The Spit Effect

‘The Spit Effect’ in diabetes and obesity: From Social Taboo to Scientific Breakthrough

Most of us rightfully consider the act of spitting to be an antisocial and abhorrent act. However, let’s consider a physiologically similar and much more acceptable act, kissing. Most people would find this form of distribution of saliva a shared and pleasant activity. So, the distribution of saliva has ripple effects that reach far beyond the pavement or the lips. Welcome to “the spit effect,” a phrase I have coined from an improvisation of the butterfly effect, where a small action (like a spit or a smooch) can set off a chain of events with big consequences. Let’s explore.

**The Legal Cloud Over Spitting**

First, let’s address the elephant - or should I say, the spitter - in the room. In many places, deliberately spitting at someone is considered assault [1]. In the UK, for example, spitting at a police officer or emergency worker is a serious offence, that may result in a custodial sentence [7]. Unsurprisingly, during the pandemic, the courts took an even harsher stance, recognising the potential for disease transmission and the psychological harm caused by such acts [7]. So, from a legal perspective, spitting in public is no trivial matter.

**Kissing: The Microbiome Sharing Superhighway**

But here’s a twist: not all saliva-sharing is created equal. Intimate kissing, it turns out, is a unique human behaviour that leads to a remarkable exchange of oral bacteria. Scientists have found that couples who kiss at least nine times a day graduate towards strikingly similar oral microbiomes. This is in part due to the transfer of up to 80 million bacteria in a single 10-second kiss [2]. This microbial mingling is thought to play a role in our health, immunity, and even our relationships. So, while spitting in anger can land you in trouble, sharing saliva the right way might just be good for you.

**The Spit Effect: Three Key Lessons**

**1. Intentional Research: The Gila Monster and Diabetes**

Now, let’s talk about a breakthrough that literally started with spit—but not human spit. Researchers discovered that the saliva of the Gila monster, a venomous lizard native to the southwestern United States and Mexico, contains a hormone-like molecule called Exendin-4[3][8][10]. This molecule is a structural analogue of human GLP-1, a hormone that helps regulate blood glucose levels. It is this GLP1 that stimulates the production of insulin when we eat. Once produced human GLP1 only last for a very limited time in the blood stream. In people living with type 2 diabetes the GLP-1 production in response to eating food is blunted. The big difference with lizard spit? Well, Exendin-4 is a more powerful GLP1 agent and lasts much longer in the body, making it a promising candidate for diabetes treatment [3][8][10].

Synthetic Exendin-4, known as Exenatide, was developed way back in 1992 and then approved for us in 2005. This drug manufactured by reproducing in a laboratory the molecular structure of lizard split has since revolutionised the management of type 2 diabetes. It helps control blood sugar, with a lower risk of hypoglycaemia and helps to limit food cravings. It even leads to weight loss - though it’s important to note that it’s not approved as a weight-loss drug [10].

**2. Maintaining an Open Mind: From Diabetes to Obesity**

The story doesn’t end with diabetes. Given the observation that these drugs resulted in weight loss when given to people living with type 2 diabetes, the researchers kept an open mind and explored whether such GLP-1 receptor agonists (the class of drugs that includes Exenatide) could help people living with obesity alone. The intentional research paid off since these drugs have shown to have significant weight-loss benefits, finally presenting a welcome treatment option for people living with obesity [4]. The weight loss benefits have been so impressive that demand for these drugs has skyrocketed, sometimes outstripping supply [6][9].

**3. Every Silver Lining Has a Cloud: Unintended Consequences**

However, with great power comes great responsibility - and sometimes, unintended consequences. The appetite-suppressing effects of GLP-1 receptor agonists have made them attractive to people with a BMI below the recommended threshold as well those living with body dysmorphia or eating disorders [5]. This off-label use has led to shortages, leaving people with type 2 diabetes struggling to access the medication they need [6][9]. The recent surge in prescriptions for weight loss has also raised concerns about the long-term effects on growth and development, especially in young people [5].

**The Spit Effect: A Final Thought**

So, what’s the lesson here? Whether it’s a spit of anger, a kiss of love, or a scientific breakthrough born from lizard saliva, our actions - big and small - have far-reaching consequences. “The spit effect” reminds us to be mindful of our choices, and responsibilities. We should keep an open mind and remember that every silver lining has a cloud. Who knew that something as simple as lizard spit could spark such a chain of events?

*Peer-reviewed sources have been used throughout this blog, ensuring that the science and legal context are robust and reliable[1][2][3][4][5][6][7][8][9][10].*

Sources

[1] Is spitting an assault? - West Yorkshire Police https://www.westyorkshire.police.uk/ask-the-police/question/Q145

[2] Oral Microbiome Shared by Kissing Partners https://www.genengnews.com/topics/omics/oral-microbiome-shared-by-kissing-partners/

[3] the use of glucagon-like peptide-1 analogues in the critically ill - PMC https://pmc.ncbi.nlm.nih.gov/articles/PMC3219279/

[4] Anti-obesogenic and hypolipidemic effects of a glucagon-like ... https://pubmed.ncbi.nlm.nih.gov/28579479/

[5] Unintended consequences of glucagon-like peptide-1 receptor ... https://pmc.ncbi.nlm.nih.gov/articles/PMC10495825/

[6] Our response to serious supply issues of drugs for people with type ... https://www.diabetes.org.uk/about-us/news-and-views/our-response-serious-supply-issues-drugs-people-living-type-2-diabetes

[7] [Assaults on Emergency Workers (Offences) Act 2018

https://www.legislation.gov.uk/ukpga/2018/23

[8] [PDF] Drug Discovery and Development of Semaglutide and Tirzepatide ... https://www.medclinrese.org/open-access/drug-discovery-and-development-of-semaglutide-and-tirzepatide-from-the-gila-monsters-heloderma-spp.pdf

[9] [PDF] Glucagon-Like-Peptide 1 Receptor Agonist National Shortage https://diabetesonthenet.com/wp-content/uploads/GLP-1-RA-Shortage-2024-ABCD-PCDS-FINALISED-170324.pdf

[10] Drug Derived From Gila Monster Saliva Helps Diabetics Control ... https://www.sciencedaily.com/releases/2007/07/070709175815.htm