The American journal of clinical nutrition
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Randomized Controlled Trial Clinical Trial
Long-term calcium supplementation does not affect the iron status of 12-14-y-old girls.
Single-meal studies have established that calcium has an acute inhibitory effect on the absorption of iron. However, there is growing evidence that high calcium intakes do not compromise iron status. ⋯ Although it remains to be shown in iron-deficient persons, long-term iron status does not seem to be compromised by high calcium intakes.
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Randomized Controlled Trial Clinical Trial
Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women.
Limited evidence suggests that a higher ratio of protein to carbohydrate during weight loss has metabolic advantages. ⋯ An energy-restricted, high-protein, low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high-carbohydrate diet.
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Randomized Controlled Trial Clinical Trial
Betaine concentration as a determinant of fasting total homocysteine concentrations and the effect of folic acid supplementation on betaine concentrations.
Remethylation of homocysteine to methionine can occur through either the folate-dependent methionine synthase pathway or the betaine-dependent betaine-homocysteine methyltransferase pathway. The relevance of betaine as a determinant of fasting total homocysteine (tHcy) is not known, nor is it known how the 2 remethylation pathways are interrelated. ⋯ The plasma betaine concentration is a significant determinant of fasting tHcy concentrations in healthy humans. Folic acid supplementation increases the betaine concentration, which indicates that the 2 remethylation pathways are interrelated.
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Randomized Controlled Trial Clinical Trial
Dietary peptides increase endogenous amino acid losses from the gut in adults.
Accurate estimates of endogenous ileal total nitrogen and amino acid flows are necessary to ascertain true dietary amino acid digestibility coefficients and for the factorial estimation of dietary amino acid requirements. ⋯ The traditional protein-free method underestimates endogenous ileal amino acid loss in adults.
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Randomized Controlled Trial Clinical Trial
Carbohydrate-restricted diets high in either monounsaturated fat or protein are equally effective at promoting fat loss and improving blood lipids.
When substituted for carbohydrate in an energy-reduced diet, dietary protein enhances fat loss in women. It is unknown whether the effect is due to increased protein or reduced carbohydrate. ⋯ The magnitude of weight loss and the improvements in insulin resistance and cardiovascular disease risk factors did not differ significantly between the 2 diets, and neither diet had any detrimental effects on bone turnover or renal function.