Why Nasal Irrigation Increases Problems & Xylitol Works Better

Nasal irrigation of bacteria is not a good idea; tweaking the nasal environment is better and can affect biofilms as well. Dr. Talal Nsouli, the Washington D.C. ear, nose, and throat physician who treated President Clinton's allergies, wrote about using a xylitol-containing nasal spray to resolve chronic rhinosinusitis in his patients. But an earlier study he conducted — one that actually led him to the xylitol work — revealed something surprising about the most commonly recommended treatment for chronic sinus problems.

Dr. Nsouli's ENT Research: Daily Neti Pot Irrigation Worsens Infections

In his earlier study, Dr. Nsouli looked at patients who used another commonly recommended treatment for chronic sinus problems — irrigation, most commonly with a neti pot. What he found was that people who used nasal irrigation on a daily basis actually experienced a worsening of their infections.

When we discussed his presentation, the reason for this result was clear to both of us: we all have bacteria at the entrances to our bodies that help us stay healthy by preventing harmful bacteria from attaching. Often these commensal bacteria even make antibiotic-like substances that address invading pathogens. Daily aggressive irrigation tends to remove this protection.

Dr. Nsouli subsequently studied xylitol nasal spray and found it effective for chronic rhinosinusitis — a very different approach from flushing the nose clean. His focus was on sinus infections; mine was on ear infections, but both conditions begin from bacteria that commonly live in our noses without causing problems. The focus for both should be in the nose.

Commensal Bacteria and the Empty House

This finding reminded me of the parable Jesus told about a man who cleaned out his devils — read bacteria here. The devils wandered around for a while, then passed by their original host and, seeing an empty and swept house, recruited other devils more evil than themselves and re-entered the man. He was worse off afterward than before.

This parable is a remarkably accurate portrayal of what happens in our bodies in this era of antibiotics, which we use to get rid of the bacterial devils that infect us. Protective bacteria — commensals with a benefit — are concentrated at our body's openings where we are most vulnerable.

Lactobacillus in the female genitourinary tract protects against infections and provides a healthy bacterial start for babies delivered via the birth canal. We once recommended washing these bacteria out regularly — until we recognized that, very much like Dr. Nsouli's sinus patients, women got worse without their protective bacteria. Similarly, a variety of friendly bacteria live in the upper airway, and a different variety live in our GI tracts. They protect us both by occupying space so the house is not swept clean and empty, and by often secreting antibiotic chemicals that keep infecting bacteria away.

Xylitol Tweaks the Environment; Irrigation Strips It

Dr. Nsouli and I both agreed that tweaking this environment was a far better option than irrigation, and that xylitol was an excellent choice to do it. Irrigation removes the protective bacterial community entirely. Xylitol works differently — it modifies conditions so pathogens have a harder time adhering while leaving the overall ecosystem intact enough to recover.

When I began working with xylitol, I spoke with Matti Uhari, the Finnish physician who showed xylitol gum prevents ear infections. His unpublished study at the time showed how xylitol decreases the adherence of nasal pathogens. Chewing xylitol-sweetened gum five times a day prevented about 40% of ear infections. My study showed that using xylitol nasally at every diaper change prevented more than 90% of ear infections.

Most of our pathogens hold on to us by binding with a sugar complex on our cell surfaces. Knowles and Boucher described how the mucus in our noses is filled with sugar complexes that can bind with almost any foreign allergen or bacteria. Xylitol looks like many of these sugars and is flexible enough to fit into bacterial lectin binding sites. The bacteria are content when holding a sugar, so there is no stimulus to develop resistance.

5% Xylitol Reduces Pneumococcus Adherence by 68%

Uhari's group demonstrated that a 5% solution of xylitol decreases the adherence of the major pathogen Streptococcus pneumoniae by 68% (PMID 9598780). For Haemophilus influenzae, adherence dropped 50% when both cells and bacteria were exposed to xylitol. These effects, combined with xylitol's promotion of our own mucins and natural cleaning mechanisms, are the main reasons nasal xylitol spray is so effective.

This is fundamentally different from irrigation, which physically removes bacteria — both harmful and protective — and disrupts the mucociliary apparatus that normally clears pollutants. Saline irrigation can temporarily relieve congestion, but daily aggressive use strips the commensal layer that prevents re-colonization by worse organisms.

Biofilms in Chronic Sinus and Ear Infections

When an infection begins, it is most often from a single bacterium that gets into a place where it can hold on and multiply. If it evades detection by the immune system, it can grow into a colony, often made up of different kinds of bacteria. When this colony senses a threat, it builds a matrix around itself that protects it from outside threats — it becomes a biofilm.

This protective cover even prevents antibiotics from affecting the bacteria living inside. Penetrating a biofilm with antibiotics often requires a dose toxic to the person. We need another way to cope with biofilm-associated problems. Ear and sinus infections fit here, since biofilms have been associated with chronic infections in both. Implanted devices like pacemakers and joints are also at risk — but you cannot remove biofilms from sinuses and ears the way you can an infected implant.

One of my first experiences with a biofilm-related problem involved a young woman whose asthma was triggered by a chronic infection in her sinuses. We had her use xylitol nasal spray four times a day. About a week later, while her mother was washing her hair, she coughed, gagged, and eventually expelled thick tissue-like material. Her mother said it looked like she was losing her brains. But in the following week she had no asthma trouble. She stopped taking her asthma medications, and six months later she was still an active teenager with no asthma.

New Zealand Study: Xylitol Reduces Biofilm

A study from New Zealand looked specifically at what xylitol does to bacteria that participate in the biofilms causing chronic sinus problems — Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. The researchers found that xylitol reduces biofilm mass and formation.

This confirms what we observed clinically: when biofilm material breaks loose from the nasopharynx, patients often experience a dramatic clearing of symptoms that had persisted despite antibiotics and irrigation. The biofilm was the reservoir; removing its structural integrity allowed the body's own defenses to finish the job.

Research from Lubbock, Texas, using the multi-species Lubbock Chronic Wound Biofilm model showed that 20% xylitol completely inhibited biofilm formation. Combined lactoferrin and xylitol treatment disrupted P. aeruginosa biofilm structure with greater than 2-log reduction in viability (PMID 19010633).

What to Use and How Often

If you have chronic sinus or ear problems, it is important to use a xylitol-containing spray where xylitol is the first listed ingredient after water. Some products claim xylitol on the label but contain an insufficient amount to be clinically useful. Look for concentrations of at least 5%, ideally around 11% in saline.

Use it often. What you are doing with xylitol is something like negotiating with bacteria — the more frequently you apply it, the better they respond. For prevention, two sprays per nostril morning and night is a reasonable baseline. During active symptoms, increase to every few hours.

The contrast with neti pot irrigation could not be clearer: irrigation strips the nasal environment and leaves it vulnerable; xylitol tweaks the environment toward health while supporting the commensal bacteria that keep worse organisms out. For the full clinical evidence behind xylitol's medical uses, see Medical Uses of Xylitol for Healthcare Professionals.