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Personalization of Nutrition Advice
Published in David Heber, Zhaoping Li, Primary Care Nutrition, 2017
Choline is not considered a B vitamin since a portion of the choline requirement can be met via endogenous de novo synthesis of phosphatidylcholine catalyzed by phosphatidylethanolamine N-methyltransferase (PEMT) in the liver. A recommended dietary intake for choline of 550 mg/day in humans was set in 1998, and although many foods contain choline, 90% of Americans do not get enough in their diets (Zeisel 2011).
Folate
Published in Judy A. Driskell, Ira Wolinsky, Sports Nutrition, 2005
The relationship between folic acid and homocysteine has been the focus of considerable research. Homocysteine is an intermediate sulfur-containing amino acid that is formed during normal metabolism and converted to the essential amino acid methionine. THFA, along with vitamins B6 and B12, is important in the conversion of homocysteine to methionine. Homocysteine is produced as a result of methylation reactions. The two most productive methyltransferases are guanidinoacetate methyltransferase and phosphatidylethanolamine N-methyltransferase. The first produces creatine and the latter produces phosphatidylcholine.22 Both reactions increase plasma homocysteine. The methylation of guanidinoacetate to produce creatine requires more methyl groups than all other methylation reactions combined.23 This is significant to athletes because creatine production is a vital factor in exercise. Because of the diseases associated with hyperhomocysteinemia, its production during exercise should be of concern to the athlete.
Vitamin B12 Supplementation and Vitamin B12 Blood Serum Levels: Evaluation of Effect Modification by Gender and Smoking Status
Published in Nutrition and Cancer, 2022
Hannah E. Fuchs, Kelli O’Connell, Mengmeng Du, Sandi L. Navarro, Theodore M. Brasky, Elizabeth D. Kantor
It is hypothesized that these gender differences could be partially explained by genetic variation. One cross-sectional study found that levels of transcobalamin, the necessary glycoprotein for vitamin B12’s active form, were also higher among females than males (37). Estrogen has been shown to increase levels of important enzymes for the one-carbon metabolism such as phosphatidylethanolamine N-methyltransferase (PEMT) (38). Female sex hormones are also associated with fluctuations in homocysteine and folate serum levels during menstrual cycles (39–41), and based on NHANES II data from 1991-1994, pregnant women presented with significantly lower serum homocysteine levels than non-pregnant, non-oral-contraceptive-using women (42). These studies can be extrapolated to the interaction between vitamin B12 and gender as B12 is frequently associated with homocysteine and folate levels in the blood (8, 43). These findings might partially explain the weakened interaction by gender in the subset of the study population 50 years or older as hormone levels decline rapidly in postmenopausal women.
Association between Dietary Choline Intake and Diabetic Retinopathy: National Health and Nutrition Examination Survey 2005-2008
Published in Current Eye Research, 2022
Weiming Liu, Chi Ren, Wenpeng Zhang, Gaoqin Liu, Peirong Lu
First, choline may directly contribute to dyslipidemia and hyperglycemia, thus predisposing diabetic patients to DR. Earlier studies have found that intraperitoneal administration of choline could directly increase glucose in rats.31,32 Recent research revealed that high choline-treated mice displayed significant dyslipidemia and hyperglycemia with vascular endothelial dysfunction and liver oxidative stress.33–35 Increased provision of choline in the diet could induce hyperglycemia and insulin resistance via increasing plasma glucagon and hepatic expression of the glucagon receptor.36 Except for diet, biosynthesis from phosphatidylcholine is another source of choline, and this synthetic process is catalyzed by the enzyme phosphatidylethanolamine-N-methyltransferase (PEMT).37 Since the PEMT gene is regulated by estrogen, women produce more endogenous choline than men.38–40 This may at least partly explain the sexual difference in the association between choline and DR.
Dietary choline is related to neural efficiency during a selective attention task among middle-aged adults with overweight and obesity
Published in Nutritional Neuroscience, 2021
Caitlyn G. Edwards, Anne M. Walk, Corinne N. Cannavale, Isabel R. Flemming, Sharon V. Thompson, Ginger R. Reeser, Hannah D. Holscher, Naiman A. Khan
Choline, an essential water-soluble nutrient, has been linked to cognitive improvements among perinatal and geriatric populations. Choline is vital for neurotransmitter synthesis (as the precursor to acetylcholine [ACh]), cell-membrane integrity (through phosphatidylcholine), and methyl-donor metabolism (through the conversion of methionine to homocysteine), and higher choline intake has been associated with lower whole body % fat and higher levels of lean mass [4,5]. Choline can also be produced through de novo biosynthesis through the phosphatidylethanolamine N-methyltransferase pathway, albeit in concentrations that are insufficient to maintain many biological processes [6]. Thus, it is imperative that choline be consumed through diet. Common foods rich in choline include eggs (147 mg/serving), soybeans (107 mg/serving), chicken breast (72 mg/serving), and beef (72 mg/serving). The Institute of Medicine recommends an Adequate Intake (AI) for choline of 425 mg/d for women and 550 mg/day for men [7]. However, 90% of the US population does not meet this AI recommendation [7].