April is designated as National Soy Month. Many questions surround whether soy is a health benefit or a health harm. Many healthy foods have been thrown under the bus for containing anti-nutrients. Anti-nutrients are compounds found naturally in many plant-based foods. They can theoretically affect the body's absorption of other nutrients. Many "experts" recommend avoiding all foods containing these compounds - including soy.
It is true anti-nutrients have had negative effects in lab and animal studies. But shouldn't the focus be directed to whether anti-nutrients are a human problem in foods as they're typically prepared and eaten?
Phylates or phytic acid has anti-inflammatory and antioxidant properties. Research indicates phylates may help prevent CVD and some forms of cancer: colon, liver, lung, breast, skin and prostate cancers. How? Phytic acid reduces proliferation of cancer cells. Phylates may contribute to cancer cells reverting to normal cells. Keep in mind phylates are primarily is found in high-fiber foods. Thus, the reason why high-fiber diets are associated with lower cancer risk. The benefits don't stop there!
Reducing starch digestion, lowering the glycemic index of foods, and positive effects on blood sugar control are also part of phylate power. In the liver, they inhibit the enzymes involved with triglyceride production. Research shows phylates may also block calcium salt crystals responsible for kidney stones. While fermenting and sprouting reduce phylates in foods, most people degrade 37-66 percent during digestion in the stomach and small intestine. Between cooking and digestion, most people are able to process phylates for the health benefits.
Lectins. Very little research backs up claims against lectins. Lectins are almost entirely destroyed by heat. Moist heat is the most effective. Unless you are eating raw beans or soy, lectin levels are not of concern. Because humans rarely eat soy or legumes without previous heat treatments, protease inhibitors are not significant problem either. Unlike with lectins, dry heat - roasting/toasting - deactivates protease inhibitors. On a more positive note, BBI (common protease inhibitor) has anti-inflammatory, antimicrobial and immunity properties. BBI in soy beans suppresses genes potential to cancer development. It also helps IBS and various autoimmune diseases.
Saponins. While the internet tauts negative properties of saponins, again cooked vs. raw comes into play. In fact, saponins have antioxidant, immune-modulating, anti-carcinogenic, anti-inflammatory and antimicrobial properties. They may have cardiovascular benefit linked to cholesterol-lowering mechanisms. Also, the anti-thrombotic effects reduce blood platelets and fibrinogen levels (reducing clot risks). Additionally, saponins improve insulin resistance. Furthermore, they downgrade formation of fat cells.
Oxalates are found in all flowering plants. For soy, the choices of soy milk, tofu and soy sauce have the lowest levels of oxalates. Is there reason for concern with other soy foods? This depends on the frequency eaten and combination with other foods. Oxalates can impair calcium absorption from leafy greens. Answer? Choose food combinations that avoid the potential impairment.
Bottom line. Soy and other foods containing anti-nutrients are staples in the healthiest populations in the world. Human research clearly shows multiple health benefits when these foods are prepared in a proper manner to avoid any potential negative effects!
Dr. Dianna Richardson has been serving Jefferson City and the surrounding communities for over 22 years. She has worked in the field of health and nutrition as a wellness practitioner for over 30 years. Core to her practice remains use of nutrition to improve health, vitality and quality of life. Richardson holds a doctorate in naturopathy, along with degrees in nutrition and a master's degree in public health education. She may be found at the Health, Wellness & Nutrition Center, LLC on Dix Road in Jefferson City.
SWEET AND SOUR TOFU
1416 ounces firm or extra firm tofu (drained for at least 15 minutes, cut into triangles, slices, or cubes, about 1/2-inch thick)
1 large carrot (peeled and cut on diagonal)
1/2 onion (peeled and sliced)
1/2 red bell pepper (cut into chunks)
1/2 green bell pepper (cut into chunks)
1 teaspoon garlic (minced)
1/2 teaspoon ginger (minced)
For the Sweet and Sour Sauce:
3/4 cup pineapple juice
4 tablespoons rice vinegar (also called white rice vinegar)
3 1/2 tablespoons brown sugar
1 tablespoon cornstarch (mixed with 4 tablespoons water)
2 tablespoons oil for stir-frying
1 cup pineapple chunks
While the tofu is draining, prepare the vegetables (carrot, onion, and bell peppers) and aromatics (ginger and garlic).
Blanch the carrot in boiling water for 4 minutes; then cool quickly in cold water bath (to stop cooking process). Drain thoroughly and pat dry with paper towels.
Prepare the sweet and sour sauce. Combine the sauce ingredients (the pineapple juice, rice vinegar, brown sugar, and cornstarch/water mixture), in a bowl, stirring in the cornstarch/water slurry last. Set near the stove.
Dry-fry (non-stick skillet with no oil) drained & sliced tofu. Set aside.
Heat 2 tablespoons oil in a pre-heated wok or skillet, swirling the oil so it coats the sides. When the oil is hot, add the ginger and garlic. Stir for a few seconds until aromatic, then add the onion. Stir briefly, then add the carrots and the green bell peppers. Stir-fry for a minute and add the red bell peppers. Stir-fry for about another minute.
Give the sauce a quick re-stir, then add into the skillet, turning up the heat if needed. When the sauce thickens, stir in the tofu and the pineapple chunks. Cook for about 2 more minutes to heat through. Serve hot over rice.