Effects of carbohydrate-containing and carbohydrate-restricted hypocaloric and eucaloric diets on serum concentrations of retinol-binding protein, thyroxine-binding prealbumin and transferrin

Proteomic analysis in type 2 diabetes patients before and after a very low calorie diet reveals potential disease state and intervention specific biomarkers

Very low calorie diets (VLCD) with and without exercise programs lead to major metabolic improvements in obese type 2 diabetes patients. The mechanisms underlying these improvements have so far not been elucidated fully. To further investigate the mechanisms of a VLCD with or without exercise and to uncover possible biomarkers associated with these interventions, blood samples were collected from 27 obese type 2 diabetes patients before and after a 16-week VLCD (Modifast ∼450 kcal/day). Thirteen of these patients followed an exercise program in addition to the VCLD. Plasma was obtained from 27 lean and 27 obese controls as well. Proteomic analysis was performed using mass spectrometry (MS) and targeted multiple reaction monitoring (MRM) and a large scale isobaric tags for relative and absolute quantitation (iTRAQ) approach. After the 16-week VLCD, there was a significant decrease in body weight and HbA1c in all patients, without differences between the two intervention groups. Targeted MRM analysis revealed differences in several proteins, which could be divided in diabetes-associated (fibrinogen, transthyretin), obesity-associated (complement C3), and diet-associated markers (apolipoproteins, especially apolipoprotein A-IV). To further investigate the effects of exercise, large scale iTRAQ analysis was performed. However, no proteins were found showing an exercise effect. Thus, in this study, specific proteins were found to be differentially expressed in type 2 diabetes patients versus controls and before and after a VLCD. These proteins are potential disease state and intervention specific biomarkers.

Trial Registration

Controlled-Trials.com ISRCTN76920690

Effect of diet-induced energy deficit and body fat reduction on high-sensitive CRP and other inflammatory markers in obese subjects

AIMS

To dissociate the possible differential effects of negative energy balance and reduction in body fat mass (FM) on inflammatory markers: C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), haptoglobin, transferrin and the adipokines leptin and adiponectin.

METHODS

Thirty-three obese subjects (BMI: 34.0+/-3.1 kg/m(2), age: 43.0+/-10.5 years, mean+/-s.d., 16 men) participated in a 20-week controlled dietary intervention divided into four periods. Weight reduction was induced by an 8-week low energy diet (3.4 MJ d(-1)) (LED-1) followed by a 4-week weight maintenance program (M-1). Subsequently participants underwent an additional 4-week LED (4.2 MJ d(-1)) (LED-2) followed by a final 4-week weight maintenance diet (M-2). Blood samples and anthropometrics were assessed at baseline and after LED-1, M-1, LED-2 and M-2.

RESULTS

Body weight was significantly reduced by 13% (13.7+/-4.0 kg, P<0.0001) after LED-1. However, a reduction in high-sensitive CRP (hs-CRP) by 35% (-1.1 (95% CI: -2.5:0.2) mg l(-1), P=0.02) only became apparent after LED-2, which produced an additional weight loss of 2.9 kg compared to baseline, and it was maintained after M-2 (-1.0 (-1.4:0.4) mg l(-1), P=0.02). Also IL-6 was reduced by 21% (-0.6 (-2.4:0.2) ng l(-1), P=0.02) after M-2. The reductions in hs-CRP and IL-6 were both associated with reduction in FM but not body weight. Haptoglobin, transferrin and leptin were significantly reduced after both LED-1 and LED-2, but increased during weight maintenance. Adiponectin was not significantly changed during the intervention.

CONCLUSIONS

The results suggest that, whereas haptoglobin and transferrin respond more rapidly and are more susceptible to the acute change in energy balance, a reduction in hs-CRP and IL-6 seems to be achieved by a reduction in FM when a new steady state has been established.

Nutrition support in clinical practice: review of published data and recommendations for future research directions

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family.

Effect of sucrose on inflammatory markers in overweight humans

BACKGROUND

Observational studies have found that dietary glycemic load is positively associated with C-reactive protein (CRP) concentrations in healthy humans, which suggests that the type of carbohydrate ingested influences inflammatory activity.

OBJECTIVE

We investigated the effect of a diet with a high content of sucrose or artificial sweeteners on the inflammatory markers CRP, haptoglobin, and transferrin in overweight subjects.

DESIGN

Overweight men and women consumed daily food and drink supplements containing either sucrose [n = 21; body mass index (BMI, in kg/m2): 28.0] or artificial sweeteners (n = 20; BMI: 27.6), predominantly from soft drinks (70%; average approximately 1.3 L/d) for 10 wk.

RESULTS

During the intervention, sucrose intake increased by 151% in the sucrose group and decreased by 42% in the sweetener group, resulting in a 1.6-kg weight gain in the sucrose group and a 1.2-kg weight loss in the sweetener group over 10 wk (P < 0.001). Concentrations of haptoglobin, transferrin, and CRP increased by 13%, 5%, and 6%, respectively, in the sucrose group and decreased by 16%, 2%, and 26%, respectively, in the sweetener group (between-group differences: P = 0.006, P = 0.01, and P = 0.1, respectively). Adjustment for changes in body weight and energy intake did not substantially influence this outcome.

CONCLUSIONS

The study shows that in the present group of overweight subjects a high consumption of sugar-sweetened foods and drinks increased haptoglobin and transferrin but had, at best, only a limited influence on CRP.

Thyroid indices and treatment outcome in bulimia nervosa

OBJECTIVE

This study examined the thyroxine (T4) and free T4 (FT4) status of women with bulimia nervosa and its value as a predictor of outcome.

METHOD

A total of 135 women with bulimia nervosa underwent 12-weeks cognitive behavioral therapy treatment. Prior to and at 3-year follow-up patients completed psychiatric assessments and serumT4 and FT4 were measured.

RESULTS

At 3-year follow-up, 71% had no eating disorder and 29% met criteria for any eating disorder diagnosis. Mean T4 and FT4 concentrations were within normal ranges. Pre-treatment T4 and FT4 concentrations were inversely associated with food restriction and purging frequency, respectively. Compared with women with no eating disorder, those with any eating disorder at follow-up had lower pretreatment T4 concentrations. When pre-treatment food restriction, oral contraceptive use and binge frequency where controlled for, low T4 concentration was the only predictor of eating disorder diagnosis at follow-up.

CONCLUSION

Low T4 concentrations at pretreatment may be a predictor of poor outcome in bulimia nervosa.

Influences of obesity and weight loss on thyroid hormones. A 3-3.5-year follow-up study on obese subjects with surgical bilio-pancreatic by-pass

The effects of changing body size, energy intake and substrate oxidation on serum T4, FT4, T3, FT3 and TSH were investigated in ten morbidly obese subjects (4 men/6 women; age: 37 +/- 6 years; BMI: 53.8 +/- 6.5 kg/m2; mean +/- SD) who had undergone a surgical bilio-pancreatic by-pass in order to reduce their body weight. The starting value of serum FT3 was inversely related to the BMI (r = -0.63; p < 0.05). After 1-3 months, all the subjects were losing weight and their intake of carbohydrates was almost negligible; at this time a significant reduction of T3 (-14.6%; p < 0.0001), T4 (-19.5%; p < 0.0001), and FT3 (-10.5%; p < 0.001) was observed. Nine to 16 months after surgery, all the subjects were still losing weight, although there was no carbohydrate restriction; T3, T4, and FT3 were lower than prior to surgery but were beginning to increase. Finally, after 36-42 months the body weight of all the patients had been stable for at least the previous six months (final BMI: 32.9 +/- 4.1) and their body composition, as assessed by bio-impedance, was almost normal; only the concentrations of FT3 proved to be significantly lower than the basal value (-11.2%; p < 0.03). The change in FT3 proved to be independently influenced by the degree of fat malabsorption but not by changes in any of the physical characteristics considered. All values were always in the normal range; FT4 and TSH did not change significantly during the whole period of study. The final concentrations of TSH proved to be independently related to the postabsorptive protein oxidation (g/24h) (TSH = 2.37-0.018* protein oxidation). These results would suggest that nutritional factors have some influence on the blood levels of thyroid hormones, especially of FT3, while the removal of obesity does not seem to have any independent effect in the long-run.

Nutrition support in clinical practice: review of published data and recommendations for future research directions. National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family.

Effects of a low calorie, low protein diet on nutritional parameters, and routine laboratory values in nonobese young and elderly subjects

The effect of a low calorie (1100 kcal), low protein (35 g) intake for 9 days on nutritional and laboratory parameters was studied in six young and six elderly healthy subjects. All subjects lost weight on the test diet (an average of 2.0 kg in the young and 2.1 kg in the elderly). Basal serum albumin, serum transferrin, creatinine height index, and creatinine clearance in the elderly subjects were lower than in the young (p less than 0.05). Serum albumin remained unchanged at the end of diet in both groups. There was, however, a significant decrease in the transferrin level in the younger subjects (p less than 0.01). The decrease in creatinine height index was not significant in either group. Baseline nitrogen balance of the elderly was -1.1 g/day compared to +0.5 g/day (p less than 0.01) in the young subjects. The test diet caused a negative nitrogen balance of about -5 g/day in both groups (p less than 0.005). Blood urea nitrogen was significantly lower at the end of the test diet and was related to the intake of protein in both groups. At the end of the diet the serum potassium and GGT were significantly lower in the young (p less than 0.01); serum creatinine was unchanged but creatinine clearance was significantly lower in both groups. From this study it appears that significant changes occur in nutritional and laboratory parameters within 9 days on a diet deficient in calories and protein in normal healthy subjects. These changes need to be recognized as having nutritional basis and should not be attributed to illness or drug therapy.

Advances in hospital nutrition

The General Clinical Research Center facilities have been largely responsible for expansion of knowledge in the field of hospital nutrition. Expansion of this knowledge base has led to major medical advances in this century. Without the meticulous attention necessary for metabolic balance studies many if not most of these advances would have been seriously delayed. The role that General Clinical Research Centers have played and will continue to play cannot be overestimated.

Obesity

Over the past 20 years, obesity has represented a significant focus of research conducted in Clinical Research Centers (CRCs) in the United States. This review will focus on the progress in our understanding of the disease that CRC-based research has produced; therefore, the reference list is not exhaustive and consists primarily of CRC-based research. Obesity is defined as an excess of body fat as measured by triceps skinfold thickness. The time of onset of obesity is an important factor; for example, early onset is associated with an increase in the number of fat cells. Weight loss reduces the size but not the number of fat cells. Type II diabetes mellitus is a common complication in obese adults; this condition has been related to fat cell size and, in women, to predominantly upper-body fat distribution. Pregnant obese women and their babies are at risk for a number of problems. Abnormalities commonly found in obese persons include increased plasma lipid levels, hyperinsulinism, increased cholesterol synthesis, high frequency of gallstones, and hypertension. Under a variety of experimental conditions, the only difference in the response of obese and normal weight subjects to food was that the obese subjects appeared to consume more, but other data suggest that the obese may have greater energy needs. Carbohydrate intake has been studied extensively. Metabolic rate increases with over-feeding, especially in response to carbohydrate. Basal metabolic rates are higher in obese adults and rise in response to overfeeding; they decrease after weight reduction. This decrease can be counteracted with sucrose, perhaps because sucrose maintains triiodothyronine levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of preoperative intravenous nutrition upon hepatic protein synthesis and plasma proteins and amino acids

The influence of 3 and 7 days of preoperative intravenous nutrition (IVN) on the capacity for protein synthesis in liver and on concentrations of plasma proteins and amino acids were investigated in patients with gastrointestinal malignancy. Thirty patients with gastrointestinal neoplasms who had lost more than 5 kg of weight over 3 months were randomized into three groups to receive preoperatively: (a) no IVN, (b) IVN for 3 days (0.18 gN/kg/day as amino acid; 30 kcal/kg/day as glucose), or (c) IVN for 7 days. Free access to a hospital diet was available to all patients including 10 patients who had not lost weight who served as controls. In the three groups of patients who had lost weight, median transferrin and fibronectin were lower than for controls, whereas other proteins and amino acids were comparable. After feeding, samples of liver were obtained peroperatively and the potential rates of protein synthesis were calculated from the in vitro incorporation of (14C)-leucine, into protein. Preoperative IVN significantly increased the potential rate of protein synthesis in liver after 3 days. Plasma amino acids were comparable with controls whereas in the unfed-group concentrations suggested utilization of alanine and breakdown of muscle. Three days of IVN also increased plasma fibronectin and IgA but increases of prealbumin, IgM, and complement C3 were only significant in the group fed for 7 days. On the 7th postoperative day plasma proteins were decreased similarly in each group. This study shows that concentrations of several plasma proteins, in preoperative patients reflect net rates of hepatic protein synthesis and are susceptible to depletion during starvation and repletion by 3 or 7 days of IVN.

Effects of aerobic exercise on energy expenditure and nitrogen balance during very low calorie dieting

Aerobic exercise in addition to severe caloric restriction was studied for its effects on resting energy expenditure (REE), weight loss, and lean tissue preservation in adult women. A formula diet providing 1.5 g protein and 0.5 g carbohydrate (CHO) per kilogram of ideal body weight daily (mean intake 720 kcal/d) was given to 12 overweight inpatients for 4 to 5 weeks. Six subjects remained sedentary (group 1), while the other six subjects (group 2) performed supervised endurance exercise (a total of 27 hours at 50% of maximal oxygen uptake (VO2max) over 4 weeks). Lean tissue preservation was excellent in both groups and was unaffected by the group 2 exercise regimen. Weight loss over 4 weeks in the two groups did not differ (group 1, 6.9 +/- 0.7 kg; group 2, 6.5 +/- 0.7 kg). The VO2max was not increased after 4 weeks of exercise compared with controls. The resting oxygen consumption (rVO2) of both groups declined 10% (P less than .001) in the first seven days of dieting. Thereafter the rVO2 in group 1 remained stable, but a further 17% reduction occurred in group 2 (P less than .03) by the third week of exercise. The free triiodothyronine (fT3) concentration also fell more in group 2 (P less than .05), suggesting a relationship between fT3 and energy expenditure during severe caloric restriction. The ergometer exercise for up to two hours daily was well tolerated. The absence of either a training effect or accelerated weight loss in group 2 may be due to the limited duration (4 weeks) or intensity of the exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein metabolism in obese patients during very low-calorie mixed diets containing different amounts of proteins and carbohydrates

To assess long-term nitrogen sparing capacity of very low-calorie mixed diets, we administered two isoenergetic (2092KJ) liquid formula regimens of different composition for 8 weeks to two matched groups of massively obese patients (group 1: proteins 60 g, carbohydrate 54 g; group 2: proteins 41 g, carbohydrates 81 g). Weight loss was similar in both groups. Daily nitrogen balance (g) during the second month resulted more a negative in group 2 with respect to group 1. However, within the groups individual nitrogen sparing capacity varied markedly; only a few in group 1 and one in group 2 were able to attain nitrogen equilibrium throughout the study. Daily urine excretion of 3-methylhistidine fell significantly in group 1 but did not change in group 2. Unlike total proteins, albumins, and transferrin, serum levels of retinol-binding protein, thyroxin-binding globulin, and complement-C3 fell significantly in both groups but per cent variations of complement-C3 were more pronounced in the first group. Prealbumin levels fell persistently in group 1 and transiently in group 2. The results indicate that even with this type of diet an adequate amount of dietary protein represents the most important factor in minimizing whole body protein catabolism during long-term semistarvation in massively obese patients. Moreover, they confirm the possible role of dietary carbohydrates in the regulation of some visceral protein metabolism.

The effect of nutritional support on outcome from severe head injury

Fifty-one brain-injured patients with peak 24-hour admission Glasgow Coma Scale (GCS) scores of 4 to 10 were prospectively randomly assigned to receive total parenteral (TPN) or enteral (EN) nutrition. Patients were studied from hospital admission to 18 days postinjury. Outcome was assessed by the Glasgow Outcome Scale at 3 months, 6 months, and 1 year postinjury. The TPN group received a significantly higher cumulative mean intake of protein than the EN group (mean +/- standard error of the mean: 1.35 +/- 0.12 vs. 0.91 +/- 0.9 gm/kg/day; p = 0.004). Mean cumulative caloric balance was also significantly higher in the TPN than in the EN group (75.6% +/- 5.13% vs. 59% +/- 4.26%; p = 0.02). Nitrogen balance was significantly more negative in the EN group during the 1st week postinjury (p = 0.002). The incidence of pneumonia, urinary tract infections, septic shock, and infections was not significantly different between groups. Classic nutritional assessment parameters such as anergy screens, total lymphocyte counts, and albumin levels were not significantly different between groups. The 11 patients in the EN group who did not tolerate tube feedings for 1 week postinjury had a significantly higher incidence of septic shock (p = 0.008). The change over time in GCS scores between groups was significantly different, with the TPN group showing a mean four-point increase in GCS score compared with a three-point increase in the EN group (p = 0.02). At 3 months the TPN group had a significantly higher percentage of favorable outcomes (43.5% vs. 17.9%, respectively; p = 0.05). At 6 months, 43.5% of the TPN group had a favorable outcome while 32.1% of the EN group had a favorable outcome (p = 0.29). By 1 year, 47.8% of the TPN group and 32.1% of the EN group had a favorable outcome (p = 0.20). In conclusion, more calories and protein usually can be administered to acute brain injury patients via the TPN route than by EN feedings via nasogastric or nasoduodenal routes. Traditional parameters for nutritional assessment are not useful in studying the efficacy of nutritional support during the first 2 weeks after head injury. Neurological recovery from head injury occurs more rapidly in patients with better early nutritional support.

Assessing the efficacy of intravenous nutrition in general surgical patients: dynamic nutritional assessment with plasma proteins

We have compared the direction of changes in four plasma transport proteins measured weekly with the direction of nitrogen balance in general surgical patients receiving intravenous nutrition (IVN). Fifty four patients had IVN for 2 weeks, and 15 had IVN for 3 or 4 weeks. Change in plasma prealbumin followed the direction of nitrogen balance in both weeks of IVN in 39 of 54 of the former group, whereas none of the other plasma proteins achieved 50% accuracy. A weekly rise in plasma prealbumin had a sensitivity of 88%, specificity of 70%, positive predictive value of 93%, and negative predictive value of 56% in detecting positive nitrogen balance. Results in the patients who received 3 or 4 weeks of IVN showed an improvement in negative predictive value to 79%. None of the other plasma proteins performed as well. Twelve patients suffered a major complication of their disease or died, following their course of IVN. Nitrogen balance was the best prognostic indicator of these patients, whereas a fall in prealbumin was the best of the plasma proteins, with a sensitivity of 67%, specificity of 79%, positive predictive value of 40%, and negative predictive value of 92% in determining the incidence of complications. Prealbumin was the most suitable plasma protein for use as a dynamic index of nutritional progress in the type of patient seen in this study.

The response of fibronectin to differing parenteral caloric sources in normal man

The relationship between circulating fibronectin concentration and nutritional status was examined in eight healthy male (31 +/- 1 yr old) volunteers in three nutritional states: the postabsorptive state, after 10 days of protein-caloric starvation, and during the 10th day of refeeding by total parenteral nutrition. Plasma fibronectin was significantly decreased from 330 +/- 22 to 154 +/- 11 micrograms/ml (p less than 0.001) from the postabsorptive to starved state which was accompanied by appropriate changes in body weight, anthropometric measurements, and nitrogen balance. Plasma fibronectin levels were restored to 402 +/- 39 micrograms/ml following 10 days of total parenteral nutrition. The plasma fibronectin response was greater (p less than 0.05) during total parenteral nutrition with dextrose as the nonprotein calorie source as compared to a 50% dextrose/50% lipid regimen. These results suggest that the calorie source must be considered during interpretation of plasma fibronectin levels in patients undergoing parenteral nutrition.

Relationship between the changes in serum thyroid hormone levels and protein status during prolonged protein supplemented caloric deprivation

The relationship between the changes in serum thyroid hormone levels and nitrogen economy during caloric deprivation were investigated in ten obese men during a 40 d, 400 kcal protein-supplemented weight-reducing diet. This regimen induced increases in the serum levels of total T4, free T4 and total rT3, and decreases of total T3, while serum TSH remained unchanged. There were progressive decreases in total body weight and urinary losses of total nitrogen and 3-methylhistidine, with the early negative nitrogen balance gradually returning towards basal values during the 40 days. Subjects with the largest weight loss had the most increase in the serum levels of total T4 and free T4 index and the greatest decrease in T3. The magnitude of the increase of the nitrogen balance from its nadir was correlated with the extent of the reduction of T3 and increase of T3 uptake ratio and free T4 levels. The decrease in the urinary excretion of 3-methylhistidine correlated with the increase in free T4 and rT3 levels. Nadir serum transferrin values were directly related to peak rT3 values, and the lowest albumin concentrations occurred in subjects with the highest total T4 and free T4 index values. Further, the maximum changes in the serum thyroid hormone levels preceded those of the nutritional parameters. These relationships suggest that: (1) increases in serum rT3 and free T4 and reductions in T3 concentrations during protein supplemented weight reduction may facilitate conservation of visceral protein and reduce muscle protein turnover; and (2) the variation in the magnitude of these changes may account for the heterogeneity of nitrogen economy.

Metabolic effects of carbohydrate in low-calorie diets

Fasting plasma glucose turnover, urinary 3-methylhistidine excretion, and fasting plasma protein profiles were compared in a 4-week randomized clinical trial of two very low-calorie weight-reduction diets. Diet A (360 kcal) provided 1.5 g egg protein per kg ideal body weight (IBW) but no carbohydrate. Diet B (340 kcal) provided 0.8 g egg protein per kg IBW plus 0.7 g carbohydrate per kg IBW. Eleven moderately obese healthy young women were studied. After 3 weeks of dieting, fasting plasma glucose appearance and oxidation decreased by equal amounts (20% and 30%, respectively) for both diets. 3-methylhistidine excretion remained at control rates for the first week on the diets, then fell by equal amounts (25% to 30%) with both diets. Similar declines were observed for both diets in serum prealbumin and retinol-binding protein concentrations. Mean serum transferrin declined with both diets, but the changes were not statistically significant. Serum albumin was unchanged by either diet. Thus, there were no significant differences between the two diets with regard to any of the measured parameters.

Decreased plasma fibronectin during starvation in man

This study evaluated the effect of 5 days of starvation followed by 5 days of refeeding on immunoreactive plasma and serum fibronectin and associated opsonic activity as studied by peritoneal macrophage monolayer bioassay in 12 healthy women volunteers. The temporal alteration of fibronectin was compared with the serum albumin, total iron-binding capacity, and retinol-binding protein levels. Fibronectin concentration and opsonic activity were also determined in two cachectic patients who were 61 and 78% of their ideal body weight. Prior to starvation, plasma fibronectin was 292 +/- 20 micrograms/ml and serum fibronectin was 182 +/- 16 in all subjects. After 5 days of starvation, immunoreactive fibronectin decreased (p less than 0.05) by 20-25%. This decrease was not great enough to impair opsonic activity as tested by the in vitro macrophage assay. Starvation caused no decrease in serum albumin or total iron-binding capacity, although retinol-binding protein decreased by 35%. During refeeding, subjects were randomized to a diet with (n = 6) and without (n = 6) carbohydrate. After 5 days of refeeding, fibronectin levels were normalized on the carbohydrate-containing diet, but were still low (82% of normal) on the carbohydrate-free diet. Retinol-binding protein did not fully normalize after 5 days of refeeding. In the two cachectic patients, fibronectin levels prior to total parenteral nutrition were 25 and 75% of normal. Thus, starvation can lower fibronectin levels and this protein is rapidly restored with adequate nutrition.

Vigorous supplementation of a hypocaloric diet prevents cardiac arrhythmias and mineral depletion

We have previously demonstrated that a hypocaloric, nutritionally deficient, liquid protein diet is associated with potentially life-threatening cardiac arrhythmias, which increased in frequency and complexity over the duration of the study. The present investigation was designed to evaluate the metabolic and cardiac changes associated with a hypocaloric, but otherwise nutritionally complete, diet. Six healthy, obese females from 154 to 182 percent of ideal body weight were evaluated in a metabolic ward for 48 days. The subjects ingested a weight maintenance diet during an eight-day period, which was followed by 40 days of an experimental diet containing 472 kcal of a mixture of protein (60 percent of calories), carbohydrate (25 percent), and fat (15 percent). This diet equaled or exceeded the recommended daily allowances for minerals, trace elements, vitamins, and essential fatty acids. The subjects were monitored for balances of nitrogen and minerals, as well as for the appearance of cardiac arrhythmias by 24-hour electrocardiographic recordings. Nitrogen balance was positive, and the previously demonstrated negative balances for potassium, sodium, calcium, magnesium, and phosphorus were either reversed or markedly decreased. In contrast to our previous study, no arrhythmias were observed in subjects ingesting the present experimental diet, and no significant change in cardiac rhythm was found in 13 obese, but otherwise healthy, outpatients. The data, based on a limited number of subjects, suggest that a hypocaloric diet vigorously supplemented with essential elements, micronutrients, and vitamins appears to be safer than the once popular, incomplete liquid protein preparation.