The Joys of Soy
Take advantage of this laudable legume’s heart-smart powers.
Tofu, miso, edamame, soy sauce, soy milk, tempeh, soy protein shakes...few plants can match soy’s widespread dietary influence. Historical references indicate that soy has been cultivated since 1100 BC, but its emergence as a food superstar in the United States is as recent as the last two decades.
The average American consumes less than 5 grams of soy each day, and this is after the surge that brought soy sales from $852 million in 1992 to $3.7 billion in 2002. In Japan, however, the average soy intake is 55g per day, which may in part account for the fact that Japan’s cardiovascular mortality rates are half those of the US. Although evidence has linked soy to anti-cancer, bone-building and menopause-mitigating properties, this little legume’s main claim to fame is its ability to support heart health.
Researchers have attributed soy’s heart-healthy benefits to its singular complex of isoflavones, which are phytoestrogens—plant compounds that act like estrogen in the body. Soy’s protein content further sets it apart—unlike other plants, soy contains “complete” protein, possessing all the necessary amino acids to promote growth and development.
In a hallmark study published in the New England Journal of Medicine in 1995, soy was shown to reduce the risk of heart disease. The study, which analyzed 38 different clinical studies, concluded that soy protein consumption may help lower total cholesterol and LDL (bad) cholesterol when compared with animal protein consumption. The Food and Drug Administration (FDA), which is notoriously strict in allowing claims, approved a breakthrough heart-health statement: “25g of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.”
Since the FDA’s approval, research has only continued to verify soy’s cardiac benefits. A 2006 study in the American Journal of Cardiology analyzed 41 randomized, controlled soy protein supplement trials. Such supplementation was found to be associated with a significant reduction in total cholesterol, LDL cholesterol and triglycerides (blood fats). In the same year, the journal Nutrition found that 27 postmenopausal women following a 12-week, low-glycemic diet—combined with daily intake of 30g of soy protein and 4g of phytosterols—experienced a significant reduction in heart disease risk.
In 2004, a study in the Journal of the National Medical Association focused on soy’s potential in treating the obesity, hypertension, high triglycerides, decreased HDL (good) cholesterol and insulin resistance of metabolic syndrome, a precursor to cardiovascular woes. The study urged recognition of soy as a major factor in preventing this disorder because soy is an abundant source of soluble fiber, phytoestrogens and vegetable protein—while remaining virtually free of saturated fat.
Your Soy Target
Whether you aim for the FDA’s 25g-a-day soy target, or pursue the loftier 55g-a-day Japanese standard, soy sources abound. Health food shoppers have gravitated to soy protein shakes and bars for their convenience and high soy content. Thanks to an ever-increasing variety of flavors, bland soy supplementation can now provide taste satisfaction, making the daily soy target even easier to reach. To really optimize cardioprotective benefits, use soy products to replace high saturated fat foods, and find a reputable source—low-quality products can lose soy’s valuable nutrients during processing.
Trying to keep your heart happy? Then it’s time to discover the many joys of soy.