Iodine status and thyroid function of Boston-area vegetarians and vegans.

CONTEXT: Adequate dietary iodine is required for normal thyroid function. The iodine status and thyroid function of U.S. vegetarians and vegans have not been previously studied. Environmental perchlorate and thiocyanate (inhibitors of thyroid iodine uptake) exposures may adversely affect thyroid function. OBJECTIVE: The objective of the study was to assess the iodine status and thyroid function of U.S. vegetarians (consume plant based products, eggs, milk; abstain from meat, poultry, fish, shellfish) and vegans (avoid all animal products) and whether these may be affected by environmental perchlorate and thiocyanate exposures. DESIGN AND SETTING: This was a cross-sectional assessment of urinary iodine, perchlorate, and thiocyanate concentrations and serum thyroid function in Boston-area vegetarians and vegans. SUBJECTS: One hundred forty-one subjects (78 vegetarians, 63 vegans) were recruited; one vegan was excluded. RESULTS: Median urinary iodine concentration of vegans (78.5 µg/liter; range 6.8-964.7 µg/liter) was lower than vegetarians (147.0 µg/liter; range 9.3-778.6 µg/liter) (P < 0.01). Adjusted for cigarette smoking (confirmed by urinary cotinine levels) and thiocyanate-rich food consumption, median urinary thiocyanate concentration of vegans (630 µg/liter; range 108-3085 µg/liter) was higher than vegetarians (341 µg/liter; range 31-1963 µg/liter) (P < 0.01). There were no between-group differences in urinary perchlorate concentrations (P = 0.75), TSH (P = 0.46), and free T(4) (P = 0.77). Urinary iodine, perchlorate, and thiocyanate levels were not associated with TSH (P = 0.59) or free T(4) (P = 0.14), even when adjusted for multiple variables. CONCLUSIONS: U.S. vegetarians are iodine sufficient. U.S. vegans may be at risk for low iodine intake, and vegan women of child-bearing age should supplement with 150 µg iodine daily. Environmental perchlorate and thiocyanate exposures are not associated with thyroid dysfunction in these groups.

Iodine in enteral and parenteral nutrition.

Iodine deficiency (ID) has multiple adverse effects on growth and development due to inadequate thyroid hormone production. Methods for assessment of iodine nutrition in individuals include the urinary iodine concentration (UI), thyroid size and thyroid function tests. The UI measured in several repeat 24-h urine samples can detect inadequate iodine intake in individuals receiving enteral or parenteral nutrition (PN) and allow for iodine supplementation before the onset of hypothyroidism. A daily dose of 1 microg iodine/kg body weight is currently recommended for children receiving PN, but this is far below their requirements. Daily iodine requirements in adults receiving enteral nutrition or PN are estimated to be 70-150 microg, but most PN formulations do not contain iodine. Despite this, ID has been unlikely because absorption from iodine-containing skin antiseptics and other adventitious sources can provide sufficient iodine. However, if chlorhexidine replaces iodine-containing antiseptics for catheter care, ID may occur during long-term PN, and periodic testing of UI and thyroid function may be prudent. Infants may be particularly vulnerable to ID because of their small thyroidal iodine store. In this review, we describe three recent patients (an infant, a child and an adult) who developed ID and thyroid hypofunction during PN.

Nutritional deficiencies in German middle-class male alcohol consumers: relation to dietary intake and severity of liver disease.

OBJECTIVE: The purpose of the present study was to compare the nutrient intake and the nutritional status between German middle-class alcohol consumers and non-drinkers. DESIGN: Cross-sectional study using patients with different stages of alcoholic liver disease (ALD) and healthy volunteers. SETTING: Southern Germany. SUBJECTS: Seventy-six hospitalized German middle-class alcohol consumers with different stages of alcoholic liver disease (ALD) and 22 healthy control subjects. METHODS: Subjects and controls were nutritionally assessed and mineral and vitamin content was measured in blood and urine. RESULTS: When compared with controls, alcohol consumers had significantly higher intakes of total calories, but intake of non-alcoholic calories did not differ between groups (P<0.05). Among drinkers, there was a decrease in percentage of energy derived from protein and fat and a significant increase in carbohydrates (P<0.05). With the exception of vitamin E, micronutrient intake of alcoholics was equal to that of controls; however, blood vitamin (vitamin C, retinol, lycopene, alpha- and gamma-carotene) and trace element (selenium, zinc) concentrations of alcohol-drinking patients were lower than those of non-drinkers. CONCLUSION: From the results of this study it is concluded that in German middle-class male alcohol consumers the status of several micronutrients is disturbed, although dietary intake hardly differs from that in non-alcoholic controls.

Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased during recovery from severe childhood malnutrition and responds to supplemental glycine.

We hypothesized that a limitation in the endogenous formation of glycine might constrain catch-up growth during recovery from severe childhood malnutrition. The urinary excretion of 5-L-oxoproline is increased when the glycine available for glutathione synthesis is limited. Urinary excretion of 5-L-oxoproline was measured throughout recovery in 12 children (aged 16 +/- 6 mo) with severe malnutrition. Urinary 5-L-oxoproline was similar at admission and after recovery, but was increased significantly during rapid catch-up growth. There was a significant relationship between the rate of weight gain and 5-L-oxoproline excretion in urine. In nine children (aged 15 +/- 5 mo), the effect of oral supplementation with glycine, [1.7 mmol/(kg x d) for 48 h] during rapid catch-up growth on 5-L-oxoprolinuria and blood glutathione concentration was determined. In seven of the nine children weight gain was less than 17 g/(kg x d) and following oral glycine supplements 5-L-oxoproline excretion was reduced up to 64% and blood glutathione concentration increased up to 100%. In the two children who were gaining weight at a rate > 17 g/(kg x d), glycine supplementation was associated with a further increase in 5-L-oxoproline excretion and a decrease in blood glutathione. If 5-L-oxoproline is an index of the relative availability of glycine, then the data indicate that glycine may be limiting during rapid catch-up growth. This would have important implications for repletion of muscle and gain in height.

[Zinc balance in malnourished children given prolonged total parenteral feeding]. / Balance de zinc en niños desnutridos con alimentación parenteral total prolongada.

Zinc balances were performed in five different occasions in three children receiving prolonged total parenteral nutrition (TPN) for 4 or more weeks. Excessive urinary zinc loss was a constant finding and one patient also presented increased fecal loss. It is concluded that TPN solutions when administered for long periods must be supplemented with zinc in order to obtain positive balances and a retention of zinc between 50-100 micrograms kg/day. In children without abnormal losses supplements recommended by the American Medical Association (100 micrograms/kg/day up to 5 years and from 2.5 to 4 mg/day in old children) seem adequate. In case of deficit in Zn and/or high digestive losses supplement of Zn in TPN must be increased up to 200 to 500 micrograms/kg/day.

Studies on skin and urinary mucopolysaccharides in malnourished/vitamin A deficient children.

In protein-calorie malnourished children, with or without associated vitamin A deficiency, skin content of acid mucopolysaccharides (MPS) and urinary excretion of MPS and amino sugars were studied. MPS content of skin in both malnourished groups was increased 3-6-fold. This increase was essentially in the non-sulphated component. In normal skin, non-sulphate MPS accounted for 68% of the MPS content, whereas in the malnourished group with vitamin A deficiency it constituted 93%. Urinary excretion of MPS (24h) was significantly reduced by 50-70% in malnourished groups. This returned to normal levels in the malnourished/vitamin A deficient group when vitamin A injections were administered. Excretion of amino sugars (24 h) in the malnourished groups was also decreased by 50-70%. In normal children 55% of the total amino sugars was dialysable whereas in the malnourished it was increased to 60%. The excretion of protein-bound and dialysable amino sugars was increased to normal level only in the group given supplements of vitamin A in addition of protein and calories.