Conclusion: The effects of soya on health and the environment

This post is the final part of a four part series of posts. You can find the introduction (part one) here, part two here and part three here. I've been asked many questions about soya and I've heard contradictory opinions too, so I asked Sagar Kirit Shah to write an article it. Here's his conclusion.

Conclusion - the effects of soya on health and the environment

In summary, my view is that soya not a health risk, but is certainly not a health panacea and is by no means necessary for good health on a vegan diet.

Buying power

I also believe it is relatively straight forward to avoid some of the adverse environmental effects by purchasing soya products made with non-GM beans from plantations not associated with rainforest destruction.

Lightly processed vs highly processed

I believe there is nothing wrong with enjoying the taste and convenience of soya products as part of a healthy, balanced diet.

Just try and remember it is much better to go for lightly processed, whole bean, products (e.g. whole bean soya milk, tofu, tempeh, natto, miso, edamame) than for products which are highly processed (e.g. meat analogues made using texturised soya protein, soya alternatives to single cream and soya ice cream).

Previous articles in this series

Part 1 - Should we consume soya or not?

Part 2 - Does soya consumption have a negative impact on health?

Part 3 - Is soya good for the environment?

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“I've been vegan for about 10 and a half years. It's been all good. I'm obviously much healthier.”
- Woody Harrelson

How does soya effect the environment?

This post is part three of a four part series. You can find the introduction (part one) here and part two here. After hearing many different comments about soya so I asked Sagar Kirit Shah to write an article about the pros and conns of soya.

So over to Sagar Kirit Shah.

The concerns about soya production

With soya beans linked to the GM industry and deforestation, it is not surprising that many are concerned about the environmental effects of the soya bean.

What we need to know about soya produce

When thinking about the environmental consequences of soya production, it is important to bear some things in mind.

First, a vast majority of the world’s soya beans are grown to produce high-protein animal feed, and not to feed humans directly.

Since animals foods are inefficient (in terms of use of inputs such as land and water) compared to plant foods, humans substituting plant foods for animal foods (including milk) is beneficial for the environment.

Second, soya is one of the most efficient plant foods when it comes to land and water use. One square metre of land can produce 40gm of soya protein, compared 29gm of rice protein, 24gm of maize protein, 22gm of protein of other legumes and 15gm of wheat protein. This means that if soya were to be replaced with other crops, it is likely that amount of arable land required to support the human population (and its consumption patterns) would actually go up, increasing pressure to cut down rainforests.

Third, living in the UK, we have considerable choice when it comes to the soya products we choose – and we also benefit from legal protections when it comes to genetically modified foods. It is relatively easy to obtain non-GM soya products (soya milk, tofu) made using soya beans from sustainable plantations.

This means we can choose to eat/use soya products which don’t destroy rainforests.

Conclusion - does soya have a negative impact on the environment?

Taken together, I think these three points mean that it is possible for green-leaning individuals to consume soya without feeling guilty about the impact their food choices have on the environment.

Final part - Conclusion: The effects of soya on health and the environment

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"Forests … are in fact the world’s air-conditioning system—the very lungs of the planet—and help to store the largest body of freshwater on the planet … essential to produce food for our planet’s growing population. The rainforests of the world also provide the livelihoods of more than a billion of the poorest people on this Earth… In simple terms, the rainforests, which encircle the world, are our very life-support system—and we are on the verge of switching it off."
- Prince Charles

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

Should we consume soya? Is it safe?

I've heard a lot of varying comments about soya so I thought I'd ask a friend of mine to write an article examining whether it's safe to consume or not! Over to Sagar Kirit Shah.

Can anyone avoid soya?

For many vegetarians and vegans, soya products may seem almost impossible to avoid. The most widely available substitutes for dairy products (milk, cheese, ice cream) and meat (tofu, tempeh, burgers, sausages) are made from the soya bean. And other soya products such as soya oil and soya lecithin are common ingredients in many processed foods found in modern supermarkets.

Stifled about soya!

For some, soya is confusing and controversial.

From a health perspective, soya is claimed to be a high protein, miracle health food which can help reduce cholesterol. But others have linked it to cancer and/or reduced fertility.

Vegetarians and vegans often note the environmental advantages of soya as it produces more protein per acre than almost any other food. Yet critics often point out how soya is associated with the GM industry and rainforest destruction.

Over the next three posts, I aim going to unpick these controversies a little to help you make up your mind about whether to eat soya products, and if so, which products to eat.

Part 2 - Does soya consumption have a negative impact on health?

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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"The Gods created certain kinds of beings to replenish our bodies; they are the trees and the plants and the seeds."
- Plato