Many of us surely know that feeling early in the morning when half asleep we go straight to the coffee maker and push the start button. But probably only few of us know that coffee does have its ups and downs in terms of health benefits.

First of all, it has been suggested by several studies that coffee can play a positive role in the reduction of Parkinson's disease (1), type 2 diabetes (2) and even in the fight against cancer (3). On another hand, the American Heart Association has reiterated in several occasions that studies investigating a direct link between coffee drinking and coronary heart disease have so far produced conflicting results (4). In top of that, there are the studies suggesting that coffee may increase the bone loss in elderly women (5), and may not be as safe for consumption during pregnancy as it was previously thought (8). Confused? Let's see... is coffee good for us or not?!?

(Un)Surprisingly, nobody knows for sure. Just as nobody knows exactly what is the active ingredient in coffee. Most researchers believe it is caffeine, but one very interesting study published in December 2002 in Circulation suggests that drinking decaf coffee may have just the same effect as regular coffee when it comes to getting a quick fix. Swiss scientists reported that occasional coffee drinkers who drank a triple espresso showed a marked increase in both blood pressure and nervous system activity, regardless of whether the espresso contained caffeine or not. These results suggest that caffeine is not responsible for the cardiovascular activation, but rather another chemical among the several hundred different substances present in coffee (6).

The link between coffee drinking and Parkinson's disease has been recently studied by scientists at Massachusetts General Hospital, who showed that caffeine is able to prevent the loss of the chemical signal that is depleted in Parkinson's disease. The study has been performed on mice, which were exposed to a chemical called MPTP, known for causing a decrease in brain dopamine, which in turn caused Parkinson's-like symptoms. When the researchers pre-treated the mice with caffeine - at levels corresponding with one or two cups of coffee for humans - the MPTP toxicity decreased, because the brain dopamine levels remained near normal. These results are encouraging and open the floor for new Parkinson's-related research in humans (1).

An interesting study performed at the Dutch National Institute for Public Health and the Environment in Bilthoven, Netherlands investigated the effect of varying coffee consumption on the development of Type 2 diabetes. The researchers found that individuals with very high coffee consumption - seven or more cups of coffee a day - were 50 per cent less likely to develop Type 2 diabetes compared with less frequent coffee drinkers (two cups a day or less). Since these results seem a bit extreme, the research leader, Dr. Rob van Dam emphasized that more studies have to be performed to assess possible adverse effects of high amounts of coffee on other health aspects. Dr. Rob van Dam also mentioned that other components of coffee such as magnesium and chlorogenic acid could be partly responsible for the anti-diabetic effect (2).

The scientists at the University College of London (UCL) in the UK used genetically engineered insect cells and proved that caffeine and theophylline - compounds commonly found in cola beverages, coffee, tea and chocolate - block the operation of a key enzyme linked to a wide range of cell functions. The results suggest that these compounds would block cell growth associated with the formation of tumors, and therefore may be used in the fight against cancer. However, professor Peter Shepherd of UCL, who conducted the project, mentioned that "the study relied on using high concentrations of caffeine that would be unhealthy for human use" and that "the next stage of [the] research will be to develop compounds which mimic the structure of caffeine but without its negative effects" (3).

While the studies above focus on the potential positive effects of coffee/caffeine on human health, many other deal with the negative impact of coffee consumption.  One example is a long-term study of osteoporosis performed on 96 women averaging 71 years old. The volunteers were divided into low (less than 300 mg/day ~ 3-4 cups coffee) or high (greater than 300 mg/day) caffeine intake levels. The researchers compared the bone mineral density (BMD) of women in high and low categories of caffeine consumption to examine the interaction between caffeine intake and osteoporosis. The results showed that women with high caffeine intakes had higher rates of bone loss. The article had emphasized, however, that a moderate caffeine intake - less than 16 ounces of brewed coffee per day or 32 ounces of brewed tea - is not associated with increased bone loss (5).

A word of caution towards a moderate caffeine intake is also addressed to pregnant women, the newest finding adding up to a conflicting body of research into the effects of caffeine on the developing fetus. ‘While some studies suggest that caffeine may increase the risk of having a low birth weight baby, pre-term delivery, fetal growth retardation and miscarriage, other research has failed to confirm these associations' (7). Thus, studies performed on animals in 1980 led to a recommendation of FDA that pregnant women should avoid caffeine altogether. Later on, in mid 2001, researchers from Yale University School of Medicine in New Haven, Connecticut found no association between the coffee intake and the intrauterine growth retardation or low birth rate, for women consuming an average of 54 mg caffeine per day (approx. half a cup) (8). These results are in concordance with the advice published by UK Food Standards Agency (FSA) in Oct 2001: "pregnant women should limit their intake of caffeine to less than the equivalent of four average cups of coffee a day". This advice followed a review by independent experts who concluded that "caffeine intakes above 300 mg/day may be associated with low birth weight and, in some cases, miscarriage" (9).

Going back to the initial question: is coffee good for us? Probably we will never get a clear ‘yes' or ‘no' answer. But from the research that has been done all over the world we learn that MODERATION is the key. Time has shown this over and over again... And not only for coffee...

References:

1- Chen, J. F., ş.a. 2001. Neuroprotection by Caffeine and A_2A Adenosine Receptor Inactivation in a Model of Parkinson's Disease. J.                           Neurosci. 21: RC143.

2-  Van Dam, R.M., Feskens, E.J.M. 2002. Coffee consumption and risk of type 2diabetes mellitus. The Lancet. 360 (9344).

3-  Foukas, L. C., Daniele, ş.a.  2002. Direct Effects of Caffeine and Theophylline on p110 and Other Phosphoinositide 3-Kinases.                       Differential Effects on Lipid Kinaze and Protein Kinaze Activity. J. Biol. Chem., Vol. 277, Issue 40, 37124-37130.

4-  www.FoodNavigator.com 21/11/02

5-  Rapuri, P.B., ş.a.  2001. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor                                       genotypes. Am J Clin Nutr  74: 694-700.

6-  Corti, R., ş.a. 2002. Coffee Acutely Increases Sympathetic Nerve Activity and Blood Pressure Independently of Caffeine Content: Role of Habitual Versus Nonhabitual Drinking. Circulation 106: 2935 - 2940.

7-  www.FoodNavigator.com 16/07/01

8-  Grosso, L.M., ş.a.  2001. Maternal Caffeine Intake and Intrauterine Growth Retardation. Epidemiology 12: 447-455.

9-  www.FoodNavigator.com 11/10/01