Will soya consumption have a negative impact on my health?

This post is part two of a four part series. You can find the introduction (part one) here. I've heard a lot of varying comments about soya so I asked a friend to write an article examining whether it's safe to consume or not! Over to Sagar Kirit Shah.

Media coverage about soya

Every few months a study in the media comes out noting beneficial or harmful effects of soya products with some media stories reporting beneficial effects and others reporting harmful effects – it is not surprising that many people are confused about whether soya is beneficial or harmful for health.

Health benefits of soya

The main health benefit associated with soya is cholesterol-lowering effect.

It is claimed that when 25gm of soya protein per day is consumed as part of a diet low in saturated fat, studies have shown a cholesterol lowering effect among people with raised cholesterol levels. This is a well-established result[1], though it is likely that some of the cholesterol lowering effect may come from the composition of diets with a high soya content[2].

Is soya isoflavone beneficial or not?

Many of the other health benefits and risks associated soya relate to isoflavones and the impact they may have on humans. Isoflavones are a class of phyto-oestrogens, hormone-like chemicals that occur in small amounts in many plants, seeds and grains.

Claims have been made the soya isoflavones may have beneficial effects for menopausal symptoms, breast cancer protection (by counteracting oestrogen’s cancer-causing potential) and bone health.

At the same time, claims have been made that soya isoflavones may have adverse effects for breast cancer risk and male fertility, and concerns have been raised regarding the impact that soya isoflavones may have on children.

A good 'story' vs. ignoring the results of lots of evidence

While many media articles have been written about these claims, in attempt to generate interesting stories, most overlook the wide evidence base examining the impact of soya on health (it is one of the most studied foods in the world), and exaggerate the importance of a small finding in a single paper.

The reality is that a majority of the studies on these issues are contradictory and inconclusive. Some studies show a weak beneficial effect, while others examining the same issue show a very weak adverse effect or find no effect at all. It is thus unsurprising that many end up getting confused at the contradictory stories reported in the media.

Summary - is soya healthy or not?

Overall, there is nothing to suggest that consuming soya products is unhealthy poses a health risk, at least in the quantities consumed by most vegans in the UK (around 15gm of soya protein per day).

Other factors that should not be ignored

If you do not already lead a very healthy lifestyle, the conclusion that most experts have reached is that it is likely there will be much bigger gains to health from increasing intake of fresh fruit and vegetables, reducing processed/fatty foods, increasing exercise or reducing smoking/alcohol than there would be from doubling/halving or eliminating your soya intake.

How to get more nutrients out of soya

That said, it is worth noting that there are differences in the healthfulness of different soya foods. Soya beans, like all other plant foods, contain a wide range of beneficial macronutrients (carbohydrates, fats and proteins) and micronutrients (vitamins, minerals and other compounds). Heavy processing typically strips away many of the beneficial micronutrients, so lightly processed, whole foods are the best way to ensure these nutrients are absorbed.

Lightly processed soya foods include soya milk made with whole beans, and the soya products traditionally consumed in East Asian countries: tofu, miso, natto, edamame, and tempeh.

Processed foods

Soya oil, soya flour, texturised soya protein and soya lecithin are typically much more processed. In fact, the process for obtaining texturised soya protein involves crushing the soya bean at very high temperatures, and then passing the crushed soya bean through chemical solvents. Many of the beneficial nutrients and compounds in the soya bean are lost during this process.

Products made using processed soya ingredients (e.g. meat analogues, soya ice creams and soya alternatives to scream) are thus likely to be less healthful than their lightly processed counterparts.

References

1] British Nutrition Foundation (2002) ‘Soya and Health’ Briefing Paper

[2] Jenkins DJ et al (2006) Assessment of the longer term effects of a dietary portfolio of cholesterol-lowering foods in hypercholesterolemia Am J Clin Nutr Mar 83(3) 582-91

Part 3 - Is soya good for the environment?

Part 4 (final part) - Conclusion: The effects of soya on health and the environment

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"You never hear anybody talk about mad tofu disease."
- John Robbins

The protein panic: where will vegans get their protein from?

One of the questions I've been asked is 'But where do you get your protein from?'Some of us are able to answer questions like this, others don't want to answer, and for some, they'd like something to help them give a response. Whichever category you fall into, it's worth reading what Gary L. Francione & Anna Charlton have to say about vegans and protein.

But…Where do you get your protein from?

This and similar “Buts,” such as “But do you feel healthy without eating meat and dairy?” are part of our desperate but futile attempt to cling to the notion that we must continue to consume meat and other animal products or risk dying of malnutrition. That is, these “Buts” maintain that there really is some necessity involved in eating animals.

As mentioned earlier, mainstream medical authorities now recognize that a vegan diet is healthy. The extremely conservative Academy of Nutrition and Dietetics, formerly the American Dietetic Association, has stated:

It is the position of the American Dietetic Association that appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.

While adequate protein intake is one of the most commonly used reasons to counter a vegan diet, numerous studies and reports over the years across the United States, the United Kingdom, Canada, New Zealand, and Australia have confirmed that a vegan diet provides ample protein. Additionally, the United States Department of Agriculture (USDA) explicitly maintains that a vegan diet is capable of providing adequate amounts of protein.

Let us be clear and concise: there is no credible evidence — none — that a vegan diet cannot supply the same quality of protein as that from animal sources. The bottom line is clear: “Plant foods have plenty of protein.”

Related content

How do vegans get enough iron if they don't eat meat? 
How do vegans get enough calcium if they don't eat dairy products? 

Link to a book by Gary L. Francione & Anna Charlton: An exploration and rejection of the various excuses — the “Buts” — that keep us eating animal foods.

“Nourish the mind like you would your body. The mind cannot survive on junk food.”

— Jim Rohn

What does the National Health Service say about vegan diets?

This post is connected to the previous one. It felt like everyone became a health expert when I told them that I was going to follow a vegan diet. It's not their fault because the media is riddled with information about how much our health depends on dairy and that it is our main source of Calcium etc. Of course this is not true, but at the time, I felt attacked, defensive, insulted and irritated. This was compounded by the fact that I hadn't researched the pros and cons of a plant-based diet, so the seed of doubt was planted and I was speechless and cross with myself at the same time. Not a good combination!

I didn't want to feel like that again, so I did some research to make the decision fact-based, rather than, the solely emotional. I felt better and more certain that this was the right shift for me.

Here's what the National Health Service (NHS) says:-

One can get most of the nutrients that are needed from eating a varied and balanced vegan diet.

The website states that a healthy vegan diet contains:

• plenty of fruit and vegetables

• plenty of starchy foods

• some non-dairy sources of protein such as beans and pulses

• some dairy alternatives such as fortified soya drink

• just a small amount of fatty and sugary foods

Do you have to convince others that your choices are right for you?
When others want to explore the choices you've made, do you have to answer?
It took me a long time to come to the decision that I don't always need to give a reply.

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"You don’t always have to say something. Let your life be your message "
- Rev Run