Some Coffee Info

COFFEE AND ALZHEIMER’S DISEASE

Interest in the possibility that the consumption of coffee or caffeine might protect against the development of Alzheimer’s disease is growing. A retrospective Portuguese study of 54 cases of Alzheimer’s disease and 54 controls recently demonstrated that caffeine intake over the preceding 20 years was inversely and significantly associated with risk of Alzheimer’s disease (1). A prospective Canadian cohort study of 4,615 elderly subjects diagnosed 194 cases of Alzheimer’s disease and showed that coffee consumption was inversely associated with disease risk (2). More prospective cohort studies of the relationship between coffee and caffeine intake and Alzheimer’s disease risk are needed.

References:

1. Maia, L. and De Mendonca, A. European Journal of Neurology, 9, 377-382, 2002.

2. Lindsay, J. et al. American Journal of Epidemiology, 156, 445-453, 2002.

COFFEE, CAFFEINE AND ASTHMA

Two large cross-sectional studies have examined the relationship between the intake of coffee and tea and the prevalence of asthma. A study of 72,284 Italians showed that there was an inverse association between intake of coffee and prevalence of asthma (1). Risk of asthma fell by 28% when three or more cups of coffee were drunk every day. The Second National Health and Nutrition Examination Survey (NHANES II) studied 20,322 Americans and found that risk of current asthma fell significantly by 29% and risk of wheeze fell insignificantly by 13% when regular coffee drinkers were compared with non-coffee drinkers (2). There was also a significant dose response relationship with current asthma.

Intervention trials of effects of caffeine intake on asthma have recently been critically reviewed (3). Nine intervention trials of effects of caffeine on pulmonary function were identified although three of them were excluded from the analysis due to a variety of design faults (4, 5, 6). A randomised controlled trial on 7 adult asthmatics was unable to show any difference between 6 mg caffeine/kg body weight and placebo on airway responsiveness to methacholine (7). By contrast, a double-blind randomised crossover study of 9 adult asthmatics using four doses of caffeine up to 7.2 mg/kg body weight showed a dose response effect of caffeine on forced expiratory volume (FEV), forced expiratory flow (FEF) and specific airway conductance (Gaw/VL) (8). This suggests that caffeine is an effective bronchodilator. The effect of caffeine on FEV was confirmed in a second trial on 8 adult asthmatics using a dose of 5 mg/kg body weight (9). However, in 10 mild asthmatics 5 mg caffeine/kg body weight had little if any effect on histamine provoked bronchoconstriction (10). By contrast, the higher of two doses of caffeine (3.5 and 7 mg/kg body weight) prevented exercise- induced bronchoconstriction in 10 asthmatics (11). In a subsequent double-blind, placebo controlled randomised crossover trial, it was shown that 10 but not 5 mg caffeine/kg body weight reduced bronchoconstriction induced by eucapnic voluntary hyperventilation in 11 asthmatics (12).

The beneficial effects of caffeine on asthma have been appreciated for over 100 years. In Scotland, caffeine has been used to treat asthma since at least 1859 (13). Marcel Proust, an asthmatic, wrote in A l’Ombre de Jeunes Filles en Fleur that he used caffeine as a child which “was prescribed to help me breathe”. He was born in 1871. As reviewed above, modern research has confirmed that caffeine and hence caffeine-containing beverages have a role to play in the management of asthma.

References:

1. Pagano, R et al. Chest, 94, 386-389, 1988.

2. Schwartz, J. and Weiss, S.T. Annals of Epidemiology, 2, 627-635, 1992.

3. Bara, A.I. and Barley, E.A. Caffeine for asthma (Cochrane Review). In: The Cochrane Library, Issue 2, 2003. Oxford: Update Software.

4. Becker, A.B. et al. New England Journal of Medicine, 310, 743-746, 1984.

5. Henderson, J.C. et al. Thorax, 48, 824-826, 1993.

6. Simmons, M. et al. Chest, 84, 332, 1983.

7. Crivelli, M. et al. Respiration, 50, 258-264, 1986.

8. Gong, H. et al. Chest, 89, 335-342, 1986.

9. Bukowskj, M. and Nakatsu, K. American Review of Respiratory Disease, 135, 173-175, 1987.

10. Colacone, A. et al. Thorax, 45, 630-632, 1990.

11. Kivity, S. et al. Chest, 97, 1083-1085, 1990.

12. Duffy, P. et al. Chest, 99, 1374-1377, 1991.

13. Salter, H. Edinburgh Medical Journal, 4, 1109-1115, 1859.