Effect Of Coffee Consumption Research Articles

Coffee, caffeine and hemostasis: results from two randomized studies

The influence of coffee and caffeine consumption on hemostatic factors was studied in 2 randomized trials. Both studies were conducted in young, healthy adults. In the first study, 107 participants were randomly allocated to one or 3 intervention groups, drinking filtered coffee, boiled coffee or no coffee at all, respectively, for a period of 9 weeks. In the second study, 69 subjects received either 4–6 tablets containing 75 mg caffeine or the same amount of placebo tablets, while using decaffeinated coffee. In this double-blind study caffeine intake from any other source was not allowed. Blood samples for hemostatic factors were obtained at baseline and after 9 weeks of intervention. The findings indicate no effect of coffee consumption on fibrinogen, clotting factor VII activity, factor VIII antigen, protein C and protein S and also no effect of caffeine consumption on fibrinogen and factor VII activity.

Coffee consumption and serum lipids: A randomized, crossover clinical trial

purpose: The purpose of this study was to determine the effect of consuming three or more cups of filter-brewed coffee per day on levels of serum lipids. subjects and methods: A prospective, randomized crossover clinical trial was performed. Twenty-one healthy white male subjects completed the trial, and consumed an average of 3.6 cups of coffee a day. Data were evaluated by analysis of variance for repeated measures and t-test for paired means. results: No effect of coffee consumption on serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, or apolipoprotein B was found. Diet, creamer use, and cigarette use as well as group assignment and time factors were controlled for in the analysis. conclusion: We found no effect of moderate consumption of filter-brewed coffee on serum levels of atherogenic lipids. This study supports previous work that filtered coffee has no adverse effect on serum lipids. This has far-reaching implications given the widespread use of coffee and the current concern over coronary risk factors.

Coffee and the immune system

The effect of coffee consumption on the immune system, studied in 15 men and women, showed that the responses to PHA and Con A were about one-third lower during coffee drinking compared to a period of abstinence from coffee (117335, 99856 and 181236, 153315, P<0.004, 0.009 respectively). There was no effect on total T- or B-cells. There was no statistically significant change in the number of suppressor T-cells (20, 26; P = 0.1) or NK cells (20, 26; P = 0.014). Chemotaxis was higher in the coffee period at all concentrations. This exploratory study suggests that coffee intake modifies various measures of the immune function. The clinical relevance of the findings is not clear, and further studies aimed at delineating the constituents responsible for the effects observed are recommended.

The effect of coffee consumption on plasma lipids, lipoproteins, and the development of aortic atherosclerosis in rhesus monkeys fed an atherogenic diet

Rhesus monkeys (seven females and six males) were fed ad libitum a diet comparable to that consumed by humans, containing 25% by weight fat (40% of calories) and 0.15% cholesterol (0.3 mg/kcal) for 12 months (phase 1). From the 13th month all monkeys were continued on the diet while four females and three males were given 50% coffee as their fluid intake and the remainder were water controls (phase 2). Major changes in total plasma lipids and lipoprotein profiles occurred within 3 months and generally plateaued thereafter. Total plasma protein remained constant while total plasma cholesterol, phospholipids, triglycerides, and free fatty acid levels increased. After the initiation of coffee, there was no difference between the diet-water group and the diet-coffee group with respect to total protein and lipids in plasma. Total concentrations of plasma lipoproteins varied throughout the study. The pre-β (very low density lipoproteins) fraction remained constant while the β (low density lipoprotein) and α (high density lipoprotein) fractions, along with their major components, increased within 3 to 6 months, then fluctuated in absolute weight thereafter. The introduction of 50% coffee was without effect on the dynamic changes in these fractions as fluctuations were found in both groups and to the same magnitude. This leads the authors to suspect that such variations are “normal” or are in response to the diet per se. The atherogenic diet induced fatty streaks in the aortas of all monkeys to a greater extent in males than females. However, there were no gross differences in the quantity or distribution of the streaks between control and coffee-drinking monkeys.