Should we include soy in our diet?

Soy is a plant-based food deriving from soya beans, which are a legume native to Asia. It is consumed in many different forms, including tofu, tempeh, soy milk, edamame beans, vegetarian meat substitutes, dairy-free cheeses and yoghurts.

It is nutrient dense, rich in polyunsaturated fats (omega-3 and –6), antioxidants, B vitamins and iron. Soy is also a great source of protein containing all of the essential amino acids, making it a complete protein. Soya beans and products using the whole beans (such as tempeh) are also a good source of fibre, which in itself is linked to a whole host of health benefits. 

So why does such a nutritious and versatile plant-based food have such a bad rep? 

There is a lot of misinformation around soy, as it is deemed one of the most controversial topics within nutrition. However, most of the negativity around soy seems to stem from poor studies conducted on animals, providing very weak evidence.  

So, let’s have a look at some of the common misconceptions of soya and see what the evidence has to say…. 

Eating soy can cause cancer 

The common myth that consumption of soy is linked to cancer originates from the misunderstanding of differences between oestrogen and isoflavones.  

Isoflavones are a type of plant-based compounds called phytoestrogens. Although they have a similar chemical structure, isoflavones function completely differently to oestrogen. In fact, phytoestrogens are estimated to be between 100 – 100,000 times weaker than oestrogen found in humans, and therefore any effect they have is very weak. 

However, by binding to oestrogen receptors, the isoflavones in soy act as antioxidants, as they block the oestrogen. There is plenty of research to show the protective effect this has against cancers and other diseases. In fact, human studies have shown consistently that regular, moderate soya consumption lowers the risk of not just breast cancer, but breast cancer reoccurrence in recovered patients.  

The reason for this misunderstanding is due to previous studies done on rodents. It has since been discovered that rodents metabolize isoflavones in a completely different way to humans, leading to the misleading conclusion that isoflavones promote the growth of breast cancer. 

Eating soy causes hormone imbalance in men 

Following on from the concern around phytoestrogen contained in soy, there have been multiple different myths and rumours regarding its effect on testosterone, and whether eating soy will cause ‘man boobs’. 

There is a strong evidence base that soy does not affect the production of testosterone in men whatsoever. There are several studies examining soy protein or isoflavone supplementation that suggest no significant changes on men’s testosterone, oestrogen, sex hormone binding globulin protein, or semen quality. 

In fact, there is good evidence to suggest that soy is linked to a significantly lower risk of developing prostate cancer. 

As for the ‘man boobs’, this rumour stems from a single, very scientifically weak, case study, in which a 60-year-old man developed breasts and sexual dysfunctions after consuming almost 3 litres of soy milk a day for 6 months. Not only is this an unrealistic amount of soy for anyone to consume, the man in question’s medical history is unknown, and his symptoms went away after he stopped consuming the soy. These findings have also not been reproduced in any studies since. 

Soy contains antinutrients 

This is based on the fact that soybeans contain high concentrations of phytate (phytic acid). Phytate is found in seeds, nuts, legumes, and grains. It can bind strongly to certain nutrients (such as iron and zinc), forming insoluble complexes that cannot be absorbed by the intestine. 

However, soaking, sprouting, cooking and fermenting are all ways to reduce the phytate content in soy, which it almost always is before consumed, meaning the effect of phytates is negligible. 

There are good and bad types of soy 

Soy can range from being minimally processed (such as edamame), moderately processed (tofu and soymilk), to isolated components that are used as ingredients (such as soy protein isolate, or soy fibre).  

The more processed the soy is, the less nutrients it contains as they are lost along the way. However, this does not make them ‘unhealthy’, they are still a great, low-fat source of complete protein. They just simply contain a little less nutrients. Furthermore, these more processed forms of soy are generally not consumed on their own, but as an ingredient, meaning the nutrients can be made up elsewhere. 

The bottom line 

Soy is a highly nutritious and versatile plant-based protein, and can be enjoyed by all, not just vegetarians and vegans. It comes with a whole host of health benefits when consumed moderately, and there is no need to be weary of the negative health claims that have derived from poorly conducted animal studies, that are not generalisable to humans. 

 

Sources:

Contribution by Rebecca Horton ANutr 

Are Vegan Diets Healthier?

An estimated 500,000 took part in Veganuary in the UK this year, mirroring the year-on-year rise of veganism. Although the main motivation to move towards plant-based diets is typically for ethical or environmental reasons, there are many reports and anecdotes on the health benefits of such a diet. News outlets often feature reports on how plant-based diets are linked to greater longevity, and reduced risk of conditions such as heart disease.

What constitutes a vegan diet can vary, and could be made of Oreos and oven chips, or exclusively fresh produce from an upmarket supermarket. As such, it is hard to say that a vegan diet is healthy simply for being vegan. But how does a well-balanced vegan diet match up against one that contains animal products?

A HEALTHY VEGAN DIET…

If featuring plenty of fruit and vegetables, wholegrains, legumes, nuts and seeds, a vegan diet will likely contain a wide variety of micronutrients. These diets are high in fibre, which may reduce the risk of colorectal cancer; and low in saturated fats. In many cases, vegan diets can be nutrient dense without being high in calories.

NUTRIENTS TO CONSIDER

In 2017, a study by the National Osteoporosis Society found that many teenagers and young adults were at increased risk of osteoporosis in their lives due to reducing dairy in their diet. Calcium can be found in in plant-based foods such as leafy greens, nuts, seeds, and fortified dairy alternatives, but can be overlooked. Non-haem iron, found in plant foods, may be less bioavailable than haem iron, the type found in animal foods, such as red meat. Care is needed to include plant-based sources, which includes lentils and beans; hemp and pumpkin seeds and fortified cereals. Ability to absorb iron seems to vary between people quite widely, so some may have better iron levels on a vegan diet than others.

Another key nutrient to think about is omega 3 fatty acids. Flaxseeds and chia seeds are the main source of omega 3s; although walnuts, hemp, and rapeseed oil also contain some of this fatty acid. To get sufficient omega 3s, consuming a source like flaxseed is recommended. If this is too difficult, a supplement may be required, such as an algae capsule.

Vitamin B12 is also virtually absent from a vegan diet, with the exception of fortified foods. As low levels of B12 over a period of time can lead to serious health problems, it is important to either take a supplement, or to be consuming sufficient amounts of fortified foods consistently.

There appear to be many benefits to eating a plant-forward diet, that meat-eaters, vegetarians and vegans alike can benefit from. And a well-planned vegan diet can absolutely be a healthy choice. However, care should be taken to include sources of certain micronutrients. Always speak to a Registered Nutritionist or Dietitan if you are doubtful in regards to how to transition to vegan diet and remember you do not have to label yourself ‘vegan’… You can simply benefit from prioritising more plant foods in your diet.

Remember, you cannot for wrong by simply adding more plant foods to your diet. You do not have to label yourself vegan or vegetarian but can make a conscious effort to include more plant proteins such as beans and legumes etc. as these are highly nutritious foods. Not only can you help support your health but switching out meat products for plants can help lower your carbon footprint too.

 

 

References

  1. https://gut.bmj.com/content/48/5/587
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5335887/
  3. https://www.bda.uk.com/uploads/assets/f2abf0e1-fa59-49db-a0afb1cb1bf9a878/Iron-food-fact-sheet.pdf

 

Contribution from Eleanor Coales ANutr

Earth bowl

Earth bowl- vegan dinner

Hey guys! So I know I’m always hitting you with healthy ‘sweet treat’ recipes because I just love recipe developing so much… However, my diet in general is extremely healthy and full of plant based goodness- so today I am sharing one my favourite dinner recipes. You can read more about plant-based diets here.
Tonight my sister and I were cooking in our West Hollywood apartment a super easy and very healthy ‘earth bowl’.

Ingredients

So I haven’t given quantities, as my sister and I made a large batch to share… We did a two hour workout today so needed to fill up on lots of plant based proteins! There are different ways you can cook up the ingredients however I have given our particular method below…

Earth bowl- vegan dinner

Method

  • Firstly, rinse the lentils and boil for approximately 15 minutes. For every 1 cup of lentils use 3 cups of water.
  • Once the lentils are almost done, in a separate saucepan, heat the teriyaki sauce on a low heat and add the black beans. After 5 minutes, add the lentils and stir (still on a low heat).
  • You can then chop the vegetables and add them to the saucepan. It is best not to heat the veg for too long otherwise you risk losing nutrients. (I do not boil my carrots as I enjoy them raw so add them at the end). Once the dish is heated enough in the saucepan it can be served into a bowl and enjoyed! Super easy and packed with nutrients!

This vegan dish is full of plant based proteins (provided by the black beans, lentils and peas) and antioxidants from the vegetables. It is also high in fibre, potassium and vitamins B and C.

Enjoy!

SHK x