Urinary Excretion

As noted earlier, the amount of riboflavin excreted in the urine is negligible at low intakes of the vitamin. As the dietary level rises there is slow increase to a transition point, above which the slope of the excretion rate increases very sharply, and then remains proportional to intake until absorption is saturated. For population studies it has been found convenient to use the creatinine excretion rate as the denominator, and the suggested interpretation of urinary riboflavin excretion rates is: <27 mg riboflavin perg creatinine for deficient; 27-79 mgg"1 for low; and >80 mgg"1 for acceptable. Detailed studies of the relation between intake and excretion rate have recently shown that this index is sufficiently sensitive to distinguish riboflavin requirements between people on low-fat, high-carbohydrate diets and the slightly higher requirement associated with high-fat, low-carbohydrate diets. Metabolic states associated with general tissue catabolism can sometimes result in liberation of riboflavin during cell turnover; this increases its urinary excretion, even though dietary intake may be low.

Good Carb Diet

Good Carb Diet

WHAT IT IS A three-phase plan that has been likened to the low-carbohydrate Atkins program because during the first two weeks, South Beach eliminates most carbs, including bread, pasta, potatoes, fruit and most dairy products. In PHASE 2, healthy carbs, including most fruits, whole grains and dairy products are gradually reintroduced, but processed carbs such as bagels, cookies, cornflakes, regular pasta and rice cakes remain on the list of foods to avoid or eat rarely.

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