A Six-Year Karolinska Study Just Confirmed What Denture Patients Already Suspected About Food and Weight
For years, the clinical literature on chewing function and nutrition in older adults was largely cross-sectional — snapshots of a population at a single point in time, showing correlations between poor chewing ability and poor nutritional status that were suggestive but not definitive about which came first.
A longitudinal study published in the Journal of Nutrition, Health and Aging in April 2025 by researchers from Karolinska Institutet’s Academic Center for Geriatric Dentistry addresses that gap directly. Over six years of follow-up in a Swedish cohort of older adults, the study found that poor chewing ability independently increased the risk of malnutrition — holding the finding stable even after accounting for other known contributors like social isolation, living arrangement, and comorbidities.
The finding matters beyond academic interest. It confirms a mechanism that patients who have lost teeth and struggled with chewing have often reported in clinical settings but that was difficult to quantify longitudinally: that reduced ability to chew properly changes what a person eats, and that change in diet has downstream consequences for weight and nutritional adequacy that compound over time.
The study, led by Duangjai Lexomboon and colleagues at Karolinska Institutet, adds to a growing body of evidence linking oral function restoration — through dentures, implant-supported prosthetics, or other means — to outcomes that extend well beyond the mouth.
What Happens to the Diet When Chewing Becomes Difficult

The dietary substitution pattern associated with reduced chewing ability is well-characterized. When biting and grinding become painful or unreliable — because teeth are missing, because a denture shifts during function, or because the remaining teeth are insufficient to handle firm or fibrous foods — people adapt.
They avoid the foods that cause difficulty and substitute easier alternatives. Grilled chicken gives way to soft pasta. Raw vegetables give way to processed options. Nuts, seeds, whole grains, and the full range of fruits that require sustained chewing pressure drop out of the diet. What remains tends to be softer, higher in refined carbohydrates, and lower in protein, fiber, and micronutrients.
Protein intake, which matters especially for muscle mass preservation in older adults, falls when high-protein foods that require chewing become difficult to manage. Fiber intake falls when whole grains and raw produce are avoided. Vitamin and mineral profiles shift as diet narrows toward softer, more processed options.
Research on older adults with severe tooth loss has consistently shown lower intake of key nutrients including potassium, calcium, fiber, and certain vitamins compared to adults with functional dentition. The Karolinska study’s longitudinal design allows a more confident reading of that relationship as causal rather than merely correlational.
A parallel 2025 systematic review and meta-analysis published in the journal Gerodontology found that older adults with fewer than 20 remaining teeth who had not been rehabilitated with dentures were four times more likely to be malnourished than their counterparts with more functional dentition. That odds ratio — OR of 4.00 — is a striking figure in the context of a condition as consequential as malnutrition in older adults.
What Dentures Restore — and What They Cannot Replace
Conventional removable dentures restore a meaningful portion of lost chewing function, and for many patients, the difference between wearing dentures and having no teeth at all is substantial. Studies estimate that people without teeth chew at approximately 20 to 25 percent of the efficiency of those with a full complement of natural teeth.
Conventional dentures recover a significant portion of that function — enough to expand the diet meaningfully, to restore the bite balance that prevents uneven jaw loading, and to allow patients to return to foods that had been inaccessible. For patients who have gone without any tooth replacement, getting properly fitted dentures changes what they can eat in ways that have direct nutritional consequences.
The limitation of conventional removable dentures, particularly as the years pass, is that the chewing function they provide is not stable over time. A denture that fit well at placement may, after several years of bone resorption, have become loose enough that chewing is again unreliable.
Patients in that situation often slide back into the dietary avoidance behaviors they had before getting dentures — not because their prosthetic failed in a catastrophic sense, but because the subtle instability is enough to make certain foods anxiety-inducing or uncomfortable. They stop eating the hard foods they were eating when the fit was better. The nutritional gains partially reverse.
Implant-supported fixed prosthetics address this by anchoring the restoration to the bone rather than resting on top of it. The chewing forces are transmitted through the implant to the jaw, which provides stability that does not degrade with bone resorption in the way that conventional denture retention does.
The Broader Argument for Restoring Chewing Function Early
The cumulative picture from the 2025 research is one that should inform how patients and providers think about tooth replacement timing. Waiting is not neutral.
The bone that resorbs while a patient defers treatment does not recover without intervention. The diet that narrows while chewing ability is impaired may not fully recover even after function is restored — habits form, food preferences shift, and the nutritional deficits accumulated over years of inadequate intake have their own downstream health consequences.
Acting earlier preserves more bone, provides more restoration options, and intercepts the nutritional and quality-of-life consequences of impaired chewing before they compound.
The research from Karolinska Institutet and the parallel findings from the Gerodontology meta-analysis make a strong case that the cost of inaction is real, measurable, and appears in domains — nutritional status, weight stability, overall health in aging — that are not always part of how patients frame the decision about whether and when to pursue treatment. They are worth framing that way.







































