Intake of thiocyanate by way of milk and its possible effect on thyroid function

Abstract

The keeping quality of milk can be improved if the lactoperoxidase system is activated. To make such an activation efficient the thiocyanate concentration has to be increased. Since, however, thiocyanate has a potent antithyroid effect, thyroid function has been studied in 37 healthy individuals during 12 wk of daily intake of 8 mg thiocyanate by way of milk. The thiocyanate increased significantly in serum and reached a maximum value after 4 wk (+3.8 mg/1). The increased serum levels coincided with an increased excretion in urine (+ 4.8 mg/g creatinine). The levels of thyroxine, triiodothyronine, and thyrotropic hormone were all in the normal range at the beginning of the investigation and no significant changes were found during the experimental period. In conclusion, a daily intake of 8 mg thiocyanate by way of milk does not have any apparent effect on the thyroid function.

The influence of time elapsed after milking and lactation stage on the lactoperoxidase system of milk in Sahiwal cattle and Nili‐Ravi buffaloes

“…Cows grazing on natural pastures are reported to have higher thiocyanate compared to nongrazing cows (Reiter and Harnulv 1984). However, higher LP activity and elevated thiocyanate contents during the middle of lactation in buffaloes compared to those in cows may be attributed to genetic factors where some breeds of animals tend to be more efficient in digesting and metabolising glucosinolates and/or cyanogenic glucosides present in rations than other breeds of animals (Dahlberg et al. 1984; Zapico et al.…”

Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism

“…One study examined the addition of thiocyanate to raw cow's milk, since stimulation of oxidation of exogenous thiocyanate to the short-lived hypothiocyanite anion (OSCN À ) by lactoperoxidase from milk has bactericidal effects, assisting in milk preservation. 29 To test whether these thiocyanate concentrations could have an effect on thyroid function in humans, Dahlberg et al 29 added 8 mg of thiocyanate each day to the milk consumed by human volunteers and reported no effect on serum thyroxine, triiodothyronine, or thyrotropin concentrations after 12 weeks. Serum thiocyanate concentrations were 69 lM and 121 lM before and after milk ingestion, respectively, among nonsmokers after the 12-week study period.…”

“…57 The maximum plasma thiocyanate value reported for smokers was 121 lM. 29 Choi et al 58 measured the concentrations of thiocyanate, cyanide, and organic isothiocyanates in the serum of rats after administration of a single dose of 50 lmol of various glucosinolates. As shown in Table 1, a dose of 50 lmol is comparable to the amount of glucoraphanin present in a 100-g serving of broccoli for a human, and thus the maximum value of 50 lM of sinigrin-derived thiocyanate they measured in rat plasma is an overestimation of what could be expected in humans.…”

Further studies on the sources of thiocyanate ion in the excreta of poultry fed low‐glucosinolate rapeseed (Brassica napus) meal

“…Antithyroid responses of humans to SCN have been reported but the level of intake was high (Fenwick et al 1983). In this regard Dahlberg and Bergmark (1984) demonstrated normal thyroid function in healthy human subjects that consumed 8 mg SCN daily for 12 weeks. The 4-5 pmol g -of indole glucosinolates unaccounted for in the current analyses require further study to assess their potential antinutritive effects, and compounds soluble in dichloromethane should be given consideration.…”