Switching to Soymilk: Effects on Heart and Metabolism Health

Jenn Hoskins
22nd August, 2024

Switching to Soymilk: Effects on Heart and Metabolism Health

Photograph of soymilk alongside a bowl of soybeans.

Photographer: Polina Tankilevitch

Key Findings

  • The study reviewed 17 trials involving 504 adults to compare the effects of soymilk and cow's milk on cardiometabolic health
  • Substituting soymilk for cow's milk led to moderate reductions in non-HDL cholesterol, systolic blood pressure, and diastolic blood pressure
  • Sweetened soymilk did not adversely impact cardiometabolic health, challenging its classification as an ultra-processed food
The shift towards plant-based diets is increasingly recommended by dietary guidelines. A key component of this transition is the use of fortified soymilk, a plant protein food that often contains added sugars to match the sweetness of cow's milk. However, soymilk is classified as an ultra-processed food (UPF), raising concerns about its potential adverse cardiometabolic effects. A recent systematic review and meta-analysis conducted by researchers at the University of Toronto aimed to assess whether substituting soymilk for cow's milk affects cardiometabolic outcomes[1]. The study reviewed 17 randomized controlled trials involving 504 adults with varying health statuses. The trials assessed the impact of consuming a median daily dose of 500 mL of soymilk (containing either 17.2 g or 6.9 g of added sugars per 250 mL) in place of 500 mL of cow's milk (containing 24 g of total sugars as lactose per 250 mL). The researchers evaluated a range of intermediate cardiometabolic outcomes, including blood lipids, glycemic control, blood pressure, inflammation, adiposity, renal disease, uric acid, and non-alcoholic fatty liver disease. The findings revealed that substituting soymilk for cow's milk led to moderate reductions in non-HDL cholesterol (-0.26 mmol/L), systolic blood pressure (-8.00 mmHg), and diastolic blood pressure (-4.74 mmHg). Additionally, there were small but significant reductions in LDL cholesterol (-0.19 mmol/L) and C-reactive protein (CRP) (-0.82 mg/L), with a trivial increase in HDL cholesterol (0.05 mmol/L). No other significant differences were observed in the remaining outcomes. Importantly, the study found no meaningful effect modification by added sugars across these outcomes, suggesting that sweetened soymilk does not adversely impact cardiometabolic health. The certainty of evidence was rated high for LDL and non-HDL cholesterol and moderate for systolic and diastolic blood pressure, CRP, and HDL cholesterol. For other outcomes, the evidence was generally moderate-to-low. These findings challenge the classification of soymilk as an ultra-processed food, especially when considering its cardiometabolic effects. Critics of UPFs argue that these foods are unhealthful due to their high energy density, high glycemic index, hyper-palatability, and low satiety potential[2]. However, this study indicates that soymilk, even when sweetened, does not exhibit these adverse effects when compared to cow's milk. This supports the argument that the NOVA classification system, which categorizes soymilk as a UPF, may be overly simplistic and not fully reflective of its nutritional attributes. Furthermore, the study aligns with earlier findings that emphasize the potential health benefits of soy-based meat and dairy alternatives. For instance, soy-based products are often considered more sustainable compared to their animal-based counterparts, which are classified as unprocessed or minimally processed foods[2]. The misclassification of soy-based alternatives as UPFs could hinder their public acceptance and negatively impact both personal and planetary health. In conclusion, replacing cow's milk with soymilk, including sweetened variants, does not adversely affect cardiometabolic risk factors. The classification of soymilk as an ultra-processed food may need reassessment, particularly in the context of promoting plant-based diets for better health outcomes. This study underscores the need for a more nuanced approach to food classification systems, one that accurately reflects the health impacts of plant-based alternatives.

NutritionHealthFitness And Diet

References

Main Study

1) A systematic review and meta-analysis of randomized trials of substituting soymilk for cow's milk and intermediate cardiometabolic outcomes: understanding the impact of dairy alternatives in the transition to plant-based diets on cardiometabolic health.

Published 22nd August, 2024

https://doi.org/10.1186/s12916-024-03524-7

Related Studies

2) Perspective: Soy-based Meat and Dairy Alternatives, Despite Classification as Ultra-processed Foods, Deliver High-quality Nutrition on Par with Unprocessed or Minimally Processed Animal-based Counterparts.

https://doi.org/10.1093/advances/nmac026


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