Iodine fortification, which has risen in popularity as a dairy plant-wide

Iodine fortification, which has risen in popularity as a dairy plant-wide

As plant-based milk becomes a staple in British diets, experts warn that consumers, particularly young women, without proper iodine supplementation could face hidden health risks.

Study:Plant-based milk alternatives: Can they replace the iodine in British cow's milk?Photo credit: Garna Zarina/Shutterstock.com

As traditional food systems often contain animal qualities, questions about their nutritional value are replaced. A recently published work inProceedings of the Nutrition Societyexamined the iodine content of milk substitute-based iodine compared to cow's milk.

introduction

Cow's milk is the major milk consumed in the UK, but its consumption has fallen over the last four decades, coinciding with increased use of dairy-based milks such as soy, grain or nut milk. These decisions, often driven by concerns about climate change, sustainability and human health, have not been adequately assessed for nutritional comparability.

Plant-based milk alternatives are mainly chosen by young women and can easily be replaced with cow's milk. This consumption pattern raises concerns about public iodine and other micronutrient deficiencies in this population, potentially impacting future generations.

The meaning of iodine

Trace amounts of iodine are important for synthesizing the thyroid hormones thyroxine and triiodothyronine (T4 and T3, respectively). These hormones are important metabolic regulators required for the development and maturation of the central nervous, muscular, skeletal, and respiratory systems.

Iodine deficiency disorders such as hypothyroidism, stillbirth, reduced mental function and congenital anomalies are present. In some cases, excessive iodine supplementation can also lead to hyperthyroidism, although this is less common.

Iodine deficiency during pregnancy is the leading cause of preventable brain damage. A congenital iodine deficiency disorder causes growth retardation and mental retardation, as well as miscarriages, stillbirths, and infant deaths. Even subtle iodine deficiency in pregnancy affects the offspring's cognitive and academic performance and increases the risk of neuropsychological problems.

Iodine recommendations

The World Health Organization (WHO) recommends iodine intake of 90-120 μg of iodine per day for up to 12 years and 150 μg per day thereafter. During pregnancy and lactation, the recommended intake is 250 μg per day.

UK recommendations recommend maintaining adequate intake throughout reproductive life, providing women can thus ensure adequate iodine stores. Contrary to what the UK does not recommend increasing iodine intake during pregnancy, this approach may not be sufficient if iodine intake has been low for a long period of time. This may not apply in the UK and other countries where iodized salt is not the norm, and the WHO recommends iodine supplements for all women of reproductive age in such places.

Iodine status

Despite sufficient iodine in children, milk consumption falls with age. In 2011, a survey in the UK found mild iodine deficiency in girls aged 14 to 15. Girls aged 11 to 18 made up 65% of the recommended intake, indicating a high risk of abnormal neurodevelopment in their offspring.

The latest National Diet and Nutrition Survey (NDNS) report (2018/19) shows inadequate intake among adults. In 10% of all individuals and 12% of women, intake fell below that required to prevent goiter.

The NDNS spot sampling collection in years 9-11 also showed inadequate iodine intake with iodine deficiency in 21% of women of reproductive age. This fits the population-level definition of iodine deficiency in this group. Reasons may include their preference for plant-based diets or exclusion of seafood and dairy products, although nearly 80% of people who use dairy alternatives also use cow's milk. Therefore, the risk of deficiency depends on whether milk-based milks are used in addition to or as a total replacement for cow's milk and the total iodine content of the diet. Vegans who don't supplement with iodine or seaweed are another high-risk group.

Iodine sources

Salt iodization is not legally compulsory in the UK and iodized salt is difficult to obtain. Sources of iodine are mainly seafood, eggs and dairy products. Adequate intake would mean consuming one serving each of white fish and oily fish or seafood per week, with three servings per day being dairy. With the exception of dairy products in the diet, this is a high risk factor for iodine deficiency in the UK.

Fortified cattle feed and iodophor during milking increase the naturally low iodine content of cow's milk to 427 μg/L or 85 μg per 200 ml glass of milk. This is 34% of the recommended intake for pregnant women and 57% for adults. Conversely, a third of British adults, mainly young adults, approximately 45% of people aged 16 to 34 and people with children under 18, use plant-based milks. These only provide about 2% of the iodine in cow's milk if they are not taken into account.

While iodized milk alternatives have increased to 20% by 2020, most remain unaccounted for. When plant-based milk alternatives are fortified, the iodine content typically ranges between 43% and 150% of cow's milk, with most being around 50% of the iodine content of cow's milk. Some fortified products are almost equivalent to cow's milk, but this is unusual. Using only plant-based milk in the UK can cause iodine deficiency. However, population risk varies depending on the presence of other iodine-rich foods or fortified milk and stage of life.

Many dietary guidelines, such as the British Dietetic Association (BDA) One Blue Dot Policy and the UK Eatwell Guide, ignore this risk and treat dairy-based milk as interchangeable with dairy products. These recommendations often promote the fortification of calcium but do not specifically advise the fortification of iodine, which leads consumers to believe that these products with cow's milk are in line with nutritional points. Even the Eat Lancet Commission's reference diet includes iodine as an essential micronutrient. Therefore, the iodine content ranges between 6% and 196% of the recommended adult intake, depending on the foods selected in each category.

The problem and the path ahead

Modeling shows that replacing dairy products with plant-based milk consumption is associated with an increased risk of iodine insufficiency in children and women of reproductive age unless fixed at 27.4 mcg/100 g. Based on current consumer behavior, iodine intake is expected to decrease by 18-44%.

Consuming only fortified plant milk alternatives at the highest levels may result in excessive iodine intake for young children, although the consequences are currently poorly understood.

When plant-based milk is treated as equivalent to cow's milk, a well-designed standardized fortification protocol is required to effectively increase iodine intake. Iodine bioavailability and proper mixing with the solution require further study. Consumers need to be educated to accept fortified products.

To avoid overdose, plant milk consumers may choose fortified milks, appropriate amounts of other iodine-rich foods, or iodine supplementation with potassium salts (150 mcg/d or less) than kelp.

Conclusions

Sustainability alone cannot define optimal nutrition. “The creaming of plant-based milk as“Alternatives“The dairy milk is based on its intended use without considering the micronutrients, bioavailability or health effects of replacing cow's milk with plant-based milk alternatives. ““This can lead to iodine deficiency in the current and future generations.

Public health experts should guide consumers to use fortified foods or supplements. It is also important to recognize that the effects of replacing cow's milk with plant-based alternatives depend on whether the replacement is total or partial, the iodine content of other foods in the diet, and the life stage of the consumer. Plant-based milk studies are needed to assess the bioavailability of supplemental iodine and to understand consumer perceptions and population-level attachment levels.

Download your PDF copy now!

Sources: