Health Benefits Of Edamame

What are edamame beans?

Edamame beans are soybeans that are harvested before the plant has matured. Because of this, they are light green in colour instead of the light beige or brown colour of mature soybeans. 

Edamame have long been consumed in Asia, but they have grown in popularity in Western countries, and you can now find them in most grocery stores. This is partly due to the increased popularity of vegetarian and vegan diets, as edamame and soybeans are a complete protein source.¹ This means that soybeans contain all the essential amino acids that your body cannot make and so need to be obtained from your diet.   

Edamame are typically sold in their pods, which are usually not eaten, but you can also purchase them ‘shelled.’ The immature soybeans inside provide an abundance of nutrients and bioactive compounds that have been suggested to prevent diseases such as cancer, diabetes, and osteoporosis.² This is largely attributed to the presence of isoflavones, a bioactive compound that plants may synthesise in response to certain environmental stressors such as a lack of water or nutrients.² Isoflavones resemble the female sex hormone, oestrogen, and can weakly bind to this hormone’s receptors in the body, having an effect on our biology and health.^3,4 

Keep reading below to find out the different health benefits edamame can have, their nutritional value, and their potential side effects. 

Health benefits of edamame

Edamame have been suggested to have a number of health benefits. Importantly, this is based on research that has been done on soybeans or soy-based nutrients rather than edamame directly. Nevertheless, the evidence strongly suggests that edamame are beneficial for a number of conditions, which you can read more about below. 

Helps in maintaining a healthy weight

Edamame beans can be a great addition to your diet to help maintain a healthy weight. In a 100g portion of cooked edamame beans, there are approximately 121 calories, with nearly 12g of protein and 5.2g of fibre. The high protein helps you to feel full for a longer period of time because protein is slower to digest. Dietary fibre has a similar effect as it slows down gastric emptying. 

The abundance of vitamins, minerals and other nutrients that edamame provides also means that they can help to support your health and meet the recommended daily intakes, even if you are eating in a calorie deficit.

Studies in both animals and humans have supported the consumption of soybeans and their nutrients for weight loss. For example, soy isoflavones have been shown to decrease body weight and visceral fat in overweight rodents, which parallels epidemiological studies that have found that consuming more than two servings of soy-based foods (like edamame) is associated with a lower BMI.⁴

Lowers the risk of heart disease

Heart disease, or cardiovascular disease, describes conditions that affect the heart and blood vessels. Edamame and its associated nutrients have been suggested to help protect against heart disease. Several mechanisms have been suggested that are driven by the nutrients edamame provide, including protein, fibre, isoflavones, and polyunsaturated fats.⁵

A main cause of heart disease is atherosclerosis, the build-up of plaque on artery walls that can cause them to become blocked. A key risk factor of atherosclerosis is high blood cholesterol. Soy protein has been shown to directly lower blood cholesterol levels, particularly the ‘bad’ cholesterol (LDL cholesterol) that is largely responsible for atherosclerosis.³ 

It has been suggested that 25g of soy protein a day is sufficient to have this protective effect, reducing LDL cholesterol levels by 4.3%.³ Soy isoflavones are also thought to lower cholesterol levels by preventing cholesterol absorption in your digestive system and have been shown to help slow the progression of atherosclerosis.^3,4 

Boosts bone health

Bone health is an important issue, particularly as we get older. During the ageing process, our bone mineral density reduces, making fractures and breaks more likely. This is worsened during menopause because the associated decrease in oestrogen has been linked to declines in bone density.³ Soy isoflavones have a similar structure to the hormone, oestrogen. This means they are able to bind to oestrogen receptors and mimic the hormone, albeit less successfully than the hormone itself. This is thought to help prevent declines in bone density during menopause and in ageing. A meta-analysis concluded that post-menopausal people who had been given a soy isoflavone supplementation had higher bone mineral density than those given a placebo.⁴ Other studies have also shown that soy and its nutrients have an effect on molecules associated with bone health, such as IGF-1.¹ The calcium and protein in edamame are also suggested to help support bone health and prevent osteoporosis.⁵

May reduce the risk of certain cancers

While there are some conflicting opinions about whether soy is protective against cancer, mainly due to soy isoflavones mimicking oestrogen in the body, most of the evidence supports its anti-cancer effect. This is largely attributed to the soy isoflavones, which may help to control the processes of cell division, signalling, differentiation, and cell death, all of which can contribute to both cancer formation and the development of tumours if they become uncontrolled.⁴ An inverse association between soy isoflavone intake and cancer risk has been reported with regard to breast, prostate, colorectal, endometrial, lung, and stomach cancers.⁵ 

An important suggestion for protection against breast cancer is that consumption of soy products may be required during adolescence, with even just one serving per day being sufficient.³ While these studies suggest an anti-cancer effect, they are only observational studies, so a causal relationship has yet to be investigated. 

Alleviates menopause symptoms 

Menopause describes the end of menstrual cycles resulting from a natural decrease in hormone levels that occurs with age. Many of the symptoms that cause discomfort, including hot flashes, sweating, and changes in mood are caused by a decrease in oestrogen levels. Soy isoflavones, which are structurally similar to oestrogen and able to weakly bind to oestrogen receptors, are thought to help alleviate these symptoms.³ This is thought to explain the observed difference in the severity of menopause symptoms between women in Asia compared to Western cultures, where soybeans and soy-related products are far less common. 

Menopause is also associated with declines in bone mineral density. As previously mentioned, edamame and soy-based nutrients can help to maintain bone health and bone mineral density, helping to prevent diseases like osteoporosis.⁴

It has been suggested that these benefits from soy-based nutrients are dependent on an individual’s gut microbiome.⁶ Specifically, only people with strains of bacteria that are able to convert soy isoflavones into a compound called equol are thought to benefit, which are less common in Western populations.⁶

Helps in managing and preventing diabetes 

Diabetes is a metabolic condition that causes an individual’s blood sugar levels to become too high. It can be classified as type 1 or type 2, depending on whether it is a lifelong condition (type 1) or preventable (type 2). It is generally recommended that for both types of diabetes, individuals consume food classified as ‘low GI’, meaning they do not cause a sudden spike in blood sugar levels. Edamame beans have a low glycaemic index (GI) due to their high fibre, high protein, and low carbohydrate content. 

There is also some evidence that soy isoflavones can increase insulin secretion, further helping to control blood sugar levels.⁴ This makes them an ideal food for individuals with diabetes or at risk of developing the condition. There is also evidence that soy isoflavones have an antioxidant effect on the body, which is also thought to help prevent and manage diabetes.⁵

Nutritional facts

The table below outlines the nutritional values found in 100g of prepared edamame beans. Notably, compared to mature soybeans, edamame provide more vitamin K and folate than the more mature form of the legume.

Uses of edamame

Edamame are usually sold in the frozen section of the supermarket, still in their ‘pod.’ However, you can also buy them ‘shelled.’ Traditionally, edamame are prepared by blanching them in salted boiling water and eaten by squeezing the beans out of the pod, which is then discarded. Eating them by themselves in this way is a great snack that you can add to your diet. Alternatively, there are endless recipes you can try out that use edamame, or you could try to replace another legume in a recipe with edamame. 

Side effects and other concerns

You might have been warned not to consume too much soy for various reasons, but research has shown little to no negative side effects of consuming soy as part of a healthy and balanced diet. 

For example, concerns have been raised over whether the oestrogen-like effects of soy isoflavones cause issues in development, fertility, and reproduction for both men and women. However, a review paper concluded that studies in this field have shown at most a minimal change in hormone levels from consuming soy products, with most finding no changes at all.²

There are also concerns about the effects of soy and soy-based products on thyroid function and thyroid hormones, but this has yet to be supported by research.⁸ Nevertheless, it has been recommended that hypothyroid patients undergoing thyroid hormone replacement therapy should not consume soy close to when they take their medication to ensure it does not interfere with the pharmaceuticals.⁵ 

Individuals with a soy allergy should also avoid edamame and other soy-based products. 

Summary

Edamame are the immature form of soybeans. While traditionally consumed in most Asian countries, they have become increasingly popular in the West. 

Soy-based foods and nutrients have been shown to provide a number of health benefits regarding weight management, bone health, heart health, cancer, menopause, and even diabetes. These health benefits are largely attributed to soy isoflavones, and edamame and soybeans are the richest sources of these bioactive compounds.² 

While you may have heard warnings about consuming too much soy in your diet, research has yet to find any solid evidence of soy-based foods having any negative effects on our health. 

With the nutrients and potential health benefits they bring, it’s worth considering adding edamame beans to your diet. They could be your new favourite snack! 

Alexandra Cullen

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