Assessing the potential of milk iodine intake to mitigate iodine deficiency in pregnant women of the United States via supplementation of Ascophyllum nodosum meal to dairy cows: A sensitivity analysis

Abstract

The brown seaweed Ascophyllum nodosum is known to bioaccumulate iodine (I). Previous research showed a linear relationship between A. nodosum meal (ASCO) intake and milk I concentration in dairy cows. Thus, improving milk I concentration by supplementation of ASCO to dairy cows may be a compelling strategy to naturally boost I intake in humans. A sensitivity analysis was conducted to gain insights regarding how different milk I intakes affect the I status of pregnant women relative to the United States Institute of Medicine (US IOM) recommended dietary allowance (RDA; 220 µg/d) and the World Health Organization (WHO) recommended nutrient intake (RNI; 250 µg/d) for I. Four studies in which dairy cows received various amounts of ASCO generated the milk I data set used in the sensitivity analysis. The annual per capita consumption of 2% reduced-fat milk in the United States, converted to daily intake (i.e., 0.26 cup; 1 cup = 236.6 mL), was used as the actual milk intake in the simulations. Five additional milk intake scenarios (2, 3, 4, and 5 times the actual per capita milk consumption and the 3 cups-equivalent recommended by the 2015-2020 Dietary Guidelines for American were also included in the sensitivity analysis with varying milk I concentrations (180, 765, and 483 µg/L). The 180, 765, and 483 µg/L values are milk I concentrations derived from cows not receiving ASCO or fed various amounts of ASCO in the diet or a single level (113 g/d) during the grazing season, respectively. With the actual United States milk per capita consumption of 0.26 cup/d and milk I concentrations of 180, 765, and 483 µg/L, 5.09, 21.7, and 13.6% of the RDA for I for pregnant women were met based on the US IOM, respectively. Similarly, 4.48, 19, and 12% of the RNI for I advised by the WHO was achieved with intake of 0.26 cup/d of milk containing I concentrations of 180, 765, and 483 µg/L, respectively.When 3 cups/d was included in the simulations, 58.2, 247, and 156% (US IOM), and 51.2, 217, and 137% (WHO) of the RDA or RNI for I required by gestating women was satisfied with milk I concentrations of 180, 765, and 483 µg/L, respectively. A regression analysis between I intake and milk I concentration revealed that 103 g/d of ASCO in the diet of dairy cows reached the maximum 500 µg/L threshold of I in milk recommended by the European Food Society Authority. Overall, milk from dairy cows fed ASCO can prevent I deficiency in pregnant women, but the amount of ASCO fed to cows needs to be fine-tuned to avoid excess I in milk. Further research is required to better understand the interactions between goitrogenic compounds from forages and concentrates and milk I concentration in cows fed ASCO. Research to evaluate the concentration of I in retail organic milk should be also conducted because of the high prevalence of ASCO fed in organic dairies in the United States.

Maine organic dairy producers’ receptiveness to seaweed supplementation and effect of Chondrus crispus on enteric methane emissions in lactating cows

“…This discrepancy may be attributed to intrinsic species differences, effects of seasonality, geographical location, and harvesting and processing methods ( 28 ). Considering that iodine can be transferred from feed into milk, the high concentration of iodine in seaweeds in studies conducted with lactating dairy cows, have raised animal and human-health concerns ( 29 ). Although high iodine intake is well tolerated by most healthy individuals, people with underlying thyroid conditions or susceptible groups (e.g., elderly and neonates), may develop goiter (thyroid enlargement), hyperthyroidism, or hypothyroidism ( 30 , 31 ).…”

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“…Concentrations of iodine in forages reach up to 0.2 mg/kg dry matter (Flachowsky et al 2014), which is comparable with Travnicek et al (2004), who determined iodine content in grass silage (213.3 ± 169.3 μg/kg dry matter). Moreover, it is also possible to administer organically bound iodine to dairy animals, using algae (Travnicek et al 2010;Brito 2020).…”

Enteric methane emissions in grazing dairy systems

“…In addition, seaweed anti-methanogenic effects would need to persist over time, which depends on the stability of bioactive compounds and on how harvesting, processing, and seasonality affect their concentrations in algal tissues. The potential for elevated iodine and bromoform concentrations in milk must also be considered in future research ( Beauchemin et al, 2020 ; Brito, 2020 ).…”