Pregnancy riboflavin

Riboflavin is also known as vitamin B2. It contains a complex isoalloxazine ring that humans are unable to synthesize. The complex ring is hooked onto a live-carbon sugar derivative, ribitol, closely related to the ribose that occurs in RNA. The RDA for adult males is 1.3 mg/day and for adult females 1.1 mg/day. Values decrease with increasing age but increase in pregnancy and lactation. Organ meats, milk, bread products, and fortified cereals are substantial sources of riboflavin. 

Merrill, A. H., Frochlich, J. A-, and McCormick, D. D. (1979). Purification of riboflavin-binding proteins from bovine plasma and discovery of a pregnancy-specific riboflavin-binding protein,. Bioi. Chem. 254,9362-9.364. 

Two HIV-1-positive women, both of whom had taken regimens containing stavudine and didanosine for at least 2 years, presented in the third trimester of pregnancy, one with acute lactic acidosis and one with acute pancreatitis and lactic acidosis (32). In the first case both mother and baby died. It is not known whether pregnancy is a risk factor for NRTI-induced lactic acidosis, perhaps in combination with riboflavin deficiency or a metabolic defect in the fetus, or whether NRTIs independently cause lactic acidosis through mitochondrial toxicity. 

Riboflavin is a nutritional supplement used during periods of deficiency known as ariboflavinosis. Riboflavin deficiency usually occurs in association with malabsorption, alcoholism, or protein-calorie deficiency, and is rarely the sole vitamin deficiency. Riboflavin needs are increased during chronic debilitative stress to the body such as malabsorption diseases of the small intestine, liver disease, hyperthyroidism, alcoholism, and during pregnancy and lactation. Neonates undergoing phototherapy for hyperbiliru-binema also have increased nutritional needs. 

Natraj U, George S, Kadam P. Isolation and partial characterisation of human riboflavin carrier protein and the estimation of its levels during human pregnancy. J Reprod Immunol 1988 13 1-16. 

B2 riboflavin Milk, enriched breads and cereals, Uver, lean meats, eggs, leafy green vegetables Male 1.4-1.7 mg Female 1.2-1.3 mg Pregnancy 1.6 mg Lactating 1.8 mg... 

Contraindications Thiamine patients with renal dysfunction Riboflavin patients with renal dysfunction Niacin or nicotinic acid hypersensitivity to niacin or tartrazine active peptic ulcer, severe hypotension, hepatic dysfunction, arterial hemorrhaging Caution diabetes mellitus, gallbladder disease, gout, history of jaundice or Uver disease. Pyridoxine IV therapy in cardiac patients Caution megadosage in pregnancy... 

Many factors affect folate metabolism, including dietary folate level, nutritional status of vitamins B6, B12, and riboflavin, zinc status, alcoholism, and physical states such as pregnancy and lactation. In many cases, the effects of these factors are seen in altered excretion rates of intact folates and metabolites, but the effects on tissue levels of the various folates and transfer rates between tissues are not well understood. Preliminary human and animal kinetic models are being devek ed in our laboratory based on studies conducted under controlled dietary conditions. These models will provide a base from which to study the effects of altered folate nutriture as well as the influence of other factors such as pregnancy and aging on folate metabolism. 

Vitamins are a well-known group of compounds that are essential for human health. Water-soluble vitamins include folate (vitamin B9) to create DNA. Folate also plays an important role in preventing birth defects during early pregnancy. Thiamine is the first vitamin of the B-complex (vitamin Bl) that researchers discovered. It allows the body to break down alcohol and metabolize carbohydrates and amino acids. Like many other B vitamins, riboflavin (vitamin B2) helps the body to metabolize carbohydrates, proteins, and fat. Niacin (vitamin B3) protects the health of skin cells and keeps the digestive system functioning properly. Pantothenic acid (vitamin B5) and biotin allow the body to obtain energy from macronutrients such as carbohydrates, proteins, and fats. Vitamin B6 (pyridoxine) acts as a coenzyme, which means it helps chemical reactions to take place. It also plays a vital role in the creation of nonessential amino acids. 

In humans, riboflavin, FAD and FMN are transported in blood plasma mainly through weak associations with albumin and some immunoglobulins. Other riboflavin-binding proteins are specific to pregnancy, including the classic case of the estrogen-induced egg-white protein. These proteins have at... 

In animals, riboflavin deficiency during pregnancy has resulted in striking abnormalities in the embryo and, at times, in abortion. Whether congenital defects in man are ever related to an inadequate maternal supply of riboflavin is unknown. 

CVR Murthy, PR Adiga. Isolation and characterisation of a riboflavin-carrier protein from human pregnancy serum. Biochem Int 5 289-296, 1982. 

RECOMMENDED DAILY ALLOWANCE OF RIBOFLAVIN. Prior to 1980, the Recommended Dietary Allowances of the Food and Nutrition Board (FNB), National Research Council-National Academy of Sciences, related the allowances for riboflavin to (1) protein allowances (1958), (2) energy intake (1964), and (3) metabolic body size (1968). In the ninth edition, 1980, the FNB concluded that the information available does not support strongly any one of these over another. In the tenth edition, 1989, the FNB listed the following factors as being known to affect the riboflavin requirements nitrogen balance, energy (work) expenditure, and pregnancy-lactation. 

Pregnancy— The recommended allowances call for an additional 0.3 mg/day of riboflavin during pregnancy. 

The recommended riboflavin requirements for humans vary with respect to sex, age, and physiological state (such is the case during pregnancy and lactation). Normal adults need to consume between 0.9 and 1.6 mg of this vitamin on a daily basis since the human body does not have deposits of riboflavin and an excess of vitamin intake is eliminated in urine (Institute of Medicine 1998). Although present in a wide variety of foods, riboflavin deficiency (ariboflavinosis) still occurs in both developing and industrialized countries (O Brien et al. 2001 Blanck et al. 2002). Even though severe cases of ariboflavinosis are not common in most societies, subclinical manifestations are frequent and these are only detectable by measuring the blood vitamin concentrations. 

Riboflavin is secreted into milk, the concentration being species specific and to a moderate extent dependent on maternal status and intake. Riboflavin is also required by the developing fetus during pregnancy, which implies a need for active transport from the maternal to the fetal circulation the flavin concentration being greater on the fetal side. Studies from India have identified a riboflavin carrier... 

Many tissues are affected by riboflavin deficiency (aribofla-vinosis). Riboflavin deficiency requires 3-4 months of deprivation to manifest and symptoms include lesions on the lips, inflammation of the tongue, lowered levels of white and red blood cells, excessive sensitivity to pain and vascu-larisation of the cornea. Deficiency also results in decreased conversion of tryptophan into niacin. A test for deficiency is to measure glutathione reductase levels, which are depressed when riboflavin levels are low as are xanthine oxidase levels. There is a link between riboflavin deficiency in pregnancy and the development of pre-eclampsia. However, supplementation with riboflavin in a trial indicated that there was no effect on the prevention of pre-eclampsia. Alcoholics are at increased risk of riboflavin deficiency as... 

When mature female rats are placed on a diet lacking riboflavin and l>red to stock males, they give birth to normal offspring if they conceive immediately. If conception is delayed they may resorb their young or become sterile before pregnancy takes place (112). It is not possible to state how long it takes to induce sterility since individual rats behave differently in this respect. This variability may be caused by differing abilities of the... 

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