In our search for convenience we often turn to vitamins and other pill-based supplements instead of adopting healthier eating habits. Many vitamins, minerals, and other supplements can be an important part of our efforts to lead a healthier lifestyle, but we shouldn’t rely on them as sole sources of micronutrients. Instead they should be complementary to a healthy diet to ensure we obtain all the nutrients our bodies need.
This is true of soy foods and soy isoflavones as well. Many people have asked the difference between soy protein and soy isoflavones and whether or not they can get the full benefits of soy by taking soy vitamins. This is an important question because soy foods and soy vitamins are very different. Soy vitamins generally consist only of isoflavones or a soy extract that is mainly isoflavones. In contrast, soy foods contain many nutritional factors including protein, isoflavones, saponins, and many vitamins and minerals.
So what exactly is the difference between soy isoflavones and soy protein?
Isoflavones are a phytochemical (natural plant chemical) found in soybeans and other legumes. Soybeans contain three main types of isoflavones. In their most common form, the ‘glycoside’ form, these isoflavones are genistin, daidzin, and glycitin. In this glycoside form, these isoflavones are found naturally attached to a glucose (sugar) molecule. Healthy bacteria in our digestive tracts remove the glucose molecule during digestion to form the corresponding ‘aglycone’ form of the soy isoflavones, genistein, daidzein, and glycitein. Soy vitamins will typically contain one or more of these isoflavones.
Protein is another component of the soybean and like other proteins is made from building blocks called “amino acids” linked together in a chain. Unlike other plant proteins, soy protein is considered a “complete” protein because it contains all 9 essential amino acids in the right balance for your body’s needs. This makes soy protein a great substitute for meats high in saturated fat and cholesterol. Unless specifically removed, soy isoflavones remain a part of soy protein and soy food products.
So why can’t I just take soy vitamins?
The isoflavones found in many soy vitamins have been shown to be responsible for some of the benefits of soy consumption. However, by themselves, soy vitamins do not provide the full benefits you can obtain from eating soy foods that contain both soy protein and soy isoflavones. For example, while purified isoflavones can help with common menopausal discomforts like hot flashes and night sweats, only the protein has received an FDA-approved heart health claim. Therefore, soy protein combined with soy isoflavones is believed to produce broader health support benefits compared to just soy vitamins. Why limit the benefits you can obtain from soy by choosing soy vitamins when you can choose soy foods that contain both the protein and the isoflavones?