How healthy are Soybeans?

Introduction

Soy is a basic food ingredient of traditional Asian diet used for thousands of years. They were introduced about a hundred years ago in Western countries. Soy foods are common nutritional solutions for vegetarians, due to their high-quality protein content and healthful fat.(1)

Soy is arguably one of the most controversial nutrition topics. It is a unique food that is widely studied for its estrogenic and anti-estrogenic effects on the body. Studies may seem to present conflicting conclusions about soy, but this is largely due to the wide variation in how soy is studied.(2)

Soy is exalted as rich in nutrients and a healthy food by some people, which is linked to health benefits, including lower blood sugar levels, improved heart health, fewer menopause symptoms, and protecting against certain cancers (prostate and breast).

On the other hand, soy is shunned by the others for the fear that it may cause breast cancer, hinder thyroid function or have feminizing effects on men, dementia, though these claims have not been substantiated.

Whether published in a popular press article or a well designed clinical study, some debate about soy remains.(2)

What are the health benefits of soy?

The popularity of soy foods has made soybean a highly consumed ingredient. Its popularity is not just for the taste but also for the amazing health benefits that it offers. There are a number of health benefits of soybeans and it helps us cure and prevent a number of health issues including skin and hair.

Health benefits eating of Soybeans are:-

Aids weight loss

Several studies have found that soybean incorporates anti-obesity effects. One 2019 study, in the journal Molecules the researchers conclude that soy isoflavone supplementation has potential for managing obesity. Still, more research is needed on soy’s effects on weight.(3)

High protein content of soybean develops lean muscle mass. Also protein is associated with appetite suppression that helps eliminate overeating, which can lead to obesity and other related risks. This is because protein helps reduce ghrelin levels, also known as “hunger hormone”.(4,5)

Soy foods have low glycemic index this means that they won’t cause rapid blood sugar spikes like high glycemic index foods. This might lead to fewer hunger cravings and better appetite control.

An adequate amount of protein in the diet ensures the system metabolic activities to work well and enhances overall well being. Soy isoflavone supplementation also provides additional benefits for fat metabolism and weight loss.

The healthy amount of fiber present in soybeans can actually help in keeping you satiated for a longer duration of time, which further promotes weight loss.(6)

Summary

The high protein, fiber and isoflavone content of soybean may aid weight loss.

Helps Lower Cholesterol levels

Soybeans have been shown to lower total cholesterol and LDL (bad) cholesterol levels both are known as risk factors of heart disease.

In 2015, researchers conducted an analysis of studies on effects of soy on cholesterol levels. They suggest that including soy in the diet can significantly reduce the levels of total blood cholesterol, triglycerides, LDL (bad) cholesterol while moderately increasing HDL (good) cholesterol levels in the arteries.(3)

The US FDA found that including 25 gm/day soy protein in a diet low in saturated fat and cholesterol can reduce LDL cholesterol by about 3-4%.(1)

Whole soy products (such as soymilk, soybeans and soy nuts) have a greater effect on improving cholesterol levels than processed soy products.

Summary

Soy protein supplementation modestly reduces LDL(bad) cholesterol. As per American Heart Association (AHA), “it is prudent to recommend including soy protein foods in a diet low in saturated fat and cholesterol to promote heart health”. Today, the FDA is reconsidering its authorized health claim. (7)

Protect heart health

Soybeans are a good source of healthy unsaturated fats (2 gms MUFA and 5.06 gms PUFA in per 100gm) which lowers the levels of cholesterol in the body. High LDL (bad) cholesterol may lead to conditions like coronary heart disease and atherosclerosis which further leads to stroke and heart attack.

It appears that soy isoflavones may help reduce inflammation in blood vessels and improve their elasticity are the two main factors which protect the health of your heart.

Consuming soybean can boost your cardiovascular system by reducing the bad cholesterol levels along with taking care of your brain and vision.(5)

A meta analysis of 17 observational studies suggests that eating more soy foods is associated with a significantly lower risk of cardiovascular disease (-17%), stroke (-18%) and coronary heart disease (-17%).

Although the meta analysis found associations between heart health and soy intake, it did not find anything between heart health and soy-protein intake or soy-isoflavone intake. (7)

Summary

No interventions have determined the effects of soy food consumption or soy isoflavone supplementation on heart disease. As per the meta-analysis of observational studies, soy consumption may reduce the risk of heart disease.

Helps manage Diabetes (type 2)

Soybean could be an excellent food choice for people suffering from diabetes as it can help manage levels of blood sugar in the body due to the presence of a compound called isoflavones.

It has been proven by multiple studies that soy isoflavones exert anti-diabetic effects as they target specific molecules that are responsible for glucose uptake. As per 2019 review of studies, soy isoflavones may reduce the risk of diabetes, though the mechanism through which they may achieve this is still unknown.(3)

Soy isoflavones may also increase insulin sensitivity which helps improve bodies’ tolerance for blood sugar levels.(3)

Diabetes is not a disease that messes with just one part or organ of your body. It also affects your cardiovascular health and your liver since the pressure is majorly on the pancreas. That’s where soy comes to your rescue.

Soybean provides diabetics with some essential nutrients and vitamins that they miss out on due to cutting out various foods from their diet.

Summary

Several studies have failed to find a strong link between soy foods and blood sugar control in healthy people and those with type 2 diabetes. Therefore, before making strong conclusions more studies are needed.(2)

Bone health

Consumption of soy products may reduce the risk of osteoporosis in women who have undergone menopause. This is a condition that affects bone growth and leads to easy fractures.(3)

When the estrogen level declines after menopause, women can lose substantial amounts of bone mass in the decade following menopause, which increases their fracture risk.(1)

The benefit is due to the isoflavone compound present in the soybean.

Soy isoflavone may also be an effective alternative to hormone replacement therapy.(3)

Due to the variety of vitamins and minerals content of soybean, such as iron, calcium, magnesium, folate, thiamine, etc. can help in promoting osteotropic activity, allowing the new bones to grow, making the existing ones stronger and healthy.

Summary

Soybeans are the legumes which cuts the risk of osteoporosis in postmenopausal women. Soy isoflavones may be an effective alternative to hormone replacement therapy (HRT) for women with osteoporosis.(3)

Alleviation of menopausal symptoms

Menopause is the period in a woman’s life when menstruation stops. Menopausal symptoms like hot flashes, abdominal cramps, hunger pains, mood swings, etc. are brought about by a reduction in estrogen levels.(9)

In a systematic review and meta-analysis of all randomized, controlled trials of isoflavone supplementation, study indicates that including soybean in your diet can help in relieving menopausal symptoms.(8, 9)

Isoflavones bind the estrogen receptors in a way that your body doesn’t feel the change.

There are several studies like the 2015 Analysis that found soybean reduces hot flashes among postmenopausal women by 11%.

An observation was made on women in some parts of Asia, who tend to have soy-rich diets and typically fewer hot flushes during menopause as compared to women on meat-rich diets. This is due to phytoestrogen content of soy which reduces menopausal symptoms (such as hot flushes).(10)

Soy products do not affect all women. They are effective to equol producers (a type of gut bacteria) which is able to convert isoflavones into equol.

Consumption of isoflavones 135mg/day for a week is equivalent to 2.4 ounces (68 grams) of soybeans per day reduced menopausal symptoms only in equol producers.(9)

Summary

More research is needed, but soybeans may help women manage menopausal hot flushes, only if taken modestly.(10)

Conclusion

Although soy foods have been part of the traditional Asian diet for thousands of years, they have become increasingly popular in non-Asian countries too. In recent times, soy foods and soy protein powders are familiar to people’s diets around the world.(7)

Soy is rich in isoflavones which are changed in the body to phytoestrogens. Phytoestrogen molecules are similar in chemical structure to the hormone estrogen. In some cases, these phytoestrogens can mimic the effects of estrogen, while in other cases, they can block the effects of estrogen.(11)

As soy is very popular and has possible health effects (many of which are attributed to its isoflavone content) soy has been the subject of various studies that are often financed by the soy industry.

References:-

Introduction