A research team from the Estación Experimental del Zaidín of the Spanish National Research Council (CSIC) in Granada has concluded that not all soy drinks provide the same nutritional benefits to the body. After evaluating different types of this product, the researchers have determined that those enriched with calcium or higher protein content contain «a greater quantity and quality of necessary micronutrients, both before and after being digested.»
According to a press release from the Junta, the ‘in vitro’ digestive process to which the different samples were subjected replicates the phases that a food goes through in humans. Thus, the experts involved in this research, funded through the project ‘Nutritional properties, bioaccessibility, and functionality of new legume-derived foods’ from the Ministry of University, Research, and Innovation of the Junta, have evaluated the nutritional behavior, before and after digestion, of five types of commercial soy drinks, including those enriched with calcium, high in protein, or low in fat.
The results of the study are presented in the article ‘Analyses of Antioxidant Properties, Mineral Composition, and Fatty Acid Profiles of Soy-Based Beverages Before and After an In Vitro Digestion Process’ in the Antioxidants journal.
Among the most relevant findings, it was highlighted that some of the beverages studied «lost part of their antioxidant capacity after digestion.» This means that not all the benefits indicated on the packaging are maintained once consumed. «However, it was also found that those enriched with calcium have a mineral content similar to cow’s milk, which can be beneficial for bone health, as this calcium is bioavailable; that is, it can be effectively absorbed by the body,» stated CSIC researcher Cristina Delgado, author of the article for the Descubre Foundation.
The research concludes that, although soy drinks are a good nutritional option overall, not all behave the same way in the body.
ARE ALL SOY DRINKS THE SAME?
The study focused on three key aspects: mineral content, such as calcium, magnesium, or iron; fatty acid profiles, including the healthy fats found in plant-based products, and antioxidant capacity; that is, their ability to neutralize free radicals and protect cells from aging and diseases like cancer.
Another aspect of the study was the variability among products. Soy drinks offered different benefits, some had a more favorable fatty acid profile, while others stood out for their mineral content or for maintaining their antioxidant properties better after simulated digestion.
Thus, calcium-enriched varieties and those with high protein content showed «better mineral absorption after digestion and greater antioxidant capacity.» The soy drink with high protein content has «a protein concentration very similar to cow’s milk and is highly bioaccessible after in vitro digestion. However, other non-enriched soy drinks did not reach those levels,» detailed the study.
On the other hand, soy drinks have a higher content of polyunsaturated fatty acids than cow’s milk, such as omega-6 and omega-3, which «help regulate cholesterol. Additionally, the study recognized a high protective capacity on intestinal cells against oxidative stress,» explained the researcher.
However, the one labeled as low-fat showed lower levels of protection against cell oxidation, both before and after simulated digestion, offering less quantity and quality of usable fatty acids, «reducing its nutritional value.»
Finally, the study authors emphasized «the need to continue researching to better understand how digestive processes affect plant-based foods and what factors determine that their benefits actually reach the body.»
