Coffee?

Dr. Weeks’ Comment:  Dr. Rudolf Steiner taught that things are neither good nor bad – but that things have specific effects and in order to make an informed decision, people are well advised to know about and to consider the effects. So it is with dietary choices. Coffee is no exception: consider its sympathetic nervous stimulant (with all those activating effects) as well as its anti-oxidants (especially when served as a mocha with the benefits of all the phytochemicals in cacao). As with all foods, best to take a minute before beginning the meal or drink to pause, cultivate a sense of appreciation, say Grace or two and count our blessings – the purpose of nourishing ourselves isn’t to try and live to 150 years old and have no adventure, but rather to fuel ourselves and our spirits to contribute to causes we value.

COFFEE: A SUMMARY

Written by Dr. Jane Higdon at the Linus Pauling Institute

  • Coffee is a complex mixture of chemicals that provides significant amounts of chlorogenic acid and caffeine. (More Information)
  • Unfiltered coffee is a significant source of cafestol and kahweol, diterpenes that have been found to raise serum total and LDL cholesterol concentrations in humans. (More Information)
  • The results of epidemiological studies suggest that coffee consumption is associated with decreased risk of type 2 diabetes, Parkinson’s disease and liver disease. However, it is premature to recommend coffee consumption for disease prevention based on this evidence. (More Information)
  • At present, there is little evidence that coffee consumption increases the risk of cancer. (More Information)
  • Despite evidence from clinical trials that caffeine in coffee can increase blood pressure, most prospective cohort studies have not found moderate coffee consumption to be associated with increased risk of cardiovascular disease. (More Information)
  • Overall, there is little evidence of health risk and some evidence of health benefits for adults consuming moderate amounts of coffee (3-4 cups/d providing 300-400 mg/d of caffeine). (More Information)
  • However, some people may be more vulnerable to the adverse effects of caffeine in coffee:
    • Caffeine consumption comparable to the amount in 2-3 cups of coffee may raise blood pressure, especially in people with borderline or high blood pressure. (More Information)
    • Until the effects of caffeine on the risk of miscarriage and fetal growth are clarified, women who are pregnant or planning to become pregnant should limit coffee consumption to 3 cups/d providing no more than 300 mg/d of caffeine. (More Information)
    • Ensuring adequate calcium and vitamin D intake and limiting coffee consumption to 3 cups/d (300 mg/d of caffeine) may help reduce the risk of osteoporosis and osteoporotic fracture, particularly in older adults. (More Information)

Introduction

Coffee, an infusion of ground, roasted coffee beans, is among the most widely consumed beverages in the world. Although caffeine has received the most attention from scientists, coffee is a complex mixture of many chemicals, including carbohydrates, lipids (fats), amino acids, vitamins, minerals, alkaloids and phenolic compounds (1).

Some Bioactive Compounds in Coffee

Chlorogenic Acid

Chlorogenic acids are actually a family of esters formed between quinic acid and phenolic compounds known as cinnamic acids (2). The most abundant chlorogenic acid in coffee is 5-O-caffeoylquinic acid, an ester formed between quinic acid and caffeic acid (Figure 1). Coffee represents one of the richest dietary sources of chlorogenic acid. The chlorogenic acid content of a 200 ml (7-oz) cup of coffee has been reported to range from 70-350 mg, which would provide about 35-175 mg of caffeic acid. Although chlorogenic acid and caffeic acid have antioxidant activity in vitro (3), it is unclear how much antioxidant activity they contribute in vivo because they are extensively metabolized, and the metabolites often have lower antioxidant activity than the parent compounds (4).

Caffeine

Caffeine is a purine alkaloid that occurs naturally in coffee beans (Figure 2). At intake levels associated with coffee consumption, caffeine appears to exert most of its biological effects through antagonism of the A1 and A2A subtypes of the adenosine receptor (5). Adenosine is an endogenous compound that modulates the response of a neurons to neurotransmitters. Adenosine has mostly inhibitory effects in the central nervous system, so the effects of adenosine antagonism by caffeine are generally stimulatory. Caffeine is rapidly and almost completely absorbed in the stomach and small intestine and distributed to all tissues, including the brain. Caffeine concentrations in coffee beverages can be quite variable. A standard cup of coffee is often assumed to provide 100 mg of caffeine, but a recent analysis of 14 different specialty coffees purchased at coffee shops in the US found that the amount of caffeine in 8 oz (~240 ml) of brewed coffee ranged from 72-130 mg (6). Caffeine in espresso coffees ranged from 58-76 mg in a single shot. In countries other than theUS, coffee is often stronger but the volume per cup is smaller, making 100 mg of caffeine/cup a reasonable estimate.

Diterpenes

Cafestol and kahweol are fat-soluble compounds known as diterpenes (Figure 3), which have been found to raise serum total and LDL cholesterol concentrations in humans (7). Some cafestol and kahweol are extracted from ground coffee during brewing, but are largely removed from coffee by paper filters. Scandinavian boiled coffee, Turkish coffee and French press (cafetiere) coffee contain relatively high levels of cafestol and kahweol (6-12 mg/cup), while filtered coffee, percolated coffee and instant coffee contain low levels of cafestol and kahweol (0.2-0.6 mg/cup) (8, 9). Although diterpene concentrations are relatively high in espresso coffee, the small serving size makes it an intermediate source of cafestol and kahweol (4 mg/cup). Since coffee beans are high in cafestol and kahweol, ingestion of coffee beans or grounds on a regular basis may also raise serum and LDL cholesterol.

For more information about Disease Prevention and the benefits of coffee brew yourself a cup and peruse the highly informative website  of the Linus Pauling Institute:  LPI’s Micronutrient Information Center (http://lpi.oregonstate.edu/infocenter)

 


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