Is soy ‘milk’ good for you?
A popular plant-based alternative to dairy milk, but is soy ‘milk’ really good for you? We asked a Registered Nutritionist to take a closer look at this popular drink.
What is soy ‘milk’?
Soy ‘milk’ is a plant-based alternative to dairy; it is made by soaking and grinding soy beans and may be made at home or bought commercially.
Commercial soy ‘milk’ may include the addition of ingredients such as sweeteners and salt, and the product may also be fortified with nutrients including vitamins B2, B12, D, calcium and iodine.
A 100ml of unsweetened, fortified soy ‘milk’ provides:
26Kcal / 108KJ
0.4mcg Vitamin B12
0.8mcg Vitamin D
The exact nutritional contribution will depend on the brand you buy, whether it’s sweetened or has other additional flavours and whether it has been fortified with additional nutrients.
Top 5 health benefits of soy ‘milk’
1. Source of protective antioxidants
Soya beans, and products made from them, contain natural compounds called isoflavones, these are powerful anti-oxidants and as such help to minimise the damage, known as oxidative stress, which is caused by molecules called free radicals. It’s this oxidative stress which is involved in aging and the onset of chronic disease. Soya beans are especially rich in isoflavones, and provide other active plant compounds including saponins.
2. May alleviate menopausal symptoms
Soya isoflavones (daidzein and genistein) have attracted a great deal of research and some studies even suggest that certain women with a soya-rich diet may experience a lower risk of breast cancer. This is, in part, because isoflavones are known as phyto-oestrogens, which means they mimic a weak form of the hormone oestrogen in the body. Some women find this helps with peri-menopausal symptoms such as poor mood and hot flushes.
Genetics, our gut microbiota and environmental factors play a huge part in how our bodies react to certain foods, so as yet, we can’t say whether a diet rich in phyto-estrogenic foods is beneficial for all women or not.
3. Source of ‘complete’ plant protein
Soya is a useful source of plant protein providing all 9 of the essential amino acids we need for growth, repair and for functions like immunity. The digestibility of the protein in soya, which refers to how well our body can use the protein is good, with some studies suggesting it may even be comparable to that of animal protein. Of all the plant-based dairy alternatives, soya ‘milk’ is the most comparable to cow’s milk in protein contribution.
4. May support heart health
Soya ‘milk’ is low in saturated fat and contains a greater proportion of poly-unsaturated and mono-unsaturated fats. In addition to its beneficial fat composition consuming soya foods may support heart health thanks to a number of soya’s components including isoflavones, saponins and lecithins.
5. A vegan alternative to cow’s milk
Soya ‘milk’ is a vegan alternative to cow’s milk, however, if you choose soya as your product of choice you should be aware that only fortified versions will supply comparable amounts of nutrients, like calcium.
Some fortified plant ‘milks’ (but not many) are now also fortified with iodine in the form of potassium iodide, but this may not necessarily be at the same levels as you’d achieve from dairy milk. Always check labels to ensure you know the nutritional contribution of the product you choose.
Is soy ‘milk’ safe for everyone?
Soy ‘milk’ is generally recognised as safe for most people unless you have a soy allergy when it should be avoided. Soybeans are also considered to be goitrogenic which means they interfere with the activity of the thyroid gland. Although in practice this effect may be minimal, if you have a thyroid condition you may wish to minimise your intake in any form.
Soy products contain oxalate, and for this reason people with a history of calcium oxalate kidney stones may choose to avoid over consuming soy products. However, studies suggest that soy products containing some oxalate and moderate amounts of phytates may actually be advantageous for kidney stone patients.
The consumption of soy has become controversial over recent years with some animal studies suggesting a link with certain cancers. In support of the food’s safety, the European Food Safety Authority has concluded that soy isoflavones do not adversely affect the thyroid, breast or uterus in postmenopausal women.
Soya contains anti-nutrients including trypsin inhibitors and phytates, these may inhibit our absorption of some of the bean’s valuable nutrients. Soaking or fermenting the soybeans before cooking can minimise these compounds.
If you have concerns speak to your GP or Registered Dietician before making any changes to your diet.
This article was reviewed on 16 November 2021 by Kerry Torrens
Kerry Torrens is a registered nutritionist (MBANT) with a postgraduate diploma in personalised nutrition and nutritional therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications, including BBC Good Food.