Hydration and cognitive function in children

Adequate fluid intake is critical for survival. While adults are at liberty to drink fluids as wanted, children and infants are dependent upon caregivers for food and fluid. Children are at greater risk for dehydration than adults due to their higher surface-to-mass ratio. Additionally, children have different thirst sensitivities and body cooling mechanisms than adults. Children differ from adults in total body water content, and boys and girls differ in body water content with maturation. Research in young adults shows that mild dehydration corresponding to only 1% to 2% of body weight loss can lead to significant impairment in cognitive function. Dehydration in infants is associated with confusion, irritability, and lethargy; in children, it may produce decrements in cognitive performance.

Age-related changes in neutral sphingomyelin-specific phospholipase C activity in striatum, hippocampus, and frontal cortex: Implication for sensitivity to stress and inflammation

Previous studies show the enrichment of mammalian brain with neutral sphingomyelin-specific phospholipase C (ceramide-phosphocholine phosphodiesterase, EC 3.1.4.12; N-Sase), a key enzyme of sphingolipid metabolism and sphingolipid-induced signaling.

OBJECTIVE

The objective of this study was to evaluate the membrane-associated and cytosolic N-Sase activities in the brain regions associated with behavior (striatum, hippocampus, and frontal cortex).

RESULTS

Results showed higher membrane-associated N-Sase activity as compared to the N-Sase activity in the cytosolic fractions of all the evaluated brain regions. In the hippocampus, the N-Sase activity was significantly higher than in the striatum and cortex. In addition, age-related changes in the hippocampal N-Sase activities were profoundly higher than in the respective fractions isolated from the striatum and cortex. Age-related decreases in the hippocampal and striatal cytosolic N-Sase activities were accompanied by increases in the membrane N-Sase activities in those brain regions. There was a significant increase in the cortical membrane-associated N-Sase activity with age; however, to a much lesser extend than in other brain regions. The increase in the hippocampal membrane-associated N-Sase activity was accompanied by a higher expression of the inflammatory marker, interleukin-1 beta (IL-1 beta), with age. One of the important findings of the present study is the region-specific expression of heat shock protein 70 (hsp70). Frontal cortex showed lower hsp70 expression in both young and old age groups as compared to the striatal and hippocampal hsp70 levels which can contribute to the recently reported higher cortical sensitivity to oxidative stress.

CONCLUSION

In conclusion (a) our results, for the first time to our knowledge, demonstrated the association between the N-Sase activity and the stress/inflammatory markers expression in the brain regions controlling behavior; (b) these findings suggest the role of N-Sase as a contributor to the increased stress and inflammatory sensitivity among the brain regions with age.

Interdepartmental Committee on Nutrition for National Defense Surveys in Asia and Africa

I suppose I should establish my bonafides for participation in this symposium. I did participate in 3 Interdepartmental Committee on Nutrition for National Defense (ICNND) surveys as far separated as one on the Blackfeet Indian Reservation (1) in Montana and 2 in Asia-Burma (2) and East Pakistan (3). In fact, the Blackfeet Reservation and Burma surveys were my training grounds for becoming the clinical chief for the East Pakistan survey and later the codirector. More importantly, in 1962, I followed Alan Forbes, who is much missed at this symposium, as the deputy to Arnie Schaefer at ICNND and NIH, and did have experience of an office in the Stone House on the NIH campus. There I participated in the transmutation of the ICNND to the Interdepartmental Committee on National Development and its alignment with the Office of International Research at the NIH and a repositioning within the Department of Health and Human Services. It was from this position that ICNND went on to organize some civilian surveys in the mid-1960s, including those in Central America and Panama (4), and it was from this position that the groundwork was laid for the application of ICNND techniques to the first U.S. domestic survey outside of an Indian reservation, culminating in the Ten State Nutrition Survey (5), which documented that there was hunger in America, as well as abroad.

Folate and brain function in the elderly

PURPOSE OF REVIEW

Over the past several decades, folate has emerged as an important nutrient in several key conditions of concern to the elderly. Subclinical levels of folate inadequacy can have significant negative impacts on health in older individuals.

RECENT FINDINGS

Serum and red blood cell folate levels are associated with depression in younger individuals, but the relationship is less clear in older people. However, folate status does predict response to antidepressant treatment in older individuals. Cognitive decline and some forms of dementia, including Alzheimer's disease, are associated with lower folate levels. Supplementation with folic acid can provide cognitive benefits in some circumstances. Folic acid supplementation is generally regarded as safe; however, there remains some concern that high levels of folic acid may exacerbate the neurological consequences of a vitamin B12 deficiency.

SUMMARY

Evidence for the role of folate in depression and dementia in the aged is increasing, although there remains much about mechanisms to be determined.

Breakfast cereal fortified with folic acid, vitamin B-6, and vitamin B-12 increases vitamin concentrations and reduces homocysteine concentrations: a randomized trial

BACKGROUND

High homocysteine and low B vitamin concentrations have been linked to the risk of vascular disease, stroke, and dementia and are relatively common in older adults.

OBJECTIVE

We assessed the effect of breakfast cereal fortified with folic acid, vitamin B-6, and vitamin B-12 on vitamin and homocysteine status.

DESIGN

A randomized, double-blind trial was conducted in 189 volunteers aged 50-85 y. The subjects had no history of hypertension, anemia, asthma, cancer, or cardiovascular or digestive disease and did not regularly consume multiple or B vitamin supplements or highly fortified breakfast cereal. Subjects were randomly assigned to consume 1 cup (0.24 L) breakfast cereal fortified with 440 microg folic acid, 1.8 mg vitamin B-6, and 4.8 microg vitamin B-12 or placebo cereal for 12 wk. Blood was drawn at 0, 2, 12, and 14 wk. Methionine-loading tests were conducted at baseline and week 14.

RESULTS

Final baseline-adjusted plasma homocysteine concentrations were significantly lower and B vitamin concentrations were significantly higher in the treatment group than in the placebo group (P < 0.001). The percentage of subjects with plasma folate concentrations < 11 nmol/L decreased from 2% to 0%, with vitamin B-12 concentrations < 185 pmol/L from 9% to 3%, with vitamin B-6 concentrations < 20 nmol/L from 6% to 2%, and with homocysteine concentrations > 10.4 micromol/L (women) or > 11.4 micromol/L (men) from 6.4% to 1.6%. The percentage of control subjects with values beyond these cutoff points remained nearly constant or increased.

CONCLUSIONS

In this relatively healthy group of volunteers, consumption of 1 cup fortified breakfast cereal daily significantly increased B vitamin and decreased homocysteine concentrations, including post-methionine-load homocysteine concentrations.

Relations of plasma homocysteine to left ventricular structure and function: the Framingham Heart Study

AIMS

Hyperhomocysteinaemia is a risk factor for congestive heart failure, especially in women. We investigated if homocysteine promotes left ventricular (LV) remodelling.

METHODS AND RESULTS

We examined cross-sectional relations of plasma total homocysteine to echocardiographic LV structure and function in 2697 Framingham Heart Study participants (mean age 58 years, 58% women) free of heart failure and previous myocardial infarction. Adjusting for age and height, plasma homocysteine was positively related to LV mass, wall thickness, and relative wall thickness in women (p=0.0004-0.04), but not in men (p=0.28-0.68). Adjusting additionally for other clinical covariates, the relations of plasma homocysteine to LV mass and wall thickness in women remained statistically significant, but the relation to relative wall thickness became of borderline significance (1.92 g, 0.01 cm, and 0.29% increase, respectively, for a 1-SD increase in ln[homocysteine], p=0.01-0.08). LV mass and wall thickness were higher in the fourth quartile of plasma homocysteine compared to the lower three in all models in women (p=0.0003-0.02), but not in men (p=0.25-0.78). Plasma homocysteine was not related to left atrial size or LV fractional shortening in either sex.

CONCLUSION

In our community-based sample, plasma homocysteine was directly related to LV mass and wall thickness in women but not in men.

Skeletal muscle cutpoints associated with elevated physical disability risk in older men and women

The purpose of this study was to determine skeletal muscle cutpoints for identifying elevated physical disability risk in older adults. Subjects included 4,449 older (> or = 60 years) participants from the Third National Health and Nutrition Examination Survey during 1988-1994. Physical disability was assessed by questionnaire, and bioimpedance was used to estimate skeletal muscle, which was normalized for height. Receiver operating characteristics were used to develop the skeletal muscle cutpoints associated with a high likelihood of physical disability. Odds for physical disability were compared in subjects whose measures fell above and below these cutpoints. Skeletal muscle cutpoints of 5.76-6.75 and < or =5.75 kg/m2 were selected to denote moderate and high physical disability risk in women. The corresponding values in men were 8.51-10.75 and < or =8.50 kg/m2. Compared with women with low-risk skeletal muscle values, women with moderate- and high-risk skeletal muscle values had odds for physical disability of 1.41 (95% confidence interval (CI): 0.97, 2.04) and 3.31 (95% CI: 1.91, 5.73), respectively. The corresponding odds in men were 3.65 (95% CI: 1.92, 6.94) and 4.71 (95% CI: 2.28, 9.74). This study presents skeletal muscle cutpoints for physical disability risk in older adults. Future applications of these cutpoints include the comparison of morbidity risk in older persons with normal muscle mass and those with sarcopenia, the determination and comparison of sarcopenia prevalences, and the estimation of health-care costs attributable to sarcopenia.

The atherogenic effect of excess methionine intake

Methionine is the precursor of homocysteine, a sulfur amino acid intermediate in the methylation and transsulfuration pathways. Elevated plasma homocysteine (hyperhomocysteinemia) is associated with occlusive vascular disease. Whether homocysteine per se or a coincident metabolic abnormality causes vascular disease is still an open question. Animals with genetic hyperhomocysteinemia have so far not displayed atheromatous lesions. However, when methionine-rich diets are used to induce hyperhomocysteinemia, vascular pathology is often observed. Such studies have not distinguished the effects of excess dietary methionine from those of hyperhomocysteinemia. We fed apolipoprotein E-deficient mice with experimental diets designed to achieve three conditions: (i) high methionine intake with normal blood homocysteine; (ii) high methionine intake with B vitamin deficiency and hyperhomocysteinemia; and (iii) normal methionine intake with B vitamin deficiency and hyperhomocysteinemia. Mice fed methionine-rich diets had significant atheromatous pathology in the aortic arch even with normal plasma homocysteine levels, whereas mice fed B vitamin-deficient diets developed severe hyperhomocysteinemia without any increase in vascular pathology. Our findings suggest that moderate increases in methionine intake are atherogenic in susceptible mice. Although homocysteine may contribute to the effect of methionine, high plasma homocysteine was not independently atherogenic in this model. Some product of excess methionine metabolism rather than high plasma homocysteine per se may underlie the association of homocysteine with vascular disease.

Plasma Homocysteine, Hypertension Incidence, and Blood Pressure Tracking

Plasma homocysteine is cross-sectionally associated with blood pressure in large, community-based studies. It is unknown whether elevated plasma homocysteine predicts hypertension incidence. We investigated the relations of baseline plasma total homocysteine levels to hypertension incidence and blood pressure tracking in 2104 Framingham Heart Study participants (mean age, 57 years; 58% women), who were free of hypertension, myocardial infarction, heart failure, atrial fibrillation, or renal failure at baseline. Baseline mean+/-SD plasma homocysteine was 10.1+/-3.7 micromol/L. On follow-up 4 years from baseline, 360 persons (17.1%) had developed hypertension, and 878 persons (41.7%) had progressed to a higher blood pressure stage. In unadjusted analyses, a 1-SD higher log homocysteine value was associated with increased odds of developing hypertension (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.05 to 1.32) and increased odds of blood pressure progression (OR, 1.17; 95% CI, 1.07 to 1.27). The relations of plasma homocysteine to the incidence of hypertension or blood pressure progression were statistically nonsignificant in age- and sex-adjusted logistic regression models (OR, 0.98; 95% CI, 0.87 to 1.11 and OR, 1.05; 95% CI, 0.96 to 1.16, respectively) and in multivariable models adjusted for age, sex, body mass index, diabetes, interim weight change, smoking, serum creatinine, baseline blood pressure, and blood pressure category (OR, 0.92; 95% CI, 0.81 to 1.06 and OR, 1.07; 95% CI, 0.97 to 1.18, respectively). In conclusion, we found no major relation of baseline plasma homocysteine levels to hypertension incidence or longitudinal blood pressure progression in a large, community-based cohort of nonhypertensive individuals after adjustment for age, sex, and other important covariates.

Age and Gender Affect the Relation between Methylenetetrahydrofolate Reductase C677T Genotype and Fasting Plasma Homocysteine Concentrations in the Framingham Offspring Study Cohort

The C677T variant of methylenetetrahydrofolate reductase (MTHFR), a key enzyme in the remethylation of homocysteine to methionine, is a frequent genetic cause of mild hyperhomocysteinemia among individuals with low folate status. However, little is known about the influence of subject characteristics, such as age and sex, on the relation between the C677T MTHFR polymorphism and fasting plasma total homocysteine (tHcy) concentrations. The aim of the present study was to explore the influence of age and gender, together with folate status, on the association between the C677T polymorphism and tHcy concentrations. The C677T genotype was determined for 1820 participants from the fifth examination of the Framingham Offspring Study. Mean age of the participants was 56 y (range 28-82 y). The allelic distribution was not different from the Hardy-Weinberg equilibrium, with a TT frequency comparable in men and women (14%). Geometric mean tHcy was 15% higher in men than in women (P < 0.001), and women had significantly higher plasma folate levels (P < 0.001). Geometric mean tHcy was significantly higher in TT participants (P = 0.001) than in participants with the CC and CT genotypes among those with plasma folate <12.5 nmol/L, but not among those with higher folate status. Because of a significant age and sex interaction (P = 0.02), we further stratified the low folate group by age and sex, and observed that the association between genotype and tHcy was confined to men <55 y old (P < 0.001). Our results suggest that age and sex modify the contribution of the MTHFR C677T mutation to fasting tHcy concentrations.

Serum total homocysteine concentrations in children and adolescents: results from the third National Health and Nutrition Examination Survey (NHANES III)

Although the elevation of circulating total serum homocysteine (tHcy) concentration in a fasting state is associated with an increased risk of occlusive vascular disease in adults, the implications of elevated levels in children are not known. The goals of this study were to describe the distribution of tHcy among a representative sample of children and adolescents in the United States, and to test for differences in tHcy among sex, age and race-ethnicity categories. Using surplus sera from Phase 2 of the third National Health and Nutrition Examination Survey, we measured tHcy for a nationally representative sample of 942 boys and 1085 girls aged 4-19 y. The age-adjusted geometric mean tHcy concentrations were 6.2 and 5.8 micro mol/L in non-Hispanic Caucasian boys and girls, 6.4 and 6.1 micro mol/L in non-Hispanic African-American boys and girls, and 6.4 and 5.5 micro mol/L in Mexican American boys and girls, respectively. A significant interaction between age and sex (P < 0.01) reflected the divergence of tHcy concentrations at about age 10 y, with higher concentrations in boys than in girls throughout adolescence. These first data on homocysteine concentrations in a nationally representative sample of American youth suggest that sexual dimorphism of tHcy concentrations occurs earlier, at approximately 10 y of age, than previously reported on the basis of smaller nonrepresentative samples. Improved understanding of the determinants of levels during growth and development may provide important clues to the etiology of adult disease.

Plasma homocysteine and risk for congestive heart failure in adults without prior myocardial infarction

CONTEXT

Elevated plasma homocysteine levels are associated with increased risk of vascular disease. It is unclear whether elevated homocysteine levels are a risk factor for congestive heart failure (CHF).

OBJECTIVE

To study prospectively the association between nonfasting plasma homocysteine and incidence of CHF.

DESIGN, SETTING, AND PARTICIPANTS

Community-based prospective cohort study of 2491 adults (mean age 72 years, 1547 women) who participated in the Framingham Heart Study during the 1979-1982 and 1986-1990 examinations and were free of CHF or prior myocardial infarction (recognized or unrecognized) at baseline.

MAIN OUTCOME MEASURE

Incidence of a first episode of CHF during an 8-year follow-up period.

RESULTS

During follow-up, 156 subjects (88 women) developed CHF. In multivariable analyses controlling for established risk factors for CHF including the occurrence of myocardial infarction (recognized or unrecognized) during follow-up, plasma homocysteine levels higher than the sex-specific median value were associated with an adjusted hazards ratio for heart failure of 1.93 in women (95% confidence interval, 1.19-3.14) and 1.84 in men (95% confidence interval, 1.06-3.17). The relation of plasma homocysteine levels to CHF risk was more continuous in women than in men. In analyses restricted to participants without any manifestation of coronary heart disease at baseline, the association of plasma homocysteine levels with risk of CHF was maintained in men and women.

CONCLUSIONS

An increased plasma homocysteine level independently predicts risk of the development of CHF in adults without prior myocardial infarction. Additional investigations are warranted to confirm these findings.

Depression and folate status in the US Population

BACKGROUND

Folate deficiency and low folate status have been linked in clinic studies to depression, persistent depressive symptoms, and poor antidepressant response. These relationships have not been demonstrated in general populations. This study examined associations between depression and folate status indicators in an ethnically diverse general US population sample aged 15-39 years.

METHODS

Healthy subjects whose red blood cell (RBC) folate concentrations had been measured were determined to have no depression (n = 2,526), major depression (n = 301), or dysthymia (n = 121) using a diagnostic interview schedule. Serum concentrations of folate and total homocysteine (tHcy) were also measured.

RESULTS

After adjustment for sociodemographic factors, serum vitamin B(12) concentration, alcohol consumption over the past year and current status as to overweight and use of vitamin/mineral supplements, cigarettes and illegal drugs, subjects who met criteria for a lifetime diagnosis of major depression had folate concentrations in serum and RBCs that were lower than those of subjects who had never been depressed. Subjects who met criteria for dysthymia alone had lower RBC folate concentrations than never-depressed subjects, but the serum folate concentrations of the two groups were comparable. Serum tHcy concentration was not related to lifetime depression diagnoses. Low folate status was found to be most characteristic of recently recovered subjects, and a large proportion of such subjects were folate deficient.

CONCLUSIONS

Low folate status was detectable in depressed members of the general US population. Folate supplementation may be indicated during the year following a depressive episode.

Demographics and trends in overweight and obesity in patients at time of kidney transplantation

BACKGROUND

The epidemic of overweight and obesity is one of the most serious public health problems in the United States, although information regarding its effect on chronic kidney transplant patients is sparse. The authors describe the prevalence, demographics, and trends in overweight and obesity at the time of kidney transplantation.

METHODS

Data were obtained from a national transplant database that included all kidney transplants since 1987. Body mass indices (BMI) at time of transplantation were stratified by demographic categories and year. Trends of overweight and obesity between the general population and subjects undergoing kidney transplantation were compared. Logistic regression analyses were performed to identify variables associated with increased likelihood of being obese.

RESULTS

The majority (60%) of subjects at time of transplantation currently are overweight or obese. Between 1987 and 2001, the proportion of obese transplant recipients rose by 116%. The rate of increase was grossly similar to that in the general population. The likelihood of being obese increased with age, female sex, noninsulin-dependent diabetes mellitus, black race, and the more recent the transplant year. Conversely, the proportion of recipients with lower BMI fell by approximately 50%.

CONCLUSIONS

Overweight and obesity are very prevalent at the time of kidney transplantation and are eclipsing protein-energy malnutrition as the more common nutritional illness. This may have profound negative effects on patient and allograft outcomes. Nephrologists may need to reexamine traditional notions of nutritional disease and therapeutic strategies to more effectively deal with this formidable challenge.

Tropical enteritis: nutritional consequences and connections with the riddle of cholera

One of the important consequences of the infection-nutrition interaction is mediated by malabsorption associated with chronic inflammation in the intestine, enteritis. Studies made possible after development of the peroral intestinal biopsy technique in the 1950s indicated the wide prevalence of enteropathy, particularly in tropical developing countries with poor levels of sanitation. Some consider this so-called subclinical tropical malabsorption to be the base of an iceberg, whose tip is tropical sprue, a severe form of malabsorption leading to nutritional deficiency that had been reported in colonial expatriates in tropical countries for 200 y. Some of the first demonstrations of the prevalence of tropical enteritis in Asia were made in quest of the pathologic lesion of cholera, and further examination of the water and electrolyte, as well as nutrient, malabsorption in cholera led serendipitously to the discovery of the oral rehydration solution for the treatment of diarrheal disease.

Elevated serum methylmalonic acid concentrations are common among elderly Americans

To describe serum methylmalonic acid (MMA) concentrations of elderly Americans and examine relationships between serum MMA and other factors, we used surplus serum samples collected from elderly (n = 1145) and young-adult (n = 1026) participants in Phase 2 of the third National Health and Nutrition Examination Survey (1991-1994). In approximately 20% of participants >/=65 y old, serum MMA was >370 nmol/L, the 90th percentile of the distribution of participants aged 30-39 y. Consistent with previous reports, we observed strong, independent positive associations between serum MMA concentration and serum concentrations of creatinine and homocysteine. After controlling for demographic factors and creatinine, geometric mean MMA concentration was lower in non-Hispanic blacks [223.6 nmol/L; 95% confidence interval (CI), 198.8-251.5] than non-Hispanic whites (265.1 nmol/L; 95% CI, 240.3-292.4). However, the prevalence of elevated levels did not vary with race/ethnicity. Serum MMA concentration bore a strong inverse relation to serum vitamin B-12 concentration. Nevertheless, elevated serum MMA concentrations affected approximately 15% of those with both normal serum creatinine concentrations and serum B-12 concentrations >148 pmol/L. We conclude that many elderly Americans demonstrate metabolic evidence of low B-12 status, that elevations occur frequently in the absence of traditional deficiency indicators and that levels vary with race/ethnicity and renal function.