Plasma riboflavin concentrations in infants fed human milk versus formula: comparison with values in rats made riboflavin deficient and human cord blood

Riboflavin and health: A review of recent human research

There has lately been a renewed interest in Riboflavin owing to insight into its recognition as an essential component of cellular biochemistry. The knowledge of the mechanisms and regulation of intestinal absorption of riboflavin and its health implications has significantly been expanded in recent years. The purpose of this review is to provide an overview of the importance of riboflavin, its absorption and metabolism in health and diseased conditions, its deficiency and its association with various health diseases, and metabolic disorders. Efforts have been made to review the available information in literature on the relationship between riboflavin and various clinical abnormalities. The role of riboflavin has also been dealt in the prevention of a wide array of health diseases like migraine, anemia, cancer, hyperglycemia, hypertension, diabetes mellitus, and oxidative stress directly or indirectly. The riboflavin deficiency has profound effect on iron absorption, metabolism of tryptophan, mitochondrial dysfunction, gastrointestinal tract, brain dysfunction, and metabolism of other vitamins as well as is associated with skin disorders. Toxicological and photosensitizing properties of riboflavin make it suitable for biological use, such as virus inactivation, excellent photosensitizer, and promising adjuvant in chemo radiotherapy in cancer treatment. A number of recent studies have indicated and highlighted the cellular processes and biological effects associated with riboflavin supplementation in metabolic diseases. Overall, a deeper understanding of these emerging roles of riboflavin intake is essential to design better therapies for future.

A novel dairy product fermented with Propionibacterium freudenreichii improves the riboflavin status of deficient rats

OBJECTIVE

Riboflavin deficiency is common in many parts of the world, particularly in developing countries. The use of riboflavin-producing strains in the production of dairy products such as fermented milk, yogurt, and cheese is feasible and economically attractive because it would decrease the costs involved during conventional vitamin fortification and satisfy consumer demands for healthier foods. The present study in a rat bioassay assessed the response of administration of yogurt containing a riboflavin-producing strain of Propionibacterium freudenreichii on the riboflavin status of deficient rats.

METHODS

Propionibacterium freudenreichii NIZO B2336 is a spontaneous roseoflavin-resistant mutant derived from P. freudenreichii B374 that produces larger amounts of riboflavin than the parental stain. Rats were fed a riboflavin-deficient diet for 21 d (depletion period), after which this same diet was supplemented with conventional yogurt, yogurt containing the riboflavin-producing strain (B2336), or the parental non-producing strain (B374) and fed to animals for 28 d (repletion period). As controls, rats were fed the same diet with different concentrations of commercial riboflavin.

RESULTS

The novel fermented product containing P. freudenreichii B2336, with increased levels of riboflavin, eliminated most physiologic manifestations of ariboflavinosis such as stunted growth, high erythrocyte glutathione reductase activation coefficient values, and hepatomegaly that were observed when using a riboflavin depletion-repletion model, whereas the product fermented with the non-riboflavin-producing strain did not show this beneficial effect.

CONCLUSIONS

Consumption of such products with increased levels of riboflavin on a regular basis may help prevent deficiencies of this essential vitamin.

Ingestion of milk fermented by genetically modified Lactococcus lactis improves the riboflavin status of deficient rats

Riboflavin deficiency is common in many parts of the world, particularly in developing countries. The use of riboflavin-producing strains in the production of dairy products such as fermented milks, yogurts, and cheeses is feasible and economically attractive because it would decrease the costs involved during conventional vitamin fortification and satisfy consumer demands for healthier foods. The present study was conducted to assess in a rat bioassay the response of administration of milk fermented by modified Lactococcus lactis on the riboflavin status of deficient rats. Rats were fed a riboflavin-deficient diet during 21 d after which this same diet was supplemented with milk fermented by Lactoccus lactis pNZGBAH, a strain that overproduces riboflavin during fermentation. The novel fermented product, with increased levels of riboflavin, was able to eliminate most physiological manifestations of ariboflavinosis, such as stunted growth, elevated erythrocyte glutathione reductase activation coefficient values and hepatomegaly, that were observed using a riboflavin depletion-repletion model, whereas a product fermented with a nonriboflavin-producing strain did not show similar results. A safety assessment of this modified strain was performed by feeding rodents with the modified strain daily for 4 wk. This strain caused no detectable secondary effects. These results pave the way for analyzing the effect of similar riboflavin-overproducing lactic acid bacteria in human trials. The regular consumption of products with increased levels of riboflavin could help prevent deficiencies of this essential vitamin.

Lactococcus lactis is capable of improving the riboflavin status in deficient rats

Lactococcus lactis is a commonly used starter strain that can be converted from a vitamin B2 consumer into a vitamin B2 'factory' by over-expressing its riboflavin biosynthesis genes. The present study was conducted to assess in a rat bioassay the response of riboflavin produced by GM or native lactic acid bacteria (LAB). The riboflavin-producing strains were able to eliminate most physiological manifestations of ariboflavinosis such as stunted growth, elevated erythrocyte glutathione reductase activation coefficient values and hepatomegalia that were observed using a riboflavin depletion-repletion model. Riboflavin status and growth rates were greatly improved when the depleted rats were fed with cultures of L. lactis that overproduced this vitamin whereas the native strain did not show the same effect. The present study is the first animal trial with food containing living bacteria that were engineered to overproduce riboflavin. These results pave the way for analysing the effect of similar riboflavin-overproducing LAB in human trials.

Thiamine, riboflavin, pyridoxine, and vitamin C status in premature infants receiving parenteral and enteral nutrition

BACKGROUND

There is a paucity of data about water soluble vitamin status in low birthweight infants. Therefore, the authors' objective was to assess current feeding protocols.

METHODS

The authors measured serum concentrations for riboflavin, pyridoxine, and vitamin C and functional assays for thiamine and riboflavin longitudinally in 16 premature infants (birthweight, 1,336 +/- 351 g; gestational age, 30 +/- 2.5 weeks) before receiving nutrition (time 1, 2 +/- 1 days), during supplemental or parenteral nutrition (time 2, 16 +/- 10 days) and while receiving full oral feedings (time 3, 32 +/- 15 days). In plasma, vitamin C was measured colorimetrically, and riboflavin and pyridoxine were measured using high-performance liquid chromatography. The erythrocyte transketolase test as a functional evaluation of thiamine and the erythrocyte glutathione reductase test for riboflavin were measured colorimetrically.

RESULTS

At time 1, nutrient intake of vitamins were negligible because infants were receiving intravenous glucose and electrolytes only. Intakes differed between time 2 and time 3 for thiamine (510 +/- 280 and 254 +/- 115 microg. kg-1. d-1, respectively), riboflavin (624 +/- 305 and 371 +/- 193 microg. kg-1. d-1, respectively), and pyridoxine (394 +/- 243 and 173 +/- 85 microg/100 kcal, respectively), but not for vitamin C (32 +/- 17 and 28 +/- 12 mg. kg-1. d-1, respectively). Blood levels at times 1, 2, and 3 were for thiamine (4.9 +/- 2.7%, 3.3 +/- 6.6%, and 4.1 +/- 9% erythrocyte transketolase test, respectively), riboflavin (0.91 +/- 0.31, 0.7 +/- 0.3, 0.91 +/- 0.18 erythrocyte glutathione reductase test, respectively), riboflavin (19.5 +/- 17, 23.3 +/- 8.6, 17.6 +/- 10 ng/mL, respectively), pyridoxine (32 +/- 25, 40 +/- 16, 37 +/- 26 ng/mL, respectively), and vitamin C (5.2 +/- 3, 5 +/- 2.2, 10 +/- 5 microg/mL, respectively) and did not differ at those times.

CONCLUSIONS

Current intakes of these vitamins, except for possibly vitamin C, during parenteral and enteral nutrition seem to result in adequate plasma concentrations and normal functional indices.

Plasma and urine riboflavin during riboflavin-free nutrition in very-low-birth-weight infants

BACKGROUND

Very-low-birth-weight (VLBW; birth weight <1500 g) infants receive enteral and parenteral nutriture that provides greater daily riboflavin (vitamin B2) than does term infant nutriture, and elevated plasma riboflavin develops in these infants after birth. The purpose of this study was to measure plasma and urine riboflavin concentrations in VLBW infants during riboflavin-free nutrition. Our hypothesis was that elevated plasma riboflavin develops in VLBW infants because of high daily intake and immature renal riboflavin elimination.

METHODS

Eighteen clinically healthy VLBW infants received parenteral nutrition and preterm infant formula during the first postnatal month. On postnatal days 10 and 28, the infants received specially prepared riboflavin-free enteral and parenteral nutrition for the 24-hour study period. Serial collections of plasma were made at time 0 and at 12 and 24 hours. Urine was collected continuously for the 24-hour period in 4-hour aliquots. Samples were analyzed for riboflavin concentration.

RESULTS

During the 24-hour riboflavin-free study period on postnatal day 10, plasma riboflavin decreased 56% from 185 +/- 37 ng/mL (mean +/- SEM), and urine riboflavin decreased 75% from 3112 +/- 960 mg/mL. Similarly, on postnatal day 28, plasma riboflavin decreased 79% from 184 +/- 32 ng/mL, and urine riboflavin concentration decreased 91% from 5092 +/- 743 ng/mL during the 24-hour riboflavin-free study period. Riboflavin half-life (t(1/2)) was 18.5 hours on postnatal day 10 and decreased 48% by postnatal day 28. Riboflavin elimination was 145.1 +/- 20.6 mg/kg per day on postnatal day 10 and increased 40% by postnatal day 28.

CONCLUSION

The VLBW infants who received parenteral nutrition and preterm infant formula had elevated plasma riboflavin on postnatal days 10 and 28. Plasma riboflavin t(1,2) was shorter and renal riboflavin elimination was greater on postnatal day 28 than on postnatal day 10. Plasma riboflavin was normal after 24 hours of riboflavin-free nutrition. The pattern of plasma and urine riboflavin in VLBW infants suggests a lower daily intake would maintain plasma riboflavin close to normal.

Plasma and urine riboflavin and pyridoxine concentrations in enterally fed very-low-birth-weight neonates

Preterm infant formulas (PIFs) for very-low-birth-weight (VLBW) infants (birth weight, < 1,500 g) are augmented to provide daily riboflavin and pyridoxine at levels up to five-fold greater than in term infant formula and 18-fold greater than in human milk. We evaluated plasma riboflavin and pyridoxine concentrations in VLBW infants who received PIF during their first postnatal month. Eighty-eight plasma and 124 urine samples were collected for riboflavin- and pyridoxine-concentration measurements from 57 clinically healthy VLBW infants weekly during their first postnatal month. Concentrations were measured using high-performance liquid chromatography. At the time of the sample, patients were receiving > or = 80% of their total calories via enteral feedings. Plasma riboflavin concentrations rose from 45.3 +/- 7.3 ng/ml at baseline (mean +/- SEM) to 173.5 +/- 20.3 ng/ml by 1 week of age and remained at 177.3-199.7 ng/ml during the following three weekly measurements; values were up to 14-fold above baseline concentration. Urine riboflavin concentration increased from 534 +/- 137 ng/ml at baseline to 3,521 +/- 423 ng/ml by 1 week of age and remained at 4,451-5,216 ng/ml during the next 3 weeks. In a similar pattern, baseline plasma (69.4 +/- 10.4 ng/ml) and urine (145 +/- 30 ng/ml) pyridoxine concentrations were significantly increased by 1 week postnatal age; they remained at 163-248 ng/ml (plasma) and 1,573-2,394 ng/ml (urine) through the first postnatal month. Plasma and urine riboflavin and pyridoxine concentrations in enterally fed VLBW infants increased from baseline concentrations by 1 week of postnatal age and remained elevated for the first postnatal month. High daily intake and immature renal development are probable contributing causes of the elevated plasma riboflavin and pyridoxine concentrations. We suggest that lower daily enteral administration of riboflavin and pyridoxine should maintain adequate blood concentrations and minimize potential toxicity.

Intravenous vitamins for very-low-birth-weight infants

Term infants and children appear to adapt to large variations in vitamin intakes. This is supported by the finding of similar blood levels of vitamins despite several-fold differences in intake on a body weight basis. By contrast, the finding of marked elevation of some vitamins and low levels of others seen in very-low-birth-weight (VLBW) infants (less than 1500 g) suggest that this group has less adaptive capacity to high- or low-dose intakes. This indicates that their vitamin intakes need to be more closely aligned with actual needs. This paper reviews previously published data on vitamins A, E, B2, and B6 from VLBW infants receiving total parenteral nutrition (TPN). Vitamin A. VLBW infants are relatively deficient in retinol (R) at birth. During TPN large losses of R onto the delivery sets result in a further decline in stores of R as reflected in a progressive decline in plasma R during TPN. Because of the reported lower incidence of bronchopulmonary dysplasia associated with intramuscular vitamin A treatment, alternative methods of vitamin A delivery during TPN have been suggested. First, the vitamins were mixed with Intralipid (IL) and, second, retinyl palmitate (RP) rather than R was used. There was little in vitro loss of R when mixed with IL, and in vivo treatment resulted in higher blood levels after 1 month of retinol administration in IL than seen previously (21.4 +/- 4.2 vs 14.1 +/- 3.7 micrograms/dl).(ABSTRACT TRUNCATED AT 250 WORDS)