Nutrition
So-ya Think Soy is Bad for You ? By Tanya Huber
With the growing popularity of plant-based diets , there is an increase in concern regarding the safety of the consumption of soya . Let ’ s unpack the issue .
With a shift in popularity of plant-based diets , there is a growing market for new alternatives to animal-based foods . The trend is showing a special interest in soya , due to its higher protein content and quality , higher fat content ( the good fats , such as polyunsaturated ) and lower carbohydrate content , when compared to other beans and pulses . However , there is now an increase in questions regarding the safety of the consumption of soya . Concerns have been raised regarding the association with menopause , muscle-building , breast cancer and men ’ s health .
These concerns stem from soya containing isoflavones , which have a chemical structure similar to the human hormone oestrogen , and hence it is occasionally classified as a phytoestrogen , or plant oestrogen . However , this argument has been debunked by a review published in the food science journal , Critical Reviews in Food Science and Nutrition . An overall study was done on 417 human studies , of which 229 where observation studies , 157 clinical trials and 32 systematic reviews , and the review confirms that soya consumption is safe when part of a healthy , balanced diet . Furthermore , neither soya , nor soya isoflavones , had a negative effect on the health of men or women when assessing the outcomes of breast cancer , hormone levels and male feminisation .
More specifically , extensive research has shown that isoflavones act differently to oestrogen in the human body , and most of the previous literature surrounding this topic comes from laboratory studies done mainly on rodents that were exposed to high doses of isoflavones . This research has now been deemed to be a poor representation of how isoflavones are absorbed and metabolised in humans . So , let ’ s look at some of the concerns a bit more in depth .
1 Consuming soya can result in the reduction of testosterone in men : This comes from speculation that the regular intake of isoflavone can cause a hormone imbalance , by increasing oestrogen and decreasing testosterone . This speculation was due to a laboratory study where animals were the subject and this effect is not replicated in humans .
2 Consuming soya can result in an increasing risk of developing Breast Cancer : This is actually opposite to what is true , and soya can in fact help to protect against breast cancer . The Phytoestrogens found in soya do not act in the same way that oestrogen does in the human body . Human studies have found that there is no increase in the breast cancer markers in those who consumed soya , and there is no evidence that breast tumour cells have an increased rate of growth due to soya . Additionally , there is some evidence that indicates that starting the consumption of soya during adolescence and maintaining this during adulthood has a significantly marked effect in the reduction of the risk of breast cancer .
3 Soya is not the same as animal protein when it comes to muscle building : It has been concluded that both plant proteins and animal proteins will provide similar benefits as long as there is an adequate intake of energy and protein for each individual ’ s needs – which should be spread evenly throughout the day – together with strength-building exercise when it comes to building and maintaining muscle growth .
4 Soya is harmful for thyroid functioning : For those individuals with a normal functioning thyroid and regular iodine intake , soya can be safely consumed . The only concern here is that should you have either hyper or hypothyroidism , and are taking the medication named levothyroxine , it is recommended that you take it on an empty stomach 30 to 60 minutes before consuming soya , due to the possible interference with the absorption of the medication .
5 Soya can have an effect on Menopause : During menopause , many women experience hot flushes , which vary in frequency and severity due to the drop in oestrogen levels . Evidence has shown that with the consumption of two servings of soya , or soya drinks , there was actually a reduction in frequency and severity of women going through hot flushes . Additionally , soya also contributed towards a reduction of LDL cholesterol levels due to the isoflavones helping to improve cell lining function in blood vessels .
Include More Soya in Our Diet
Some foods you might want to add to your shopping cart are tofu , edamame beans , soya protein powder , soya chunks or mince , soya milk and soy sauce . Most of these items are readily available in your local supermarket and there are many different recipes that you can find online that incorporate them .
Lastly , it is important to note that plant-based products are not always guaranteed to be healthy , and it is advisable to check the nutritional labels and go with the options that have less saturated fat , salt and sugar . Make sure you ’ re choosing options that can form part of a balanced diet overall .
Tanya Huber is a Johannesburg-based dietitian with a passion for mindful eating , women ’ s health and helping people to be the best version of themselves . Her practice focuses mainly on weight-loss , chronic disease such as high cholesterol and diabetes , Polycystic ovary syndrome ( PCOS ) and mental health . She believes in changing habits and reforming one ’ s mindset in order to have a healthy relationship with food , because food is life – literally and figuratively . More info at www . tanyahuber . com .
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