Yogurt and cheese are rich in protein, but do they help aging muscles?

By Dr. Chinta SidharthanReviewed by Susha Cheriyedath, M.Sc.Nov 11 2026

Could yogurt and cheese help preserve muscle strength as we age? Researchers examined the diets and physical function of nearly 6,800 older adults across two Irish cohorts, revealing an unexpected finding that deserves a closer look.

Study: Fermented dairy intake and markers of musculoskeletal ageing on the island of Ireland: insights from the Northern Ireland Cohort for the Longitudinal Study of Ageing (NICOLA) and The Irish Longitudinal Study on Ageing (TILDA). Image Credit: Caftor / Shutterstock

Muscle loss is a major driver of frailty and loss of independence in later life, prompting researchers to examine protein-rich foods that might help aging muscles stay strong. In a recent study published in the European Journal of Nutrition, researchers examined whether fermented dairy intake is associated with grip strength and frailty in aging populations.

Scientists from Teagasc Food Research Center, VistaMilk, and APC Microbiome Ireland at University College Cork in Ireland conducted the research in collaboration with Queen's University Belfast and King's College London in the United Kingdom.

Age-related muscle loss

Aging-related sarcopenia, or loss of muscle mass and strength, severely reduces physical performance and increases the risk of frailty and loss of independence in older people. While protein helps maintain muscle, older bodies respond less strongly to it, a state called anabolic resistance. Protein quality, amino acid composition, and distribution across meals also warrant attention alongside total intake.

Dairy foods supply high-quality protein, and fermented dairy foods such as yogurt and cheese may also influence muscle through the gut, along the gut-muscle axis. Yet evidence from large populations on associations between fermented dairy consumption and muscle strength remains limited.

About the study

For this cross-sectional analysis, the researchers analyzed data from two population-based aging cohorts of adults aged 50 and older in Northern Ireland and the Republic of Ireland. The first was the Northern Ireland Cohort for the Longitudinal Study of Aging (NICOLA), which included 2,791 participants with a mean age of 64 years. The second was the Irish Longitudinal Study on Aging (TILDA), which included 3,999 participants with a mean age of 66 years.

Participants in both studies completed food frequency questionnaires that recorded how often they ate certain foods over the previous year. In NICOLA, the team added up daily grams of cheese, yogurt, and other fermented dairy items. In TILDA, the questionnaire covered only yogurt and cheese, so the team treated the combined answers as an approximate daily consumption frequency rather than an amount in grams. Each cohort was analyzed separately, using intake as a continuous measure and in three roughly equal groups.

The study measured physical function in several ways. Hand grip strength was recorded in kilograms with a handheld dynamometer, and low strength was defined using established European sarcopenia thresholds.

The Timed Up and Go test timed how long a person took to rise from a chair, walk three meters, turn, return, and sit. Self-reported difficulty with basic daily self-care tasks, known as activities of daily living, was also recorded. Frailty was scored with a frailty index built from 30 reported health deficits, and people were grouped as frail, pre-frail, or robust.

Linear regression models were used to analyze continuous outcomes, while logistic regression models were used for yes/no outcomes. All models were adjusted in stages, first for age and sex, then for body mass index and physical activity, and finally for alcohol use, smoking, income, and education. NICOLA models also included energy intake, protein intake, and area deprivation.

Major findings

The results reported that eating more fermented dairy was not consistently linked to better physical function or lower frailty after accounting for other influences on health.

In NICOLA, people who ate more fermented dairy had weaker grip strength in raw comparisons, but the link was no longer apparent after adjustment for age, sex, and lifestyle and socioeconomic factors. Descriptive comparisons also showed somewhat lower frailty and fewer daily activity limitations among higher consumers, but no consistent associations with mobility, frailty, or self-care limitations remained after full adjustment. There was no clear dose-response trend. Those eating the most fermented dairy were more often women, better educated, and more physically active.

The results from TILDA showed a similar pattern. Raw comparisons tied higher intake to weaker grip and slightly faster mobility test times, but these faded after adjustment. In one fully adjusted analysis, people in the top third of intake had more than twice the odds of low grip strength compared with the bottom third. The authors considered this a potentially spurious finding because it did not appear when grip strength was measured continuously or in other outcomes.

Separate analyses suggested that yogurt intake contributed particularly to the initial association with weaker grip strength, but this was no longer evident after adjustment. Cheese intake showed no consistent associations in the TILDA results.

Overall, the findings provided no consistent evidence that higher yogurt or cheese consumption was independently associated with better muscle strength, physical function, or lower frailty in older adults.

The authors suggested that patterns in the raw data may have reflected broader differences in health habits, diet quality, and income. Older adults with declining health might favor softer foods such as yogurt, which could help explain associations between higher intake and poorer muscle function. Because diet and physical function were assessed at one time point, the study could not establish cause and effect.

Conclusions

Taken together, findings from two large Irish cohorts showed that fermented dairy intake was not reliably tied to physical function or frailty after accounting for other factors. Initial associations were inconsistent and may have reflected differences in lifestyle and background. The researchers did not measure muscle mass or gut microbiome composition, and dietary reporting could have introduced inaccuracies.

The authors concluded that the results did not establish whether fermented dairy benefits muscle health, and longitudinal studies and controlled trials were needed to clarify whether fermented dairy supported healthy muscle aging. They also called for research examining the contribution of physical activity, particularly resistance exercise.