Mechanisms – beyond caffeine

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In the past, it was thought that any effect of coffee on the cardiovascular system was likely to be due to caffeine. Many studies therefore only tested for the effect of caffeine. However, consideration should be given to other factors, such as polyphenols, as well as the potential effect on circulating cholesterol levels.

Cholesterol

The coffee components responsible for increasing cholesterol are cafestol and kahweol31. These are naturally-occurring compounds found in coffee oil. Whether these compounds permeate in the brew and to what extent depends on the brewing method.

Filtered coffee and soluble coffee contain hardly any cafestol or kahweol and have virtually no effect on the cholesterol levels4. Moderate consumption of espresso also has a negligible effect, as levels of cholesterol-raising compounds are approximately half that of unfiltered coffee and serving sizes are small35. However, Scandinavian boiled coffee, Cafetière (plunger pot), Greek and Turkish coffee contain cafestol and kahweol in higher amounts4,31-35. Consuming substantial amounts of these types of coffees can raise serum cholesterol levels4,31-35. The effects on the cholesterol level are transient after the cessation of consumption4,31-35.

Polyphenols

The antioxidant potential of different foods and beverages also provide further insight into potential mechanisms. Different antioxidant compounds found in coffee may affect the body. Research published in 2016 concluded that coffee consumption increases the antioxidant capacity of plasma and the overall effect of this on the body could be interesting38, but there is a need for further research on the bioactive and potential health-related roles of these compounds before conclusions can be drawn65.

The effect of habitual coffee consumption on blood pressure is smaller than expected from tests with challenging caffeine doses. One study tested the effect of caffeine capsules versus placebo on blood pressure60. There is ample scientific research to show that volunteers who abstain from, or are used to a low caffeine level, show a short-term increase in blood pressure when challenged with a high caffeine dose60. The size of the blood pressure effect of these caffeine doses is clearly larger, e.g. 4mm systolic in this study, than the effect of coffee containing similar amounts of caffeine e.g. 1-2mm systolic60. This indicates that in habitual coffee consumption, more factors are involved than just caffeine, and some of them seem to have opposing effects.

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