Coffee

Introduction:

The active ingredient in coffee is caffeine, which is a stimulant but coffee also contains antioxidants. Scientists have studied the effects of coffee on various aspects of health. Research has shown that coffee is associated with a decrease risk of various forms of cancer, lowers the risk of cardiovascular disease, affects the risk of kidney stones, and may be beneficial in diabetes. Coffee is associated with improvements in risk of neurodegenerative diseases and may improve mood. The potential benefits specific to research on coffee is included here, but for further information, please see the section about caffeine in Preventive Health Advisor.

 

Coffee consumption and colorectal cancer:

Highest vs lowest coffee intakes and colon cancer: In a meta-analysis, authors identified 25 case control and 16 cohort studies related to coffee consumption and colorectal cancer risk. Results from case control studies comparing the highest versus the lowest/non category of coffee consumption showed a significant reduction in colorectal cancer (15% risk reduction) and colon cancer (21% risk reduction), but not rectal cancer (5% risk reduction). For cohort studies, risk of colorectal cancer, colon cancer, and rectal cancer were reduced by 6%, 7%, and 2%, respectively. In subgroup analyses using case–control studies, significant inverse associations were found in females for colorectal cancer and in Europe for colorectal and colon cancer, while the subgroup analyses of cohort studies found that coffee drinks substantially decreased risk of colon cancer only in Asian women. (1)

 

Gender, coffee intake, and colon cancer:

An analysis of 96,162 subjects (46,023 men and 50,139 women) found that the higher the amount of coffee consumption, the lower the risk of developing colon cancer. Specifically, women drinking 3 or more cups of coffee a day were found to have half the risk of developing colon cancer (but not rectal cancer) compared with those who drank no coffee at all. No benefit in terms of colon cancer risk reduction, however, was found in men. (2)

 

Coffee and endometrial cancer:

Researchers conducted a meta-analysis of 16 studies (10 case-control and six cohort studies) involving coffee consumption and cancer risk. A total of 6,628 cases of endometrial cancer were identified from the studies. The results showed that, overall, women who drank 3 to 4 cups of coffee per day had a 29% reduced risk of endometrial cancer compared with women who drank little or no coffee. By study design, case-control studies had a 31% risk reduction and cohort studies a 30% risk reduction.  Each additional cup of coffee consumed was associated with about an 8% further risk reduction. The association was strongest among Japanese studies (60% risk reduction), followed by USA/Canada studies (31% risk reduction), and European studies (21% risk reduction). (3)

 

Caffeine intake and basal cell skin cancer:

Caffeine may reduce the risk of developing skin cancer, specifically basal cell carcinoma (BCC), according to a study of 112,897 participants (72,921 female nurses and 39,976 male health professionals). When participants were ranked according to caffeine consumption, with the highest consumption at the top and the lowest at the bottom, they found for women, the top 20% of caffeine consumers had an 18% lower risk of BCC than the bottom 20%. For men, the risk was lowered by 13%. The researchers also found that drinking 3 cups of caffeinated coffee was linked to a 21% lower risk of developing BCC in women and a 10% lower risk in men, compared to drinking less than 1 cup per month. And caffeine from other dietary sources (tea, cola, and chocolate) also had a similar effect: the higher the intake, the lower the risk of BCC. (4)

 

Coffee intake and renal cell cancer:

A clinical study to evaluate associations between coffee, tea, milk, soda, and fruit and vegetable juice intake and risks of developing renal cell cancer (RCC) was conducted. This study included results from 13 studies including 530,469 women and 244,483 men. Follow-up was between 7-20 years. Information about diet was gathered at the beginning of the trial. The results indicate that individuals who drank 3 or more 8-ounce cups of coffee per day had a 16% reduced risk of developing RCC compared with those who drank less than one 8-ounce cup per day. Individuals who drank one or more 8-ounce cups of tea per day had a 15% reduced risk of developing RCC compared with those who did not drink tea. There were no associations between milk, soda, or juice intake. These results suggest that a greater intake of coffee and tea appears to lower the risk of renal cell cancer. (5)

 

Caffeine intake and cardiovascular disease:

In a population study researchers found that consumption of coffee, green tea and oolong tea and total caffeine intake was linked to a reduced risk of death from cardiovascular disease (CVD). Participants included 76,979 adults followed for 1,010,787 person years, all of whom were ages 40 to 79 and free of stroke, heart disease, and cancer at the start of the study. Researchers determined that compared to non-coffee drinkers, men consuming 1-6 cups/week, 1-2 cups/day and ≥ 3 cups/day had a protective effect from coffee with a 22%, 33%, and 55% less rate of stroke occurrence than the control population. Compared with non-tea drinkers, women consuming 1-6 cups/week, 1-2 cups/day, 3-5 cups/day and ≥ 6 cups/day had a 66%, 72%, 61%, and 58% reduced rate of coronary heart disease compared to non-tea drinkers. Men drinking ≥ 1 cups/day of oolong tea benefited from a 61% reduced rate of CVD when compared to non-tea drinkers, (p = 0.049 for trend). Individuals in the second highest quintile of total caffeine intake had a total CVD risk reduction of 38% in men and 22% in women. (6)

 

Caffeine and kidney stones:

45,289 men without previous renal stones were followed in the Health Professionals Follow-up Study for formation of stones.  Increasing intake of fluid reduced kidney stone formation. Specific types of beverages were found to decrease risk of stone formation. For each 8 ounce serving of the following beverages consumed per day, stone formation risk decreased by the following amounts on average: coffee with or without caffeine, 10%; tea, 14%; beer, 21%; and wine, 39%. Also, for each 8 ounce serving of apple juice, stone formation risk increased by 35%, and grapefruit juice increased risk by 37%. (7)

 

Coffee consumption and diabetes:

Drinking caffeinated coffee with meals may decrease insulin sensitivity and exacerbate control of blood glucose, according researchers. Ten healthy men 5 mg/kg of caffeinated coffee one hour before eating a meal (75-g oral glucose load) with either a high glycemic index (Crispex) — comprised of foods that raise blood sugar levels quickly, such as processed carbohydrates — or a low glycemic index meal (All Bran). Caffeinated coffee before a high glycemic index meal resulted in significant insulin sensitivity reduction of 40% compared to decaffeinated coffee before the same meal. Caffeinated coffee prior to a low glycemic index meal led a 29% decrease in insulin sensitivity than the same meal eaten after consuming decaffeinated coffee. (8)

 

Coffee consumption and amyotrophic lateral sclerosis:

Beghi et al compared the coffee consumption of 377 patients newly diagnosed cases of amyotrophic lateral sclerosis (ALS), a disease nerve cell degeneration in the brain and spinal cord that results in lost control or muscle movement, with that of three control groups. The group found that some levels of elevated coffee consumption were associated with decreased risk of ALS. Lifetime coffee consumption for ALS patients was lower compared to the neurologic, nonneurologic, and general population controls (odds ratios of 0.7, 0.6, and 0.4, respectively). (9)

 

Coffee, dementia and Alzheimer’s:

Studies consistently support coffee’s favorable effects against cognitive decline, dementia, and Alzheimer’s disease (AD). In a review done by Eskelinen et al., it was determined that moderate caffeine intake, coffee in particular, is associated with a decreased risk in the diagnosis of dementia and AD. This review included nine longitudinal studies and the CAIDE study (Cardiovascular risk factors, Aging and Dementia). The results from the longitudinal studies were inconsistent, but most studies (3 out of 5) support coffee’s favorable effects against cognitive decline. The CAIDE study showed that drinking 3 to 5 cups per day at midlife appears to decrease the risk of dementia and AD by about 65 percent later on. These findings suggest that coffee drinking may be associated with a decreased risk of dementia and AD. (10)

 

 

Assessment and Plan:

• Coffee contains caffeine, a substance which may result in adverse reactions and interactions:

 

• Be aware that caffeine is classified as a methylxanthine and stimulant which may cause indigestion, palpitations (rapid heart beat), tremor, headache, diuretic effect and sleep difficulty.

 

• Caffeine should be avoided when taking the medications theophylline, aminophylline and pentoxyfylline which may potentiate (increase) the effects of these drugs.

 

• Caffeine may increase risk of premature death in patients with hypertension, cardiovascular disease, and stroke.

 

• Caffeine consumption increases calcium excretion in the urine and may increase the risk of kidney stones but other research shows a lower risk, so this is unclear.

 

• Excessive caffeine in supplements may cause stroke.

 

• High caffeine intake may result in hypokalemia.

 

 

• Consumers should be aware that the herb guarana has one of the highest concentrations of caffeine in any plant and intake of this herb supplement is not advised due to lack of standardization of caffeine content.

 

• The subject of caffeine and fibrocystic breasts is controversial. Research supports both that caffeine may increase breast pain in this condition and possibly affect hormone levels leading to the condition. Other studies have shown that decreasing caffeine intake does not result in improvement.

 

• Colorectal cancer:

 

• Case control studies comparing the highest versus the lowest coffee consumption showed a significant reduction in colorectal cancer (15% risk reduction) and colon cancer (21% risk reduction), but not rectal cancer (5% risk reduction) and in cohort studies risk of colorectal cancer, colon cancer, and rectal cancer were reduced by 6%, 7%, and 2%, respectively (1).

 

• An analysis of 96,162 subjects (46,023 men and 50,139 women) found that women drinking 3 or more cups of coffee a day had about half the risk of developing colon cancer (but not rectal cancer) compared with those who drank no coffee but no benefit in risk was seen in men (2).

 

• Endometrial cancer: Je, Y et al researched 6,628 cases of endometrial cancer and found that women who drank 3 to 4 cups of coffee per day vs little or no coffee had a 29% reduced risk of endometrial cancer, and risk reduction varied between 21% and 60% depending on study type (case control or cohort study) and on the country of origin (3).

 

• Basal cell skin cancer: Drinking 3 cups of caffeinated coffee was linked to a 21% lower risk of developing BCC in women and a 10% lower risk in men, compared to drinking less than 1 cup per month (4).

 

• Renal cell cancer (RCC): Lee, J et al reviewed 13 studies including 530,469 women and 244,483 men with a follow-up of 7-20 years and it was found that those who drank 3 or more 8-ounce cups of coffee per day had a 16% lower risk (5).

 

• Cardiovascular disease: Mineharu, Y et al found that compared to non-coffee drinkers, men consuming 1-6 cups/week, 1-2 cups/day and ≥ 3 cups/day had a protective effect from coffee with a 22%, 33%, and 55% less rate of stroke and those in the second highest quintile of total caffeine intake had a total cardiovascular disease risk reduction of 38% in men and 22% in women (6).

 

• Kidney stones: Curhan, GC et al noted that increasing intake of fluid reduced kidney stone formation and coffee with or without caffeine reduced stone formation risk by 10% (7).

 

• Diabetes mellitus: Drinking decaf coffee before meals should be avoided by patients with diabetes mellitus as this may worsen the control of blood sugar. Moisey, LL et al found that caffeinated coffee before a high glycemic index meal resulted in insulin sensitivity reduction of 40% (low glycemic index meal reduced insulin sensitivity by 29%) compared to decaffeinated coffee before the same meal (8).

 

• Amyotrophic lateral sclerosis (ALS): Beghi et al compared the coffee consumption of 377 patients newly diagnosed cases of amyotrophic lateral sclerosis (ALS) and determined that lifetime coffee consumption for ALS patients was lower compared to controls (odds ratios of 0.7, 0.6, and 0.4, respectively) (9).

 

• Dementia and Alzheimer’s disease: In a review done by Eskelinen, et al it was determined that in most studies moderate caffeine intake, coffee in particular, is associated with a decreased risk in the diagnosis of dementia and AD which included a review of the CAIDE study which showed that drinking 3 to 5 cups per day at midlife appears to decrease the risk of dementia and AD by about 65 percent later on (10).

 

• Please see the caffeine section of Preventive Health Advisor for further evidence-based benefits of caffeine.

 

 

References:

 

1.Li G, Ma D, Zhang Y, Zheng W, Wang P. Coffee consumption and risk of colorectal cancer: a meta-analysis of observational studies. Public Health Nutr. 2013 Feb;16(2):346-57.  Epub 2012 Jun 14. http://www.ncbi.nlm.nih.gov/pubmed/22694939

 

2.Lee KJ, et al. Coffee consumption and risk of colorectal cancer in a population-based prospective cohort of Japanese men and women. Int J Cancer. 2007 Sep 15;121(6):1312-8. http://www.ncbi.nlm.nih.gov/pubmed/17450527

 

3.Je Y, Giovannucci E. Coffee drinking and risk of endometrial cancer: findings from a large up-to-date meta-analysis. Int J Cancer. 2012 Oct 1;131(7):1700-10. Epub 2012 Jan 31. http://www.ncbi.nlm.nih.gov/pubmed/22190017

 

4.Song F, Qureshi AA, Han J. Increased caffeine intake is associated with reduced risk of basal cell carcinoma of the skin. Cancer Res. 2012 Jul 1;72(13):3282-9. http://www.ncbi.nlm.nih.gov/pubmed/22752299

 

5.Lee J, Hunter D, Spiegelman D, et al. Intakes of coffee, tea, milk, soda and juice and renal cell cancer in a pooled analysis of 13 prospective studies. Int J Cancer. 2007 Nov 15;121(10):2246-53. http://www.ncbi.nlm.nih.gov/pubmed/17583573

 

6.Mineharu Y, Koizumi A, Wada Y, et al. Coffee, green tea, black tea and oolong tea consumption and risk of mortality from cardiovascular disease in Japanese men and women. J Epidemiol Community Health. 2011 Mar;65(3):230-40. Epub 2009 Dec 8. http://www.ncbi.nlm.nih.gov/pubmed/19996359

 

7.Curhan GC, Willett WC, Rimm EB, Spiegelman D, Stampfer MJ. Prospective study of beverage use and the risk of kidney stones. Am J Epidemiol. 1996;143:240–7. http://www.ncbi.nlm.nih.gov/pubmed/8561157

 

8.Moisey LL, Kacker S, Bickerton AC, Robinson LE, Graham TE. Caffeinated coffee consumption impairs blood glucose homeostasis in response to high and low glycemic index meals in healthy men. Am J Clin Nutr. 2008 May;87(5):1254-61. http://www.ncbi.nlm.nih.gov/pubmed/18469247

 

9.Beghi, E., Pupillo, E., Messina, P., et al. Coffee and Amyotrophic Lateral Sclerosis: A Possible Preventive Role American Journal of Epidemiology. 2011 Nov 1;174 (9), 1002-1008. http://www.ncbi.nlm.nih.gov/pubmed/21946385

 

10.Eskelinen MH, Kivipelto M. Caffeine as a protective factor in dementia and Alzheimer’s disease. J Alzheimers Dis. 2010;20 Suppl 1:S167-74. http://www.ncbi.nlm.nih.gov/pubmed/20182054

 

11.Shirlow MJ, Mathers CD. A study of caffeine consumption and symptoms; indigestion, palpitations, tremor, headache and insomnia. Int J Epidemiol. 1985 Jun;14(2):239-48. http://www.ncbi.nlm.nih.gov/pubmed/3874838

 

12.Baghkhani L, Jafari M. Cardiovascular adverse reactions associated with Guarana: is there a causal effect? J Herb Pharmacother. 2002;2(1):57-61. http://www.ncbi.nlm.nih.gov/pubmed/15277107

 

13.Rigato I, Blarasin L, Kette F. Severe hypokalemia in 2 young bicycle riders due to massive caffeine intake. Clin J Sport Med. 2010 Mar;20(2):128-30. http://www.ncbi.nlm.nih.gov/pubmed/20215898

 

14.Vahedi K, Domigo V, Amarenco P, Bousser MG. Ischaemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for body building. J Neurol Neurosurg Psychiatry. 2000 Jan;68(1):112-3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1760579/pdf/v068p00112.pdf

 

15.Massey, L.K., Sutton, R.A. Acute caffeine effects on urine composition and calcium kidney stone risk in calcium stone formers. Journal of Urology. 2004 Aug;172(2):555-8. http://www.ncbi.nlm.nih.gov/pubmed/15247728

 

16.James JE. Critical review of dietary caffeine and blood pressure: a relationship that should be taken more seriously. Psychosom Med 2004; 66 (1): 63-71. http://www.ncbi.nlm.nih.gov/pubmed/14747639

 

17.Boison D. Methylxanthines, seizures, and excitotoxicity. Handb Exp Pharmacol. 2011;(200):251-66. http://www.ncbi.nlm.nih.gov/pubmed/20859799

 

18.Bullough B, Hindi-Alexander M, Fetouh S. Methylxanthines and fibrocystic breast disease: a study of correlations. Nurse Pract. 1990 Mar;15(3):36-8, 43-4. http://www.ncbi.nlm.nih.gov/pubmed/2314678