Caffeine energy metabolism effects

A study by Dulloo et al. showed that caffeine and catechins produced a thermogenic effect via sympathetic activation of NE, and that the effect of green tea extracts on the metabolic rate in humans is greater than that explained by caffeine content per se. In table 13.2, diurnal, nocturnal, and total 24 h energy expenditure values are presented for placebo, caffeine, and green tea extract. Diurnal energy expenditure... 

Table 15-1], Amphetamines and caffeine (a melhylxanthine alkaloid) stimulate catecholamine release, and tricyclic antidepressants and cocaine inhibit the uptake of released catecholamine neurotransmitters. Fluoroacetate is a metabolic inhibitor of aconitase in the tricarboxylic acid (TCA) cycle and its cardiac effects are the result of acute severe energy deficit in the myocardium.

Chronic alcoholism may also precipitate beriberi since alcohol cannot be converted to fat in the body, but must be metabolized by the same thiamin- dependent processes as carbohydrate and protein. Furthermore, alcohol increases urinary excretion of water (diuretic effect) and water-soluble vitamins. A similar, but lesser, effect may result from the heavy consumption of caffeine (in beverages such as coffee, colas, and tea) coupled with a diet chronically high in refined foods which are rich in carbohydrates. (Like alcohol, caffeine is a diuretic. Also, it stimulates the utilization of stored carbohydrate for energy.)... 

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