Previously, a number of studies have demonstrated that soy protein reduces low-density lipoprotein (LDL, "bad") cholesterol and increases high-density lipoprotein (HDL, "good") cholesterol, providing evidence for beneficial effects exerted for heart health and cholesterol profile. Elaine Krul and colleagues completed a randomized, controlled three-phase crossover trial involving 352 American adults with serum total cholesterol level of <240 mg/dl, conducted for a five-year period. Study subjects were assigned to 40 g/day supplementation of soy protein, milk protein or complex carbohydrate for 8 weeks in random order. The team observed a total cholesterol reduction as well as the total/HDL cholesterol ratio reduction that was statistically significant with soy protein supplementation compared with carbohydrate. Compared with milk protein, soy protein supplementation significantly increased HDL and significantly reduced total/HDL cholesterol ratio as well as lowered LDL cholesterol.  Observing that: “Compared with carbohydrate, soy protein supplementation was significantly associated with a net change in total cholesterol and total/HDL cholesterol ratio of −3.97 mg/dl and −0.12 mg/dl, respectively,” the researchers conclude that: “ Soy protein … supplementation improves the lipid profile among healthy individuals.”