Riboflavin, Flavin Mononucleotide and Flavin Adenine Dinucleotide in Human Plasma and Erythrocytes at Baseline and after Low-Dose Riboflavin Supplementation.

Background: Vitamin B2 exists in blood as riboflavin and its cofactors, flavin mononucleotide (FMN) and FAD. The erythrocyte glutathione reductase activation coefficient (EGRAC) has traditionally been used to assess vitamin B2 status in humans. We investigated the relationships of EGRAC and plasma and erythrocyte concentrations of riboflavin, FMN, and FAD in elderly volunteers and their responses to riboflavin administration. Methods: EGRAC and plasma and erythrocyte concentrations of riboflavin, FMN, and FAD were determined in 124 healthy individuals with a mean age of 69 years. The same measurements were made in a subgroup of 46 individuals with EGRAC 1.20 who participated in a randomized double-blind 12-week intervention study and received riboflavin (1.6 mg/day; n = 23) or placebo (n = 23). Results: Median plasma concentrations were 10.5 nmol/L for riboflavin, 6.6 nmol/L for FMN, and 74 nmol/L for FAD. In erythrocytes, there were only trace amounts of riboflavin, whereas median FMN and FAD concentrations were 44 and 469 nmol/L, respectively. Erythrocyte FMN and FAD correlated with each other and with EGRAC and plasma riboflavin (P

A Debriefing Session with a Nutritionist Can Improve Dietary Assessment Using Food Diaries.

The objective of the current study was to evaluate the effect of a debriefing call on nutrient intake estimates using two 3-d food diaries among women participating in the Women's Health and Interview Study (WISH) Diet Validation Study. Subjects were 207 women with complete data and six 24-h recalls (24-HR) by telephone over 8 mo followed by two 3-d food diaries during the next 4 mo. Nutrient intake was assessed using the food diaries before and after a debriefing session by telephone. The purpose of the debriefing call was to obtain more detailed information on the types and amounts of fat in the diet. However, due to the ubiquitous nature of fat in the diet, the debriefing involved providing more specific detail on many aspects of the diet. There was a significant difference in macronutrient and micronutrient intake estimates after the debriefing. Estimates of protein, carbohydrate, and fiber intake were significantly higher and total fat, monounsaturated fat, saturated fat, vitamin A, vitamin C, -tocopherol, folic acid, and calcium intake were significantly lower after the debriefing (P <0.05). The limits of agreement between the food diaries before and after the debriefing were especially large for total fat intake, which could be under- or overestimated by 15 g/d. The debriefing call improved attenuation coefficients associated with measurement error for vitamin C, folic acid, iron, tocopherol, vitamin A, and calcium estimates. A hypothetical relative risk (RR) = 2.0 could be attenuated to 1.16 for folic acid intake assessed without a debriefing but to only 1.61 with a debriefing. Depending on the nutrients of interest, the inclusion of a debriefing can reduce the potential attenuation of RR in studies evaluating diet disease associations.

Homocysteine is lower in the Third Trimester of Pregnancy in Women with Enhanced Folate status from continued Folic Acid Supplementation.

Background: In many countries current recommendations are that women take a daily 400ug folic acid supplement, from before conception until the end of the 12th week of gestation, for the prevention of neural tube defects. Low folate status is associated with an elevated concentration of plasma total homocysteine (tHcy), a risk factor that is associated with pregnancy complications such as pre-eclampsia. Methods: In a longitudinal study, tHcy and corresponding folate status were determined in 101 pregnant women at 12, 20 and 35 weeks of gestation, in 35 non-pregnant control subjects sampled conconcurrently, and in a subgroup (n=21 pregnant, 19 non-pregnant women) at 3 days post-partum. Results: Plasma tHcy concentrations were significantly lower throughout pregnancy compared with control subjects, with values lowest in the 2nd trimester before increasing toward non-pregnant values in the 3rd trimester. Importantly, tHcy concentrations were lower in pregnant women taking folic acid supplements compared to those not, an effect which reached significance in the 3rd trimester (5.25 umol/l v 6.89 umol/l, P <0.05). Furthermore, during the 3rd trimester, tHcy concentrations were significantly higher in pregnant women with a history of miscarriage compared to those with no previous history (7.32 umol/l v 5.62 u­mol/l, P <0.01). Conclusion: This is the first longitudinal study to show that homocysteine levels rise in late pregnancy towards non-pregnant levels; a rise which can be limited by enhancing folate status through continued folic acid supplementation. These results indicate a potential role for continued folic acid supplementation in reducing pregnancy complications associated with hyperhomocysteinaemia.