User:Karimrowel/sandboxannotatedbib

Postnatal High Protein Intake Bad for Infants

This review examines the effects of a new experimental low-protein formula for infants between 3 and 12 months of age. In one study it is benchmarked against a higher protein formula and found lower weight (p = 0.031) but not lower than the healthy lower-bound as set by WHO. Another study was conducted in Chile on children who had mothers with a BMI above 25. The same results held here with a slightly lower p-value of 0.022. I include this study in the annotated bibliography and not in an actual wikipedia entry just because it has a lot of the indicators of a bad study that we learned to be cautious of and I found that interesting when I came across it. I was first cautious because I noticed that it was published by Nestle. This "experimental formula" is likely something they hope to sell and market as "research shows that this is more like breast milk than other formulas". The abstract contained the phrase meta analysis but it was in relation to a separate study, so it may have been included there to pop-up even when filtering for meta analysis and simply to seem more credible. Finally, the conclusion mentions that using this formula will result in cost savings for individuals and society. This "study" is unlike any other on PubMed and I include it here exclusively as an example of the kind of research that I tried to avoid when contributing to Wikipedia.

Dietary Protein Intake and Chronic Kidney Disease

This fairly extensive systematic review (including meta-analysis) makes note of prior studies demonstrating potential harm of high protein diets (> 1.2 g/kg/d) on renal function and has an additional focus on the potential benefits of a low protein diet (0.6 g/kg/d - 0.8 g/kg/d) on chronic kidney disease (CKD) management. Although glomerular filtration rate (GFR) has been shown to increase in the short term with a high protein diet, continuing the diet for a long period may cause kidney damage and decreased renal function. Moreover, a high protein diet is shown to cause a more rapid decrease in GFR in subjects with pre-existing kidney disease but the results have been mixed as it relates to a healthy population. On the flip side, a low protein diet has been shown to lead to metabolic processes that may preserve kidney function in patients suffering from CKD. The problem is that a low protein diet in these patients may cause additional complications such as malnutrition in some subjects. The study concludes that a low protein diet may be beneficial in patients with CKD and that this dietary intervention should be considered. Overall, this study leans on the side of the debate that long-term increased consumption of protein may have negative effects in both individuals with CKD, as well as healthy individuals. It also calls for more research into the potential benefit of low protein diets for people already suffering from CKD.

Comparison of High vs. Normal/Low Protein Diets on Renal Function in Subjects Without Chronic Kidney Disease

This systematic review and meta analysis examines the effects of a high protein diet (as compared to a baseline normal or low protein diet at least 5% difference in total energy intake) on individuals without chronic kidney disease (CKD). This meta analysis, which pools together 30 reports and a total of 2160 healthy participants, shows that high protein diets led to increased glomerular filtration rate (GFR), serum urea, and urinary calcium excretion. Increased GFR should be interpreted conservatively because the study uses creatine-based estimations, which can be both inaccurate as well as adversely affected by increased protein intake. Differences in urinary calcium excretion were not clinically relevant. Increased serum urea levels were noticed when a study that used only vegetable protein as a supplement was excluded from the study, indicating potentially more detrimental effects of animal protein. This also means that it is likely not the protein itself that causes the increased serum urea but rather that this is the effect of consuming an increased amount of purines, which are abundant in animal source foods. There is not a clear consensus of whether or not the source of protein matters when examining long term high protein diets. There is an additional note that CKD patients who reduce protein consumption decrease occurrence of renal death by 32% versus the CKD patients who do not take these measures. Overall the systematic review and meta analysis leans towards the side of the debate that recommends caution in long-term high protein diets because of inconsistent results and little certainty of the effects. This study leans towards the side of the debate that CKD patients should decrease protein consumption.

Effects of Higher- Versus Lower-Protein Diets on Health Outcomes

This systematic review of 74 eligible studies includes exclusively randomized controlled trials to ensure minimal to no bias and conducts a meta analysis regression to determine both the weight loss effects of a high protein diet, as well as to examine potentially detrimental effects of such diets to an individual's health. In this analysis the median age of participants was 45 years, median BMI was 25, median high protein diet was defined as 27% of total energy intake, and median low protein diet was 18% of total energy intake. The analysis concludes that a high protein diet does seem to help with loosing an additional average of 1.21kg over 3 months. BMI is also reduced by 0.51 units when on a high protein diet. Benefits of decreased BMI as well as HDL cholesterol were more strongly observed in studies with only a slight increase in protein rather than closer to the extreme trials (high protein was classified as 45% of total energy intake). Detrimental effects to cardiovascular activity were not observed in measurements including blood pressure, LDL cholesterol, and CRP. It should be noted that 80% of the selected studies measured outcomes over a period of less than 6 months. This study takes the position that moderate increase in protein content can be moderately beneficial for weight loss but should be tempered with an awareness of the fact that little is known about the long-term effects of high protein diets.

Effect of Short-Term High-Protein Compared With Normal-Protein Diets on Renal Hemodynamics and Associated Variables in Healthy Young Men

This study notes that high protein diets have been effective in weight loss and explores potential negative effects on renal hemodynamics. A High-Protein diet was defined as 2.4 g * kg(-1) * d(-1); a Normal-Protein diet is defined as 1.2 g * kg(-1) * d(-1). The variables explored were the glomerular filtration rate and renal plasma flow in 24 healthy young men after 7 days of following the diet. The study concludes that a short-term high protein diet does alter renal hemodynamics and associated variables such as renal excretion of uric acid. This study directly relates to my area of research in that it explores the effect of a high protein diet vs a normal diet. A strength of this study is that it, unlike many other studies researching similar issues, was conducted on healthy young men and not on rats or people who already have a disease. The diet was also very clearly communicated with the participants and daily phone calls were made during the high protein week to ensure that the participants were achieving their protein intake goals. Finally, subjects were used as their own controls by following both diets with a 7-10 day period in between the high-protein and normal-protein diets. A potential flaw of the study lies in the fact that sodium was not restricted. It is likely that increased consumption of animal protein during the high-protein period was accompanied by increased consumption of sodium. To that point, it is possible that the altered renal hemodynamics were due to the increased levels of sodium intake. Moreover, the study monitors the patients for a short period of time and does not explore the possibility of normalized behavior of renal hemodynamics and associated variables after a period of greater than 7 days. The study leans more towards the side of the debate that increased consumption of protein may have negative effects for overall health.

Alternation between dietary protein depletion and normal feeding cause liver damage in mouse

This study examines the effects of 3 consecutive iterations of a 5-day period of complete removal of protein from a female mouse's diet, followed by a 5-day period of a normal protein diet on the mouse's liver. Effects on variables measured include a 90% increase in fatty acid synthesis versus the control group, a 48% decrease in expression of carbonic anhydrase III, and a 95% increase in lipid peroxidation. Moreover, the mice showed characteristics of hepatic liver damage similar to precancerous and cancerous conditions. Further research should be done to examine the potentially adverse effects of irregular consumption of protein, alternating between no protein and normal amounts of protein, on a human liver. Strengths of the study include the highly controlled environment that it was conducted in, as well as the fact that the overall method seems to focus on precision (In cytosol preparation, for example, each test was carried out in triplicate). Additionally, the fact that the study was done on healthy mice makes it somewhat more transferable to my are of focus.The weaknesses include the fact that the results of the study are not necessarily directly applicable to human livers. Moreover, the study seems to lack transparency - there is no discussion of the limitations of the study anywhere and the number of mice used is never disclosed. Overall, the study leans toward the side of the debate that consumption of protein can be harmful to health. It presents in interesting perspective in that it does not examine low or high doses, but rather the effect of alternating low doses.

Refeeding with a high-protein diet after a 48 h fast causes acute hepatocellular injury in mice

This study looks at the effect of consuming a high protein diet after a fasting period. mice were fasted for 48 hours and then fed diets containing casein ranging from 3 to 50%. Effects on the liver were then examined through looking at variables such as serum alanine aminotransferase and aspartate aminotransferase. The conclusion is that a 48 hour fast followed by a high protein diet was shown to cause acute hepatocellular injury in healthy animals. This study is extremely relevant to my area of focus because it mirrors two trends in dieting - intermittent fasting and high protein diets. Because these two are commonly used in conjunction, it is interesting to see the effects that it has on animals. Previous studies have not shown much higher levels of AST and serum ALT activities in rats consuming a high protein diet for two weeks versus the control group of rats. This study, on the other hand, shows that after a 48 hour fast the rats fed a 50% casein diet experienced abnormal elevation of serum ALT and AST activities in as fast as 2-3 hours. another strength supporting the finding includes the fact that liver heat shock protein 72 transcript levels greatly increased for mice fed casein levels of 3-35%. Conversely, a weakness that refutes the finding is that this same effect was not observed the the group of mice being fed a 50% casein level. Overall, this study supports the side that a high protein diet can be harmful. The study does show in several places that this is an effect that is observed after a 48 hour fast but not after gradual increase in protein level of the diet. It is, however, not necessarily directly transferable to a human anatomy. Moreover, even the most extreme popularized version of intermittent fasting only requires a 24 hour fast, which is half the time examined in this study. Hence, it is not a certainty that the results will hold for this duration of time.

The Effects of a High-Protein, Low-Fat, Ketogenic Diet on Adolescents With Morbid Obesity

This study monitors obese adolescents on a strict high-protein, low-fat, low-carb diet for 8 weeks, followed by 12 more weeks of the same diet with a slightly increased intake of carbohydrates. The 12 to 15 year olds lost an average of 15.4 kg during the first 8 weeks, followed by an average of 2.3 kg during the next 12 weeks. The weight lost was predominately from fat cells and lean tissue was relatively unaffected. LDL levels showed a decrease but so did HDL levels, keeping the ratio the same as at the start of the experiment. A side effect of this diet was a decrease in bone mineral density, despite regular levels of calcium consumption. This effect occurs because urinary calcium excretion is increased during ketosis. I.e. this is a side effect of low cars (25 g/day) and not the higher intake of protein. This study showed no negative side effects due to the consumption of protein over the total 20 weeks. Strengths include accuracy due to use of DEXA scans to monitor body fat percentage and distribution of fat across all parts of the body. The flaws of the study, however, seem to outweigh the benefits. There were only 6 participants; there was no control group; the study was meant to show the effects of a high-protein diet on weight loss but total calories consumed per day was between 650-725 calories - it is impossible to attribute the positive effects of weight loss to the high-protein diet without a control group that was at a similar deficit with a different macronutrient distribution; participants only came in once every 4 weeks and the only way observation of diet was monitored was through a journal; there was no follow-up examination of the subjects for any period after they were no longer on the diet. Overall, the study does not support the view that a high-protein diet causes detrimental effects to health but it should be noted that participants were given many supplements in the form of pills to avoid any potential micronutrient deficiencies that would almost certainly arise from this type of diet.

Restricted Protein Diet Leads to Protein Craving, Increased Palatability, and Hyperphagia

In this study rats were given a low (restricted) protein diet (5% casein) and a baseline diet (20% casein). At the end of the study rats were given a choice of the solution high in casein and or a saccharin-sweetened carbohydrate solution. The rats that were restricted from protein exhibited a preference for the high protein pollution, whereas the control rats did not. Further analysis revealed that this preference occurred due to increased palatability. This study is relevant to my area of research because it is important to be aware of the psychological effects of different levels of consumption of protein. If the research does show a negative effect of excess protein consumption, people may decide to decrease this consumption. Being aware of the fact that this decreased consumption may increase the person's desire for protein is an important psychological consideration. Additionally, the rats on a low protein diet exhibited hyperphagia. This is to say that limiting protein intake may cause excess hunger. The discussion section mentions that the study was also done with a restriction of only 10% protein but results for the were not published because no behavioral differences were detected. This is a point against the ability to relate the study to humans in the developed world because it is unlikely that such a protein deficit will occur. Hence, this study shows that it is unlikely that if a person decides to decrease consumption of protein, they will experience any real change in hunger. This will only be a concern at extremely low levels of protein.

Protein Enriched Pasta

Five different types of pasta were given to 20 healthy Italian women on five separate occasions to examine the effect on satiety. Pastas included a high fiber past, high protein and high fiber, high protein from egg whites, high protein from soy, and regular pasta. After consuming the pasta, a survey containing questions about level of satiety was given to the women at 30-minute intervals for 2 hours, at which point a snack was given to them and the macronutrient content consumed was calculated. While all pastas had a statistically significantly positive effect on fullness as compared to the regular pasta, only the high-protein high-fiber pasta resulted in a significantly lower energy intake during the snack period. It was also noted that sensory properties of food, such as appearance, were also important determinants of feelings of satiety. This study shows that consuming additional protein can lead to feeling more full. A potential cause of this is that protein intake is correlated with increased levels of hormones that have been related to feelings of satiety. Strengths of this study include the use of the women as their own control variables by feeding them the base pasta, as well as all of the other pastas on different occasions. This removes any person-to-person differences in feelings of fulness without a need for a very large sample size. A potential downside, however, is that the study was conducted only on healthy women. This may mean that the women were suppressing their appetites to an extent due to social pressures to look a certain way. Hence, it may not be possible to extrapolate the results of this study to a wider population. Overall, the results show a benefit of increased protein consumption for decreasing appetite but not for decreasing consumption of food at the next meal or snack.

Dietary Guidlines for Americans

Congress report that sets dietary recommendations for US citizens older than the age of 2. The recommendations presented in this document are highly relevant from a social standpoint because they are used in creating school meals and guiding legislation around food. In relation to red meat, the 2015 - 2020 DGA report does not set a recommended limit for the intake of red and processed meat. While the report acknowledges research showing that lower intake of red and processed meat is correlated with reduced risk of cardiovascular disease in adults, it also notes the value of nutrients provided from these meats. The recommendation is not to limit intake of meats or protein, but rather to monitor and keep within daily limits the sodium, saturated fats, and added sugars from these meats. This report is influenced by a DGAC committee of non-federal experts in fields such as nutrition and health. Hence, the report is vulnerable to industry bias. And although there is an acknowledgement of risk from red and processed meats, this report, by not setting any upper-bound on protein intake, is leaning on the side of the debate against detrimental health effects of excess protein consumption.

Kidney Disease and Diet

This article states that a doctor will likely recommend a decreased intake of protein if a person already has kidney disease because it becomes more challenging for the kidneys to process all the protein. As a benefit of protein, the article does state that protein helps to repair and maintain cells in the body. The article mentions decreased protein intake for already damaged kidneys. It does not, however, make a claim that the kidneys were damaged due to eating excess amounts of protein. It is not specified what range the decreased amount of protein eaten might fall into either. This article is intended for a popular audience and has only been reviewed by one MS, RDN, LDN. No research citations provided. Article leans toward the side that excess consumption of protein may be detrimental to health but is not appropriate for the Wikipedia page. It provides a look into how public perception of the issue is being shaped and is from one of the suggested websites for Assignment 5 - Academy of Nutrition and Dietetics.