Effect of protein dose on serum glucose and insulin response to sugars.

To clarify the effects of protein on insulin and glucose response to sugars, 14 healthy normal-weight males and females were fed test meals containing 0, 15.8, 25.1, 33.6, and 49.9 g protein along with approximately 58 g carbohydrate. Serum samples were obtained at fasting time zero and 15, 30, 60, and 120 min postprandial. Mean areas of the glucose curves above fasting decreased with increasing protein dose. Protein-containing meals produced significantly lower (p less than 0.01) areas than the protein-free meal and the relationship between blood glucose area and protein dose was significant (p less than 0.001). Protein-containing meals produced significantly greater (p less than 0.01) insulin areas compared with the protein-free meal. However, no differences in insulin areas among the protein-containing meals were observed. These data support previous studies showing a blood glucose moderating and insulin-enhancing effect of protein ingestion.

Repletion and depletion of serum alpha and beta carotene in humans with carrots and an algae-derived supplement.

A 10-day low-carotene diet phase (LCD), followed by a 7-day treatment phase (TP) and then another LCD, was adhered to by 32 adult human subjects. Serum alpha carotene (SAC) and serum beta carotene (SBC) levels were examined using HPLC and found to have decreased 44.7% and 35.8% respectively in the first LCD. Alpha and beta carotene, from algae-derived capsules and raw carrots, significantly increased SAC and SBC levels during the TP. Half-lives of SAC and SBC averaged 7.8 days and 12.4 days respectively during the two LCD. Serum vitamin A remained unchanged throughout the study.

Multivitamin-mineral supplementation: effects on blood chemistries of college-age women.

Forty-two female college students, age 18-29 yr. and consuming nutritionally balanced meals in the college cafeteria participated. Subjects discontinued all vitamin-mineral supplements (VMS) for 17 days and were randomly assigned to one of two treatments, either a placebo, or VMS supplying the United States Recommended Daily Allowance (USRDA) of all vitamins, zinc, iron, iodine, copper, and 60% of the USRDA of calcium, 50% of magnesium and 45% of phosphorus. Treatments were consumed for 77 days. Fasting pre-and post-treatment blood chemistries were compared. VMS yielded significant increases (p less than 0.05) in serum vitamin B-12 (+25.05 pg/ml), vitamin C (+0.35 mg/dl) and folate (+7.40 ng/ml). No significant changes (p greater than 0.05) in hematological or other blood chemistries were observed. Significant decreases in the number of below-normal serum indicators of vitamin status (p less than 0.05) and iron status (p less than 0.005) were seen with VMS. No significant changes were seen with placebo (p greater than 0.05).

Simultaneous determination of vitamins B1, B2, B6, and niacinamide in multivitamin pharmaceutical preparations by paired-ion reversed-phase high-pressure liquid chromatography.

A high-pressure liquid chromatographic procedure for the simultaneous determination of vitamins B1, B2, B6, and niacinamide in multivitamin pharmaceutical preparations was developed and evaluated. The method uses paired-ion reversed-phase partition chromatography for baseline separation of the four water-soluble vitamins. This method was applied to the analysis of a multivitamin and multivitamin-multimineral tablets, and a technique was developed to reduce vitamin adsorption by the minerals. The results obtained by this method were compared with those obtained by the official methods. It was concluded that this method is fast, accurate, specific, and suitable for routine quality control use.