Soy milk—a popular dairy alternative in the West—has long been consumed as a traditional breakfast beverage in China, Japan, and other parts of Asia. In the United States, people with lactose intolerance often choose soy milk, as do vegans and those who perceive it as a healthier option to cow's milk.
But the touted health benefits of soy raise some questions. It's a common food allergen and many store-bought brands of soy milk contain sugar, fillers, and other questionable additives.
What Is Soy Milk?
A plant-based beverage, soy milk production is made by cooking soybeans in water, then grinding and pressing them to separate the insoluble fiber from the resulting liquid. Commercial soy milk ranges from chalky and thin to rich and sweet. Some brands use thickening agents to add the creamy mouthfeel associated with full-fat dairy. Soy milk contains a similar amount of protein per serving, making it a closer nutritional match for cow's milk than other non-dairy milk alternatives such as almond, rice, and coconut.
How to Use Soy Milk
Soy milk can be substituted for cow's milk in coffee drinks, with breakfast cereal, for making yogurt or ice cream, in smoothies, and using a one-to-one ratio in baked goods, although the flavor and texture may not be quite the same. If you use sweetened soy milk, you may need to otherwise adjust the sugar. For savory dishes, unsweetened soy milk typically works best, and you will get a better result in dishes that do not rely on the creaminess of full-fat dairy. Brands abound at the grocery store, but you can better control the ingredients if you make soy milk at home yourself.
What Does It Taste Like?
Fresh soy milk in Asia retains a notable bean flavor, but soy milk produced for Western markets loses some during pasteurization for long-term packaging; added sugars and other natural and artificial flavorings further disguise the soybean taste. Soy milk enthusiasts describe the flavor as nutty or even grassy.
Soy Milk Recipes
You can use soy milk in place of dairy in most any recipe to make vegan baked goods or as a replacement for cream in savory dishes.
Where to Buy Soy Milk
Look for soy milk at any U.S. grocery store; you can find it in the refrigerator section near the dairy or in shelf-stable packaging often located on the same aisle as the breakfast cereals. It's also available at any health food store, most convenience stores, and from online grocery retailers.
Soy milk from the refrigerator section at the grocery store should be kept in the refrigerator whether it's open or not; unopened soy milk in shelf-stable packaging can be kept for extended periods at room temperature, but it should be immediately refrigerated upon opening. Use up any opened soy milk within eight to 10 days. You can freeze soy milk to keep it from spoiling, but it significantly degrades the quality, affecting both taste and texture.
Nutrition and Benefits
Soy milk contains on average 7 grams of protein per 1-cup serving, putting it right on par with cow's milk. But one drawback of using soy milk as a cow's milk replacement is the comparably low levels of calcium in soy. Unfortified soy milk contains about a quarter of the calcium found in cow's milk. Fortified brands do claim a comparable amount of calcium, but human bodies don't absorb fortified calcium as easily as naturally occurring calcium.
Do note that unless it's labeled "unsweetened," store-bought soy milk most likely contains added sugar, with some chocolate-flavored varieties packing almost as much as a candy bar. Some soy milk brands contain fillers such as carrageenan, an indigestible thickener blamed for causing inflammation in the digestive tract.
Cow's Milk vs. Soy Milk
"Got Milk?" ad campaigns tout the health benefits of cow's milk—it's high in protein, Vitamin D, and calcium, and it's a source of good fats. Fats provide energy and make you feel satiated long after you eat them, which can aid in losing weight.
Soy milk is naturally low in saturated fat with no cholesterol. Dairy milk, in contrast, contains about 20 milligrams of cholesterol per cup. So, for people with high cholesterol or certain types of heart problems, soy milk may be a smart alternative to cow's milk.
Japanese consumers can choose from more than 50 types of soy milk, including some seasonal and rare flavors such as cherry blossom and black sesame seed. In the United States, you're likely to find only basic flavors such as vanilla, chocolate, and strawberry, although larger stores may carry brands with seasonally flavored offerings. Flavored varieties usually contain sugar, although you can find unsweetened vanilla versions. Soy milk is also typically available in low fat and non-fat, as well as certified organic products.
Soy milk contains naturally occurring isoflavones, or phytoestrogens, a plant-derived compound with "estrogenic activity," which mimics the effects of natural estrogen. Some studies have linked high consumption of phytoestrogens with an increased risk of certain types of cancer as well, but without conclusive evidence.
US Department of Agriculture. Soy milk. Updated April 1, 2020.
Peng CC, Liu CY, Kuo NR, Tung TH. Effects of Phytoestrogen Supplement on Quality of Life of Postmenopausal Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Evid Based Complement Alternat Med. 2019. doi:10.1155/2019/3261280