Coca Cola: Christmas in the toilet!

Christmas is fast approaching and, as it gets nearer, we all make more and more excuses to indulge in fatty foods and sweet drinks that we know can be very bad for our health! Chief candidates among these luxury foods and beverages are the family of carbonated drinks, such as Coca Cola and Pepsi, which are often drunk in much greater quantities than normal throughout the festive season.

Coca Cola and Pepsi are both examples of carbonated drinks, which essentially means that they have had carbon dioxide gas dissolved in them under high pressure to improve their taste, texture and to give them their fizzy characteristics.

Most of us understand that such carbonated drinks can be damaging to our health if we drink them excessively, over long periods of time, and know that they are associated with a range of clinical problems that include obesity, tooth decay and diabetes, which are all related to their high sugar content.

What many of us don't know however, is that drinking large quantities of drinks like Coca Cola and Pepsi in one sitting also has side-effects; mainly, in making us need the toilet more often! Although this isn't quite as serious as, say, becoming diabetic, having to regularly queue for the toilet during Christmas festivities can be highly irritating to say the least!

Basically Coca Cola and Pepsi (along with tea - another popular drink here in the UK), contain chemicals in them that belong to a family of compounds called diuretics, which essentially alter the body so that it absorbs less water; meaning that its bladder fills up faster and we have to urinate more regularly. The diuretics found in these drinks are not particularly strong however and are not associated with any negative side-effects like any of artificial powerful diuretic drugs you may know, so don't worry - they carry no cause for concern!

Although the diuretics found in Coca Cola and Pepsi are weaker than medicinal drugs, they do however, work in the same manner and assert their effects by modulating the synthesis of antidiuretic hormone* (ADH), which controls how much water is absorbed and secreted from the body.

As you may have guessed by its name, ADH stimulates the body so that it retains water in its kidneys - making us urinate less often. ADH does this by activating normally dormant protein carriers called aquaporins, causing them to bind to the walls of the Distal Convoluted Tubule (DCT) in the kidney and to those of the collecting duct that the DCT opens into. Once present in the walls of these vessels, the tiny aquaporins actively collect molecules of water and transport them back into the bloodstream via the vasa recta.

Diuretic compounds then, interfere with the expression of ADH and cause less to be secreted by the brain's posterior pituitary gland. Thus, less water is reabsorbed back into the bloodstream and our bladders fill up faster - meaning that if we drink glasses and glasses of Coca Cola or Pepsi, the only place for the liquid to go is out!

* commonly called vasopressin

Cancerous coke & perilous pepsi?

Recently, Californian legislation has changed to classify 4-methylimidazole (4-MEI), a colouring ingredient in Coca-Cola and Pepsi, as a possible carcinogen to humans. This change will require the companies to display a 'cancer warning' on the packaging of their products. However, instead of doing this both companies have opted to alter the recipes of their drinks in the USA by replacing 4-MEI with another caramel-based colouring agent, thereby circumnavigating the new law.

Both of the popular drinks are already being sold with the new recipe in California.

Despite this new legislation, a statement from Coca-Cola has said that "not one single regulatory agency around the world considers the exposure of the public to 4-MEI as present in caramels as an issue" and consequently, the recipes of the drinks sold throughout Europe will not change. Experts say that there is no risk from the chemical, which is also present in many roasted foods, dyes and agricultural chemicals, claiming that an individual would have to drink over 1, 000 cans of either of the drinks a day in order to be risk.

However, the chemical does correlate with an increased incidence of tumour development in lab mice, so is it really safe for humans to consume? The answer, simply put, is difficult to conclude. Mice do have a different physiology to us and obviously, are much smaller. Thus, the chemical could quite plausibly pose no risk to us. On the other hand however, it may and officials in California obviously have cause for concern...