Experts in the field of carotenoids met to summarize the current knowledge with respect to beta-carotene. The results of this beta-carotene consensus conference were just published in the Journal of Nutrition. The experts established:
Archive for 'October 2010'
Dr L Bettendorff and colleagues published an interesting insight into human requirements for thiamin, vitamin B1. Although the essentiality of thiamin has been known for centuries, its structure was identified in 1911 (almost one century ago), and the reference daily intake (RDI) is established, the amounts found in individual organs/tissues and their relative need for a specific organ/tissue to function optimally has not been established. This is actually the case for many vitamins and essential nutrients.
In a prospective study conducted on 161 individuals (10-70y) with irritable bowel diseases (IBD), gastroenterologists found that patients with vitamin D deficiency (< 30ng/mL) were 9 times more likely to have abnormal bone density than those with normal levels of vitamin D. They also reported that 22% of patients had abnormal bone density, and 50% of these were under 40y. This finding isn’t a total surprise as genetic variations in vitamin D receptor (VDR) binding sites have been associated with autoimmune diseases.
Dr Robert Parker and associates studied common variants in cytochrome 450 which catalyzes the hydroxylation reactions in vitamin E metabolism. It has been suggested that individual mutations in the CYP4F2 gene may contribute to 2 common variants in CYP4F2 structure and associated variation in vitamin E status in humans. They found indviduals carrying the W12G allele seemed to have lower plasma and tissue concentrations of vitamin E metabolites and showed less response to vitamin E supplementation.
Neurology publishes a study where researchers followed 271 dementia-free subjects (65-79y) for 7y to detect incident Alzheimer’s disease. They measured serum total homocysteine and holotranscobalamin levels and concluded that inadequate vitamin B12 status may be involved in the development of Alzheimer’s disease.
A study published in JAMA examined the effect of docosahexanoic acid (DHA) supplementation in a randomized control study (RCT) involving 2399 women with at approximately 22wk gestation at 5 Australian hospitals. The pregnant women received fish oil capsules (800 mg DHA and 100mg eicosapentaenoic acid (EPA) daily) or matched 500mg vegetable oil capsules (equal proportions of rapeseed, sunflower and palm oil) without DHA from study entry to birth. Women completed a self-administered Edinburgh Postnatal Depression Score (EPDS) at 6wk and 6mo postpartum.
Dr G Liu and associates report in Pediatrics on three boys with autism who exhibited optic nerve damage and vision loss related to vitamin B12 deficiency. Treatment with B12 injections helped normalize B12 levels and improve vision. The deficiency came about because of food selectivity and a severely limited diet. The number of autism cases among individuals up to age 22 is increasing annually in the US and outlying areas.
Food dyes are in the news again. Three food colorings – quinoline yellow, sunset yellow, and ponceau 4R – are under review. The United Kingdom Food Standards Agency is asking food businesses for comments on new EU proposals to reduce levels of three food colors in food and drinks. Thus, 3 of 6 food colors used in the Southampton University study associating food colors with hyperactivity in children are under review.
The Institute of Medicine Committee charged with examining Front-of-Package Nutrition Rating Systems and Symbols released their report. After reviewing 20 different labeling systems, the IOM Committee recommended a nutrient-specific system highlighting four nutrients - calories, trans fat, saturated fat and sodium – in addition to serving size. These four nutrients were chosen because they are routinely over consumed.
Vitamin D status of 310 monozygotic and 200 dizogotic male twins was published in the American Journal of Clinical Nutrition. Dr P Raggi and colleagues measured the effect of genetics and season on serum 25(OH)D3 levels. During the winter months, 70% of the variation in vitamin D levels was attributable to genetic factors.
A new report in the Journal of the American Medical Association highlights the increasing prevalence of age-related macular degeneration (AMD). AMD leads to vision loss and is associated with genetic and environmental risk factors. With the discovery of new genes associated with AMD risk, it is hoped that abnormalities in the innate immune system and cholesterol metabolism may be targeted to help maintain eyesight.
Elevated plasma homocysteine levels have been associated with increased risk of cardiovascular disease. Increasing folic acid intakes has been shown to decrease homocysteine levels and to reduce the risk of neural tube defects during pregnancy. A meta-analysis of 8 randomized control trials (RCT) of folic acid supplementation involving 37,485 individuals at increased risk of heart disease found a 25% reduction in plasma homocysteine levels.
The haptoglobin protein binds free hemoglobin released from red blood cells to prevent oxidative reactions which can damage cells and even cause mutations to DNA. The haptoglobin gene has 3 common polymorphisms, called HP 1-1, 2-1, and 2-2. In humans, these variants have been shown to bind erythrocytes with different affinity, HP 2-2 being the weakest. A new report published in the American Journal of Clinical Nutrition studied 1046 nonsmoking men and women
Researchers reviewed the scientific literature for randomized control trials (RCT) of vitamin D supplementation for 3 or more months in healthy youth (1m to 20y) with bone density outcomes. They identified 6 RCTs meeting these conditions. From these 6 short-term RCTs with 541 subjects being supplemented with vitamin D, they concluded "the results do not support vitamin D supplementation to improve bone density in healthy children with normal vitamin D levels". They acknowledged that children with low serum 25(OH)D3 levels might benefit from supplements. Try this perspective. The public shouldn’t be distracted from the REAL issue of widespread vitamin D deficiency among people worldwide by headlines that young people with adequate vitamin D
Dr Andrew Shao, Council for Responsible Nutrition, reminds us that vitamins C, D, E, folate, calcium, magnesium, and omega-3 fatty acids are shortfall nutrients for most Americans. For this reason, the more than 50% of Americans who use dietary supplements are trying to follow the 3 pillars of health - eat a healthy diet, exercise regularly, and use supplements to improve their nutrition where needed. In a survey of multivitamin supplement users vs adults who do not use multivitamin supplements, Dr Suzanne Murphy and colleagues found that dietary supplement users were more likely to make more nutritious food choices (vs non-users) and that multivitamin supplements did indeed help
Vitamin E acts as a chain-breaking antioxidant that prevents the propagation of lipid peroxidation. Although overt deficiency is rare, approximately 90% of Americans are not consuming recommended daily intakes. This is important because vitamin E deficiency causes peripheral neuropathy in humans. Burn injury increases the production of reactive oxygen species (ROS) and upregulates inflammatory responses which then cause damage beyond the initial injury. Dr Maret Traber and associates studied the impact of burn injury on plasma levels and body stores of vitamin E in 8 pediatric patients over the first 30d after burn injury and up to 1y in some individuals. The Recommended Dietary Allowance for these adolescents was 7mg alpha-tocopherol/d. The authors found adipose vitamin E concentrations decreased almost 50%
The 2010 CRN Consumer Survey on Dietary Supplement use in the US reports that 27% of American adults are taking vitamin D supplements, up from 19% in 2009 and 16% in 2008. This is great news given that 59% of males and 68% of females 31-50y are not consuming recommended amounts of vitamin D daily (200 IU/d). And self-reported usual food intakes from vitamin D are only the tip of the iceberg. The REAL concern is the inadequate vitamin D3 status of people worldwide, typically adults most have serum 25(OH)D levels below 80 nmol/L. Tuberculosis (TB) is a case in point. The number of people with TB is increasing worldwide. More than 2 billion people are infected with TB, and HIV epidemics are contributing to its transmission. Dr Elizabeth Corbett and colleagues
How do governments weight investments in disease prevention versus disease treatments? This was a question discussed at the CRN's The Conference by Michael Samuelson, Health & Wellness Institute, and Robert Gould, Partnership for Prevention. It is timely with an ongoing discussion in Canada where the governments of Manitoba, Nova Scotia, Newfoundland and Labrador, and now Ontario may limit vitamin D testing to just people already diagnosed with disease conditions. The Winnipeg Free Press quotes Health Minister Deb Matthews as saying it's important to "ensure that precious health-care dollars are invested in care that is evidence-based."