First published May 2008, Updated August 2010

When I was growing up, soy was something that was pretty much confined to being used in our Chinese take-out or something that hippies and health nuts crowed about... that I knew of.

The humble soybean now plays a role in so much of our lives and while it is certainly a wonderful plant, our reliance upon it and exploitation of the land suitable for cultivating the crop has also presented some major challenges.

Here's the good, the bad and the ugly about the soybean in brief.

Soy - the good.

Soybeans are an amazingly versatile crop, providing oil, carbohydrates and protein. The protein content is around 40%, oil approximately 20% and 35% of a soybean is carbohydrate.

Soybeans can grow in a wide range of soil and as they are a legume, can help restore nitrogen levels to nitrogen depleted earth. The many uses of soy include:

• A food in their own right
• Meat replacement; as in tofu and the base of many mock meat products.
• Dairy replacement - soy milk and cheese
• Biofuel stock for biodiesel
• Stock feed
• Candles
• Soaps
• Cooking oil
• Flour
• Butter (like peanut butter)
• Ice cream
• Chips
• Cosmetics
• Clothing
• Resins
• Plastics
• Inks
• Clothing
• Vodka
• Insulation

During my days as a baker, I used soy flour instead of gluten to give the bread more strength as we had many customers with gluten allergies. If you look on the ingredients listing of many processed food products these days, you'll likely see soya flour or oil listed.

A meal or two of soy-based meat replacements each week can go some way to reducing the impact of meat consumption on the environment. Given that products such as tofu absorb the flavors of what they are cooked with, even a partial substitution is a good way to go if you simply cannot give up meat altogether. The same goes for dairy products.

Candles are often made from petroleum, crude oil, as are cosmetics, plastics and resins - so soy offers an earth friendly (to a degree) alternative to these too.

With so many uses, you'd think that we could just about live on soy alone; but there are some issues you need to know about before you start making radical changes in your diet and general consumption habits by replacing traditional products with soy.

Soy - the bad

While any well educated vegetarian or vegan will tell you soy contains many health benefits, they will also warn you it is not the be all and end all replacement for meat and dairy. For example, it's not high in calcium or iron, two critical elements of good health; so these nutrients need to be sourced from other products. Many manufacturers of soy dairy replacements fortify their products with calcium to address this.

Soy also contains appreciable levels of phytoestrogens - plant hormones. There's a great deal of controversy as to whether a diet high in soy contributes to issues in men such as lowered libido, increased breast tumor growth rates in women with a high risk of breast cancer and soy formula for infants is thought by some to increase the risk of autoimmune disorders of the thyroid gland.

Soya flour has also been shown to cause cancer in rats, but no equivalent human studies have been done.

According to Wikipedia, approximately 8% of children in the USA are allergic to proteins in soybeans. The allergies can cause skin irritation.

Back in 2000, a study published in the Journal of the American College of Nutrition stated brains of elderly people who ate tofu at least twice a week for several decades were aging faster than normal.

I'm not any sort of expert on diet, but it seems to me that just about everything is linked to cancer or some sort of malady these days and it's really more of a matter of "all things in moderation" - and some of the above could be due to a lack of something else that was replaced by soy or perhaps how the crop was grown - pesticides for example.

If you are considering switching to a soy-rich diet, exercise due diligence and research thoroughly.

Soy - the ugly

Probably one of the most disturbing issues related to the burgeoning soy industry is the destruction of the Amazon forest and deforestation in other countries to make way for the crop. However, this is where meat again has a direct link as so much soy is fed to beef cattle. Soy also has a more complex link in Amazon deforestation.

In the Amazon, rainforests are often cleared to graze cattle in such a way that the land degrades quickly. The cattle farms are being replaced by soy farmers who buy or rent land from cattle farmers. The cattle farmers then push on deeper into the Amazon forest.

For those of us who eat meat and even soy, this is a double whammy of the environmental impact of our diets.

Biodiesel made from soy is also a concern. Around 500 million gallons of biodiesel will be produced from soybeans in the US this year, representing approximately 12.5 million acres of soy production - that's a lot of land being used to produce what is really a drop in the bucket of US liquid fuel consumption - not even a day's worth.

It's my opinion that food as fuel on an industrial scale is just wrong on so many levels - environmental and humanitarian. It takes an incredible amount of land and feedstock just to make enough fuel to fill up a car. Additionally, food prices are rising around the world due in part to the demand of biofuels. There are better alternatives and I really hope that governments wake up to the fact that food as fuel is going to cause as many problems as crude oil has.

The lucrative soy market has also seen agribusiness sinking their claws in for control over the crop. Soybeans are a popular biotech food crop, meaning that it's increasingly being genetically modified.

The biotech companies actually own these variants and no-one can use them without their approval. The danger in this, aside from the unknown long term health and environmental effects of GM crops, and in addition to the legal ramifications of GM crops infecting non-GM crops, is that big business is increasingly controlling our food, and the future of our food. For example, in the case of soybeans, Monsanto has 25% global market share.

Like anything else we buy these days, just because something is made from soy, it doesn't mean that soy has been grown in a sustainable way. Exercise caution when buying soy products - after all, if you're choosing soy for environmental reasons, it would be terrible for you to discover rainforest was recently destroyed in order to make your "earth-friendly" alternative.