Vitamin B2 (Riboflavin)


Clinical Studies
References


A vitamin which helps with energy production and amino acid production. Vitamin B2 helps the body obtain energy from protein, carbohydrates and fats. It helps maintain good vision and healthy skin. Deficiency may cause cracking of lips at corners, eye problems, light sensitivity and blurred vision.


Published Clinical Studies
Vitamin B2 (Riboflavin)


Nutritional abnormalities in HIV/AIDS.

Dunn JM.

AIDS: The nutritional abnormalities resulting from HIV/AIDS are discussed, including the consequences of wasting and its profound effects on patient quality of life. Deficits of vitamins A, E, B6 and B12, and riboflavin, zinc, and copper have been found in asymptomatic HIV-positive persons. The nutrient abnormalities may be linked to HIV disease progression. The cyclic process of contracting infections, requiring increased nutrients, is discussed. How the body suffering from HIV/AIDS-related wasting reacts to daily protein loss is examined, focusing on nitrogen depletion and increased lipogenesis.

Publication Types:

  • Newspaper Article


PMID: 11365362 [PubMed - indexed for MEDLINE]

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Riboflavin (vitamin B-2) and health.

Powers HJ.

Centre for Human Nutrition, The University of Sheffield, United Kingdom. h.j.powers@sheffield.ac.uk

Riboflavin is unique among the water-soluble vitamins in that milk and dairy products make the greatest contribution to its intake in Western diets. Meat and fish are also good sources of riboflavin, and certain fruit and vegetables, especially dark-green vegetables, contain reasonably high concentrations. Biochemical signs of depletion arise within only a few days of dietary deprivation. Poor riboflavin status in Western countries seems to be of most concern for the elderly and adolescents, despite the diversity of riboflavin-rich foods available. However, discrepancies between dietary intake data and biochemical data suggest either that requirements are higher than hitherto thought or that biochemical thresholds for deficiency are inappropriate. This article reviews current evidence that diets low in riboflavin present specific health risks. There is reasonably good evidence that poor riboflavin status interferes with iron handling and contributes to the etiology of anemia when iron intakes are low. Various mechanisms for this have been proposed, including effects on the gastrointestinal tract that might compromise the handling of other nutrients. Riboflavin deficiency has been implicated as a risk factor for cancer, although this has not been satisfactorily established in humans. Current interest is focused on the role that riboflavin plays in determining circulating concentrations of homocysteine, a risk factor for cardiovascular disease. Other mechanisms have been proposed for a protective role of riboflavin in ischemia reperfusion injury; this requires further study. Riboflavin deficiency may exert some of its effects by reducing the metabolism of other B vitamins, notably folate and vitamin B-6.

Publication Types:

  • Review
  • Review, Tutorial




PMID: 12791609 [PubMed - indexed for MEDLINE]

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Nutritional importance of animal source foods.

Murphy SP, Allen LH.

Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI 96813, USA. suzanne@crch.hawaii.edu

Animal source foods can provide a variety of micronutrients that are difficult to obtain in adequate quantities from plant source foods alone. In the 1980s, the Nutrition Collaborative Research Support Program identified six micronutrients that were particularly low in the primarily vegetarian diets of schoolchildren in rural Egypt, Kenya and Mexico: vitamin A, vitamin B-12, riboflavin, calcium, iron and zinc. Negative health outcomes associated with inadequate intake of these nutrients include anemia, poor growth, rickets, impaired cognitive performance, blindness, neuromuscular deficits and eventually, death. Animal source foods are particularly rich sources of all six of these nutrients, and relatively small amounts of these foods, added to a vegetarian diet, can substantially increase nutrient adequacy. Snacks designed for Kenyan schoolchildren provided more nutrients when animal and plant foods were combined. A snack that provided only 20% of a child's energy requirement could provide 38% of the calcium, 83% of the vitamin B-12 and 82% of the riboflavin requirements if milk was included. A similar snack that included ground beef rather than milk provided 86% of the zinc and 106% of the vitamin B-12 requirements, as well as 26% of the iron requirement. Food guides usually recommend several daily servings from animal source food groups (dairy products and meat or meat alternatives). An index that estimates nutrient adequacy based on adherence to such food guide recommendations may provide a useful method of quickly evaluating dietary quality in both developing and developed countries.

PMID: 14672292 [PubMed - indexed for MEDLINE]

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Effect of physical activity on thiamine, riboflavin, and vitamin B-6 requirements.

Manore MM.

Food and Nutrition Laboratory, the Department of Family Resources and Human Development, Arizona State University, Tempe, AZ 85212, USA. melinda.manore@asu.edu

Because exercise stresses metabolic pathways that depend on thiamine, riboflavin, and vitamin B-6, the requirements for these vitamins may be increased in athletes and active individuals. Theoretically, exercise could increase the need for these micronutrients in several ways: through decreased absorption of the nutrients; by increased turnover, metabolism, or loss of the nutrients; through biochemical adaptation as a result of training that increases nutrient needs; by an increase in mitochondrial enzymes that require the nutrients; or through an increased need for the nutrients for tissue maintenance and repair. Biochemical evidence of deficiencies in some of these vitamins in active individuals has been reported, but studies examining these issues are limited and equivocal. On the basis of metabolic studies, the riboflavin status of young and older women who exercise moderately (2.5-5 h/wk) appears to be poorer in periods of exercise, dieting, and dieting plus exercise than during control periods. Exercise also increases the loss of vitamin B-6 as 4-pyridoxic acid. These losses are small and concomitant decreases in blood vitamin B-6 measures have not been documented. There are no metabolic studies that have compared thiamine status in active and sedentary persons. Exercise appears to decrease nutrient status even further in active individuals with preexisting marginal vitamin intakes or marginal body stores. Thus, active individuals who restrict their energy intake or make poor dietary choices are at greatest risk for poor thiamine, riboflavin, and vitamin B-6 status.

Publication Types:

  • Review
  • Review, Tutorial




PMID: 10919966 [PubMed - indexed for MEDLINE]

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Diet and premalignant lesions of the cervix: evidence of a protective role for folate, riboflavin, thiamin, and vitamin B12.

Hernandez BY, McDuffie K, Wilkens LR, Kamemoto L, Goodman MT.

Cancer Research Center of Hawaii, University of Hawaii, 1236 Lauhala Street, Honolulu, Hawaii 96813, USA. brenda@crch.hawaii.edu

OBJECTIVE: A case-control study was conducted among a population of multiethnic women identified from clinics on Oahu, Hawaii between 1992 and 1996 to explore the relationship between diet and cervical dysplasia. METHODS: Two-hundred and fourteen women with biopsy-confirmed high and low grade squamous intraepithelial lesions of the cervix (SIL) and 271 controls were identified. Exfoliated cervical cells were collected for HPV DNA testing. Surveys were administered to assess non-dietary risk factors and intake of nutrients from over 250 specific food items as well as nutritional supplements. RESULTS: Riboflavin and thiamin from food sources, vitamin B12 supplements, and total (food and supplements) folate displayed inverse, dose-responsive associations with high-grade SIL (HSIL). Riboflavin from food sources and total folate also demonstrated inverse, dose-responsive associations with low-grade SIL (LSIL). The odds ratios for LSIL and HSIL were reduced by 50-90% for the highest compared to the lowest levels of intake of these nutrients. A number of major food sources of these vitamins, including all types of breads, bran cereal, and fruit juice, also demonstrated inverse associations with HSIL. There was some evidence that the increased risk of HSIL associated with low nutrient intake was most pronounced among drinkers and smokers. CONCLUSIONS: This investigation provides evidence that thiamin, riboflavin, folate, and vitamin B12 may play a protective role in cervical carcinogenesis.

PMID: 14682443 [PubMed - in process]

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Effect of riboflavin status on the homocysteine-lowering effect of folate in relation to the MTHFR (C677T) genotype.

Moat SJ, Ashfield-Watt PA, Powers HJ, Newcombe RG, McDowell IF.

Cardiovascular Sciences Research Group, Wales Heart Research Institute, University of Wales College of Medicine, Cardiff, Wales CF14 4XN, United Kingdom. moatsj@cardiff.ac.uk

BACKGROUND: Riboflavin (vitamin B(2)) is the precursor for FAD, the cofactor for methylenetetrahydrofolate reductase (MTHFR). MTHFR catalyzes the formation of 5-methyltetrahydrofolate, which acts as a methyl donor for homocysteine remethylation. Individuals with the MTHFR 677C-->T mutation have increased plasma total homocysteine (tHcy) concentrations, particularly in association with low folate status. It has been proposed that riboflavin may act together with folate to lower plasma tHcy, particularly in individuals with the thermolabile MTHFR T variant. METHODS: We measured B-vitamin status and plasma tHcy in 126 healthy individuals 20-63 years of age (42 CC, 42 CT, and 42 TT MTHFR genotypes) at baseline and after three interventions (4 months): placebo plus natural diet; daily 400 microg folic acid supplement plus natural diet; and increased dietary folate to 400 microg/day. RESULTS: At baseline and after nutritional intervention, lower riboflavin status was associated with increased plasma tHcy concentrations. Plasma tHcy was 2.6 micromol/L higher in the lowest plasma riboflavin quartile compared with the highest (P <0.02) and was 4.2 micromol/L higher in the highest erythrocyte glutathione reductase activation coefficient (EGRAC) quartile compared with the lowest (P <0.001). This effect was not restricted to those with the T allele. Folic acid given as a 400 microg/day supplement appeared to exacerbate a tendency toward riboflavin deficiency, as suggested by an increase in the proportion of individuals with EGRAC > or =1.4 from 52% to 65% after supplementation (P <0.05). CONCLUSIONS: Folate and riboflavin interact to lower plasma tHcy, possibly by maximizing the catalytic activity of MTHFR. The effect may be unrelated to MTHFR genotype.

PMID: 12560354 [PubMed - indexed for MEDLINE]

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Vitamin nutritional status of women using oral contraceptive pills.

Murthy NK, Vijaya S.

PIP: A comparative study was conducted to assess the biochemical effects of a low-estrogen combined OC (oral contraceptive). The focus of the study was on possible biochemical effects indicative of altered nutritional status. Both low and high income women on pills were compared with others not on pills. The groups were further divided according to the duration of OC usage. Blood hemoglobin, serum Vitamin A, plasma ascorbic acid, folic acid, riboflavin, and aspartate transaminase levels were measured. Higher income women had better measures on all the indices than the low income women, indicating a better initial nutritional status. Deficiencies increased with duration of use. Results of the study show that OCs reduce the vitamin nutritional level in women. For poor women on OCs, special nutrition intervention programs should be instituted.

PMID: 12262495 [PubMed - indexed for MEDLINE]

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Immune system and surgical site infection.

Esposito S.

Dept. of Infectious Diseases, Second University of Naples, Italy.

It is well known that altered host defenses in general can play a significant role in the development of infection in any patient but their role becomes even more important in surgical patients where infections are the result of individual risk factors associated with the patient and other specific factors associated with the surgery itself. Thus all possible factors that can help modify the immune response should be taken into account in order to intervene, whenever possible, with therapies based on defined abnormalities to reduce the rate of post-surgical infections. Many factors associated with the patient have been clearly identified as responsible for a decreased immune response: old age, concomitant diseases (diabetes, renal and liver failure, solid and hematologic neoplasias, malnutrition, autoimmune diseases, AIDS) and concomitant therapies (corticosteroid, cytotoxic agents). Old age can affect both humoral and cell-mediated immune responses. Chronic diseases can be responsible for a reduced primary response or depression of delayed hypersensitivity reactions (renal failure, neoplasias) or changes in leukocyte function (diabetes, leukemia, lymphomas). Malnutrition frequently accompanies diseases such as cancer, chronic and acute pancreatitis, inflammatory bowel diseases. Deficiencies in important vitamins and minerals (B6, A, folate, biotin, riboflavin...) can alter significantly the leukocyte function and immune response. Finally, there appears to be innate immune-suppression following any form of injury which is correlated with its magnitude and can affect any aspect of immunity. This has been well studied both in burn and surgical trauma. Alteration of phagocytosis, opsonization and chemotaxis are typically affected in burns, whereas surgical stress can include some reduction of cell mediated immunity. The best approach today to minimizing post-surgical infections is probably, besides use of antibiotic prophylaxis, to reduce the surgical trauma which consequently reduces the stress response and immune-suppression and to optimize the immune response by maintaining homeostasis through nutritional support.

Publication Types:

  • Review
  • Review, Tutorial




PMID: 11936355 [PubMed - indexed for MEDLINE]

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References

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