Iodine status of consumers of milk-alternative drinks v. cows’ milk: data from the UK National Diet and Nutrition Survey

Abstract

Milk is the main source of iodine in the United Kingdom (UK), however, the consumption and popularity of plant-based milk-alternative drinks is increasing. Consumers may be at risk of iodine deficiency as, unless fortified, milk alternatives have a low iodine concentration. We therefore aimed to compare the iodine intake and status of milk-alternative consumers to that of cows’-milk consumers. We used data from the UK National Diet and Nutrition Survey from Years 7-9 (2014-2017; before a few manufacturers fortified their milk-alternative drinks with iodine). Data from four-day food diaries were used to identify consumers of milk-alternative drinks and cows’ milk, along with the estimation of their iodine intake (µg/day) (available for n=3976 adults and children ≥ 1.5 years). Iodine status was based on urinary iodine concentration (UIC, µg/L) from spot-urine samples (available for n=2845 adults and children ≥ 4 years). Milk-alternative drinks were consumed by 4.6% (n=185; n=88 consumed these drinks exclusively). Iodine intake was significantly lower in exclusive consumers of milk-alternatives than cows’-milk consumers (94 vs 129 µg/day; P<0.001). Exclusive consumers of milk-alternatives also had a lower median-UIC than cows’-milk consumers (79 vs 132 µg/L; P<0.001) and were classified as iodine-deficient by the WHO criterion (median-UIC < 100 µg/L) whereas cows’-milk consumers were iodine-sufficient. These data show that consumers of unfortified milk-alternative drinks are at risk of iodine deficiency. As a greater number of people consume milk-alternative drinks, it is important that these products are fortified appropriately to provide a similar iodine content to that of cows’ milk.

Iodine Intake Estimated by 24 h Urine Collection in the Italian Adult Population: 2008–2012 Survey

“…The authors estimated that 42% of the population total iodine intake was provided by the use of iodized salt and that this represented approximately 28% of the total salt used by the study participants. A more recent (2014–2017) UK survey in 2845 adults and children showed that the median UIC exceeded 100 µg/L only in regular consumers of cow milk, whereas the median UIC was lower in consumers of alternative types of milk [ 33 ]. Finally, the study of Trofimiuk-Müldner et al on children of school age ( n = 1000) and pregnant ( n = 300) and breastfeeding women ( n = 100) living in Poland showed that the mandatory sale of iodized salt to customers in the supermarkets markedly improved the iodine status in children but was not sufficient for pregnant and breastfeeding women [ 34 ].…”

Healthier and more sustainable diets: What changes are needed in high‐income countries?

“…Exclusion of dairy products by women of reproductive age could therefore be of concern because ‘milk and milk products’ currently contribute almost a third (32%) to daily iodine intakes for UK adults aged 19–64 years (Bates et al, 2020). A recent analysis of NDNS participants (aged 1.5 years and above) also reported that those exclusively consuming milk alternatives had a median UIC (79 µg/l) below the WHO cut‐off for iodine deficiency (100 µg/l), while those consuming cows’ milk (median UIC of 132 µg/l) were considered iodine sufficient (Dineva et al, 2020). Since the survey data were collected, some manufacturers have started to fortify plant‐based milk alternatives with iodine.…”

Dairy as a Source of Iodine and Protein in the UK: Implications for Human Health Across the Life Course, and Future Policy and Research

“…The low iodine content of unfortified milk alternative products, coupled with the positive trend in consumption, might be particularly concerning in countries with limited availability of iodised salt, such as the UK. Indeed, in a study that extracted data from the UK NDNS (between 2014 and 2017; when most milk alternatives on the market were not iodine-fortified), individuals who exclusively consumed milk-alternative drinks had a significantly lower iodine intake (94 vs. 129 μg/day) and iodine status (measured by the median urinary iodine concentration (UIC): 79 vs. 132 μg/L) than cow's milk consumers, suggesting that consumers of milk alternatives were not replacing the iodine elsewhere in the diet ( 87 ). The results are meaningful from a public health perspective, as those who consumed cow's milk were classified as iodine-sufficient according to the WHO criterion (median UIC 100 μg/L), whereas the exclusive consumers of milk alternatives were classified as iodine deficient.…”