Take a stroll down the dairy or alternative dairy aisle, and you’ll see every imaginable non-milk beverage, including hemp, cashew, oat, pea protein and the ever popular coconut and almond. These milk alternative beverages, also nicknamed ‘mylks,” are increasingly popular even among people who do not have to avoid dairy for medical reasons. As the popularity of these beverages grows, sp have new insights about whether people may not be getting all the nutrients they need when primarily consuming these milk alternatives. In this story, we review recent studies you should be aware of when your patients tell you they don’t drink dairy milk.
Vitamin D Regulations Have Changed for Milk Alternative Beverages
In 2016, the Food and Drug Administration increased the amount of vitamin D that can be added to both dairy milk and milk alternatives. The amended law allows manufacturers to voluntarily add up to 84 IU/100g of vitamin D3 (cholecalciferol) to milk, 84 IU/100g of vitamin D2 (ergocalciferol) to plant-based beverages intended as milk alternatives, and 89 IU/100g of vitamin D2 to plant-based yogurt alternatives. The FDA chose to allow D2 in alternative milks because the form of vitamin D is derived from irradiating yeast, while D3 is derived from lanolin found in sheep;s wool.
Iodine Deficiency and Milk Alternatives
A new study shows that government regulators may also need to consider whether iodine should be added to milk alternative products. A University of Surrey study, published this month in the British Journal of Nutrition, examined the iodine content of 47 milk-alternative drinks (including soy, almond, coconut, oat, rice, hazelnut and hemp, but excluding those marketed specifically at infants and children) and compared it with that of cows’ milk.
Researchers discovered that the majority of milk-alternative drinks did not have adequate levels of iodine, with concentration levels found to be around 2% of that found in cows’ milk. Cows’ milk and dairy products are the main source of iodine in the UK diet however findings from the study show that most milk-alternative drinks are not an adequate substitute.
This same concern was raised in 2015 from Boston University School of Medicine when four patients were diagnosed with iodine deficiency–induced goiter during a 4-year period in an endocrine clinic in central New Jersey. At the time, researchers considered whether the under use of iodized salts and the overuse of non-iodized kosher and “designer” sea salts might be to blame.
Researchers from Surrey and Boston agree that most adults, children and adolescents are not at risk for a deficiency as they are able to consume the recommended 150mcg per day. However when the recommendations rise to 200mcg, such as during pregnancy, that is when the risk for deficiency becomes very real. A glass of a milk-alternative drink only provides around 2 mcg of iodine
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 realize that they will not be replacing the iodine from cows’ milk which is the main UK source of iodine.
Boston University researchers recommend that U.S. clinicians manage patients at risk for iodine deficiency with preventive measures. The American Association of Clinical Endocrinologists and other societies currently recommend that U.S. women who are pregnant, lactating, or planning a pregnancy should ingest a daily supplement containing 150 μg of iodine. Patients need to actively seek out such supplements because half of prenatal multivitamin preparations marketed in this country contain no iodine, according to a New England J of Medicine study. Although increasing sodium intake cannot be recommended, patients who already add table salt to their food are best advised to make sure they are using iodized salt.
Height Differences in Children
An American Journal of Clinical Nutrition study published in August 2017 gained a great deal of attention among milk and non-milk drinking parents. The study, took a cross sectional look at 5034 healthy Canadian children, ages 24–72 months, who were enrolled in the Applied Research Group for Kids cohort. They measured the volume of non-cow’s milk consumption (number of 250-mL cups per day) and found a dose-dependent association between higher non-cow milk consumption and lower height (P < 0.0001).
For each daily cup of non-cow’s milk consumed, children were 0.4 cm (95% CI: 0.2, 0.8 cm) shorter. In the mediation analysis, lower cow’s milk consumption only partially mediated the association between non-cow’s milk consumption and lower height. The height difference for a child aged 3 y consuming 3 cups non-cow milk/d relative to 3 cups cow milk/d was 1.5 cm (95% CI: 0.8, 2.0 cm). The researchers could not find a casual relationship and called for more research.
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. doi:10.1017/S0007114517002136
Elizabeth N. Pearce (2015) Is Iodine Deficiency Reemerging in the United States?. AACE Clinical Case Reports: Winter 2015, Vol. 1, No. 1, pp. e81-e82.
Morency ME, Birken CS, Lebovic G, Chen Y, L’Abbé M, Lee GJ, Maguire JL; TARGet Kids! Collaboration. Association between noncow milk beverage consumption and childhood height. Am J Clin Nutr. 2017 Aug;106(2):597-602. doi: 10.3945/ajcn.117.156877. Epub 2017 Jun 7. PubMed PMID: 28592600.