Why eating banana is beneficial to those who quit smoking cigarette (tobacco)?

Quitters of cigarette smoking usually find it very stressful during the withdrawal period. This is always takes period of 2-3 weeks when they stop smoking. But do you know that these people can overcome this challenge by just eating banana which has great benefits to human life? Let’s understand what banana contains which is responsible for the same effect as nicotine in tobacco. 

Banana contains tryptophan, which is the nonessential amino acid with aromatic side chain. Nonessential amino acids are amino acids that cannot be synthesized in our bodies but can be obtained from our diets. Tryptophan's structure consists of hydrophobic R-chain group (side chain) and this is called indolering (aromatic ring) which gives rise to nicotinate (niacin), indoleacetate, and serotonin. 

This means that  tryptophan is a precursor in the synthesis of serotonin which is the contributor to the same effects of nicotine in our body. Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. It is located  in gastro-intestinal tract and central nervous system (CNS) in our bodies, about 90% of serotonin in our bodies is located in our enterochromaffin cells. The enterochromaffin cells are types of enteroendocrine and neuroendocrine cells which occur in the epithelial lining of digestive tract and respiratory tract. Their occurrence in the digestive epithelial lining  aids in the regulation of the intestinal movements. 

The main question is, how do we synthesize serotonin from tryptophan in our body? This is achieved by; first tryptophan is catalyzed by enzyme tryptophan hydrolase (TPH-1) in the presence of oxygen (O₂), tetrahydrobiopterin to form 5-hydroxytryptophan with the release of water (H₂O) and dihydobiopterin. 5-hydroxytryptophan is then converted by aromatic amino acid decarboxylase in the presence of pyridoxal phosphate, the prosthetic group of aminotransferase  to serotonin with the release of carbon (IV) oxide (CO₂). 

Banana also contains another nonessential aromatic amino acid (tyrosine). Tyrosine has hydroxyl group attached to its aromatic ring at carbon number four of aromatic rings. It is a precursor in the synthesis of the following:(i) dopamine-which regulates energy, alertness and mental concentration. (ii) Epinephrine and norepinephrine which are stress hormones that affect body functions. How these chemicals (neurotransmitters) are being synthesized from tyrosine? Tyrosine is converted to dopa in the presence of tetrahydrobiopterin, oxygen (O₂) and in the process dihydrobiopterin and water (H₂O) are released. This reaction is catalyzed by tyrosine hydroxylase. This introduced hydroxyl group (^-OH) at carbon number five (5) of the aromatic ring of tyrosine and this is what is called dopa. The next reaction is the decarboxylation of alpha-carboxyl group, a reaction which is catalyzed by aromatic amino acid decarboxylase in the presence of PLP (pyridoxal phosphate, the prosthetic group of aminotransferase). This results in a dopamine (one of neurotransmitters). The next step is the conversion of dopamine to norepinephrine (another neurotransmitter). This reaction is characterized by introduction of hydroxyl group (^-OH) to beta- carbon of tyrosine, a reaction facilitated by dopamine beta-hydroxylase in the presence of ascorbate and oxygen (O₂) with the release of dehyroxyascorbate and water. The final step is the transfer of the methyl group (-CH₃) from S-adenosyl methionine to alpha-amino group of norepinephrine to form the last neurotransmitter (epinephrine). This reaction is catalyzed by phenylethanoalamine N-transferase with the release of AdoHey(S-adenosylhomocysteine). 

Now how does eating banana help cigarette smoking-quitters during the withdrawal period? Nicotine or (s)-3-{1-methylpyrrolidin-2-yl} pyridine is potent parasympathomimetic alkaloid found in the nightshade family of plants or ‘Solanaccae’. ‘s’ in the bracket in the name of nicotine indicates that it rotates the plane of polarized light to the left. It is a stimulant drug and also nicotinic acetylcholine receptor (nAchR) agonist. In dry tobacco by weight, the nicotine content is about 0.6 – 3.0%. It causes the activation of nicotine receptors , within 7 seconds of smoking cigarette the blood rich in nicotine passes from the lungs to brain thus stimulating the release of chemical messengers for example acetylcholine, norepinephrine, epinephrine, arginine, vasopressin, serotonin, dopamine and beta-endorphin. 

It can be seen that the relationship between banana and nicotine is the release of serotonin, dopamine, norepinephrine, and epinephrine. These are responsible for action of banana to induce the same effects as nicotine. The effects during withdrawal period encompass:  headache, nausea and craving for tobacco, anxiety, depression, drowsiness or trouble sleeping, increased appetite and weight gain. Nicotine creates chemical dependency that makes the body to need certain levels of nicotine all times which have to be maintained and this why when these individuals eat banana, banana will induce the same effects as nicotine in their bodies. Hence, this will reduce/ prevent these feelings during this period. It can also be seen that tryptophan is also a precursor of the synthesis of an intermediate (niacin or nicotinate) of nicotine, thus justify this argument. 

The withdrawal peaks are 48 hours when you quit and will disappeared totally after 6 months. It takes eight (8) to twelve (12) days before a person starts feeling comfortable with his/her current situation. It is important to note that tobacco contain other chemicals which greatly affect a person life negatively. For instance,  ‘tar’ is an example which is a carcinogenic. Therefore, it is advisable to eat banana instead of smoking cigarette (tobacco).