Effects of Culinary Spices on Liking and Consumption of Protein Rich Foods in Community-Dwelling Older Adults

**Background:** Age-related muscle loss (3–8% per decade after age 30) is exacerbated by inadequate protein intake, which is prevalent among older adults. Expert groups recommend 1.0–1.2 g protein/kg body weight/day for adults over 65, equating to ~0.4 g/kg/meal. Reduced appetite and declining sensory acuity with age may limit protein consumption. Culinary spices have been proposed as a strategy to enhance flavor, liking, and intake of protein-rich foods, but few studies have tested this in community-dwelling older adults or compared meat-based vs. plant-based protein sources.

**Methods:** This randomized, two-period crossover study enrolled 109 community-dwelling adults aged ≥60 years from the Denver metro area; 100 completed the protocol (50 per protein-source group). Participants received either a meat-based (chicken salad) or plant-based (chickpea, brown rice, and soy protein) lunch meal in two versions: salt-and-pepper only (NS) or with added culinary spices (S). Meals were matched for macronutrients within each protein type. Entrée portions were individualized based on body weight to deliver ≥0.36 g protein/kg body weight/meal, with an additional 20% served to allow ad libitum intake. A one-week washout separated the two test conditions. Outcomes included protein and energy consumption (weighed before and after), liking (9-point hedonic scale), flavor intensity (5-point Likert scale), appetite (100 mm VAS), and self-reported sensory acuity. Linear mixed effects models were used for analysis.

**Key Results:** For the meat-based meal, total protein intake was 30.24 ± 1.26 g (NS) and 30.90 ± 1.26 g (S) (p=0.510), corresponding to 0.40 ± 0.01 and 0.41 ± 0.01 g/kg body weight/meal. Sixty-four percent (NS) and 68% (S) achieved the 0.4 g/kg target (p=0.534). For the plant-based meal, protein intake was 18.24 ± 1.36 g (NS) and 18.25 ± 1.36 g (S) (p=0.995), or 0.25 ± 0.02 and 0.26 ± 0.02 g/kg body weight/meal. Only 18% (NS) and 20% (S) achieved the 0.4 g/kg target (p=0.745). Spice addition did not significantly increase food or protein consumption for either meal type. However, spices significantly improved liking for the plant-based entrée at the beginning (5.28 vs. 6.56, p<0.001), end (4.78 vs. 6.04, p<0.001), and overall meal (5.26 vs. 6.28, p<0.001). Flavor intensity was significantly higher for spiced versions of both meals at all time points. Significant entrée-by-recipe interactions (p<0.001 to p=0.017) confirmed that spices had a greater positive effect on the plant-based meal. Among participants with self-reported sensory decline (24–32% of the sample), the effect of spices on liking and flavor intensity was attenuated. No significant effects of gender, BMI, COVID-19 history, or VARSEEK score on consumption were observed.

**Clinical Implications:** This study demonstrates that community-dwelling older adults can achieve the recommended 0.4 g protein/kg body weight/meal target using affordable, readily available meat-based foods that are easy to chew and swallow. Achieving equivalent protein intake from plant-based sources is substantially more challenging due to lower protein density, even with fortification (soy protein powder). While culinary spices significantly improve flavor intensity and liking—particularly for less palatable plant-based dishes—this does not necessarily translate into increased protein consumption. Clinicians should prioritize protein density and food source when counseling older adults on meeting protein targets, rather than relying solely on flavor enhancement. The findings also highlight that older adults with self-reported sensory decline may derive less benefit from spice-enhanced foods, suggesting that multimodal strategies (texture modification, familiar foods, and possibly flavor amplification beyond spices) may be needed for this subgroup. Future research should examine whether sustained use of spiced, high-protein foods can improve total daily protein intake over multiple meals and longer periods.