Researchers from the University of Surrey examined the iodine content of 47 milk alternatives including soy, almond, coconut, oat, rice, hazelnut and hemp, in comparison to semi-skimmed cows’ milk. They found that the majority of the dairy-free options did not have adequate levels of iodine, offering only two per cent of that found in cows’ milk.
The World Health Organisation states that, “Iodine deficiency is the world’s most prevalent, yet easily preventable, cause of brain damage.”
The micronutrient is an essential component of thyroid hormones, which regulate the metabolic activities of most of the body’s cells. A lack of iodine in the diet can affect muscle, heart, liver, kidney and brain development, especially in growing children.
Margaret Rayman, Professor of Nutritional Medicine at the University of Surrey, said: “Many people are unaware of the need for this vital dietary mineral and it is important that people who consume milk-alternative drinks realise that they will not be replacing the iodine from cows’ milk which is the main UK source of iodine. This is particularly important for pregnant women and those planning a pregnancy.
Melanie McGrice, Accredited Practising Dietitian and spokesperson for the Dietitians Association of Australia, says that Australians who drink milk alternatives don't need to be alarmed by these finding but it should be a consideration.
“I don’t think they need to be concerned, I just think everybody needs to be aware whether they’re drinking milk or not," Melanie told Women's Health. "The reason is that our milk used to have a lot of iodine in it but now with different processing techniques it doesn’t have as much iodine in it as it used to. As a result the Australian Government has been fortifying bread with iodine since 2009. So I think it is important, particularly for women, to be aware of their iodine intake, also especially in the lead up to pregnancy and during pregnancy. But I don’t think it’s a massive concern as such because our iodine levels are generally pretty good in Australia.”
However, if you're not consuming bread you will need to meet your iodine requirements in other ways.
"So our Australian food sources tend to be a bit different but obviously bread, milk, seaweed is probably one of the best source of iodine so consuming sushi rolls or seaweed salads is a really good choice," Melanie says. "Also fish is another source of iodine, but Australians tend not to eat enough fish so that’s something that people could keep in mind as well."
As for vegetarians and vegans, stock up on the seaweed or speak to your doctor or dietitian about iodine supplements.
"You should definitely speak to a doctor and/or dietician before starting iodine supplements because if you do have any underlying thyroid issues you could actually make them a lot worse."
And whether you're drinking milk alternatives or not, if you're thinking about trying for a baby you definitely need to check your levels.
"One of the most important times is in the lead up to pregnancy because women’s iodine requirements significantly increase during pregnancy, so if somebody is thinking about having a baby that’s a really good time to be speaking to a doctor or dietitian about your iodine levels."