Short term elevation in dietary protein intake does not worsen insulin resistance or lipids in older adults with metabolic syndrome: a randomized-controlled trial

Background There is a great deal of controversy as to whether higher protein intake improves or worsens insulin sensitivity in humans. The purpose of the study was to determine the influence of a short-term elevation in dietary protein on hepatic and peripheral insulin sensitivity in twelve older subjects (51–70 yrs) with metabolic syndrome. Methods Individuals were randomly assigned to one of the dietary groups: recommended protein intake (RPI, 10% of daily calorie intake) or elevated protein intake (EPI, 20% of daily calorie intake) for 4 weeks. Prior to and immediately following the dietary intervention, subjects were studied with primed continuous infusion of [6,6-2H2]glucose and [1-13C]glucose dissolved in drink during the dual tracer oral glucose tolerance test (DT OGTT) to determine hepatic and peripheral insulin sensitivity. Plasma lipids were measured pre- and post-dietary intervention. Results In both intervention groups: 1) hepatic insulin sensitivity as assessed by the endogenous glucose rate of appearance (glucose Ra), 2) peripheral insulin sensitivity as assessed by the metabolic clearance rate of glucose normalized to plasma glucose concentration (MCR) and/or the rate of glucose utilization (Rd) or 3) glucose/insulin AUC were unaffected by the diets. Moreover, fasting lipid was not affected by RPI or EPI. Conclusion Our findings suggest that a short-term elevation in EPI with correspondingly higher branched chain amino acid (BCAA) contents has no detrimental impact on hepatic and peripheral insulin sensitivity or plasma lipid parameters in older adults with metabolic syndrome. Trial registration ClinicalTrials.gov Identifier: NCT02885935; This trial was registered retrospectively (Study start date, April 01, 2013, date of registration, August 26, 2016). Electronic supplementary material The online version of this article (doi:10.1186/s40795-017-0152-4) contains supplementary material, which is available to authorized users.

Fasted samples for study endpoints: glucose, insulin, stable isotopes, C-peptide, plasma lipids, Creactive protein, TNF-alpha, and IL-6. Visit 11 will also have HbA1c testing. 3 Infusion of 6-6-2H2 glucose for 4 hours and ingestion of 1-13C glucose isotope one time. 4 Ingestion of 75g oral glucose tolerance test solution. 5 DEXA scan at RIOA 3 rd floor for whole body analysis of body composition.

Summary of Project
We will investigate changes in insulin sensitivity before and after 4 weeks of dietary intervention and control in subjects with metabolic syndrome. Two groups of subjects will be studied before and after a weight maintenance diet. Group 1 will be fed a common American diet with a macronutrient distribution of 10% protein, 55% carbohydrates, and 35% fat. Group 2 will consume a higher protein diet (20%; 1.5 g/kg/d of protein), the proposed optimal intake for an older population 1 , with dairy protein as the predominant source of protein. Carbohydrate intake will be lower in Group 2 (45%), with fat intake (largely derived from dairy sources) similar between groups. Glucose utilization, endogenous glucose production, and insulin secretion will be determined during an oral glucose tolerance test (OGTT) with a novel double-tracer approach. Our secondary aim will be to determine the effect of a diet high in dairy consumption on inflammatory cytokines and blood lipid profiles. We will measure blood lipids and pro-inflammatory cytokines before and after dietary intervention in each group.

Hypothesis
Higher dairy protein and lower carbohydrate intake will result in a better metabolic profile versus a diet which is lower in dairy/protein intake and higher in carbohydrate.

Specific Aims
Our first specific aim will investigate glucose utilization and endogenous glucose production during an oral glucose tolerance test (OGTT) with a novel double-tracer approach. We will determine insulin sensitivity by measuring glucose disposal and glucose production, as well as insulin secretion.
Our second specific aim will be to compare the effects of the two dietary interventions on certain risk factors for metabolic disease, namely blood lipid and pro-inflammatory cytokine profiles. We will measure blood lipids (total cholesterol, HDL, LDL, and triglycerides) and systemic indices of inflammation, such as C-reactive protein (CRP), TNF-α, and IL-6 before and after dietary intervention in each group. This inverse correlation between dairy consumption and CVD may seem counterintuitive, given the accepted evidence which links consumption of saturated fat to increased CVD risk factors.
While the stronger association between dairy intake and reduced CVD risks exists with low-fat products 2 , there is still evidence to suggest that all saturated fat is not equally bad. For example, Tholstrup et al. 3 conducted a 3 wk dietary study to investigate the effects of fat intake from whole milk, butter, or cheese on blood lipids and postprandial glucose/insulin response. The authors found that a diet high in butter resulted in significantly greater total and LDL cholesterol concentrations than a diet high in cheese 3 . Overall, examination of most observational studies reveals no association between the intake of dairy products and the increased risk of CVD, coronary heart disease, or stroke, regardless of milk fat levels 4 . Rather, closer examination of the epidemiological data indicates the advantages of higher dairy intake on the non-lipid related CVD risk factors.

Dairy and Reduction of CVD Risk Factors
The association between hypertension and CVD is well-established. A number of dietary strategies are often employed to reduce blood pressure, including the restriction of dietary sodium and alcohol intake. However, dairy consumption as a preventative measure for hypertension has been derived from substantial evidence from the NHANES I study. In the examination of over 10,000 individuals, it was noted that lower consumption of milk products was associated with a higher incidence of hypertension 5 . Further evidence lies in the prospective examination of almost 29,000 women over 45 yrs of age who were followed over a 10 yr period. The findings indicate that the highest intake of low-fat dairy products was associated with a significant 11% reduction in the risk of developing hypertension 6 . The most acknowledged intervention study on the association between dairy foods and blood pressure is the multicenter DASH (Dietary Approach to Stop Hypertension) study. The DASH diet, which was rich in fruits and vegetables, as well as low-fat dairy products, reduced systolic and diastolic pressure by 5mm Hg and 3 mm Hg, respectively 7 . While this reduction may not seem clinically Dairy foods have also been shown to reduce inflammatory and oxidative stress, two key etiological factors in the development of atherosclerosis and CVD. A recent study in a transgenic rat model of diet-induced obesity fed a high dairy diet demonstrated an adipose tissue reduction in the inflammatory cytokines IL-6 and TNFα 9 . Twenty-four week feeding of a high-dairy eucaloric and hypocaloric diet in overweight men and women significantly reduced plasma CRP and adiponectin concentrations 9 . The clinically significant reductions in each gender suggest that high dairy consumption suppresses adipose tissue oxidative and inflammatory stress that accompanies obesity. These data also suggest that the alterations in CRP and adiponectin are independent of changes in body weight.
The incidence of type 2 diabetes (DM) is increasing at an alarming rate, and is itself an important risk factor for CVD. In addition to its association with a dysregulation of glucoseinsulin homeostasis, DM is a dyslipidemic and pro-inflammatory state, each constituting singular and combined risk factors for CVD 10  and calcium intake has been associated with an 18% reduction in DM, while general dairy intake reduces the risk of DM by 14% 11 . The association of vitamin D and calcium intake to the reduced risk of DM is more pronounced in populations with existing glucose intolerance 11 .
For this reason, it is relevant to examine the relationship of dairy intake and the metabolic syndrome. Dairy consumption has been shown to be inversely associated with several aspects of the metabolic syndrome. NHANES data derived from over 4500 people with metabolic syndrome revealed a significant inverse correlation between the intake of whole milk, yogurt, calcium, and metabolic disorders 12 . The authors noted that ethnic differences related to the incidence of metabolic syndrome were partly explained by variations in dairy intake and related nutrients 12 . In the CARDIA study involving 3157 adults between the ages of 18 and 30 yrs, consumption of ≥ 5 servings/d of dairy products reduced the risk of developing the metabolic syndrome by 70% over those consuming < 1.5 serving/d over a 10 yr period 13 .
Further, the association between dairy intake and metabolic syndrome was also demonstrated in the Women's Health Study 14 . Based upon these data, we propose to study individuals with metabolic syndrome for two primary reasons. First, it precludes complications due to the insulinsensitizing agents and medications that accompany overt DM. Second, based upon the existing  15 . However, our extensive work with essential amino acids (EAA) and their beneficial effects on muscle 16 , blood lipids, and insulin sensitivity (see Preliminary Data) enable us to focus upon the effects of dairy proteins, which contain a high proportion of EAA. While the exact mechanisms explaining the demonstrated effects of EAA on blood lipids and insulin sensitivity have yet to be elucidated, existing research on milk proteins provide important insight. Of the two primary milk proteins, casein and whey, there is substantial evidence as to the benefits of whey protein on several aspects of the metabolic syndrome. Whey protein has been associated with improved lipid profiles 17 , blood pressure in hypertensive individuals 18 ), and insulin sensitivity 17,19 . Improved lipid profiles with whey protein may be due to the inhibition of angiotension-converting enzyme (ACE) and the subsequent inhibition of angiotensin II hormone 20 . Angiotensin II has a well-established role in blood pressure management 18 but is also involved in adipocyte lipogenesis 21 . Thus, the inhibition of ACE leads to a reduction in endogenous fat production 22 , a decrease in plasma triglycerides 23 , and the transport of the low density cholesterol fraction 17 . In a clinical trial, whey consumption reduced TG by 13% after 6 week of supplementation 17 , which is consistent with our findings after 4 week of EAA + whey supplementation (Preliminary Data). Whey is a rapidly digested protein resulting in a higher peripheral amino acid concentrations 24 and a concomitant stimulation of the insulin response 25 .
Blood glucose was significantly reduced after whey protein consumption 25 and twice daily supplementation of meals with whey protein for 12 weeks resulted in a significant decrease in fasting insulin 17 . These results are consistent with our data demonstrating the effects of higher EAA + whey consumption/supplementation on blood lipids and glucose control/insulin sensitivity. Thus, we propose to examine the effects of higher diary protein consumption on insulin sensitivity and blood lipids, and compare these parameters to a common American diet with lower dairy protein and higher carbohydrate consumption.
The Real CVD Culprit may be… The American diet has evolved to a greater consumption of carbohydrates, and in particular, carbohydrates with little nutritional value and high glycemic index (GI). Chronic altering this pattern to include a higher consumption of dairy products, with their concomitant quality protein and fat distribution, an improvement in CVD risk factors will be realized.

Preliminary Data
Dairy proteins (casein and whey) are complete proteins with high biological value, owing to the completeness of amino acid profile, in particular, essential amino acid content. aged individuals with mild hypertriglyceridemia were given this formula TID for 4 weeks. To put this intake into dietary perspective, the leucine intake was equivalent to approximately 40g of dairy protein, or approximately 3 servings of milk per day. This dairy protein intake is quite reasonable for a 75 kg man consuming 1.5g/kg/d of protein, as we propose, and has been linked to a reduced incidence of metabolic syndrome 13 . The results of our study demonstrated that TID consumption of this amino acid profile resulted in a significant decrease in triglycerides, total cholesterol, VLDL, and LDL ( Figure 1A). In addition, formula administration resulted in a significant increase in insulin sensitivity ( Figure 1B) as determined by oral glucose tolerance test (OGTT). These data indicate that EAA/leucine consumption comparable to a higher dairy intake can reduce several important risk factors for CVD. Further, the data demonstrate the ability to improve insulin sensitivity in a population exhibiting conditions of the metabolic syndrome within the proposed dietary intervention period. These data shed new light on the potential benefits of higher EAA/leucine ingestion, and offer a potential explanation for the observed benefits of higher dairy consumption. Given the favorable amino acid profile of dairy protein, including leucine, our data offer a feasible hypothesis for the observed relationship between dairy intake and lower CVD risks. We will explore this hypothesis further and anticipate that the favorable content of EAA/leucine in dairy products will serve to decrease blood lipids and enhance insulin sensitivity in subjects with metabolic syndrome.

Trial Design
Our goal is to study up to 12 subjects in each of two groups between the ages of 45-75 years from Central Arkansas with metabolic syndrome utilizing a modified definition from the International Diabetes

Exclusion Criteria
• Hemoglobin A1c > 7.5 • History of malignancy in the 6 months prior to enrollment • History of lactose intolerance or dairy allergy • History of gastrointestinal bypass surgery (Lapband, etc) • History of a chronic inflammatory condition or disease (Lupus, HIV/AIDS, etc) • Subjects who do not or will not eat animal proteins • Subjects who cannot refrain from consuming protein or amino acid supplements during their participation in this study • Subjects who use insulin to control their blood sugar • Subjects whose physician will not allow suspension of oral diabetes medications for the duration of the study (~5 weeks)

• Concomitant use of corticosteroids (ingestion, injection or transdermal)
• Any other disease or condition that would place the subject at increased risk of harm if they were to participate, at the discretion of the study physician

Randomization
Randomization order will be predetermined by coin flip method. Subjects who are found eligible at Visit 1 will be randomized to one of two groups: group 1 or group 2.

Study Interventions
Group 1 will consume 28 (±2) days of a macronutrient intake consistent with Center for Disease Control and NHANES data regarding the average American diet 35 . Macronutrient intake will consist of 55% carbohydrate, 35% fat, and approximately 10% protein.
Group 2 will consume 28 (±2) days of a diet containing a greater amount of protein (1.5 g/kg/d of protein; 20%), weighted towards dairy protein with its accompanying fat content (both low and normal fat products; 35% fat), with the remainder of caloric requirement being carbohydrate (45%).
This study design enables several important investigations. First, we will determine the effect of increased dairy protein consumption on insulin sensitivity, a potential explanation for the epidemiological data demonstrating an inverse relationship between diary consumption and CVD risk factors. Second, we will determine if this diet in subjects with metabolic syndrome results in an improvement of CVD risk factors. Finally, we will examine the effects of a higher carbohydrate and lower protein diet, indicative of individuals with metabolic syndrome and representative of a common American intake 35 , on insulin sensitivity and CVD risk factors. The vigilance and thorough metabolic feeding inherent in this design will enable a clear distinction between dietary patterns and allow the determination of metabolic changes associated with each.

Stable isotope studies for determination of glucose kinetics
Two peripheral catheters will be inserted in arm veins; one for infusion of a stable isotope of glucose, the other for blood sampling. Blood samples will be collected during the 4-hr stable isotope infusion study as shown in the figure below. Oral glucose test product is obtained from Fisher HealthCare (75 SUN-DEX®, Houston, TX). Stable isotopes will be obtained as sterile powders (Cambridge Isotope Labs, Andover, MA), and they will be compounded and dispensed by the UAMS Research Pharmacist in Little Rock; AR. Subjects will ingest a small amount of a different stable isotope of glucose with their SUN-DEX, in order to evaluate the contribution to plasma glucose from the exogenous glucose test solution.
Our primary endpoints will be glucose rate of appearance (Ra), glucose disposal (Rd), and insulin secretion. These data will allow us to determine the variable impact of glucose ingestion on the hepatic and peripheral mechanisms that may be responsible for potential improvements  36 . In addition, c-peptide will be measured to assess insulin secretion. In order to compare our studies with previous investigations, we will also determine the glucose AUC and the insulin responses to the OGTT. Infusion rate of the (6,6, 2 H 2 ) glucose stable isotope is based upon subject's mass. Ingestion of the 1-13 C glucose isotope is concurrent with the oral glucose test drink as described by Basu et al. 37 . Volume of the ingested glucose stable isotope is based upon the subject's mass. See Figure 2 for an overview of the metabolic study.

Whole body DEXA scan
Subjects will undergo two whole-body DEXA scans; one at the screening visit (1) and the second at visit 11. These scans will allow us to determine any changes in body composition as well as allow comparisons between subjects using % lean body mass as the units of expression. Scans will be done in the UAMS RIOA by study staff at no cost to subjects.

Blood sampling
Study staff will draw approximately 5 mL of venous blood during the screening visit to measure lipid panel and HbA1c. Approximately 88 mL will be drawn during each stable isotope/OGTT study. Total amount drawn over the estimated 5-week participation time frame is approximately 181 mL.

Subject Compensation
Subjects receive financial compensation in the form of up to a $325 check for participation in the study. Payment will be prorated as: $25 for visit 1, $50 for visit 2, $25 each for visits 3-10, and $50 for visit 11. Subjects will be mailed their check within 2-3 weeks after their participation ceases, regardless of whether they completed all visits.

Blinding
Most subjects will likely recognize the protein/carbohydrate content of the diet to which they have been assigned; therefore, blinding is not feasible. However, samples will be coded to prevent analytical bias.

Subject compliance
Compliance and caloric intake will be determined by supplying subjects with a point-and-shoot digital camera and instructions to photograph each meal before and after consumption. Subjects will also be given instructions to not rinse/clean food containers. Caloric intake will then be calculated and/or adjusted by the Research Dietician after each week's container return. In addition, container return and pre-post meal photos will help ensure adequate compliance. If subjects do not consume ≥ 80% of provided meals, they will be judged non-compliant and replaced with another subject. In the past, we have been successful in maintaining a high level of subject compliance (> 80%) by utilizing several techniques. First, we counsel each subject during the phone screening and outline each detail of the study protocol, including randomization to groups. Subjects must agree to all facets of the study protocol prior to enrollment. Second, each subject is provided with a personal calendar that outlines each specific detail of the study and their responsibilities as a

Subject Recruitment
Subjects will be recruited using four separate methods. First, IRB-approved flyers will be posted in public areas around the Little Rock, AR area including the UAMS campus. Second, the Research Match online tool will be utilized in conjunction with the UAMS TRI staff. Third, we will call past subjects who have previously agreed to be contacted about future studies. Lastly, we will use the UAMS Data Warehouse to search for eligible subjects as defined below.
Step 1: After IRB permission is obtained to use the database, we will submit a query to the database to provide study staff with a list of patients who meet the following criteria: • Ages 45-75 AND • Systolic blood pressure >140 • Diastolic blood pressure >90 • Triglycerides > 130 mg/dl • Glucose > 100 mg/dl Step 2: With the list of results, study staff will contact (via UAMS email) the patient's PCP as documented in Centricity. If a PCP is not listed, staff will contact the physician who has been treating the patient for the majority of the most recent visits. Study staff will ask the physician if they would mail or otherwise provide their patient an introductory letter about this study (see Appendices).
Step 3: Patients that were provided the introductory letter who are interested in this study can then contact the study coordinator who will speak with them in detail about this study.

Blood plasma analyses
Glucose enrichment in blood will be performed by GCMS, and is well-established in our laboratory. Blood lipids will be measured on our automated clinical analyzer (Cobas C 111, Roche). Insulin, C-peptide (to determine insulin secretion), CRP, TNF-α, and IL-6 will be determined by ELISA.

Statistical Analysis
Demographic and metabolic characteristics will be summarized and tabulated by group using means, standard deviations, medians and ranges for continuous variables, while counts and percentages will be used for categorical variables. To address specific aim 1, Hotelling's T2 test will be used to compare the metabolic profile of subjects randomized to the Americanized diet to that of subjects in the high dairy diet. In this case, the metabolic profile will consist of the following three measures determined during the dual tracer oral glucose tolerance test: glucose disposal, glucose production and insulin secretion. We will also use the Hotelling's T2 to compare the groups with respect to the pre-diet and post-diet changes in metabolic profiles. If the Hotelling's test is found to be significant, Student's two-sample t-tests will be used to compare the groups with respect to each component. To address specific aim 2, we will also use Hotelling's T2 to compare blood lipid profiles and pro-inflammatory profiles of the groups.
An α-level of 0.05 will be used to determine the statistical significance of the Hotelling's T2 tests.
Sime's procedure will be used to adjust p-values for multiple comparisons when individual profile components are tested using Student's t-tests.

Power and Sample Size
The Hotellings T2 test will have approximately 85% power to detect effect sizes of 1.71 or larger in the Matsuda insulin sensitivity index (ISI; Figure 1B) when 12 evaluable subjects are enrolled in each group and an α-level of 0.05 is used to determine the statistical significance. It is important to note that combined utilization of isotope methodology with the OGTT to determine the rates of glucose appearance and disappearance is a more precise method of evaluating insulin sensitivity than the Matsuda index39. It will also allow us to distinguish changes in hepatic and peripheral glucose metabolism.
In terms of our secondary outcome measures, the Hotellings T2 test will have approximately 84% power to detect effect sizes of 47 mg/dl or larger in plasma triglycerides when 12 evaluable subjects are enrolled into each group and an alpha level of 0.05 is used to determine statistical significance. The effect size for the Hotelling's T2 is simply the difference between group profile means adjusted by the variance-covariance matrix of the profile components. Analyses of dietary compliance will be an ongoing process by study staff. Analyses of blood samples will take place in batch format to minimize analytical error and variability. The PI will review data as it becomes available. Data will be documented on case report forms.

Data Storage
Source documents and CRFs will be stored in a secure area of the PI's laboratory. Access will be limited to study personnel. Documents will be archived according to UAMS policies regarding destruction of research records. At no time shall Protected Health Information be released to non-study personnel. Electronic data will be kept on an UAMS server that is password protected and is only accessible by study personnel.

Sample Storage
Blood samples will be kept frozen at -80 degrees Centigrade or colder once the initial processing has taken place. Samples shall be stored in appropriate freezers in the PI's laboratory, located in the UAMS IOA building. Said freezers are monitored continuously for proper temperature and working condition. Samples will be destroyed only after all data has been analyzed and reported to the sponsor. All blood samples shall be identified using a unique study acronym. None of a subject's personal identifiers shall be present on any biological sample.

Definitions
ICH-GCP definition: An Adverse Event is any untoward medical occurrence in a patient or clinical trial subject administered a study product and which does not necessarily have a causal relationship with this product.
A Serious Adverse Event (SAE) is any untoward medical occurrence or effect that, after intake of any amount of study product: -Results in death.
-Is life-threatening (at the time of the event).
-Requires hospitalization or prolongation of existing inpatients' hospitalization. -Is a congenital anomaly or birth defect.

(Serious) Adverse Events handling
Any clinical study event that is judged to be an (S)AE, either reported spontaneously by the subject or observed by the investigator or his staff, is recorded on the (S)AE form during the course of the study. The investigator must ensure that this information, including onset, duration and nature of event, severity, and action taken, is captured.
The severity of any (S)AE is scored as follows: -Mild: transient or mild discomfort; no medical intervention/therapy required. -Moderate: mild to moderate limitation in activity; some assistance may be needed; and/or minimal medical intervention/therapy required.
-Severe: marked limitation in activity; some assistance usually required; and/or significant medical intervention/therapy/hospitalisation required.
The relationship of the (S)AE to the study product is assessed as being not related/unlikely/possibly/probably/ definitely related.

(S)AE reporting
Serious adverse events must be reported to the UAMS Institutional Review Board (IRB) 48 hours (2 working days) after their discovery. AEs will be reported in aggregate at routine intervals, e.g. Continuing Review, etc.

Follow-up of (S)AEs
All (S)AEs are followed by the investigator until they have abated, or until a stable situation has been reached. Depending on the event, follow up may require additional tests or medical procedures as indicated, and/or referral to the general physician or a medical specialist.

Risks/Benefits
There are no special benefits for the subjects apart from the possibility to get knowledge of their own results of the assessments at the screening visit. Expected risks associated with this protocol are described in detail below. All experimental procedures will be performed by appropriately trained and credentialed personnel. IRB-approved SOPs will be used for the infusion procedures.

Peripheral catheter placement:
Briefly, the risks related to the catheter placement include pain, bleeding, bruising, risk of infection and vaso-vagal response. Some individuals have a sudden drop in blood pressure in response to the placement of catheters (vasovagal response). Symptoms may include light-headedness, nausea and possibly vomiting. There are no long-term effects associated with this response. In our experience, symptoms occur in 3.3% of our subjects. All subjects experiencing this response will be examined by a physician and given the option of discontinuing the study. If the physician and investigators find no reason to stop the study and the subject wishes to continue, the subject will be able to finish the study.

Blood sampling:
Blood samples will be collected solely for the purpose of experimentation. The blood will be used to measure the enrichment of the infused stable isotopes and the concentrations of glucose and insulin. About 181 mL of blood will be drawn during the entire study (including screening appt). This volume is much less than a blood donation and should not produce any noticeable effects.

Stable isotope infusion:
Briefly, the risk related to the isotope infusion is pyrogenic response.
All infusions are prepared by a licensed pharmacist at UAMS. The IRB-approved SOP for infusion procedures will be utilized. All stable isotopes are tested for sterility and pyrogenicity before the infusion study. The stable isotopes will be filtered during infusion occurring isotopes by 7-10%. Any adverse reactions during the isotope infusion that suggest allergic reaction or infection (urticaria, flushing, nausea, vomiting, sweating, chills, altered heart rate, hypo/hypertension, and hyperthermia) will be promptly addressed by the study physician. Depending on the seriousness of the reaction, the infusion study will be terminated.

Stable Isotope ingestion:
Ingestion of approximately 4g of a stable isotope of glucose during each OGTT should pose no risk to subjects. This isotope will also be compounded and dispensed by the UAMS research pharmacist and is indistinguishable from normal glucose in the body.

Informed Consent Process
This study will be conducted in accordance with all applicable government regulations and University of Arkansas for Medical Sciences research policies and procedures. This protocol and any amendments will be submitted and approved by the UAMS Institutional Review Board (IRB) to conduct the study.
The formal consent of each subject, using the IRB-approved consent form, will be obtained before that subject is submitted to any study procedure. All subjects for this study will be provided a consent form describing this study and providing sufficient information in language suitable for subjects to make an informed decision about their participation in this study. The person obtaining consent will thoroughly explain each element of the document and outline the risks and benefits, alternate treatment(s), and requirements of the study. The consent process will take place in a quiet and private room, and subjects may take as much time as needed to make a decision about their participation. Participation privacy will be maintained and questions regarding participation will be answered. No coercion or undue influence will be used in the consent process. This consent form must be signed by the subject or legally acceptable surrogate, and the individual obtaining the consent. A copy of the signed consent will be given to the participant, and the informed consent process will be documented in each subject's research record.

Use of Data
Study data and interpretation of results will be sent to DRI. Given the pervasive problem of sarcopenia and functional disability in older individuals, recommendations concerning varied protein intake pattern or increased protein intake represent an economical and practicable solution. Results may provide a strong scientific basis for recommending increased total dietary protein consumption. This evidence will support the recommendation of increased dairy consumption, because dairy ingredients are an excellent source of dietary protein that can conveniently be eaten at breakfast and lunch, as well as dinner.
Results will be disseminated to the sponsor (DRI) via a final technical report. The PI has the option to submit results for publication in scientific literature.