Still, the body – including the skin, eyes and tongue – can indicate various health states.
Skin rashes can, of course, indicate allergic reactions, while jaundice suggests liver conditions. The colour of the lower eyelid can be a sign of anaemia, while retinal scans can diagnose diabetes.
On the tongue, a thick white coating might suggest a fungal infection like oral thrush; a very red tongue, smooth tongue could indicate vitamin deficiencies; while sores or lumps could be a sign of something more serious, like oral cancer, Lim explains.
A yellow tongue may indicate diabetes; a very dry tongue might suggest dehydration; a puffy, swollen tongue might indicate poor circulation or fluid imbalance; while the tongues of some people with cancer may appear purple and greasy. Autoimmune diseases and hormonal imbalances can also lead to noticeable changes in the tongue.
A connected organ
The tongue is revealing of our health because it has a rich blood supply and is full of nerve endings.
“It’s connected to the heart, digestive and nervous systems through various nerves and blood vessels,” Lim explains. “Changes in the body’s systems can directly influence the tongue’s appearance, sensation, and function.”
As the first organ in the digestive tract, the tongue may also reflect the health of the stomach and intestines, he adds. “A healthy digestive system often translates to a healthy-looking tongue, while issues like indigestion, malabsorption or inflammation might manifest changes in the tongue’s coating, colour or texture.”
A picture of good health
But how accurate is the tongue as a diagnostic tool? A new paper by researchers from Middle Technical University in Baghdad and the University of South Australia, examining the advances in computer-aided disease diagnosis based on tongue colour, aimed to find out.
Using image processing techniques to compare the tongue images from 50 patients with diabetes, renal failure and anaemia with a database of 9000 tongue images, they correctly diagnosed the diseases in 94 per cent of cases, compared to laboratory results.
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With 80 per cent accuracy, they were able to diagnose a further seven diseases: asthma, heart diseases, cancer, infection of the papillae (the tiny bumps on our tongue that house our taste buds), inflamed tongue and flu, including COVID-19.
Lead author and adjunct Associate Professor Ali Abdulelah Al-Naj says the research, in tandem with progress in medical diagnostics, offers “substantial promise”.
“The envisaged imaging system stands to play a pivotal role in advancing more efficacious and non-invasive diagnostic approaches for a broad spectrum of medical conditions.”
The “cool part” is that they’re using advanced computer processes, like artificial intelligence, to make this happen, Lim says. “This tech can be a big help because it depends less on people, which means fewer mistakes.”
Kaye agrees that AI and the quality of photography has changed the way doctors do remote analysis of patients. “Remote monitoring is an increasing and valuable tool.”
As for tongue diagnostics, he says much more data is needed to confirm the accuracy of the approach. “But, I’m certainly open to it as an additional enhancement of clinical medicine,” he says, adding that imaging techniques or analysis will never displace pathology – in Western medicine, at least.
“The imaging can always make mistakes. But if a tongue analysis suggests a patient has a condition, you’ll look to confirm it, or you’ll look to deny it. It gives you an area to focus on rather than fumbling around in the dark.”
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