By accident I discovered bad breath, and how to reduce it, in a particular group of people.
As a dietitian I helped people who suspected they were having adverse reactions to food investigate their diet. They often suspected they, or their children, reacted to foods high in additives, rich food, chocolate, herbs and spices, acidic fruit, or monosodium glutamate [MSG]. Over time I realized that suspect foods were usually high in flavour. The symptoms they often had included eczema and other allergic conditions, migraine and headaches, irritable bowel syndrome [IBS], and attention deficit hyperactivity disorder [ADHD].
A symptom many commented on was bad breath.
As I collected information about their reactions I often heard about their supersentivity to various smells. These included petrol products, cigarettes, strong perfumes, and foods they thought are “going off”. Since they are more sensitive to smell it is no surprise that they notice smells and comment on them in their family members. What was surprising was that I, and other researchers, found that on the elimination diet used to investigate possible food intolerance, bad breath was a symptom reported as reduced along with the main presenting symptom.
After 20 years of learning about food sensitive people I read with interest an article The science of bad breath in the Scientific American April 2002 issue. It considered research into what dentists and other scientists were finding. It discussed how sensitive some people with bad breath are to how others view them. It mentions that two compounds found in bad breath are putrescine and cadaverine. Fish odour syndrome was mentioned. It is due to the body’s inability to break down a chemical called an amine. One researcher reports that it is a lack of a sulphotransferase enzyme in the gut that allows amines to get into the bloodstream. Another reports that it is lack of a sulphotransferase in the kidney that prevents additive colours, flavours and natural salicylates [other suspect chemical groups] being broken down.
How did this apply to my patients?
Food sensitive people are the group who are likely to smell and be conscious of their breath smell as they are supersmellers. Because some people, usually only a few, often including relations, comment on their smell they think that everyone can smell their bad breath to the same degree. However it is likely that the supersmellers are only a small proportion of the community and so most people do not notice anything out of the ordinary.
Puterescine and cadaverine were of special interest to me.
They are among the amines that are produced in food as it ages and goes “off”. The names say it all! Food sensitive people often want to throw out food in the refrigerator as they are sure it smells “off”, when their friends or relations say there is no bad smell. But, as supersmellers they can detect these smells much better than others can. What is more, while they are on their low chemical elimination diet, if they avoid smells that smell stale to them they can reduce production of their particular symptoms.
How does this connect to the sulphotransferase enzyme problem? This was very interesting to me. I had been researching why food sensitive people react to additive colours, flavours, some preservatives, as well as another group similar shaped natural chemicals: salicylates, many more amines, and MSG. This work was frustrating! Those who worked in the area knew by gradual food testing just which foods were implicated in reactions. But why people reacted was not known. I noted that one sulphotransferase enzyme was used to metabolise, or “detoxify” amines. This includes the offensive smelling ones, as well as the usually attractive smelling ones in chocolate, red wine, aged meats, cheeses, and dark sauces. What tied it together was the finding that another sulphotransferase was used to metabolise the suspect additives and salicylates. Just who is food sensitive and what other possible mechanisms are involved is still complex and controversial.
How does bad breath and diet connect?
A group of people with bad breath are among those who appear to be slow metabolisers of all the aromatic compounds that are suspect in food sensitive people. Sulphotransferase enzymes are reported to lower in those with bad breath. Food sensitive people who investigate diet report that where bad breath was among the initial symptoms, it resolved when they responded to dietary investigation. In food sensitive individuals there can be a connection between what goes into the gut and bad breath because excretion of some compounds via breath is one way the body can rid itself of aromatic compounds from the blood, after they have been absorbed from the gut.
The big picture is even more interesting. It would take a whole book to cover all the other connected issues, such as bad breath not being the only body odour reported a problem, individuals differing in what they react to, and foods differing in their likelihood of causing reactions. See my book Tolerating Troublesome Foods, for the detail.
Overall what can we say?
Those with bad breath should have medical and dental investigation to exclude any problems that can be solved there. As well consider that bad breath often occurs in people who are food sensitive. This group of people are often supersmellers so they are more sensitive about the smell of their breath. Where they also have any of the usual food sensitivity symptoms they can investigate their diet, preferably with the help of a dietitian experienced in the area, and using my books. Where the diet produces reduction in other symptoms they often very pleased to also report a reduction in their bad breath.