Nancy F. Sheard

Columbia University, New York, New York, United States

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Publications (25)127.39 Total impact

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    ABSTRACT: Regulation of blood glucose to achieve near-normal levels is a primary goal in the management of diabetes, and, thus, dietary techniques that limit hyperglycemia following a meal are likely important in limiting the complications of diabetes. Low-carbohydrate diets are not recommended in the management of diabetes. Although dietary carbohydrate is the major contributor to postprandial glucose concentration, it is an important source of energy, water-soluble vitamins and minerals, and fiber. Thus, in agreement with the National Academy of Sciences-Food and Nutrition Board, a recommended range of carbohydrate intake is 45-65% of total calories. In addition, because the brain and central nervous system have an absolute requirement for glucose as an energy source, restricting total carbohydrate to < 130 g/day is not recommended. Both the amount (grams) of carbohydrate as well as the type of carbohydrate in a food influence blood glucose level. The total amount of carbohydrate consumed is a strong predictor of glycemic response, and, thus, monitoring total grams of carbohydrate, whether by use of exchanges or carbohydrate counting, remains a key strategy in achieving glycemic control. A recent analysis of the randomized controlled trials that have examined the efficacy of the glycemic index on overall blood glucose control indicates that the use of this technique can provide an additional benefit over that observed when total carbohydrate is considered alone. Although this statement has focused primarily on the role of carbohydrate in the diet, the importance of achieving/ maintaining a healthy body weight (particularly in type 2 diabetes) in the management of diabetes should not be ignored. Moderate weight loss in overweight/obese individuals with type 2 diabetes results in improved control of hyperglycemia as well as in a reduction in risk factors for cardiovascular disease. Because much of the risk of developing type 2 diabetes is attributable to obesity, maintenance of a healthy body weight is strongly recommended as a means of preventing this disease. The relationship between glycemic index and glycemic load and the development of type 2 diabetes remains unclear at this time.
    Full-text · Article · Oct 2004 · Diabetes Care
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    ABSTRACT: Overweight and obesity are important risk factors for type 2 diabetes. The marked increase in the prevalence of overweight and obesity is presumably responsible for the recent increase in the prevalence of type 2 diabetes. Lifestyle modification aimed at reducing energy intake and increasing physical activity is the principal therapy for overweight and obese patients with type 2 diabetes. Even moderate weight loss in combination with increased activity can improve insulin sensitivity and glycemic control in patients with type 2 diabetes and prevent the development of type 2 diabetes in high-risk persons (ie, those with impaired glucose tolerance). The American Diabetes Association, the North American Association for the Study of Obesity, and the American Society for Clinical Nutrition have joined together to issue this statement on the use of lifestyle modification in the prevention and management of type 2 diabetes.
    Full-text · Article · Sep 2004 · Diabetes Care
  • Nancy F Sheard
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    ABSTRACT: The prevalence of type 2 diabetes mellitus is rising significantly, paralleling the increase in obesity observed around the world. Diabetes is a progressive disease that frequently results in serious complications including retinopathy, neuropathy, nephropathy, and cardiovascular disease. Early detection and treatment of hyperglycemia, the cornerstone of diabetes, can decrease the incidence of these sequelae. Moderate changes in both body weight and physical activity improve the control of hyperglycemia associated with diabetes. Recent studies indicate that similar lifestyle changes can help to prevent or delay the onset of diabetes in people at risk of developing this disorder.
    No preview · Article · Mar 2003 · Nutrition Reviews
  • Renee P. Lauber · Nancy F. Sheard
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    ABSTRACT: Recently, the American Heart Association published a revision of its dietary guidelines. The recommendations are based on new scientific findings, and address the contribution of growing rates of obesity, hypertension, and diabetes to heart disease in the United States. The guidelines for the general public are similar to dietary recommendations made by other health-related groups and government agencies and, therefore, place a greater emphasis on the adoption of healthy eating patterns and behaviors rather than a singular focus on dietary fat intake.
    No preview · Article · Oct 2001 · Nutrition Reviews
  • Heather K. Nelson · Renee P. Lauber · Nancy F. Sheard
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    ABSTRACT: In previous studies, sodium pivalate has been administered to rats in their drinking water (20 mmoles/L; equivalent to 0.3% of the diet) as a way to lower the concentration of carnitine in tissues and to produce a model of secondary carnitine deficiency. Although this level of supplementation results in a marked decrease in carnitine concentration in a variety of tissues, it does not produce the classical signs of carnitine deficiency (i.e., decreased fatty acid oxidation and ketogenesis). The present study was designed (1) to determine if increasing the level of pivalate supplementation (0.6, 1.0% of the diet) would further reduce the concentrations of total and free carnitine in rat tissues without altering growth or food intake, and (2) to examine the effect of length of feeding (4 vs. 8 weeks) on these variables. Male, Sprague-Dawley rats were randomly assigned to either a control (0.2% sodium bicarbonate) or experimental diet (0.3, 0.6, 1.0% sodium pivalate) for either four or eight weeks. Animals (n = 6/group) were housed in metabolic cages; food and water were provided ad libitum throughout the study. Supplementation with sodium pivalate did not alter water intake or urine output. Ingestion of a diet containing 1.0% pivalic acid decreased food intake (g/day; P < 0.05), final body weight (P < 0.007), and growth rate (P < 0.001) after four weeks. The concentration of total carnitine in plasma, heart, liver, muscle, and kidney was reduced in all experimental groups (P < 0.001), regardless of level of supplementation or length of feeding. The concentration of free carnitine in heart, muscle, and kidney was also reduced (P < 0.001) in rats treated with pivalate for either four or eight weeks. The concentration of free carnitine in liver was reduced in animals supplemented with pivalate for eight weeks (P < 0.05), but no effect was observed in livers from rats treated for four weeks. Excretion of total carnitine and short chain acylcarnitine in urine was increased in pivalate supplemented rats throughout the entire feeding period (P < 0.001). Free carnitine excretion was increased during Weeks 1 and 2 (P < 0.01), but began to decline during Week 3 in experimental groups. During Weeks 6 and 8, free carnitine excretion in pivalate supplemented rats was less than that of control animals (P < 0.01). In summary, no further reduction in tissue carnitine concentration was observed when rats were supplemented with sodium pivalate at levels greater than 0.3% of the diet. Food intake (g/day) and growth were decreased in rats fed a diet containing 1.0% sodium pivalate. These data indicate that maximal lowering of tissue carnitine concentrations is achieved by feeding diets containing 0.3% sodium pivalate or less.
    No preview · Article · Apr 2001 · The Journal of nutritional biochemistry
  • Nancy F. Sheard
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    ABSTRACT: Diet has long been recognized as the primary treatment modality for individuals with phenylketonuria (PKU) during infancy and childhood. Recent findings from the Maternal PKU Collaborative Study clearly indicate that dietary restriction of phenylalanine is also necessary to prevent the adverse effects of an elevated plasma phenylalanine concentration during pregnancy, which include microcephaly, physical anomalies, and mental retardation.
    No preview · Article · Sep 2000 · Nutrition Reviews
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    ABSTRACT: We present a case of an African-American child with vitamin D-deficient rickets. In addition to being solely breast-fed for the period of 1 year, he resided in New England, where exposure to ultraviolet light is limited owing to its northern latitude and long cold winters. He presented with classical signs of nutritional rickets and was immediately responsive to treatment with vitamin D supplementation.
    No preview · Article · Aug 2000 · Nutrition Reviews
  • Nancy F. Sheard
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    ABSTRACT: Studies show conflicting results regarding the protective effect of dietary fish and fish oil on certain types of cardiovascular disease. A recent epidemiologic study supports the hypothesis that moderate consumption (1-2 meals/week) of fish lowers the risk of sudden cardiac death in humans.
    No preview · Article · Jul 1998 · Nutrition Reviews
  • Dietrich Rein · Bruce Krasin · Nancy F. Sheard
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    ABSTRACT: Choline and choline-containing compounds are used in the treatment of certain neurological disorders. Limited information is available regarding the metabolic consequences of choline supplementation. The effect of both acute and chronic dietary choline supplementation on carnitine concentration in plasma, urine and tissues was studied in adult, male Sprague-Dawley rats. Eight groups of rats (n = 6/group) were assigned to four timepoints and two diets. Carnitine concentrations in choline supplemented (CS) (10 g choline chloride/kg diet) rats were measured after 1, 3, 21, and 42 days and results compared to control (C) animals (1 g choline chloride/kg). The carnitine concentration of plasma, urine, liver, heart, kidney, and gastrocnemius muscle was determined by radioenzymatic assay. Urinary choline and betaine levels were analyzed by single proton NMR spectroscopy. Both choline and betaine excretion were higher in CS animals throughout the study period. A single choline supplemented feeding (one 3 h meal) produced no significant changes in carnitine concentrations 3 h post prandial. Plasma and kidney carnitine concentrations increased over time in both dietary groups (P = 0.0001, P = 0.0004, respectively) and choline supplementation depressed concentrations in both of these pools when compared to controls (P = 0.0001, P = 0.006, respectively). No effect on urinary carnitine excretion was observed. Heart carnitine concentration increased over the course of the study in both dietary groups (P = 0.006). Carnitine concentration in liver was increased due to supplementation (P= 0.016). We conclude that the administration of a single, large dose of choline in rats does not alter carnitine concentrations during the first 3 h post prandial. Chronic choline administration decreased plasma and kidney carnitine concentrations and increased liver concentration. Choline supplementation influences the distribution of carnitine in specific body compartments, perhaps, by influencing the the transport of carnitine into or out of the liver.
    No preview · Article · Feb 1997 · The Journal of Nutritional Biochemistry
  • Nancy F. Sheard
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    ABSTRACT: The dietary prescription for noninsulin-dependent diabetes mellitus remains an important component in the treatment of this disorder. Recent studies indicate that a diet high in monounsaturated fat and low in carbohydrate can produce a more desirable plasma glucose, lipid, and insulin profile.
    No preview · Article · Feb 1995 · Nutrition Reviews
  • Nancy F. Sheard · Kerry-Ann da Costa · Steven H. Zeisel
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    ABSTRACT: The role of choline in the human diet continues to be debated, in part due to the lack of an appropriate assessment technique. Information regarding the turnover of this nutrient in various body pools in humans is lacking. An intravenous infusion of (d9methyl)-choline chloride was administered over 1 hour to human subjects fed either a choline-containing (5 mmoles/day choline chloride) or a choline-deficient diet for 3 weeks. Blood samples were collected during the infusion and for 1 hour postinfusion. Plasma levels of choline, (d9methyl)choline, and phosphatidylcholine were measured. The uptake of (d9methyl)-choline from plasma was calculated by nonlinear regression analysis. In control subjects (n = 4), the half-life of (d9methyl)-choline in plasma was 7.0 ± 0.85 minutes, while in deficient subjects (n = 6) it was 3.5 ± 0.42 minutes (P < 0.004). Extracellular choline pools were also decreased in deficient subjects (mean ± SEM; control: 2.6 ± 0.2 mmoles; deficient: 2.0 ± 0.2 mmoles; P < 0.05). The rate of appearance of unlabeled choline into the plasma was unaffected by the level of dietary choline. We conclude that intravenously administered choline chloride is cleared more rapidly in humans fed a choline-deficient diet than in control subjects, and that choline deficiency decreases choline pools in the body. Our results also indicate that an intravenous load test, similar to the one used in these studies, may be useful as a method of measuring choline nutriture.
    No preview · Article · Jun 1994 · The Journal of Nutritional Biochemistry
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    N F Sheard · B Krasin
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    ABSTRACT: Previous reports in animals indicate that choline deficiency alters carnitine metabolism. Recent studies in humans suggest that choline deficiency occurs in individuals during long term total parenteral nutrition. Malnutrition is also a frequent complication in this population. We therefore examined the effect of restricting the intake of a choline-deficient diet on carnitine concentrations in plasma and tissues. Adult male rats were randomly assigned to one of four dietary regimens: control, choline deficient, restricted control (85% of control), or restricted choline deficient for 42-43 d. At the end of the experimental period, restricted animals weighed significantly less than their respective controls (P < 0.01). Liver weight relative to body weight and fat concentration were greater in choline-deficient animals (P < 0.01 and 0.001, respectively). Choline-deficient rats fed free access had elevated plasma carnitine concentration (P < 0.01). Urinary carnitine excretion was elevated in both groups of choline-deficient rats (P < 0.01), while liver, heart and muscle carnitine concentrations were lower than in controls (P < 0.05). Restricting dietary intake reduced plasma carnitine concentration in choline-deficient animals (P < 0.01), but did not alter tissue or urine carnitine concentrations in either group. Restricted, choline-deficient animals did not exhibit a worsening of the sequelae of choline deficiency. We conclude that choline deficiency alters carnitine concentrations in plasma and tissues and that restricting the intake of a choline-deficient diet does not alter this effect in tissues.
    Preview · Article · May 1994 · Journal of Nutrition
  • Nancy F. Sheard
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    ABSTRACT: It has been shown that iron-deficient anemic infants are not as successful in tests of mental and motor development as their iron-sufficient age-matched counterparts. A recent study has confirmed that iron intervention can reverse developmental delays, while placebo-treated anemic infants showed no such improvement. The etiology of the developmental delay and its effect on later performance remain to be elucidated.
    No preview · Article · May 1994 · Nutrition Reviews
  • Nancy F. Sheard
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    ABSTRACT: Although exclusive breast-feeding decreases infant mortality and morbidity in developing countries, its protective effects in infants living in industrialized nations have been more difficult to quantitate. A recent study provides strong evidence that exclusive breast-feeding for at least four months decreases the incidence of otitis media in the first year of life.
    No preview · Article · Oct 1993 · Nutrition Reviews
  • N F Sheard
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    ABSTRACT: Recently, a link between the serum level of antibody to cow's milk protein and the onset of insulin-dependent diabetes mellitus in humans was reported. This observation renewed controversy regarding the suitability of cow's milk in infant diets.
    No preview · Article · Apr 1993 · Nutrition Reviews
  • N F Sheard
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    ABSTRACT: The use of reference standards, such as those of the National Center for Health Statistics (NCHS), for determining the health and nutritional status of breast-fed infants and children has been questioned. A recent study found that the mean weight of formula-fed infants remained at about the 50th percentile throughout their first year, whereas that of breast-fed infants fell below the 50th percentile well before age one year. Although these children probably are not at nutritional risk, deviation from the national reference data could lead to unnecessary infant monitoring and testing as well as undue parental concern.
    No preview · Article · Mar 1993 · Nutrition Reviews
  • N G Clark · N F Sheard · J F Kelleher
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    ABSTRACT: We present a case of a child with iron-deficiency anemia, folic acid deficiency, and scurvy. His anemia proved refractory to treatment with iron until he received both folic acid and vitamin C supplementation. This case illustrates the importance of the evaluation of ascorbic acid and folate status in treating iron-deficiency anemia initially refractory to iron supplementation, because multiple nutrient deficiencies may coexist.
    No preview · Article · Jun 1992 · Nutrition Reviews
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    ABSTRACT: Choline is required to make essential membrane phospholipids. It is a precursor for the biosynthesis of the neurotransmitter acetylcholine and also is an important source of labile methyl groups. Mammals fed a choline-deficient diet develop liver dysfunction; however, choline is not considered an essential nutrient in humans. Healthy male volunteers were hospitalized and fed a semisynthetic diet devoid of choline supplemented with 500 mg/day choline for 1 wk. Subjects were randomly divided into two groups, one that continued to receive choline (control), and the other that received no choline (deficient) for three additional wk. During the 5th wk of the study all subjects received choline. The semisynthetic diet contained adequate, but no excess, methionine. In the choline-deficient group, plasma choline and phosphatidylcholine concentrations decreased an average of 30% during the 3-wk period when a choline-deficient diet was ingested; plasma and erthrocyte phosphatidylcholine decreased 15%; no such changes occurred in the control group. In the choline-deficient group, serum alanine aminotransferase activity increased steadily from a mean of 0.42 mukat/liter to a mean of 0.62 mukat/liter during the 3-wk period when a choline-deficient diet was ingested; no such change occurred in the control group. Other tests of liver and renal function were unchanged in both groups during the study. Serum cholesterol decreased an average of 15% in the deficient group and did not change in the control group. Healthy humans consuming a choline-deficient diet for 3 wk had depleted stores of choline in tissues and developed signs of incipient liver dysfunction. Our observations support the conclusion and choline is an essential nutrient for humans when excess methionine and folate are not available in the diet.
    Full-text · Article · May 1991 · The FASEB Journal
  • J A Tayek · B Bistrian · N F Sheard · S H Zeisel · G L Blackburn
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    ABSTRACT: A prospective study was performed in clinically malnourished patients in which liver function was tested during a 4-week period of total parenteral nutrition (TPN). The purpose was to determine if concomitant intravenous lipid administration would reduce liver function abnormalities noted to occur frequently in patients receiving TPN. Twenty-five patients were randomly assigned to receive either daily infusions of 200 cc of a 20% lipid emulsion with TPN or TPN without lipid for the first week. In the subsequent 3 weeks all patients received daily intravenous lipid. The early lipid treatment group received 0.7 g lipid/kg BW/day and approximately 280 mg of choline/day from the lecithin emulsifier throughout the entire study period. Liver function tests were performed twice in the first week, then weekly thereafter. There were significant (p less than 0.05) elevations in liver function tests in the early lipid treatment group (for aspartate aminotransferase in weeks 1, 2, and 3, and lactic acid dehydrogenase in weeks 2 and 3). Alkaline phosphatase activity was elevated at weeks 2, 3, and 4 for the lipid-treatment group and at week 1 for the lipid-restricted group. The two groups had a similar elevation in gamma-glutamyltransferase activity. Analysis of covariance demonstrated that the overall duration of TPN, and not the presence or absence of intravenous lipid, was significantly related to the elevations in both alkaline phosphatase and gamma-glutamyltransferase (GGT) levels. In contrast, the early intravenous administration of lipid was significantly related to the increase in aspartate aminotransferase levels. The peak increase in AST was noted at day 7 in the lipid-administration group.(ABSTRACT TRUNCATED AT 250 WORDS)
    No preview · Article · Mar 1990 · Journal of the American College of Nutrition
  • N F Sheard · S H Zeisel
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    ABSTRACT: Choline (trimethyl-beta-hydroxyethylammonium) is a quaternary amine which is widely distributed in plants and animals. It contains three methyl groups which are important in a number of metabolic reactions, including the synthesis of methionine and carnitine. Choline is also a component of the phospholipids phosphatidylcholine and sphingomyelin, important constituents of all cell membranes. Finally, choline is necessary for the synthesis of the neurotransmitter acetylcholine. Although this compound is considered an essential nutrient in numerous mammalian species, this has not been established for humans.
    No preview · Article · Jan 1989 · Nutrition

Publication Stats

1k Citations
127.39 Total Impact Points


  • 2004
    • Columbia University
      New York, New York, United States
  • 1995-2003
    • University of Vermont
      • Department of Nutrition and Food Sciences
      Burlington, Vermont, United States
  • 1994
    • Beverly Hospital, Boston MA
      Beverly, Massachusetts, United States
  • 1991-1994
    • University of Massachusetts Amherst
      • • Department of Nutrition
      • • Department of Food Science
      Amherst Center, Massachusetts, United States
  • 1992
    • Baystate Medical Center
      • Department of Medicine-Pediatrics
      Springfield, Massachusetts, United States
  • 1990
    • Harbor-UCLA Medical Center
      Torrance, California, United States
  • 1988
    • Boston Children's Hospital
      Boston, Massachusetts, United States
  • 1986
    • Boston University
      • Department of Pediatrics
      Boston, Massachusetts, United States