Time for coffee and tea
Health implications of drinking coffee
Elsewhere in this site, we have articles on coffee and weight reduction and the beneficial effects of coffee on diabetes. But did you know that regular (or shall we say habitual) consumption of coffee increases our body’s heat production by a significant degree. The caffeine in coffee seems to be the primary agent responsible for this thermogenic effect.
Researchers have found that coffee increases thermogenesis in part by increasing our body’s ability to oxidise fat. It in fact appears that the weight loss that comes with drinking coffee may be due to increased lipid metabolism which burns away excess body fat. It is caffeine that induces the fat oxidation.
Lipid metabolism is also indicated by lipolysis, and there are several studies that have observed greater lipolysis as a consequence of caffeine or coffee intake among volunteers. In these studies, the indicators for lipolysis are assays of plasma free fatty acids and glycerol (with glycerol being the more reliable indicator). An acute increase in lipolysis usually followed consumption of caffeine or caffeinated coffee (whether ground or instant). But when decaffeinated coffee was used, lipolysis did not increase.
The consumption of caffeine and certain types of coffee is known to result in acute increase of blood pressure and peripheral circulatory resistance. This is referred to as the pressor effect, and is probably caused by caffeine. This effect has some bearing on coffee health effects such as the relationship between coffee and diabetes.
One reason is that the pressor effect requires more energy. This would contribute to increased thermogenesis, leading to more weight loss and reduced diabetes risk. It would thus seem that the pressor effect contributes to coffee’s ability to lower risk of diabetes.
A second reason is that the pressor effect tends to raise the risk of cardiovascular disease events, notably among those with hypertensions. In populations with high incidence of risk factors for cardiovascular disease, the pressor effect would limit the usefulness of coffee as a means to prevent or treat diabetes.
Coffee consumed in moderation is generally safe. But some toxic compounds in coffee may have adverse health effects in pregnant or breastfeeding women and in children. Some of these coffee health effects are: high concentrations of caffeine had teratogenic effects on animals, but researchers insist there is not enough evidence to establish risk of congenital abnormalities in babies with the mother’s caffeine consumption.
Coffee Caffeine may have deleterious effects in elderly people, which could include increased risks of kidney stones and osteoporosis. It must be noted, though, that a study involving middle-aged women concluded that 8 oz of coffee (caffeinated or decaffeinated) or tea consumed daily was associated with a small reduction (by 8-10%) in risk of kidney stones. Caffeine increases urinary concentrations of calcium, which impacts negatively on calcium metabolism.
There is strong evidence that caffeine and caffeinated coffee lower insulin sensitivity shortly after ingestion. This is more likely to occur in obese people than non-obese individuals.
Caffeine has shown some potential to cause mutations (mutagenic) in in vitro studies. But there is nothing that would point to carcinogenic potential in humans. There are indications of a weak potential to induce cancers of the bladder and the pancreas, and a weak ability to prevent colon cancer.
A large body of evidence, both from epidemiologic and laboratory studies, shows some ability for caffeine to prevent the development of Parkinson's. Caffeine has found therapeutic uses for bronchial asthma, as a cardiac stimulant, and as a diuretic.