(P39-04-26) Effects of Two Servings of Yogurt per Day on Dietary Intake and Gastrointestinal Health of Healthy, Older US Adults

Objectives: A limited number of prior studies suggests that live-culture dairy yogurt intake may improve gastrointestinal (GI) mucosal immunity. We aimed to test the impact of twice-daily servings of yogurt on GI symptoms, stool consistency, fecal pH, gut immune function and dietary intakes among older adults.

Methods: Healthy adults (n=24) age 50-75 yrs with no diet restrictions on dairy and no regular consumption of live-culture fermented foods were enrolled in the 7-wk study. A 2-wk non-intervened baseline was followed by a 3-wk intervention of twice-daily 6-ounce servings of lightly sweetened whole milk yogurt, then a 2-wk non-intervened follow-up. The intervention yogurt was made with L. Acidophilus, L. Bulgaricus, S. Thermophilus and Bifidobacterium Lactis. Participants provided stool samples and completed GI symptom surveys at baseline, weekly during intervention and at follow-up. Three 24-hour dietary recalls were completed during baseline and intervention. Bristol stool score and fecal pH were recorded for each stool sample. Gut mucosal immune function markers—fecal secretory IgA (sIgA) and mucin-2 gene expression—were quantified by ELISA and RT-qPCR, respectively. Repeated measures ANOVA, paired t-tests and Friedman tests were used to test differences in outcomes by study phase.

Results: No changes in GI symptoms, stool consistency, total fecal sIgA or mucin-2 gene expression were detected. Fecal pH increased from mean (SD) of 7.19 (0.476) at baseline to 7.41 (0.468) at intervention week 2 and returned to 7.09 (0.607) at follow-up (p < 0.05). An additive dietary effect of the yogurt intervention was observed, with mean (SD) increases from baseline to intervention of 272 (430) kilocalories, 15 (19) g protein, 48 (59) g carbohydrates and 617 (360) mg calcium (p < 0.01).

Conclusions: A 3-wk yogurt intervention did not impact GI symptoms or markers of gut immune function among healthy older adults. Two servings of yogurt per day could help underweight or normal-weight older adults increase intakes of protein and calcium, nutrients of concern for this age group.

Funding Sources: California Dairy Research Fund, US Department of Agriculture