Soya and the media
Soya/Soy is a popular food native to East Asia. Soya is made out of beans that can be found in foods such as tofu, miso, edamame beans, tempeh and of course soya milk. The soya bean contains a range of essential nutrients including high quality plant protein, fibre, essential fatty acids and a range of vitamins and minerals.
We can also find soya in many other forms in the supermarket and is used to bulk out many processed foods such as burgers, sausages and lasagne, allowing manufacturers to claim high protein contents.
It is a great source of protein for vegans and lactose intolerant individuals. However, some of its health benefits have been strongly debated in the media. For instance, it has been said that Soya is associated with:
o Cancers
o Fertility
o Endocrine problems (thyroid problems)
In this article, I want to show you the science base evidence on this topic.
Soya product can be divided into something called First-and Second-Generation of Soya foods.
First generation:are those foods made out of soya that are the least processed. They generally contain moderate to high amounts of soya isoflavones. For example: Tofu, tempeh, edamame and pure soya milk.
Second generation:Include processed foods, that have multiple non-soya ingredients and have less isoflavones per serving. Some second-generation soy foods include soya ice cream, soya cheese, meat substitutes such as soya burger and soya enriched bakery goods.
Mixing soya with other products, makes it difficult to judge the health benefits of soya.
Soya Isoflavones
Soya Isoflavones are found in legumes and beans and are Phyto-oestrogens, a type of plant oestrogen. A healthy human will produce oestrogen and is commonly refer to as “the female hormone” because it is responsible for the development and regulation of the female reproductive system.
Soya isoflavones are weaker than human isoflavones. However, when consumed by humans our body can utilise it and act like human oestrogen. Soya isoflavones can also block oestrogen from working and prevent the body’s enzymes from producing more oestrogen.
This blockage may be positive or negative and more research is needed to understand its impact.
CANCER AND SOYA
Asian countries, whose population traditionally consumed moderatelyfirst-generation soya foods has demonstrates to have lower cancer rates. In fact, according to the World Cancer Research Fund International, Japan ranks 43 out of 50 countries for cancer rates in both men and women. Whereas the UK ranks 13 for overall cancer rates. The average Japanese male would consume 6 to 11g of soya daily, while an average individual in the UK consumes 1 gram or less.
Conclusion:Cancer rates will depend upon a variety of factors and cannot be attributed to soya alone.
o Prostate Cancer: The University of Illinois have found that isoflavones have the potential to reduce significatively prostate cancer. They explain that isoflavones build up in the prostate tissue have the possibility become toxic to cancer cells. Moreover, a meta-analysis also supports the following study.
o Breast Cancer: Although one of the risks factors for breast cancer seems to be related to high levels of oestrogen, soya isoflavones appears to reduce the risk of breast cancer as it has been demonstrated that it may blocks the cancer-causing effects of human oestrogen.
Conclusion:Soya is not found to be the main cause or the origin of neither breast nor prostate cancer. In fact, soya foods as part of a healthy balanced diet and are perfectly safe for women with and without cancer diagnosis.
FERTILITY IN MEN AND SOYA
Many controversies around soya and oestrogen levels in men have been thought around the media. However, cross-sectional research and the NHS have numerous articles showing that men who consume soy should not worried about infertility. Even if they have low sperm counts, consuming soya will not cause sperm counts to drop further.
THYROID AND SOYA
A review of 14 studies has confirmed that there is no harmful effect of soya food consumption in healthy humans with a normal thyroid function. Soya foods do not interfere with thyroid function, but they can interfere with the absorption of thyroid medication levothyroxine like many herbs, drugs, fibres and calcium supplements. For this reason, thyroxine medication is always advised to be taken on an empty stomach and soya should not be excluded by those with an underactive thyroid gland as their medication dose can easily be modified.