A recent study published in the British Journal of Nutrition aimed to investigate iodine levels of milk-alternative drinks and compare it with cow’s milk.
Iodine, although not frequently discussed as a vital nutrient, is important for proper thyroid function and is especially important in early pregnancy as it aids in brain development of the fetus. The issue of iodine deficiency was tackled by fortifying both salt and cow feed, however, in the UK where iodized salt is not readily available, the leading source of iodine is, in fact, cow’s milk. With increasing awareness of dairy allergies, intolerances, and ethical and environmental concerns regarding dairy farming, many are abandoning the consumption of cow’s milk and switching to milk-alternative drinks such as plant-based alternatives. Replacing cow’s milk in a diet may inadvertently result in removing significant amounts of iodine from the diet if the plant-based milk does not measure up. These concerns have driven UK scientists to test multiple brands of milk-alternative drinks and varieties and compare their iodine levels to that of conventional and organic cow’s milk.
A 2017 study published in the British Journal of Nutrition, tested the iodine levels of 47 varieties from 20 brands of milk alternative drinks available in the UK. They included soya, almond, coconut, rice, oat, hemp, and hazelnut varieties, including both shelf and chilled versions. The cow’s milk chosen for comparison was partly skimmed milk from UK cows, from both conventional and organic brands.
The results showed that, if unfortified, none of the milk alternatives are able to provide adequate iodine, containing only about 1.7% of the iodine found in cow’s milk. In addition, organic cow’s milk also did not even measure up quite as high as that of conventional cow’s milk. One UK brand, Marks and Spencer, produces three fortified varieties of milk alternative drinks which contained enough iodine to be considered a good substitute for cow’s milk.
In the UK, cows are fed an iodine fortified diet in order to produce iodine rich milk for human consumption. Currently, there are no standardized practices in order to ensure iodine fortification in plant-based milks. The only brand that did adequately fortify their milk alternative with potassium iodide is not a mainstream brand that is readily available at large chain supermarkets. This suggests that most people making the switch are not consuming fortified milk alternatives. It is standard for milk-alternative drinks to be fortified with vitamin B12 and Calcium, but this study stresses the importance of adding iodine to that list of nutrients.
The study is one of the largest, looking at the highest variety of brands and types of milk-alternative drinks, however, it was limited to just UK brands. Additionally, only UK cow’s milk was used as a comparison. It is questionable how these results affect Canadians, as iodized salt is readily available, but it may not be the principal source of iodine for everyone especially those avoiding salt for health reasons. Therefore, investigating and suggesting the fortification of iodine in milk alternative drinks in Canada may be of benefit as well.
Since salt and dairy were historically staple ingredients in the everyday diet, it made sense to fortify them with iodine. Our diets, however, are changing and this shift in food choices is, unfortunately, leaving many more vulnerable to iodine deficiencies. For those in the milk alternative industry, it would be advisable to find an appropriate way to fortify the plant-based milk alternative drinks. Furthermore, for those who do not consume dairy or iodized salt, it would be advisable to find an appropriate external supplement of iodine until fortification of milk alternatives becomes a regular practice.
Written by Elena Popadic
Reference: Bath, S., Hill, S., Goenaga Infante, H., Elghul, S., Nezianya, C., & Rayman, M. (2017). Iodine concentration of milk-alternative drinks available in the UK in comparison with cows’ milk. British Journal Of Nutrition, 1-8. http://dx.doi.org/10.1017/s0007114517002136