Soy story. Navigating the ins and outs of the little legume.

For such a little bean, there seems to be almost constant debate about the merits or mediocrity of soy on our bodies. In this article, we take a little look at this mighty legume.
 
Oh, soy. Where to start? For such an innocent bean, there seems to be a constant debate about the merits or mediocrity of soy. And it’s fair to say views are decidedly split on whether this little legume is good or bad for you. Which is funny, given that a decade or so ago, soy would have been derided as a faux-meat wannabe for the hippy set.
 
And today? Well, soy is widely consumed. Not only as a plant-based protein, but as an ingredient in a tonne of processed foods. As soy’s profile has grown, so has the information, studies and divergent views on its qualities. And not just by ordinary folk. Even scientific studies seem to struggle to arrive at a consensus.
 
Say soy
But let’s back it up a little. Exactly what is soy? Well, as mentioned above, it’s a legume – which is essentially a member of the pea family. In whole form, soy is a bean or edamame. And boy it’s versatile. From the raw beans, a huge number of products are created: from the less-processed, more wholesome tofu, tempeh and soy milks, all the way through to products almost unrecognisable as the plant food it once was. We’re talking soy protein isolate, soy lecithin and other soy extracts.
 
When it comes to studies, most focus on one particular part of the soy, and whether this has any health risks or health benefits. But focussing on soy’s compound elements, and isoflavones in particular (a form of phytoestrogen or plant oestrogen), studies tend to miss the wider, more holistic view of soy as a whole food.
 
The problem with this approach is no-one eats isoflavones in isolation. Eat a whole, intact food with other nutrients and compounds, and they act very differently in the body to a refined, isolated compound. We also have to remember most studies are done in-vitro (in a test tube) or in animals.  It's a pretty big stretch to assume the same results are translatable to us as humans.
 
Other studies look at the effects of eating over 14 servings of soy per day. Fourteen! Hey, that might be realistic for chocolate on Christmas day. But is it’s unrealistic and irrelevant for, well… pretty much everyone else on any given day.
 
Soy and oestrogen
What most people seem to be concerned about is whether soy has oestrogen-like properties. Isoflavones do have a similar chemical structure to the oestrogen found in humans. This allows isoflavones to bind to our oestrogen receptors. But does it behave like oestrogen in human bodies?
 
Well, it turns out there are actually different oestrogen receptors in the human body. And isoflavones don't bind to all of them. They selectively bind to receptors different from the ones our own oestrogen hormone binds to. Which means they have very different effects in the body, and sometimes the exact opposite effects of oestrogen.
 
Isoflavones block some of oestrogen's effects, and mimic others generally associated with health benefits. Isoflavones also have antioxidant and anti-inflammatory properties. What most people don’t know – or tend to overlook – is that these phytoestrogens are also found in chickpeas and flaxseeds, amongst other plant foods. And yet we don’t have such fiery debates about those foods.
 
Studies show soy can actually reduce the risk of oestrogen-dominant conditions, like breast cancer, endometriosis and menopause symptoms. Some of the lowest breast cancer rates in the world are in countries, where the most soy is consumed. Worried about 'man boobs'? don’t be. That’s something we can leave to the mammalian oestrogen found in animal products, such as dairy (which, unlike soy oestrogens, DO have the same effects in our bodies as our own oestrogen hormone). Also, let’s not forget the majority of GMO soy is fed to chickens, cattle and pigs, which are then consumed by people.
 
A clear look at the evidence
So, what DOES the evidence say on soy?

• Soy is a great source of plant-based protein
• It contains all the essential amino acids, making it a complete protein
• Soy is a high in fibre, and the type of carbohydrate it contains is easily digestible.
• It can help feed our good gut bacteria and promote healthy bowels
• Soy may reduce the risk of cardiovascular disease, as well as reduce LDL cholesterol levels and blood pressure
• Moderate consumption of soy may be protective against breast cancer and endometrial cancer, as well as reduce the risk of breast cancer reoccurrence 
• Soy may reduce the symptoms of menopause, such as hot flushes
• Soy consumption for men does not have any known effect on hormone levels or sexual development. It may even have a protective role in reducing the risk for prostate cancer.
• Soy has been shown to improve bone density and protect against osteoporosis
• Soy appears to have no effects on the thyroid, as long as you are meeting your iodine needs
• Phytic acid is found in soy. And phytic acid can reduce the absorption of other nutrients, such as zinc, iron, calcium, etc. But cook or ferment soy, and the phytic acid is usually deactivated.

 
Soy made simple
Quite a list, huh? I wouldn’t blame you if you felt a tad overwhelmed right now. So, let’s go back to basics and answer the questions that matter most; what soy is healthy to eat and how much?

• Aim to eat whole-food sources of soy. That’s a big, fat hello to edamame, soy nuts, tempeh, and tofu

• Avoid highly processed and refined soy products. These contain little-to-no nutrients at all, and like all refined foods, they ain’t great to consume regularly. So, if you can, steer clear of mock meats, soy protein isolate (often found in protein/energy bars and some soy milks) and other highly processed soy products
• Always aim to choose organic and non-GMO
• Moderation is key: two to three servings of soy a day is safe. And potentially beneficial.
• Balance is vital. Keep your diet varied with other plant protein sources, such as chickpeas, lentils, beans, quinoa and other whole grains, nuts and seeds.

 
I hope this article shows you there's really nothing to be scared about when it comes to soy. Remember to choose the right kind of soy and focus your diet on a variety of whole, healthy plant foods and you’ll find soy isn’t a lazy legume but one mean bean.