Unfiltered coffee increases plasma homocysteine concentrations in healthy volunteers: A randomized trial

Wageningen University, Wageningen, Gelderland, Netherlands
American Journal of Clinical Nutrition (Impact Factor: 6.77). 03/2000; 71(2):480-4.
Source: PubMed


An elevated plasma homocysteine concentration is a putative risk factor for cardiovascular disease. Observational studies have reported an association between coffee consumption and plasma homocysteine concentrations.
We studied the effect of coffee consumption on plasma homocysteine in a crossover trial. We used unfiltered coffee so as to include the possible effects of coffee diterpenes, which are removed by filtering.
Sixty-four healthy volunteers (31 men and 33 women) with a mean (+/-SD) age of 43 +/- 11 y were randomly assigned to 2 groups. One group (n = 30) drank 1 L unfiltered cafetière (French press) coffee daily for 2 wk. Such coffee is rich in the cholesterol-raising diterpenes kahweol and cafestol. The other group (n = 34) received water, milk, broth, tea, and chocolate drinks instead of coffee. After a washout period of 8 wk, both groups received the alternate intervention for another 2 wk.
Consumption of 1 L unfiltered coffee/d for 2 wk significantly raised fasting plasma homocysteine concentrations by 10%, from 12.8 to 14.0 micromol/L.
Unfiltered coffee increases plasma homocysteine concentrations in volunteers with normal initial concentrations. It is unclear whether the effect is caused by the cholesterol-raising diterpenes present exclusively in unfiltered coffee or by factors that are also present in filtered coffee.

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    • "Hyperhomocysteinaemia is considered to be a risk factor for the development of cardiovascular diseases [van Oijen et al., 2007]. A randomized study performed in the Netherlands suggested that drinking 1 L of unfi ltered coffee per day for two weeks increases mean plasma homocysteine by 10% [Grubben et al., 2000]. However, a study in the Norwegian population showed a strong dose-response relationship between coffee intake and total homocysteine levels, irrespective of the type of coffee (fi ltered, boiled, instant). "
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    ABSTRACT: The question whether coffee has a negative or a positive impact on human health has been the topic of much heated debate for years. Nevertheless, recent studies have not only failed to confirm earlier concerns, but in fact suggested a positive effect of coffee intake. Latest studies revealed that people who drink at least 3 cups of coffee per day are at a lower risk for type 2 diabetes, as well as liver and colon cancer. The reports on a possible correlation between coffee drinking and heart diseases have also generated optimistic results. No adverse associations between coffee consumption and coronary heart disease, stroke, and hypertension have been found. What is more, some authors demonstrated that coffee drinking may prevent cardiovascular diseases. Composition of coffee is determined by the strength of the brew and brewing methods. Unfiltered coffee is rich in cholesterol-raising diterpenes, therefore patients with dyslipidemia should be advised to drink filtered rather than non-filtered coffee. On the other hand coffee contains polyphenols which act as antioxidants, and these compounds are probably responsible for the suggested beneficial effect of coffee on health. This article summarizes the current literature reports on this controversial topic.
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    • "We also explored the relationship between tea-derived polyphenol O-methylation and tHcy response to tea and observed no linear relationship. Tea and coffee, and their major constituents, polyphenols and caffeine, can raise tHcy (Grubben et al. 2000; Urgert et al. 2000; Olthof et al. 2001; Verhoef et al. 2002). "
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    • "The positive association reported between coffee consumption and tHcy concentration is consistent with several observational (Nygard et al, 1997; Stolzenberg-Solomon et al, 1999; De Bree et al, 2001a; Jacques et al, 2001) and intervention studies (Grubben et al, 2000; Urgert et al, 2000; Christensen et al, 2001). Caffeine has been proposed as the causative agent as it might act as a B6 antagonist inhibiting the conversion of homocysteine to cysteine (Grubben et al, 2000; Verhoef et al, 2002). Chlorogenic acid, a polyphenol, also present in coffee may also be partly responsible for the increase in tHcy (Olthof et al, 2001). "
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