The truth about Soya
Soya has been caught up in some controversy in recent years as it has caused confusion with some being concerned about soya and whether it has a negative impact on health.
What is Soya?
Soya is extracted from soya beans and is commonly processed into a variety of foods. The consumption of Soya has risen in the UK and can be found in products such as soya milk, tofu, tempeh and miso.
Unlike other beans, soya is different as it has a lower carbohydrate content but a higher protein and fat content. The protein content is equivalent to animal protein quality making it a good source of protein for vegetarians and vegans.
A serving of soya includes (1):
100g soya mince
Half a block of tempeh
100g young green soya beans (edamame)
250g soya milk
Concerns with the consumption of soya
Soya foods and drinks contain naturally occurring plant components called phytoestrogens The most important source of phytoestrogens is isoflavones found in soybeans and their processed products, isoflavones, which have a similar structure to the hormone Oestrogen (2). Therefore, many are concerned that Soya will increase levels of oestrogen in the body but this is not the case! Although isoflavones do have ‘oestrogenic properties’, their effects are not the same as oestrogen. They are different compounds to oestrogen and do not affect oestrogen or testosterone levels (3).
What does the research show?
10 global leading experts reviewed human data from over 400 publications examining the safety of soya and isoflavones in adults and children confirmed that soya food and drinks can be consumed as part of a balanced diet. Evidence indicates that neither soya nor soya isoflavones negatively impacted on women’s or men’s health.
The evidence has shown that isoflavone intake does not adversely affect thyroid function, breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although it has been found that the menstrual cycle length may be slightly increased, ovulation is not prevented (4).
What are the health benefits of Soya (1)?
- Soya is a high quality protein source that builds muscle as effectively as whey and other animal proteins and is environmentally sustainable due to the low amounts of water and land it requires to produce.
- Source of antioxidants.
- Research has shown that consumption of soya reduced the frequency of hot flushes and improved heart health in menopausal women. However, further research is required to make a health claim.
- Soya is also safe for women at risk of developing or with breast cancer and there is some evidence to suggest that starting consumption during adolescence and maintaining intake during adulthood can reduce the risk of developing breast cancer!
Some of the benefits will depend on those that have the people who have the beneficial bacteria to metabolise it (5).
Our advice
- The recommended daily intake of Soya food/drink is 1 to 2 servings as part of a balanced diet. It is advised to spread out the consumption of Soya throughout the day as it is said to maximise the protein intake.
- To shift towards a more sustainable environment, you might like to consider calcium fortified soya milk as an alternative to dairy milk.
- Small changes can make a difference! To add more soya products into your diet, you might like to try adding them into your meals e.g. accompanying your meals with edamame beans or replacing animal meat for plant-based alternatives e.g. swapping beef mince for soya mince.
Written by: Zoe Panaretou (ANutr)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390141/
https://pubmed.ncbi.nlm.nih.gov/33383165/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390141/#ref3