Coffee- Should We Start Taking It More Often?

A recent study published in NEJM on 17th May 2012 showed that-

¨Inverse associations were observed for deaths due to heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections, but not for deaths due to cancer.

¨Similar associations were observed whether participants drank predominantly caffeinated or decaffeinated coffee. They studied the association of coffee drinking with subsequent total and cause-specific mortality among 229,119 men and 173,141 women in the National Institutes of Health–AARP Diet and Health Study who were 50 to 71 years of age at baseline. 

This is a large study by all means. If you are wondering how they could study so many individuals, it could be because, they could not find half a million rats in one place! Since there is no funding for multi center Rat trials, they proceeded to study the humans directly. It is actually good, since the results would be directly applicable to all of us. The Mice trials have been mystifying so far.

Pediatric Research journal Vol. 69, No. 4, 2011, discussed that postnatal mice exposed to hypoxia showed decreased ventriculomegaly and better myelination of the brain, when caffeine was administered compared to placebo. Chronic low-dose caffeine administration in an immature hypoxic-ischemic rat model was neuroprotective. However, other studies also showed decreased seizure threshold, sleep issues in these rat models.

As sleep deprivation is considered as equivalent to harsh CIA interrogation techniques, research began focus more on humans and disease prevention (just kidding). There is strong evidence to show that caffeine is very protective in the preterm animals exposed to hypoxia. Hypoxia, which releases adenosine, causes premature acceleration of maturation of oligodendrocyte precursor cells leading to decrease in the the number of mature oligodendrocytes that which leads to decreased myelination of neurons and white mater injury of the brain in the prematurely born animals and human beings. Adenosine inhibits oligodendrocyte proliferation, & caffeine inhibits A1AR receptor and prevents white matter injury and hence, cerebral palsy. 

  Caffeine also a role in the lungs and the brain in the premature beings. A2a adenosine receptor activation leads to neutrophil migration and A2b adenosine receptor activation leads to cytokine release, which lead to capillary leakage and inflammation, which in preterm infants can lead to lung damage and intraventricular bleeding. Caffeine being a non-specific adenosine inhibitor counters these effects and reduces the consequences.

Studies published in NEJM in 2006, J.Peds in 2010 confirmed that caffeine indeed protects the preterm infants from chronic lung disease and laso reduces the incidence of cerebral palsy. However, the 2012 JAMA article, which followed the same infants up to 5-6 years did not show sustained caffeine effect on survival without severe disability. On the other hand,

The gross motor impairment was less severe in caffeine-treated children than in controls. Odds ratio 0.64 (0.47-0.88) P=0.006.

Well, this caffeine is useful in adults as well. It is evident from a huge metanalysis involving about 500,000 men and women that type 2 diabetes risk decreases by 7% with each cup of coffee. Several mechanisms are proposed.

¨Adiponectin (regulates the catabolism of glucose and insulin sensitivity) is protective in diabetes is ↑ by coffee. (Nutr j. 2011 Sep 13;10:93.) 

¨Recent prospective study showed ↓ IL-18 (pro-inflammatory cytokine) with coffee.

¨Antioxidant effect on the beta cells of pancreas, chelating actions on iron preventing excessive accumulation are also noted. ¨It also decreases corticosteroid production.

Other benefits of coffee are-

¨Study suggests that caffeinated coffee consumption may be associated with lower endometrial cancer risk among obese postmenopausal women, but the association with decaffeinated coffee remains unclear. Nutrients. 2011 Nov;3(11). 45,696 women followed.

 

¨ Coffee ↓ lethal prostate cancer-J Natl Cancer Inst. 2011 Jun 8;103(11) 47,911 men prospectively followed.

¨European Prospective Investigation into Cancer and Nutrition (EPIC)-Germany study (Am J Clin Nutr. 2012 Apr)- coffee consumption does not increase the risk of chronic disease, but it may be linked to a lower risk of T2D. 42,659 participants and 8.9 year follow up.

 

¨Direct animal studies have shown that caffeine protects against Alzheimers.

¨AD mice given caffeine since young adulthood showed decreased cognitive impairment and low amyloid in the brains.

¨J.Alzheimers Disease in June 2012 published a study which showed direct link between high caffeine levels and decreased progression from mild cognitive impairment to dementia.¨ A critical level of 1200ng/ml and above was protective. 

With all the current evidence, it appears that coffee has quite a few health benefits. So, should we consume coffee more! You decide. 
The relationship of coffee intake to health benefits is direct. Higher the consumption, higher the benefits at least from the studies. Caffeinated or decaffeinated did not matter.