Why do we develop bad breath while fasting?

Bad breath is commonly known as Halitosis or Fetor Oris. Foul breath is a troublemaker especially when you are attending social gatherings. Surprisingly though, people are unaware about their bad breath. It is relatively common in old age people but recently seen in youngsters also.

Friends and relatives who come in contact of the sufferer often hesitate to inform him/her of the condition just to protect the sentiments. That results in people believing that bad breath is incurable.

Reasons behind bad breath

• Periodontal diseases such as diseases of the gums, ill-fitting dentures, carious teeth, poor oral hygiene, metabolic activity of bacteria in plaque or putrefaction of sulfide-yielding food
• Smoking, alcohol, sinusitis, lung disease and less common diseases of the oesophagus.
• Other reason include local bacteria which metabolize sulfur-containing amino acids (cysteine, methionine) in protein to yield volatile hydrogen sulfide and methyl mercaptane

Hydrogen sulfide and methyl mercaptane contain foul smell and may damage the surrounding tissue. Hence, they add to bacterial retention and periodontal disease. At night and between meals conditions are most favorable for odor production.

Eating regularly may help prevent bad breath because prolonged fasting may cause a condition called Ketosis in which too much body fat is burned. Ketosis does not result from just overnight fasting. Fasting has to be longer than that to give rise to ketosis.

The body has enough glucose stored as glycogen which can last through the day. Beyond that it relies on its fat reserves. All the fat that is mobilized is not burnt in the final common pathway of metabolism. The excess fatty acid gets diverted to form ‘ketone bodies’, a product of fat metabolism. They are usually located in the liver and used by multiple tissues.

When the rate of synthesis exceeds the metabolic capacity of tissues, the result is ketonemia (presence of more than normal amount of ketones in blood) and ketonuria (presence of ketones in urine), together called ketosis. In ketosis, ketone bodies are excreted in breath leading to ‘bad breath’.