Soya and Cholesterol - Ruchihealth.com

How Does Soya Lower Cholesterol?

     The exact mechanism of soya's ability to lower blood cholesterol is not fully known, but that is not unusual in science, as you no doubt know. We can postulate any number of reasons for soya's protective action, including the fact that its isoflavone content makes it an effective antioxidant, meaning that it protects the walls of the arteries from damage by free radicals.
     Other nutrients are also known to have similar effects. Vitamin E, for example is also considered effective against plaque build-up and hence, reduces the risk of heart attack. Once scoffed at, Vitamin E in now part of the treatment protocol for patients following by-pass surgery. Vitamin C, another antioxidant, is also linked with reduced risk of heart disease.
      We can also examine the amino acid composition of soya protein. Increases of arginine and glycine are associated with decreases in serum cholesterol; soya protein is rich in both arginine and glycine. In addition, animal protein is proportionately lower in these amino acids, but is higher in lysine, which raises insulin levels and promotes cholesterol synthesis--or production--in the liver.
       Estrogen, an important reproductive hormone, is believed to have a protective mechanism for heart disease, which is one of the reasons women are urged to take estrogen during and following menopause. The plant estrogens found in soyabeans may offer similar benefits. These are "weak" estrogens, meaning they do not have the potential to stimulate hormonally dependent cancers, but they may be one key to soya's protective effect on the heart. Studies involving monkeys have shown that soya isoflavones account for up to 75 percent of soya's ability to lower cholesterol in the blood. (Note) If soya protein that lacks isoflavones is fed to primates, cholesterol counts remain unchanged. However, when soya protein that contains isoflavones is given, then blood cholesterol is reduced. Monkeys are the closest animal models to humans, so these important data should be considered relevant when evaluating the research that again and again, confirms the value of adding soya isoflavones to the diet.
     Soyabeans also contain lecithin, which has been touted as a cholesterol-lowering agent. However, large amounts of lecithin are required to reduce cholesterol, making it an impractical treatment. The presence of lecithin in soyabeans is advantageous, but apparently not critical to the ability of soya to promote healthful cholesterol levels.
      Fiber is also an important part of a dietary approach to lowering blood cholesterol. The fiber in soyabeans can play a role, but it is one that other sources of fiber share. Bran, oats, and other grains are helpful in this regard, as long as they are not overly refined. In other words, while the fiber found in soyabeans has potential health benefits, they do not comprise a significant reason to include soya in the diet because other plants can supply fiber. The many other health benefits of soya overshadow the fiber issue.
     Saponins found in soya products may also act to lower blood cholesterol. Saponins bear a chemical similarity to cholesterol and may either block the absorption of cholesterol or enhance its excretion. In some countries whose populations have reduced their consumption of vegetables containing saponins, a coincidental increase of the prevalence of heart disease has been noted. I use the word "coincidental" because the link between the two trends has not been established, nor have the beneficial effects of saponins on cholesterol status been universally confirmed.

Soya has a role to Play....

    The lifestyle risk factors for high blood pressure are similar to those for coronary artery disease and other conditions as well. In addition, hypertension is itself a risk factor for developing cardiovascular diseases, so prevention for both conditions tends to include similar recommendations. While a soya-based diet cannot eliminate risk factors such as smoking or a sedentary lifestyle, it can offer beneficial dietary modifications that promote cardiovascular health. In addition, vegetarians tend to have lower blood pressure than those who use animal protein as the mainstay of their diets. This fact alone should offer important clues about prevention and treatment of hypertension.
   The amino acid content of soya protein is considered key in its ability to control blood pressure, and this appears to be related to calcium conservation. Soya protein, with its lower content of sulphur-containing amino acids, leads to greater excretion of salt and less loss of calcium through the kidneys. Calcium, a mineral whose value in building and maintaining the health of the bones and teeth is well known, appears to play a role in regulating blood pressure. Several studies have demonstrated that supplementing the diet with calcium results in small but significant reductions in blood pressure in those with mild to moderate disease. (note) Calcium supplements may also aid in reducing blood cholesterol and triglycerides.
    Japanese researchers have shown that fermented soya foods, such as nato and miso, contain anti-hypertensive peptides (chains of amino acids occurring in a specific sequence) that appear to interfere with an enzyme (angiotensin-converting enzyme) that promotes a chemical (angiotensin), which in turn, elevates blood pressure. (note) What is remarkable about this is that many of the medications used in standard medical practice attempt to block the same enzyme. We may not need to look to synthetic drugs when nature has provided a substance critical to blood pressure regulation in the form of soya.

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