Large Variability of Iodine Content in Retail Cow's Milk in the U.S.

Iodine intake is of contemporary public health interest. The recommended daily iodine intake is 150 µg for most adults, and milk is an important source of iodine in the U.S. diet. Iodine concentration in cow's milk is affected by diet and iodine supplementation levels, milking sanitation practices, and other factors. Current analytical iodine data in U.S. retail milk are crucial for evaluating population-wide health outcomes related to diet. Samples of whole (3.25% fat), 2%, 1%, and skim (0-0.5% fat) milk were procured from 24 supermarkets across the U.S. using a census-based statistical plan. Iodine was analyzed by inductively coupled plasma mass spectrometry, including certified reference materials and control samples to validate results. No difference in iodine content was found between milkfat levels (F3,69 1.033, p = 0.4). Overall mean (SEM) was 85(5.5) µg/serving (240 mL). However, the 95% prediction interval of 39-185 µg/serving for individual samples indicated high variability among individual samples. Given the recommended 150 µg iodine per day for most adults along with the study mean, one milk serving can provide approximately 57% of daily intake. Researchers, health care professionals, and consumers should be aware of iodine variability in milk, while additional research is needed to investigate the impact of iodine variability factors.

Assessing Changes in Sodium Content of Selected Popular Commercially Processed and Restaurant Foods: Results from the USDA: CDC Sentinel Foods Surveillance Program.

This report provides an update from the U.S. Department of Agriculture - Centers for Disease Control and Prevention Sentinel Foods Surveillance Program, exploring changes in sodium and related nutrients (energy, potassium, total and saturated fat, and total sugar) in popular, sodium-contributing, commercially processed and restaurant foods with added sodium. In 2010-2013, we obtained 3432 samples nationwide and chemically analyzed 1654 composites plus label information for 125 foods, to determine baseline laboratory and label sodium concentrations, respectively. In 2014-2017, we re-sampled and chemically analyzed 43 of the Sentinel Foods (1181 samples), tested for significant changes of at least ±10% (p < 0.05), in addition to tracking changes in labels for 108 Sentinel Foods. Our results show that the label sodium levels of a majority of the Sentinel Foods had not changed since baseline (~1/3rd of the products reported changes, with twice as many reductions as increases). Laboratory analyses of the 43 Sentinel Foods show that eight foods had significant changes (p < 0.05); sodium content continues to be high and variable, and there was no consistent pattern of changes in related nutrients. Comparisons of changes in labels and laboratory sodium shows consistency for 60% of the products, i.e., similar changes (or no changes) in laboratory and label sodium content. The data from this monitoring program may help public health officials to develop strategies to reduce and monitor sodium trends in the food supply.