Liquid Protein Diet Research Articles

Effect of liquid protein diet on collagen metabolism of the gingiva of young rats.

The effects of liquid protein diet (LPD) on gingival collagen metabolism were evaluated in young rats. Experimental animals received a LPD, while pair-fed and ad libitum groups received a 20% casein diet. Prior to sacrifice at days 23, 35 and 48 post-partum, animals from each group were injected with C14-proline. Gingival tissues from the palate were excised and analyzed for collagen content and collagen synthesis. Results of body-weight changes at day 48 showed a 20% decrease in the LPD group, while pair-fed and ad libitum groups increased 47% and 267%, respectively. Collagen content per gram of gingiva was not significantly different among the three groups. Gingival collagen synthesis, however, did show significant differences among the three groups. It was concluded that while LPD effects on the overall body condition were profound, LPD exerts minimal effect on gingival collagen metabolism in young rats.

Biochemical alteration of the skin in newborn rats by feeding liquid protein diet during early pregnancy

Pregnant rats were fed a 20% LPD from day 1 to day 10 of pregnancy; on day 10, the diet was changed to a 20% casein and the animals were fed this diet until delivery. A pair-fed control group was fed the 20% casein diet throughout pregnancy. The body weights of the LPD group stayed constant for the first 10 days. When the casein diet was begun at day 10, however, body weight increased within 24 hours. The body weight in the LPD group then increased continuously. In contrast, the body weight of the pair-fed control group increased throughout pregnancy. On delivery, newborns and their mothers were killed and their skins were removed. Compared with the controls, the contents of both type III collagen and α 1 trimer were increased in the newborn of the LPD-fed mothers; however, total collagen content of the LPD newborn was less. In contrast, the mothers' skins did not differ between the groups in any measurements determined. The data suggest that the quality of the maternal protein source in the diet influences the content and nature of skin collagen in the growing fetus, whereas the mother's skin is less affected by the nutritional stress during pregnancy.

Effects of a liquid protein diet during pregnancy on newborn rats

Liquid protein was introduced in the mid 1970's as a means of weight control, and has been used extensively within the general population. The protein portion of the standard casein diet was substituted with liquid protein and fed to pregnant rats. The newborns whose mothers were fed liquid protein with all the other necessary nutrients showed an increased rate of stillbirths and cataracts. The total body weight was decreased compared to the pair-fed and/or ad libitum controls, whereas the organs such as the heart, lung, kidney and liver were smaller than ad libitum controls. The data suggest that taking liquid protein requires caution, particularly during pregnancy.

2 BODY COMPOSITION CHANGES IN OBESE ADOLESCENTS ON A PROTEIN SPARING MODIFIED FAST

Weight reduction involves loss of both Lean Body Mass (LBM) and adipose tissue. Total Body Potassium (TBK) has been used to estimate LBM, but is an unreliable predictor of Total Body Nitrogen (TBN), and therefore, of body protein in the undernourished. 17 obese adolescents, 12.5-17.5 yrs, weight >150% Ideal Body Weight (IBW), (70-126 kgs) were followed over a 3-month period on a diet of lean meat, fish and poultry (2.5 g protein/kg IBW/d, and 900 kcal/d). Body composition was assessed by estimating Fat Free Body Mass (FFBM) from 4 skinfold thickness, and LBM as derived from 40K, or from TBN by neutron activation.Potassium supplements, 75-100 mEq/d, did not reduce TBK loss, which was biphasic, with significant falls at 2 wk and at 10 wk. There was a significant correlation (p<0.005) between TBK and TBN. There was no relationship between change in TBK and change in body weight nor in LBM as estimated from TBN. The N/K ratio was 12.0-17.4 g/g. A substantial fall in TBK with relative sparing of TBN was demonstrated. The biphasic nature of the TBK loss may explain the late and unexpected deaths reported on Liquid Protein Diets. The wide range of N/K ratios confirm that TBK cannot be used to predict TBN in a changing nutritional state.

Electrocardiographic Abnormalities in Obese Rats Fed a Commercially Available Liquid Protein Diet

Male, obese and non-obese Osborne-Mendel rats were fed a commercially available liquid protein (LP) diet of poor nutritional quality in an amount proportional to that consumed by humans on this diet. Rats fed LP plus vitamins and minerals or a vitamin and mineral mixture only served as control groups. Electrocardiograms (ECG) were recorded weekly until the animals lost 45–50% of their original body weight. ECG's were normal in all groups at the start of the experiment. All rats consuming the LP diet only had arrhythmias. Intractable arrhythmias in the human have been of ventricular origin; in rats in this study various atrial disorders of an inconsistent nature were observed. Serum calcium was low in rats fed the LP diet, but normal in magnesium and potassium concentrations. Calcium, magnesium and potassium were in normal concentrations in cardiac and skeletal muscle, and in bone. Zinc and copper concentrations were low in hearts of rats fed the LP diet. The suggested role of calcium, magnesium and potassium in producing cardiac arrhythmias when subjects consume the liquid protein diet studied here as the sole source of calories is questioned.liquid protein diet electrocardiograms arrhythmias

Abnormal electrocardiograms in rats deficient in copper

According to a new hypothesis based on epidemiologic observations, iatrogenic maneuvers, natural occurrences, and animal experiments, absolute or relative deficiency of copper is of prime importance in the etiology of ischemic heart disease. Male weanling rats were made copper deficient with a purified diet containing 0.79 microgram Cu/g diet and containing all other nutrients known to be essential. Deficiency was verified by a 39% increase in cholesterolemia. Electrocardiograms of copper-deficient rats showed several abnormalities including S-T segment depression for one-third to one-half of the R-R interval, bundle branch block with R waves three times normal height and width, Q waves, and second- and third-degree heart block. Copper deficiency shortened the lives of the rats by 73%. Copper deficiency is the only nutritional insult that has produced rapid unfavorable alterations in lipid metabolism, cardiac and arterial anatomy, and cardiac electrophysiology. Copper metabolism may be important in the etiology of ischemic heart disease and in the arrhythmias associated with the consumption of liquid-protein diets.

Cardiac arrhythmias associated with a liquid protein diet for the treatment of obesity.

OBESITY that is greater than 20 per cent of ideal body weight affects 25 to 45 per cent of Americans over 30 years of age.1 Since a review in 1959 indicated that less than 5 per cent of patients who need to lose 18 kg or more were successful, 2 several therapeutic approaches, including fasting, 3 have been introduced. More recently, exogenous protein has been added to minimize catabolism during a total fast.4 5 6 On such a diet, 405 of 519 obese patients (78 per cent) lost at least 18 kg, with an average loss of 1.5 kg per week.6 However, serious complications . . .

Liquid Protein Diet Carries Risk of Sudden Death

Liquid Protein Diet Carries Risk of Sudden Death

Liquid protein diets and electrolyte deficiency

Liquid protein diets and electrolyte deficiency

Sudden cardiac death on the liquid protein diet: Clinical and morphologic findings in 16 women

Sudden cardiac death on the liquid protein diet: Clinical and morphologic findings in 16 women

Cardiac Complications of Liquid Protein Diets

<h3>To the Editor.—</h3> Two articles in a recent issue ofThe Journalby Singh et al (240:115, 1978) and Brown et al (240:120,1978) report the deaths from refractory ventricular tachycardia and fibrillation of three young women, obese but apparently otherwise healthy, who had been given a program of weight reduction by fasting with liquid protein. Each of the three had been fasting for five or six months and had lost about 41 kg. In each case the ECG on admission was marked by gross QT_cprolongation. Singh et al state: "It is not known what proportion of patients using various liquid protein diets have such ECG abnormalities and whether all such patients are at risk for the development of serious arrhythmias." In connection with the programs of supplemented fasting with protein of high biologic availability, carbohydrates, and minerals at The Mount Sinai Hospital of Cleveland and at the University

Fatal Hyperkalemia From Accidental Overdose of Potassium Chloride

To the Editor.— We have recently investigated the deaths of two previously healthy individuals who died of hyperkalemia following accidental oral overdose of potassium chloride. Report of Cases.—Case 1.— A 32-year-old medical secretary became hypokalemic after she had begun taking liquid protein diet. She was given slow-release potassium chloride for this, and subsequently used the medication indiscriminately whenever she felt weak or tired. One evening diarrhea developed; she said she had taken a lot of potassium pills. She was told that the diarrhea probably resulted from potassium chloride, to take no more pills, and that the diarrhea would probably remove the excess potassium. She was found dead the next morning. Findings from an autopsy showed that she had ingested 47 tablets of potassium chloride. The ocular fluid potassium level (about 18 hours postmortem) was 10.8 mEq/liter. Results of toxicologic analysis of fluids and tissues were normal, except

Liquid Protein Diets and Torsade de Pointes

Three women, aged 27, 33, and 35 years, experienced recurrent syncope five months after losing 36 to 41 kg using liquid protein diets. No abnormalities were noted during physical examination except in one who was hypothyroid. Serum potassium levels varied between 2.9 and 3.9 mEq/liter. The ECGs demonstrated prominent U waves, QUc prolongation, and ST and T wave abnormalities, with left axis deviation in two patients. Syncopal episodes were due to ventricular tachycardia and fibrillation, which were not responsive to conventional antiarrhythmic agents used in two patients. Patients using liquid protein diets may thus experience reversible QUc prolongation giving rise to serious arrhythmias that are probably best treated with drugs that shorten the QTc interval. Caution should be exercised in the use of liquid protein diets for weight reduction in obesity.

Liquid Protein Mayhem

In this issue ofThe Journal, Singh et al (p 115) and Brown et al (p 120) report a total of three deaths of female patients who had adhered faithfully to a liquid protein diet (providing about 300 kcal/day in the form of protein hydrolysate) for five to six months. The immediate cause of death in every case was refractory ventricular tachycardia and fibrillation. A fourth patient experienced repeated episodes of ventricular tachycardia, but, after a stormy course, her condition was controlled with phenytoin sodium. The patient subsequently recovered. The ECGs of all four patients showed gross abnormalities of repolarization characterized by prominent U waves and QT c prolongation. All of the patients were relatively young women aged 27 to 35 years, and, except for their obesity, all had been in good health before undergoing supplemented fasting. At the time the cardiac complications were first observed, the patients had lost