Soy: A Purely Nutritional Perspective
Considering the rich history and heritage of soy, it’s a disproportionately controversial little bean. We recently published an article outlining a few of the ins and out of soy, including how to get more of it into your diet.
But when it comes to the nutritional value of soy, it remains a subject of heavy debate. On one side of the argument, you have those who claim soy is the ultimate wonder-food and should be celebrated. Elsewhere, others are convinced it does more harm than good, and should therefore be avoided at all costs.
Either way, soybeans have played an important role in the cuisines of many cultures for more than 10,000 years. Extensive research has shown how the humble soybean is loaded with B vitamins, fibre, potassium, magnesium, high-quality protein, and certain phytonutrients.
Even so, there’s a ton of hearsay with regard to whether you should eat it, how much of it you should it eat and if you should avoid it entirely. Hence, we thought it prudent to take a second look at the whole soy debate - this time from a purely nutritional perspective.
What Does Science Say About Soy?
Starting off with a brief summary, there are several important things scientific research has taught us about soy. Each of the following is a fact and is absolutely not up for debate:
- Soy is one of the only complete sources of protein from a plant-based ingredient, which makes it an excellent like-for-like alternative to animal proteins.
- The phytonutrients contained in soy have strong associations with numerous long-term health benefits.
- Fibre is one of the most important contributors to a healthy gastrointestinal system, which soybeans are naturally loaded with.
- The consumption of soy has been associated with interference with certain physiological processes, but this is neither a cause for concern nor is it rare when consuming a plant-based diet.
- The isoflavones in soy have also been linked with a long list of potential health benefits, when consumed in moderate quantities. However, some experts recommend that elevated isoflavones intake (more than 150 mg per day) should be avoided by menopausal and post-menopausal women.
- Comparatively few people are genuinely allergic to soy, but it is also possible to have a mild and/or undiagnosed soy sensitivity. Only your doctor or nutritionist can advise you on whether you should cut out soy entirely, or carefully control your intake.
- Most research into the potential negative effects of soy is based on a daily consumption levels that go beyond those recommended by nutritionists or doctors. Scientific evidence clearly indicates that quality soy products can be consumed confidently in moderation as part of a healthy diet.
- Soy foods and products differ radically in terms of nutritional value and general composition. Just because something contains soy does not mean it is healthy. Soy is often the base ingredient for countless vegan, vegetarian and gluten-free junk foods.
Emphasising an important point from the above, it is ultimately down to your doctor to decide whether soy is a good choice for you. If you have any questions or concerns regarding your tolerance of soy or its potential health benefits, book a consultation with a qualified professional.
What Are Phytonutrients?
Increasingly, phytonutrients have been attracting the attention of the scientific community as of late. Phytonutrients are naturally occurring compounds in plants, which provide them with protection from the environment around them.
While phytonutrients are not strictly necessary to sustain human life, research suggests that they may be beneficial to human health in many ways. Phytonutrients are responsible for giving fruits and vegetables their different colours, which is why it is often recommended to ‘eat the rainbow’ as part of a balanced diet.
Isoflavones are a group of phytonutrients, which as outlined above are present in generous quantities in soybeans.
Does Soy Contain Oestrogen?
This is perhaps the biggest point of contention when it comes to the potential benefits (or otherwise) of soy. For some time, it’s been theorised by some that soy either contains oestrogen or can influence the way the body produces and managers oestrogen levels.
In truth, soy contains two primary soy isoflavones - genistein and daidzein - which have the potential to bind with estrogenic receptors in the body. However, no extensive scientific study to date has brought to life any evidence to suggest that the consumption of soy has an adverse effect on any human hormone level - oestrogen included.
The only studies that have been conducted into the supposed phenomenon have found no such links whatsoever. What’s more, there’s a long list of other foods and ingredients that contain phytoestrogens, though for some reason don’t face the same controversy or scrutiny as soy.
Is Soy Safe For Men?
The fact that there are phytoestrogens in soy is the main concern for men who consider bringing it into their diets. Though again, all major studies conducted to date indicate no adverse effects whatsoever on testosterone production in men who consume moderate quantities of soy.
One of the biggest studies into the effects of soy on men was conducted in 2010, which took into account the effects of soy foods, soy protein powders, isoflavone supplements and other products. The results showed no adverse effects on testosterone whatsoever, while a second study suggested that soy could be beneficial in the maintenance of prostate health.
In addition, soy products have been consumed in vast quantities by billions of Asian males for countless generations. Logically speaking, therefore, any adverse effects soy could potentially have on male health would have been evident by now.
Though again, anyone concerned about soy with regard to their own health and wellbeing should consult with a qualified physician.
Can Soy Cause Allergies?
The short answer is yes - it is perfectly possible to be allergic to soy. It’s also possible to have a mild intolerance to soy and soy products, which could go undiagnosed indefinitely.
Research suggests that soy allergies are comparatively rare, and that those affected tend to experience much milder symptoms than what is typical with other food allergies. Research suggests that most allergies to soy are detected in children under the age of four - around 0.2% to 0.4% of children may be diagnosed with a soy allergy.
However, up to 90% of children with soy allergies outgrow them by the time they reach the age of four. Among the adult population, this suggests that true soy allergies affect less than one in every 1000 adults.
Symptoms of soy allergies can be mild or severe in nature, though should never be overlooked or ignored. If you suspect you may have an allergy or intolerance to any ingredient, it is essential to bring it to the attention of your doctor as a matter of urgency.
Is All Soy Genetically Modified?
GMO soy is more widely associated with adverse health benefits than organic soy. In the United States, the overwhelming majority of soy products are genetically modified. Something that has escalated the controversy surrounding soy in general, which has subsequently become the most widely genetically modified crop worldwide.
Thankfully, steering clear of GMO soy is fairly simple in the UK. Most soy products produced here are non-GMO in nature, and those that are GMO are clearly labelled as such. If you’d prefer to keep genetically modified organisms out of your diet, always look for the non-GMO label when shopping for anything - not just soy products.
What are the Benefits of Soy?
Rounding things off, the benefits of soy are numerous and diverse. Soy has been a staple ingredient in Asian culture for thousands of years, with countries like Japan being known for its world-leading life expectancy.
More people in Japan live well into their hundreds than anywhere else in the world, which some attribute to traditional Asian eating habits.
Of course, long life expectancy isn’t something that can be attributed directly to soy. Nevertheless, more than 14,000 papers have to date been published on soy (referenced in PubMed). Among which, none have drawn direct or conclusive links between moderate soy consumption and adverse effects on human health.
In fact, it’s quite the contrary. Soy is a complete protein, packed with nutrients, fibre and other beneficial compounds. It has been associated with a reduced risk of certain diseases, improved immune system function and more efficient energy production.
Likewise, those who consume soy as an alternative to meat are statistically more likely to eat a healthier and more balanced diet than their counterparts. Soy production also has an exponentially lower impact on the environment than meat and dairy production.
Ultimately, soy has the potential to form part of a healthy balanced diet for men and women of all ages. But just as is the case with all foods, it’s important to discuss any questions or concerns you have with your doctor, if you’re worried about bringing soy products into your diet.