While some symptoms of ill health can be obvious, other less common signs might be hiding inside your mouth.
The tongue is regularly referred to as a good indicator of overall health - as it can come in different colours and shapes. And an expert who reads them for a living argues they are the 'biggest indicator' yet often ignored.
Jiaming Ju is a Chinese medicine practitioner who says we can learn "a vast amount" from our tongues. "By analysing them, we can determine how everything from our diet to the weather, impacts us," she told the Mirror.
"The tongue serves as a mirror reflecting not just our oral health but also offering insights into our overall well-being. Its colour, texture, moisture level, and even the presence of coating can unveil a plethora of information about the body's internal workings, serving as a diagnostic tool for various health conditions."
Describing a healthy tongue, Neil Sikka, the Director of Dentistry at Bupa Dental Care, said: "A healthy tongue is pink in colour with a slightly rough surface. What gives it this texture are the tiny bumps on top, called papillae."
Abnormal patches, lumps or spots could be a sign of mouth cancer and your dentist will look out for these during your check-up. However, there are some other worrying signs Jiaming has mapped out. She has gone viral online for analysing celebrity tongues and here, she outlines four worrying symptoms to look out for.
Scalloped edge
"Teeth marks on the edge of the tongue is a sign of Qi deficiency - the Chinese medicine term for life vitality," the 38-year-old founder of Kun Health claims. She says the common symptoms include feeling sleepy or tired, especially after a big meal, muscle soreness for days after workouts and irregular menstruation.
"The cause? Poor digestive health and overworking," she explained, before advising: "Chew your food slowly, eat away from your desk/workplace, do gentle and consistent core exercises three times a week."
Pale tongue
"This is a sign of blood deficiency accompanied by the following symptoms: chronic fatigue, long menstruation with pale bleeding, dizziness and dull headaches," Jiaming said. "The causes? Diet, anaemia and trauma. To resolve it, optimise digestive health and eat iron-rich foods".
Meanwhile, Neil warns about creamy white spots or lesions. He says: "These can indicate a fungal infection, such as oral thrush. It’s usually harmless and can be easily treated with mouth gel from the pharmacy.” It’s important not to ignore it because if left untreated, oral thrush may spread to other parts of your mouth or the back of your throat.
Dry, intensely red tongue
Jiaming explained: "A dry intensely red tongue with no coating, often with cracks and smaller than the mouth is a sign of yin deficiency, which comes with the following symptoms: hot flashes in the afternoon, poor sleep, knee/lower back pain and a surge in appetite and thirst which is not met."
She says these signs are largely down to lifestyle, such as late nights and hectic schedules, and age, along with genetics. Jiaming advises avoiding spicy food and warm spices such as nutmeg and cinnamon.
Meanwhile, periodontist Sally Cram told Health.com that a red or glossy tongue could mean a folic acid or vitamin B12 deficiency. And red sores, such as ulcers, could be a sign of stress.
Pale, wet and swollen tongue
"This is a sign of a yang deficiency accompanied by the following symptoms: feeling cold easily when the weather changes, seasonal affective disorder in the colder months, and lack of energy and motivation," Jiaming continued. To help relieve symptoms, she advises brisk outdoor walking every day and getting sunlight, and keeping your feet warm to help with circulation.
Doctor Siobhan Deshauer - an internal medicine and rheumatology specialist, elsewhere warned a glossy, red tongue could be a sign you have a vitamin B12 deficiency. Speaking on her YouTube channel, Dr Deshauer said: “A normal healthy tongue is pink with little bumps called papillae on the surface but if your tongue looks like this red and smooth, we call this glossitis and it can be from a nutritional deficiency." Vitamin B12 is naturally found in many animal products such as meat, cheese and eggs.
You can read more about Chinese medicine tongue readings on the Kun Health website or download Jiaming's DIY tongue analysis booklet here. If you're concerned about a sore tongue or other symptoms, please head to the NHS website here for more information. See a GP if you have tongue pain or itchiness that does not go away or gets worse, or if you have white patches on your tongue.