Article

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

ABSTRACT

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.

Full-text preview

Available from: ajcn.org
  • Source
    • "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). "
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Jan 2016
  • Source
    • "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). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Plasma total homocysteine concentrations (tHcy) are a putative risk factor for CVD. Tea is a rich dietary source of polyphenols and caffeine, both of which may raise tHcy. However, it is possible that much of any effect is transitory and may be influenced by the consumption of food. Our objective was to investigate the acute effect of tea, at a dose representative of ordinary population intakes, on tHcy and to determine whether consumption of a meal influences the magnitude of any effect. Measurements of tHcy were performed in twenty participants at baseline and 3.5 h after drinking three cups of black tea or hot water (consumed at time 0, 1.5 and 3 h) with and without a meal: a total of four treatments administered in random order. Drinking tea resulted in an acute increase in tHcy (0-30 (95 % CI 0.04, 0.56) micromol/l, P=0.022). The meal resulted in an acute decrease in tHcy (-0.42 (95 % CI -0.68, -0.16) micromol/l, P=0.002). There was no interaction between tea and meal on tHcy (P=0.40); that is, the effect of tea on tHcy was not different in the fasting and non-fasting state. Our results suggest that drinking black tea can cause a small acute increase in tHcy and that this effect is not enhanced in the non-fasting state. Given that results of population studies have generally shown a negative association between tea intake and tHcy, the significance of these findings to CVD risk remains uncertain.
    Full-text · Article · Jun 2007 · British Journal Of Nutrition
  • Source
    • "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). "
    [Show abstract] [Hide abstract]
    ABSTRACT: To examine the associations between various lifestyle factors--smoking habits, physical activity, dietary habits, coffee, tea, and alcohol consumption--and homocysteine (tHcy) in relation to MTHFR(C677T) genotype. Cross-sectional population-based study. Residents of Copenhagen County, Denmark. A random sample of 6457 men and women aged 30-60 years drawn from the Civil Registration System and invited to a health examination in 1999-2001. A total of 2788 participants were included in the statistical analysis. tHcy was measured using a Fluorescent Polarization Immuno Assay. MTHFR-genotype was determined by PCR and RFLP analysis. Information about lifestyle factors was obtained from a self-administered questionnaire. Daily smoking, less healthy dietary habits, and coffee drinking were associated with elevated tHcy concentrations independent of other determinants. Wine consumption was related to tHcy in a J-shaped manner, whereas beer consumption was negatively associated with tHcy after multiple adjustments. Interaction was observed between smoking status and MTHFR-genotype, smoking status and sex, and beer consumption and age. The effect of smoking was more pronounced in persons with the TT genotype and in women. The effect of beer consumption was more pronounced at younger than at older ages. Smoking status, dietary habits, coffee intake, wine, and beer consumption were major lifestyle determinants of tHcy. Changes in these lifestyle factors may reduce tHcy concentrations, thereby lowering cardiovascular risk in the general population. Danish Medical Research Council, Danish Centre for Evaluation and Health Technology Assessment, and Danish Heart Foundation.
    Full-text · Article · Sep 2004 · European Journal of Clinical Nutrition
Show more