Eating Tofu: Fighting Heart Disease

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Eating Tofu: Fighting Heart Disease

A number of research studies have demonstrated the beneficial effects of eating soy protein on serum lipoprotein levels. However, little research has investigated the relationship between soy and other coronary heart disease factors. Some soy products, including tofu, contain phytochemicals, which have estrogen-like properties and are sometimes called phytoestrogens.

The effect of soy phytoestrogens on LDL oxidation may be through their ability to act as free radical scavengers. This dietary intervention study was designed to compare the effect of tofu, a soy product, to meat on serum lipids, lipoprotein, hemostatic factors, and the susceptibility of LDL to a particular kind of oxidation.

Forty-five healthy males, aged 34 to 62 years, with no symptoms or prior diagnosis of coronary heart disease followed two diets for one month each, with a two-week "washout" period in between. Diets were designed to be similar in energy, protein, fat, carbohydrate, and alcohol and dietary fiber, with only the source of protein changing from an animal source to a plant source. During the meat diet, subjects consumed 150 grams of cooked lean red meat, with all visible fat removed. The tofu diet was designed to replace 90 to 100% of the animal protein with 290 grams of tofu.

Individuals who replaced lean meat with tofu cut their risk of heart disease by reducing levels of cholesterol and other fatty substances in the blood, and slowing the rate at which LDL cholesterol is oxidized. Other studies have shown that patients with heart disease have higher levels of oxidized LDL in their blood. In the tofu group, total cholesterol and triglycerides were significantly lower, and the LDL oxidation lag phase was significantly longer on the tofu diet compared to the meat diet.

Conclusion: the replacement of lean meat with the same amount of protein as tofu beneficially alters a number of coronary heart disease factors. Estrogens, including plant-based forms of the hormone known as phytoestrogens found in soy products such as tofu, may lower a person's susceptibility to LDL oxidation. These compounds contain antioxidants that are thought to prevent cholesterol from oxidation.

Ashton EL, Dalais FS, Ball MJ. Effect of meat replacement by tofu on CHD risk factors including copper induced LDL oxidation. Journal of the American College of Nutrition 2000:19(6), pp. 761-767.