(P06-12-26) Effect of a Sugars-Sweetened Beverages Reduction Strategy Using Soymilk vs. Cow’s Milk on Liver Fat: The Soy Treatment Evaluation for Metabolic Health (STEM) Randomized Trial

Objectives: Liver fat is an early metabolic lesion in cardiometabolic diseases. Sugar-sweetened beverages (SSBs) reduction has emerged as a dominant clinical and public health target for cardiometabolic risk reduction. Low-fat cow’s milk is the standard of care caloric replacement for SSBs in nutrition programs. Fortified soymilk is a dairy alternative recognized for its comparable nutritional value and approved heart health claims. Whether it provides similar benefits to cow’s’ milk is unclear owing to its added sugars content and classification as an ultra-processed food. The Soy Treatment Evaluation for Metabolic health (STEM) trial evaluated the effect of replacing SSBs with 2% soymilk vs 2% cow’s milk on liver fat in SSBs consumers with obesity.

Methods: STEM is a pragmatic, combined superiority and non-inferiority, 24-week, parallel, 3-arm, randomized trial in adults with obesity consuming ≥1 SSBs/day. Participants were randomized to their usual SSBs; sweetened, fortified 2% soymilk; or 2% cow’s milk. The primary outcome was change in intrahepatocellular lipid (IHCL) measured by ¹H-MRS at 24 weeks. Hierarchical testing controlled the familywise error rate. Superiority of cow’s milk and soymilk to SSBs was assessed first. If superiority was established, then the non-inferiority of soymilk to cow’s milk was assessed using a pre-specified margin of 1.5%. (Clinicaltrials.gov NCT05191160)

Results: We randomized 186 participants (57% male; mean [SD] age, 39.9 [11.8] years; BMI, 34.6 [6.1] kg/m², waist circumference, 112.6 [13.8] cm; IHCL, 10.0% [8.2%]; 64.1% metabolic dysfunction-associated steatotic liver disease; SSBs intake, 2.3 [1.3] 12 oz servings/d). Cow’s milk (mean difference [95% CI], −1.68% [−3.23% to −0.14%]) and soymilk (−1.96% [−3.41% to −0.50%]) reduced IHCL vs. SSBs at 24 weeks, demonstrating superiority. Soymilk was non-inferior to cow’s milk (difference of means [90% CI], 0.003% [−1.22% to 1.22%]).

Conclusions: In adult SSBs consumers with obesity, replacing SSBs with sweetened, fortified 2% soymilk is non-inferior to 2% cow’s milk for liver fat reduction over 24 weeks. These data support SSBs reduction guidelines with fortified soymilk as an alternative effective SSBs reduction strategy for improving metabolic health.

Funding Sources: United Soybean Board through SNI Global