,a Martijn B Katan, professora

a Department of Human Nutrition, Wageningen Agricultural University, Bomeneg 2, 6703 HD Wageningen, the Netherlands

Correspondence to: Dr Katan. martijn.katan{at}et3.voed.wau.nl.

Abstract
Objective: To study the effects of prolonged intake of cafetierecoffee, which is rich in the diterpenes cafestol and kahweol,on serum aminotransferase and lipid concentrations.
Design: Randomised parallel controlled trial.
Subjects: 46 healthy men and women aged 19 to 69.
Intervention: Consumption of five to six strong cups (0.9 litres)a day of either cafetiere (22 subjects) or filtered coffee (24subjects) for 24 weeks.
Main outcome measures: Mean changes in serum aminotransferaseand lipid concentrations.

Results: Cafetiere coffee raised alanine aminotransferase concentrationby up to 80% above baseline values relative to filtered coffee.After 24 weeks the rise was still 45% (9 U/l (95% confidenceinterval 3 to 15 U/l), P = 0.007). Alanine aminotransferaseconcentration exceeded the upper limit of normal in eight ofthe 22 subjects drinking cafetiere coffee, being twice the upperlimit of normal in three of them. Cafetiere coffee raised lowdensity lipoprotein cholesterol concentrations by 9-14%. After24 weeks the rise was 0.26 mmol/l (0.04 to 0.47 mmol/l) (P =0.03) relative to filtered coffee. Triglyceride concentrationsinitially rose by 26% with cafetiere coffee but returned closeto baseline values within six months. All increases were reversibleafter the intervention was stopped.

Conclusions: Daily consumption of five to six cups of strongcafetiere coffee affects the integrity of liver cells as suggestedby small increases in serum alanine aminotransferase concentration.The effect does not subside with prolonged intake. High intakesof coffee brews rich in cafestol and kahweol may thus be responsiblefor unexplained increases in this enzyme activity in apparentlyhealthy subjects. Cafetiere coffee also raises low density lipoproteincholesterol concentration and thus the risk of coronary heartdisease.
Key messages

This randomised study found that cafetiere coffee also increased alanine aminotransferase and low density lipoprotein cholesterol concentrations, and they were still raised after six months of daily intake.

Filtered coffee had no effect

The increase in liver enzyme activity could be innocuous, but the increase in cholesterol concentration may increase coronary risk and could be a reason to advise patients to drink filtered coffee

J Intern Med. 1991 Oct;230(4):293-7.

The hypercholesterolaemic factor in boiled coffee is retained by a paper filter.
Ahola I, Jauhiainen M, Aro A.
Department of Biochemistry, National Public Health Institute, Helsinki, Finland.
In order to study the effects of filtering on the serum cholesterol-elevating effect of boiled coffee, 20 healthy volunteers consumed, in random order, 6-10 dl d-1 of strong boiled coffee (BC) and similarly boiled coffee that had been passed through a conventional paper filter (BFC), for periods of 4 weeks in a crossover design. During periods of BC consumption serum total cholesterol and LDL-cholesterol levels (P less than 0.05), as well as serum triglyceride and apoprotein B concentrations and the LDL/HDL ratio (P less than 0.01), were significantly higher than during BFC periods. Serum HDL-cholesterol and apoprotein A-I levels remained unchanged. Filtering removed more than 80% of the lipid-soluble substance that was present in boiled coffee.The results indicate that the hypercholesterolaemic factor in boiled coffee, which is presumably lipid-soluble, is retained by the paper filter. They also suggest that boiling is not essential for the previously observed difference between the effects on serum lipoproteins of boiled coffee and filtered coffee.

Coffee Consumption and Serum Lipids: A Meta-Analysis of Randomized Controlled Clinical Trials

Sun Ha Jee1,,3, Jiang He4, Lawrence J. Appel2,3,5, Paul K. Whelton4, II Suh6 and Michael J. Klag2,3,5,7

1 Department of Epidemiology and Disease Control, YonseiUniversityGraduateSchool of Health Science and Management, Seoul, Republic of Korea.
2 Welch Center for Prevention, Epidemiology, and Clinical Research, The JohnsHopkinsUniversitySchool of Medicine, Baltimore, MD.
3 Department of Epidemiology, The JohnsHopkinsUniversitySchool of Hygiene and Public Health, Baltimore, MD.
4 Tulane University School of Public Health and Tropical Medicine, New Orleans, LA.
5 Department of Medicine, The JohnsHopkinsUniversitySchool of Medicine, Baltimore, MD.
6 Department of Preventive Medicine and Public Health, YonseiUniversityCollege of Medicine, Seoul, Republic of Korea.
7 Department of Health Policy and Management, The JohnsHopkinsUniversitySchool of Hygiene and Public Health, Baltimore, MD.

Coffee drinking has been associated with increased serum cholesterollevels in some, but not all, studies. A Medline search of theEnglish-language literature published prior to December 1998,a bibliography review, and consultations with experts were performedto identify 14 published trials of coffee consumption. Informationwas abstracted independently by two reviewers using a standardizedprotocol. With a random-effects model, treatment effects wereestimated by pooling results from individual trials after weightingthe results by the inverse of total variance. A dose-responserelation between coffee consumption and both total cholesteroland LDL cholesterol was identified (p < 0.01). Increasesin serum lipids were greater in studies of patients with hyperlipidemiaand in trials of caffeinated or boiled coffee. Trials usingfiltered coffee demonstrated very little increase in serum cholesterol.