For most people, especially students, coffee is a necessity for everyday life. Whether it’s that morning cup to get you out of bed, that midday “pick-me-up,” or the 2:00 am recharge during finals; if we were cars, coffee is our fuel– a non-negotiable in order to function. The American population drink approximately 491 million cups of coffee per day and 66% drink coffee more than water. Therefore, it is important that people are aware of coffee’s impact on health, specifically coffee’s impact on cellular pathways and the epigenetic effects.
Epigenetics is a subset of genetics that focuses on gene regulation and expression, and can be influenced by a person’s environment. Gene expression is a vital operation, as it is responsible for important processes like protein production. Gene activity in our cells is partly controlled by the modification of DNA. The sequence remains the same, but a chemical group that modifies the gene’s activity is attached to the sequence. This dictates whether the gene is expressed (turned on or off). Modification is an automatic and natural process that differs between every individual. For example, DNA methylation is the addition of a methyl molecule, which turns off or silences a gene, thereby stopping protein production. External factors such as environment, pollutant exposure, and diet influence this modification process.
Chemical drugs and substances have a significant epigenetic effect, demonstrated in 1907 by American researcher C.R. Stockard. Stockard used an environmentally harmful chemical, magnesium chloride, to study the effect of cyclopean fish embryos’ environment on their development. He observed that half the embryos only developed one eye, when they should have developed two. This study paved the way for other gene-environment interaction research, specifically the intersection between environment, cancer, and genes. By now, we also know that smoking tobacco is detrimental to one’s health since it increases the risk of developing many cancers and other serious health conditions. Bladder cancer is a common cancer associated with smoking tobacco, as smokers have triple the chance of developing it compared to non-smokers. It was found that smokers with a certain variant of the N-acetyltransferase 2 (NAT2) gene, which codes for carcinogen regulation, have an even greater risk of developing bladder cancer. Most people are unaware of which gene variants they possess, meaning those with the variant would not know just how harmful smoking could be for them.
Thankfully, the relationship between coffee and genetics is less worrying. Even though ordering coffee is seemingly simple, it may induce more stress than a college workload. It’s a process that’s comprised of many parts: the rush to order so you don’t take too much time and irritate the people behind you in line, the internal struggle of deciding between a latte or cappuccino, the debate of adding one of the one million syrups offered, and the most crucial yet dreaded question of all: which type of milk. If it hasn’t been made clear, people have enough pressure to deal with. Therefore, it would be unfair to assume people have had the chance to consider a loaded topic like coffee’s history. While there is no certainty of how or when coffee was discovered, historians agree that the most likely place of origin was forests in the Ethiopian highlands. A goat farmer named Kaldi came across beans on a specific tree, which he fed his goats. When he noticed his goats became extremely energetic and restless at night, he discussed this incident with monks at a local monastery, who made him a drink from the same beans. Kaldi exhibited the same behavior as the goats; he felt restless and was able to stay awake throughout the night of prayer. From then the word spread quickly to other monasteries about this revolutionary discovery and eventually reached the Arabian peninsula, where the cultivation and trade of these coffee beans began.
In the 15th century, coffee started being grown in what is now present-day Yemen, followed by Egypt, Syria, Turkey and the Persian Empire in the 16th century. Coffee’s popularity led to the formation of public coffee houses, known as qahveh khaneh, which became the main places for socialization. Soon enough, coffee houses spread to many countries including England, Austria, France, Germany and the Netherlands. By the mid 17th century London had over 300 coffee houses, some of them known as “penny universities,” where guests could buy a cup of coffee for a penny–if only this were still the case! However, the drink was met with skepticism. The clergy in Venice disapproved of coffee, quoting it as “the bitter invention of Satan,” but ultimately, Pope Clement VIII granted coffee with papal approval. In the 17th and 18th centuries, coffee made its way to the Americas, with Thomas Jefferson claiming it as “the favorite drink of the civilized world.” By the end of the 18th century, coffee was the 2nd most desirable commodity globally, after crude oil.
Caffeine has a plethora of effects on various parts of the body. The caffeine in coffee is classified as a psychostimulant, a drug that increases brain and motor activity due to the inhibition of adenosine. Adenosine is a chemical that regulates heart rate and nerve activity and prevents abnormal electrical signals being sent to the heart in order to stop irregular heart rhythms. As caffeine suppresses adenosine, heart and nerve activity are increased, leading to heightened overall activity and energy. Research has found that caffeine activates calcium release and the cyclic AMP (cAMP)/protein kinase A (PKA) pathway by inhibiting phosphodiesterase, an enzyme that regulates cAMP activity. This pathway regulates a variety of critical cellular processes, such as metabolism, transcription, and cell growth/death. In skeletal muscle cells, caffeine optimizes the uptake of glucose, oxidation of fat, and mitochondrial biogenesis (growth). Researchers also found that caffeine increases myoglobin activity using the cAMP/PKA pathway. Myoglobin supplies myocytes, or muscle cells, and mitochondria with oxygen and regulates mitochondrial function. An increase in myoglobin allows for increased muscle activity. Therefore, caffeine seems to benefit certain cellular pathways and mechanisms that in turn benefit your health.
Further research has shown that coffee consumption lowers blood sugar, protects the liver and nerves, slows the progression of Alzheimer’s disease, nonalcoholic fatty liver disease, certain cancers, and cardiovascular disease. Studies about the relationship between colon carcinoma and coffee have shown that coffee suppressed cancerous cell growth by inhibiting the Mitogen-activated Protein Kinase (MAPK) and Phosphatidylinositol 3-kinase (PI3K) pathways. These pathways contribute to cell signaling and transmission, so coffee’s suppression of these pathways stops cancerous cell signaling and cancer growth.
It was also found that chlorogenic acid, an active ingredient in coffee, stops cancerous cell proliferation through the inhibition of the miR-31 oncogene, which is responsible for the promotion of the cell cycle. Oncogenes are mutated genes that have an increased risk of causing cancer. Cancers form due to uncontrollable cell division; therefore inhibiting miR-31, a gene that promotes cancerous cell growth, is favorable. Oncogenes can be activated due to cancer-causing substances (carcinogens), an example of which is Dimethyl-Benz(a)anthracene (DMBA). Coffee reduces one’s risk of developing cancer from carcinogens like DMBA. In turn, the expression of oncogenes is also dramatically decreased, due to the promotion of tumor suppressor gene expression such as PTEN and SIRT.
The caffeine in coffee has also been quoted as a “neuroprotector” for cerebellar tissue against alcohol consumption, as it can restore damaged miRNAs within the brain’s cerebellum. miRNAs are essential in regulating brain function and development. In the case of hypoxic ischemia reperfusion (HIR), where tissue is damaged by blood flow after oxygen deprivation, chlorogenic acid significantly reduced the damaging effects of HIR by decreasing inflammation, oxidative stress and neuron death, via initiation of the SIRT1/nuclear factor-kappa B (NF-κB) signaling pathway due to upregulation of the tumor suppressor SIRT1. Specific components of coffee also change epigenetic modifications of genes used in the metabolism of lipids within the liver. This improves certain liver-related diseases, such as liver fibrosis, the production of scar tissue that prevents the liver from functioning normally. Liver fibrosis was reduced through chlorogenic acid’s regulation of the miR-21-regulated TGF-β1/Smad7 signaling pathway, which is responsible for growth and regulation.
Overall, it seems that coffee has a multitude of promising health benefits. However, the downsides of coffee must not be overlooked. Unfortunately, not everyone can reap the benefits that coffee has to offer all the time. Consumption of caffeine during pregnancy can lead to intrauterine growth retardation (abnormal fetal growth), low birth weight, difficulties conceiving, and a higher risk of miscarriage within the second trimester. Consumption also increases the baby’s risk of childhood lymphoblastic leukemia, a rare blood cancer originating from white blood cells in the bone marrow. A recent study also found that high coffee consumption led to a smaller brain volume, which in turn increases the risk of developing dementia. Caffeine also increases anxiety, especially for those who suffer with panic or anxiety disorders, and can lead to addiction and withdrawal symptoms. There have also been fears of an increased cancer risk due to the acrylamides, a carcinogenic compound found in roasted coffee beans. However, the amount of acrylamides in coffee is small enough to the point where studies have shown that there is no grave risk.
In conclusion, moderate consumption of filtered coffee without too much cream or sugar seems to be beneficial in the regulation and function of cellular pathways. Promising epigenetic effects are produced from this type of consumption, as opposed to the consumption of unfiltered coffee with added sweeteners that raise cholesterol levels. Every now and then, it may be wise to opt for a decaffeinated beverage or even just a simple glass of water. However, if coffee is enjoyed in moderation as part of a healthy and balanced diet, maybe that extra latte you were considering wouldn’t be such a bad idea after all…
Works Cited:
https://www.nature.com/scitable/topicpage/environmental-influences-on-gene-expression-536/
https://www.genome.gov/genetics-glossary/Gene-Environment-Interaction
https://www.ncausa.org/About-Coffee/History-of-Coffee
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8123560/
https://www.healthline.com/nutrition/coffee-good-or-bad#TOC_TITLE_HDR_14