Soybeans – Exploring the Health Concerns

Soy beans, with their many uses and culinary forms, have become an important nutritional staple for many vegans and vegetarians. It is used in non-dairy milks, yoghurts and cheeses, baby formulas, soy drinks, protein bars, frozen desserts, as textured protein, soy sauce, veggie burgers and sausages, as well as tofu and bean curd.

However, after quite an easy early ride in the media during which soya made huge market gains as a healthy and natural food, several recent press articles have begun to question the virtues of soy beans.

With strong financial interest weighing in on both sides of the argument, it can be confusing for the consumer to get to the truth behind the media hype. YouMed The well funded United Soybean and the Soyfoods Association of North America leads the soya bean public relations crusade, whilst allegations fly that several critical institutional research studies were funded by the competitor meat industry with its not-so hidden agenda.

Here, we take a look at the soy health battleground, laying out both sides of the arguments, and review where current legislation lies in relation to soy food and health.

Background

The soybean was first used as a food upon the discovery of fermentation techniques, some time during the Chinese Chou Dynasty (1100-600 BC). The first soy foods were fermented products like tempeh, miso and soy sauce. Quite some time later, possibly around 200-100 BC, the Chinese discovered tofu or bean curd and the use of fermented and precipitated soya products soon spread to other parts of Asia, most notably Japan, Korea and Indonesia.

Soy proteins contain all the essential amino acids in appropriate ratios needed for human growth and body maintenance, and are readily digestible. The FAO/WHO Expert Consultation on Protein Quality determined that soy protein and egg white have the maximum score of 1, followed by milk and meat proteins. Soy protein is “complete”, which means it has all of the amino acids needed in the human diet and is the only plant source of complete protein.

The health claim battleground

Here’s a review of the main health issues regarding soya:

Hormonal balance –

Soya beans contain phytochemicals, the most controversial of which are isoflavones. Isoflavones are described as phyto-estrogens (plant oestrogens) because their structure and metabolism resembles that of human estrogens. Oestrogen is a natural hormone important in the sexual development of both male and female humans.

Concern: In studies conducted on hamsters and rats, it was observed that the consumption of isoflavones caused hormonal imbalance and significantly accelerated the onset of puberty in the rodents. These findings might be relevant to humans, and are especially concerning for babies who are fed soy-based formulae which contain high dosages of phyto-estrogens.

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