Writer disclosures: SM Pasiakos, HR Lieberman, and VL Fulgoni, no conflicts of curiosity.
The opinions or assertions contained herein are the personal views of the authors and are to not be construed as official or as reflecting the views of the Military or the Division of Protection. Any citations of economic organizations and commerce names on this report don’t represent an official Division of the Military endorsement of approval of the services or products of those organizations.
Stefan M Pasiakos, Harris R Lieberman, Victor L Fulgoni, III, Larger-Protein Diets Are Related to Larger HDL Ldl cholesterol and Decrease BMI and Waist Circumference in US Adults, The Journal of Vitamin, Quantity 145, Subject 3, March 2015, Pages 605–614, https://doi.org/10.3945/jn.114.205203
Summary
Introduction
Diets that promote protein consumption above the RDA [0.8 g/kg body weight (BW)] are extraordinarily well-liked. Research have demonstrated that higher-protein diets promote wholesome weight administration (1, 2) and spare lean physique mass throughout weight reduction (3–10). Rising dietary protein consumption on the expense of carbohydrate may decrease cardiometabolic danger (11) as a result of diets larger in protein and decrease in carbohydrate seem to scale back blood strain (12, 13) and enhance glycemic regulation (11, 14) and blood lipid profiles (10, 12, 15–17). The cardiometabolic advantages of higher-protein diets are sometimes better than or equal to these noticed when consuming lower-fat, higher-carbohydrate diets in step with the 2010 Dietary Pointers for Individuals (18) and proposals of the AHA (19). Nevertheless, a lot of the research reporting advantages of higher-protein diets have been performed in obese and overweight adults throughout well-controlled weight reduction interventions. Whether or not these findings apply to free-living adults habitually consuming higher-protein diets impartial of physique measurement, whole power, and macronutrient consumption has not been established.
Regardless of proof from medical trials suggesting that higher-protein diets might decrease cardiometabolic danger, considerations exist relating to the potential long-term adversarial well being results of habitually consuming excessive protein diets (20–23), and exactly what stage of protein consumption ends in optimum well being stays controversial (24–27). Potential research have recommended that consuming dietary protein at higher ranges of the appropriate macronutrient distribution vary (10–35% whole power consumption) might enhance cardiometabolic danger (28) and all-cause mortality (29, 30). Partial information from the NHANES III means that cardiometabolic-related mortality is larger in middle-aged adults (50–65 y of age) consuming higher-protein diets in contrast with equally aged adults consuming lower-protein diets (20). The authors of that paper advocate that middle-aged adults devour dietary protein at ranges in step with the RDA, though the authors additionally really helpful that older (>65 y of age) adults ought to enhance protein consumption above the RDA to extend longevity and decrease cardiometabolic-related mortality. Conflicting information and experimental limitations (e.g., pattern measurement, dietary evaluation, interventional vs. potential) inside and throughout research make it tough to reconcile these research resulting in confusion amongst clinicians, the vitamin group, and the lay public relating to the true affiliation between dietary protein and cardiometabolic well being.
This examine evaluated dietary protein consumption patterns amongst US adults and assessed relations between recurring protein consumption and cardiometabolic danger with use of information from the NHANES, 2001–2010. Whether or not recurring protein consumption patterns and their associations with cardiometabolic danger are differentially influenced by BW standing was additionally assessed by stratifying the examine inhabitants by BMI. We anticipated that protein consumption would exceed the RDA. We hypothesized that higher-protein diets can be related to biomarkers suggestive of lowered cardiometabolic danger, and that the consequences of dietary protein can be extra pronounced in obese and overweight adults than in regular weight adults.
Strategies
Members.
The examine inhabitants consisted of 23,876 adults (≥19 y of age) who accomplished a 24-h dietary recall in “What We Eat in America,” the dietary interview element of the NHANES, 2001–2010 (31). Analyses included solely people with full and dependable dietary information as decided by the Nationwide Heart for Well being Statistics employees. Pregnant or lactating girls have been excluded. Underweight people (BMI <18.5 kg/m2) were also excluded (n = 421, 1.76% of population; 164 males and 257 females) because these individuals could have a chronic disease or an eating disorder. Individual usual protein intake (g/kg BW) was determined with use of the National Cancer Institute method (32) with DRI age groups, day of the recall, and a weekend flag (Monday–Thursday vs. Friday–Sunday) as covariates. All subjects were separated into deciles of individual usual protein intake. The population was then stratified by BW status: normal weight (BMI: 18.5–24.9 kg/m2; n = 7131), overweight (BMI: 25.0–29.9 kg/m2; n = 8374), and obese (BMI: >30 kg/m2; n = 8376). Particular person regular protein consumption deciles have been then decided in keeping with BMI classes. Demographics (age, intercourse, race/ethnicity) and dietary consumption traits (power and macronutrient consumption) of the inhabitants inside deciles of protein consumption have been decided for the complete inhabitants and stratified by BMI classes.
Cardiometabolic danger components.
BMI, waist circumference, blood strain (diastolic and systolic), fasting serum TGs, whole ldl cholesterol, LDL ldl cholesterol, HDL ldl cholesterol, blood glucose, and insulin concentrations have been obtained from examination (33) and laboratory recordsdata (34). HOMA-IR was calculated because the product of plasma insulin (pmol/L) and glucose (mmol/L)/22.5 (35).
Statistical evaluation.
Analyses have been accomplished with use of SAS 9.2 (SAS Institute) and SUDAAN launch 11.0 (Analysis Triangle Institute) for sexes mixed and individually for every intercourse. Applicable weighting components have been used to regulate for oversampling of chosen teams, survey nonresponses of some people, and for day of the week the interview was performed (36). Least sq. means (± SEs) of cardiometabolic danger variables have been decided for topics in every decile of recurring protein consumption (g/kg BW) with use of PROC REGRESS of SUDAAN after adjustment for covariates. Three covariate fashions have been employed: mannequin 1—adjusted all variables for intercourse (mixed sexes solely), race/ethnicity, age, bodily exercise (categorized as sedentary, reasonable, or vigorous primarily based on responses to questions on exercise), and poverty-income ratio; mannequin 2—adjusted all variables for the covariates in mannequin 1 and likewise for particular person regular power consumption (kcal/d); and mannequin 3—the place BMI and waist circumference have been adjusted for the covariates in mannequin 1 and likewise particular person regular consumption of carbohydrates (g/kg BW) and whole fats (g/kg BW), whereas the remaining cardiometabolic variables have been adjusted for covariates in mannequin 1, particular person regular consumption of carbohydrates (g/kg BW) and whole fats (g/kg BW), and BMI. Analyses have been additionally performed to find out whether or not remedy use (associated to blood strain, lipids, or insulin administration) affected mannequin 3 outcomes.
Each a linear pattern of recurring dietary protein consumption as a steady variable and a linear pattern throughout deciles of recurring protein consumption have been computed with use of the covariate-adjusted fashions described above. Topics with lacking information for a variable of curiosity have been eradicated from that individual evaluation. Significance was set at a Bonferroni-adjusted α of P < 0.00125 [P < 0.05 divided by 40 (4 weight classification groups and 10 sets of variables analyzed)].
Outcomes
Median recurring protein consumption for the complete inhabitants greater than doubled from decile 1 to decile 10 (Desk 1). A better proportion of females consumed protein inside deciles 1 by means of 5, whereas a better proportion of males consumed protein inside deciles 6 by means of 10 (Desk 1). Age decreased throughout growing deciles of protein consumption. Related demographic traits have been noticed when the analyses have been stratified by weight standing. Power and macronutrient consumption additionally elevated throughout the deciles for the whole inhabitants and inside weight classifications (Desk 2).
BMI and waist circumference, for the whole inhabitants and inside weight classifications, have been inversely related to recurring protein consumption as a steady variable and when examined by deciles of recurring protein consumption (Desk 3). Utilizing mannequin 2 (moreover adjusted for power consumption), the relation between recurring protein consumption and BMI was important for deciles of recurring protein consumption in the complete inhabitants however not when the analyses have been stratified by weight classification. Utilizing mannequin 3 (moreover adjusted for different macronutrient consumption), recurring protein consumption as a steady variable and deciles of recurring protein consumption have been related to BMI in all topics and for obese and overweight however not regular weight topics. Utilizing mannequin 2, the relation of recurring protein consumption with waist circumference was important for protein consumption as a steady variable and for deciles of recurring protein consumption in all topics. When the inhabitants was stratified by weight classification and changes for power consumption have been made (mannequin 2), there was a major affiliation of recurring protein consumption in obese topics solely. Utilizing mannequin 3, recurring protein consumption as a steady variable and deciles of recurring protein consumption have been related to waist circumference in all topics and inside every weight classification.
Routine protein consumption was not related to every other cardiometabolic danger issue after applicable changes for power and macronutrient consumption except HDL ldl cholesterol (Desk 4). There was a optimistic affiliation of recurring protein consumption as a steady variable, and deciles of recurring protein consumption, with HDL ldl cholesterol in all topics and when topics have been stratified by weight classification. Utilizing mannequin 2, the optimistic relation between recurring protein consumption and HDL ldl cholesterol was important for all topics, and notably for obese people. Utilizing mannequin 3 (together with adjustment for BMI), each decile and steady measurement of recurring protein consumption have been nonetheless related to HDL ldl cholesterol in all topics and for obese people. Steady measurements of recurring protein consumption have been additionally positively related to HDL ldl cholesterol in regular weight people, however decile of recurring protein consumption relation was not important.
Analyses have been additionally performed to look at sex-based variations, nonetheless, the outcomes weren’t totally different from these described above; recurring protein consumption was inversely related to BMI and waist circumference and positively related to HDL ldl cholesterol to the same extent in women and men (Supplemental Tables 1–4). No different associations have been noticed when analyzing the info by intercourse. Lastly, together with related remedy use in fashions the place applicable didn’t alter the associations between dietary protein and cardiometabolic danger (information not proven).
Dialogue – “does protein reduce cholesterol”
The foremost findings from this potential, cross-sectional examine are the next: 1) Individuals habitually devour protein in extra of the RDA; and a couple of) higher-protein diets are related to decrease BMI, waist circumference, and better HDL ldl cholesterol. The potential well being results of higher-protein diets look like extra pronounced in obese people (BMI: 25.0–29.9 kg/m2) than in regular weight (BMI: 18.5–24.9 kg/m2) and overweight people (BMI: >30 kg/m2). These findings are in step with earlier research (10–17) and recommend that the cardiometabolic benefits of higher-protein diets are largely impartial of power, carbohydrate, and fats consumption, however seem restricted to HDL ldl cholesterol, waist circumference, and BMI.
The RDA (0.8 g/kg BW) represents a minimal stage of protein consumption required to keep away from a deficiency that will result in a progressive lack of muscle mass in wholesome adults, as mirrored by adverse nitrogen stability (37). Nevertheless, quite a few research exhibit benefits of consuming protein in extra of the RDA for skeletal muscle mass (1, 2, 38–42). Our findings recommend that recurring dietary protein consumption may function a dietary determinant of adiposity (15). Extra particularly, waist circumference and BMI have been inversely related to protein consumption, suggesting that central adiposity was decrease for Individuals consuming higher-protein diets. The affiliation between waist circumference and dietary protein was current in every BMI classification, though the consequences of protein on BMI look like largely restricted to obese adults. These findings are in step with a latest meta-analysis demonstrating a small, however extremely important, inverse affiliation of dietary protein consumption with fats mass in obese and overweight people adhering to higher-protein, ad libitum diets after finishing a managed weight reduction intervention (43).
It needs to be famous that our analyses didn’t present any detrimental affiliation between dietary protein and cardiometabolic danger. Elevated dietary protein consumption on the expense of carbohydrate is mostly thought-about to scale back cardiometabolic danger as a result of research have constantly reported enhancements in glycemic regulation (11, 14), blood lipids (10, 12, 15–17), and blood strain (12, 13) in obese and overweight adults adhering to managed higher-protein, lower-carbohydrate weight reduction diets. Our information recommend that the cardiometabolic benefits of recurring higher-protein diets in free-living adults are restricted to will increase in HDL ldl cholesterol. As a result of we adjusted for a number of physiological confounders, the strong affiliation between dietary protein and HDL ldl cholesterol is especially intriguing. Extra particularly, HDL ldl cholesterol concentrations for individuals who consumed ∼1.5 g protein/kg BW have been ∼15% larger than those that consumed protein at or beneath the RDA, notably in obese people. The mechanism by which protein is related to upregulated HDL ldl cholesterol manufacturing and the extent to which BW standing modulates this response requires additional examine. Nonetheless, as a result of habitually consuming a higher-protein weight loss program was related to larger HDL ldl cholesterol (and decrease adiposity) no matter whole dietary power, carbohydrate, and fats consumption, the intrinsic properties of protein, unrelated to its power content material, look like partially accountable for these results.
This examine demonstrates the health-related advantages related to recurring consumption of dietary protein past the RDA. The degrees of protein routinely consumed in deciles 6 by means of 10 (∼1.0–1.5 g/kg BW), that have been related to decrease waist circumference, BMI, and better HDL ldl cholesterol, are in step with nationally acknowledged suggestions (i.e., primarily based on nitrogen and skeletal muscle retention) for bodily lively adults (42, 44), army personnel (45, 46), older adults (47), and for people making an attempt weight reduction (9, 10, 48, 49), all of that are larger than the present RDA. No matter suggestions, Individuals overwhelmingly devour protein at or above the RDA. A earlier evaluation of the NHANES (2003–2004) confirmed that the proportion of inhabitants reporting consuming protein beneath the RDA was minimal and that imply protein consumption for adults >18 y of age was ∼1.3 g/kg excellent BW (50). Our present examine, which examined patterns of dietary protein consumption throughout BMI classifications in a a lot bigger pattern and managed for the potential confounders of power, fats, and carbohydrate consumption, confirms the earlier report that Individuals are hardly ever protein poor (lower than the estimated common requirement or RDA). Many consumed protein at ranges in step with the RDA (sometimes girls and older adults) and greater than half reported consuming protein exceeding 1.0 g/kg BW. We additionally discovered that protein consumption didn’t exceed ∼19% of whole power consumption whatever the absolute and relative quantity of protein within the weight loss program, suggesting that the upper-end of the appropriate macronutrient distribution vary for protein (35%) is tough to realize, and that protein consumption was not influenced by BW standing.
This population-based examine offers a novel examination of recurring dietary protein consumption patterns and their associations with cardiometabolic danger. The big pattern measurement (∼24,000), and our assessments of regular dietary protein consumption and cardiometabolic well being in keeping with weight classifications, are strengths of the present report. Though our findings recommend that growing dietary protein consumption lowers cardiometabolic danger, there are limitations that warrant consideration when deciphering outcomes from a cross-sectional examine. Relying solely on correlative information to guage cardiometabolic danger and 24-h remembers to characterize dietary habits could be problematic and result in misinterpretations of the info with potential over- and underestimations of dietary consumption (51). Nevertheless, the inherent variability with self-report dietary consumption information is addressed partly by utilizing the Nationwide Most cancers Institute technique to estimate long-term dietary patterns.
As a organic measure to help the validity of the same old dietary consumption information we derived from the NHANES, we examined the affiliation of blood urea nitrogen (BUN) and BUN/creatinine ratio with deciles of regular protein consumption in grams/kilograms. BUN is the ultimate product of physique protein metabolism. We discovered extremely important (P < 0.0001) will increase in concentrations of BUN and BUN/creatinine ratio as a result of regular protein consumption elevated throughout deciles in evaluation of sexes mixed and separate analyses of men and women, even after adjusting for the covariates used on this examine (information not proven). Though these variables could also be thought-about a crude measurement of nitrogen metabolism, they exhibit that regular protein consumption measurements from NHANES information are strongly related to biochemical measures of protein metabolism. It needs to be acknowledged that the organic mechanisms accountable for our findings should not absolutely understood and there are limitations inherent with the examine design we used. Nevertheless, we utilized a number of biologically related covariates in our regression analyses to keep away from confounding, though there's nonetheless a risk that our outcomes are resulting from residual results of variables that we didn't management. In conclusion, our analyses verify that Individuals sometimes devour protein at ranges that exceed the RDA, and their consumption is in step with suggestions to optimize skeletal muscle well being no matter BW standing and power, carbohydrate, and fats consumption. Rising dietary protein consumption was related to lowered cardiometabolic danger, a profit that could be extra pronounced in obese people. People consuming higher-protein diets had a decrease BMI and waist circumference and better HDL ldl cholesterol concentrations in contrast with people consuming protein at ranges in step with the RDA. The cardiometabolic benefits related to higher-protein diets have been largely impartial of whole power, carbohydrate, and fats consumption. Though our examine was cross-sectional, our findings strongly recommend that consuming protein effectively above the RDA (1.0–1.5 g/kg BW) is protected and could also be thought-about a legitimate dietary technique to enhance cardiometabolic well being.
Acknowledgments
SMP, HRL, and VLF analyzed the info and wrote the paper. All authors learn and permitted the ultimate manuscript.
References
“does protein reduce cholesterol”