Recent large prospective studies found that coffee consumption was associated with benefit for a range of health outcomes, with estimates largest relative risk reduction at intakes of three to four cups a day versus none :
· Reduced all cause mortality
· Reduced Cardiovascular (CV) mortality and adverse CV outcomes, including coronary heart disease, congestive heart failure, and stroke
· Improvements in some CV risk factors, including type 2 diabetes (T2D), depression, and obesity
· Decreased risk of breast, colorectal, endometrial, and prostate cancers
· Lower risk of Parkinson's disease, depression, and cognitive disorders, especially for Alzheimer’s disease
· Lower risk of non-alcoholic fatty liver disease, liver fibrosis, liver cirrhosis and gallstone disease
The main components of coffee described as exerting such effects are phenolic compounds, caffeine, diterpenes, trigonelline, and melanoidins.
Phenolic compounds, diterpenes, trigonelline, and melanoidins have been shown to induce antioxidants effects and anti-inflammatory activity. But Caffeine has been by far the most studied coffee component, act as mild stimulant of the central nervous system due to its effects on adenosine receptors in the brain, as well as in the cardiovascular, respiratory, renal, and gastrointestinal systems, and in adipose tissue.
While coffee consumption may appear to be healthful for many, others should proceed with caution :
· In pregnancy, high coffee consumption was associated with low birth weight, preterm birth in the first and second trimester and pregnancy loss.
Caffeine passes through placental barriers, thus potentially exposing the fetus to caffeine for a long period of time, which may affect fetal growth.
Current evidence suggests that in pregnancy, consuming moderate amounts of caffeine up to 200 mg per day, the amount in a 12-ounce cup of coffee, is not associated with increased risks for miscarriage or preterm birth, however, data are contradictory regarding these pregnancy outcomes when women consume more than 200 mg per day of caffeine.
You don’t need to cut caffeine out completely, but you should limit how much you have to no more than 200mg a day. Try decaffeinated tea and coffee, fruit juice or water, and limit the amount of energy drinks you have, as they can be high in caffeine.
· Increased risks of lung and gastric cancers
The increased risks of lung and gastric cancers are potentially modifying effect of smoking habits, because no increased risk of lung cancer was observed in a subgroup analysis of studies conducted on nonsmokers.
· For hypertension, there were no significant estimates of risk at any level of consumption.
Most of the evidence, however, is from observational studies, which can only find probable associations but can’t prove cause and effect. So can’t extrapolate the findings to suggest people start drinking coffee or increasing their intake in attempts to become healthier. But people who already enjoy moderate amounts of coffee as part of their diet are most probably getting health benefits from it, rather than harm.
How much caffeine in your drink ?
Caffeine is found naturally in lots of foods, such as coffee, tea and chocolate. It’s also added to some soft drinks, energy drinks, and cold and flu remedies. 99% of caffeine is absorbed in the stomach and small intestine within 45 minutes of ingestion.
A large review by European Food Safety Authority concluded that a daily safe dose of 400mg is safe for adults and single doses of 200mg at one time are fine for those engaging in exercise directly after the dose.
The largest benefit appeared to be associated with drinking three to four cups of coffee each day. Drinking coffee beyond these amounts was not associated with harm, but the benefits were less pronounced.
References
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Caffeineinformer. Caffeine Safe Limits: Determine Your Safe Daily Dose. 2017
Clark J. Caffeine: Facts, Contents & Side Effects. Best Online MD. 2016
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Grosso G, Godos J, Galvano F, Giovannucci EL. Coffee, Caffeine, and Health Outcomes: An Umbrella Review. Annu Rev Nutr. 2017 Aug 21;37:131-156. doi: 10.1146/annurev-nutr-071816-064941.
NHS Choices. Should I limit caffeine during pregnancy?
NutrientsReview.com. Caffeine Effects, Half-Life, Overdose, Withdrawal. 2016
O'Keefe JH, DiNicolantonio JJ, Lavie CJ. Coffee for Cardioprotection and Longevity. Prog Cardiovasc Dis. 2018 Feb 20. pii: S0033-0620(18)30039-2. doi: 10.1016/j.pcad.2018.02.002.
Poole R. Health Benefits of Coffee: Three or Four Cups per Day Does Far More Good Than Bad. Newsweek 2018 Feb 28.
Poole R, Kennedy OJ, Roderick P, Fallowfield JA, Hayes PC, Parkes J. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ. 2017 Nov 22;359:j5024. doi: 10.1136/bmj.j5024
Sagon C. Caffeine for Your Health — Too Good to Be True?. AARP
Authorship:
1. Dr. Wilhan Tjiang, 2. Dr. Amy SL Ooi, 3. Dr. Kris KS See, The Frontier Medicine Institute, Osel Diagnostics, Osel Clinic
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