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8/11/2019 MSSE (2000) HMB Blood Kidney and Liver
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-hydroxy--methylbutyrate ingestion, PartII: effects on hematology, hepatic and renalfunction
PHILIP M. GALLAGHER, JOHN A. CARRITHERS, MICHAEL P. GODARD, KIMBERLEY E. SCHULZE,AND SCOTT W. TRAPPE
Human Performance Laboratory, Ball State University, Muncie, IN 47306
ABSTRACT
GALLAGHER, P. M, J. A. CARRITHERS, M. P. GODARD, K. E. SCHULZE, and S. W. TRAPPE. -hydroxyl--methylbutyrate
ingestion, Part II: effects on hematology, hepatic and renal function. Med. Sci. Sports Exerc., Vol. 32, No. 12, 2000, pp. 2116–2119.
Purpose: The purpose of this investigation was to examine the effects of differing amounts of -hydroxy--methylbutyrate (HMB),
0, 36, and 76 mg·kg-1·d-1, on hematology, hepatic and renal function during 8 wk of resistance training. Methods: Thirty-seven,
untrained collegiate males and were randomly assigned to one of the three groups, 0, 38, or 76 mg·kg-1·d-1. Resistance training consisted
of 10 exercises, performed 3 d·wk -1 for 8 wk at 80% of their 1-repetition maximum. Blood and urine was obtained before training, 48 h
after the initial session, 1 wk, 2 wk, 4 wk, and at 8 wk of resistance training. Blood was analyzed for glucose, blood urea nitrogen,
hemoglobin, hepatic enzymes, lipid profile, total leukocytes, and individual leukocytes. Urine was analyzed for pH, glucose, and protein
excretion. Results: The 38 mg·kg-1·d-1 group had a greater increase in basophils compared with 0 or 76 mg·kg-1·d-1 groups (P 0.05).
No difference occurred in any other blood and urine measurements. Conclusion: These data indicate that 8 wk of HMB supplemen-
tation (76 mg·kg-1·d-1) during resistance training had no adverse affects on hepatic enzyme function, lipid profile, renal function, or
the immune system. KEY WORDS: CHOLESTEROL, LEUKOCYTES, PLASMA ENZYMES, RESISTANCE TRAINING
-hydroxy--methylbutyrate (HMB) is a derivative of the
amino acid leucine and is metabolized from -ketoisocap-
roate (KIC), the keto acid of leucine, in the liver by KIC-
dioxygenase (12). HMB is present in both plant and animalfoods and is currently available as a nutritional supplement
(14). The theory behind HMB supplementation is that HMB
is metabolized to -hydroxy--methylglutaryl CoA (HMG-
CoA), which is used for cholesterol synthesis (8). HMG-
CoA can be a rate limiting substrate when cholesterol syn-
thesis is in great demand, such as during periods of rapid cell
growth or membrane repair (8). Thus, HMB may provide
the necessary amount of HMG-CoA for cholesterol synthe-
sis and subsequent membrane production during periods of
high muscular stress. Preliminary studies indicate that HMB
ingestion may enhance strength gains, decrease low-density
lipoprotein (LDL) concentrations, decrease muscle damage,and increase lean body mass during periods of intense
resistance training (4– 6,8,10,13). Extensive animal re-
search has been conducted analyzing the safety of HMB
supplementation. No adverse effects have been reported in
animals consuming between 8 and 5000 mg·kg·d-1 for a
period of 1–16 wk (7,8,10). Furthermore, HMB has been
shown to increase immune function in sheep (8) and chick-
ens (9), decrease total subcutaneous fat in cattle, and lower
LDL levels in chickens (9). Several studies have examined
the safety of HMB consumption in humans (6,8). Previousstudies indicate that ingestion of 1.5–4 g·d-1 of HMB (man-
ufactures recommended dose of HMB in humans is 3 g·d -1
or approximately 38 mg·kg·d-1) for up to 7 wk elicits no
negative effects (8). In addition, HMB has been shown to
increase strength gains and fat free mass, and lower LDL
levels in humans (6,8). Use of HMB has increased in recent
years and numerous consumers are ingesting more than the
recommended dose (11). However, no studies have been
published investigating the safety of higher doses of HMB
in humans (i.e., 4 g·d-1). Therefore, the purpose of this
investigation was to compare different amounts of HMB
supplementation (0, 38, and 76 mg·kg·d-1
) on hematologyand hepatic and renal function during 8-wk of resistance
training. This study was performed in conjunction with an
investigation of HMB effects on muscle strength and body
composition: -hydroxy--methylbutyrate ingestion, Part I:
effects on strength and fat free mass (3).
METHODS
Subjects. Thirty-seven healthy untrained male volun-
teers aged 18–29 completed the 8-wk supplementation and
resistance training program. Subject characteristics are re-
ported in Table 1 of the companion paper (3). Before any
0195-9131/00/3212-2116/$3.00/0
MEDICINE & SCIENCE IN SPORTS & EXERCISE®
Copyright © 2000 by the American College of Sports Medicine
Received for publication May 2000.
Accepted for publication May 2000.
2116
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testing, the subjects were interviewed by a member of the
investigating team, and potential subjects were excluded
from the study if they had engaged in resistance training
within the last 3 months or were taking any nutritional
supplements. Subjects were also excluded if they smoked or
had a history of metabolic, cardiac, and/or pulmonary dis-
ease. All subjects gave written informed consent in accor-
dance with the University’s Institutional Review Board be-
fore participating in the study.
Experimental design. The subjects were matched
based on their body weights and randomly assigned, in a
double-blind order, to one of three groups: placebo, 38
mg·kg-1·d-1, or 76 mg·kg-1·d-1 of HMB. These doses corre-
spond to doses reported in previous studies (4,6,8) of ap-
proximately 0, 3 or 6 g·d-1, respectively. Further description
of the supplementation protocol is provided in part I (3).
Resistance training protocol. The subjects partici-
pated in an 8-week resistance training protocol. Each train-
ing session was supervised and the subjects were required toattend the sessions three times per week. A detailed descrip-
tion of the resistance training program is illustrated in part
I (3).
Blood collection. Blood samples were taken from the
antecubital vein after an overnight fast for the measurement
of blood variables. Samples were collected before the ini-
tiation of the training program and 48 h after the first, 3rd (1
wk), 6th (2 wk), 12th (4 wk), and 24th (8 wk) lifting session.
Approximately 4 mL of blood was collected in a vial con-
taining SST® gel and clot activator (Vacutainer, Franklin
Lakes, NJ) and then centrifuged for 15 min. An additional 3
mL of blood was collected in a vial containing 0.057 mL of 0.34 molar EDTA (Vacutainer, Franklin Lakes, NJ).
Urine collection. Approximately 5 mL of urine was
collected in a urine collection vial from the subjects at the
same time that the blood was drawn (within 5 min) and
immediately placed in a 4°C environment.
Blood analysis. The blood and urine samples for each
collection time point were placed in a specimen delivery kit
and shipped overnight to Labcorp (Roche Biomedical Lab-
oratories, Inc.) at 4°C for analysis. The blood was tested for
lactate dehydrogenase (LDH), alkaline phosphatase (ALP),
aspartate aminotransferase (SGOT), and alanine amino-
transferase (SGPT) on an Olympus AU5200 automated
chemistry analyzer (Melville, NY). Quantities of hemoglo-
bin, total white blood cells, polysinophils, lymphocytes,
monocytes, eosinophils, and basophils were determined us-
ing a Coulter counter (Miami, FL). A lipid profile was also
performed to examine the levels of total cholesterol, high-
density lipoproteins (HDL), low-density lipoproteins
(LDL), very low-density lipoproteins (VLDL), and triglyc-
erides (TRI). Total cholesterol and triglycerides were deter-
mined using an enzymatic colorimetric techniques. HDL
concentration was determined after precipitation with sul-
fated -cyclodextrin in alkaline magnesium chloride. LDL
and VLDL concentrations were calculated based on the
Friedewald equation (2). In addition, the blood was also
analyzed for blood urea nitrogen (BUN) and glucose using
urease with glucose dehydrogenase and hexokinase reac-
tions, respectively.Urine analysis. Urine was analyzed for pH, glucose
using a hexokinase reaction, protein using a biuret assay,
and ketone levels using a nitroprusside reaction.
Statistical analysis. The data were analyzed using the
SPSS for windows statistical program (v. 8.0.0). A general
linear model with repeated measures was performed on all
variables with the within and between subject factors being
time and group (0 mg·kg-1·d-1, 38 mg·kg-1·d-1, or 76 mg·kg-
1·d-1), respectively. The alpha level was set at P 0.05.
Values found to be significantly different were compared
using a Bonferroni post hoc test. All data are presented as
mean standard error.
RESULTS
Blood enzyme activity. Group mean pre- and post-
supplementation values for the plasma enzymes are reported
in Table 1. Normal values were observed for LDH, ALP,
SGOT, and SGPT. No differences were exhibited among the
three groups at any point during the investigation.
Leukocyte levels. Pre- and post-supplementation
mean leukocyte levels are reported in Table 2. No differ-
ences were detected in any leukocyte variables at any time
point except for basophils. The 38 mg·kg·d-1
group exhibited a
TABLE 1. Pre- and post-supplementation plasma enzyme activity.
0 mgkg1d1 38 mgkg1d1 76 mgkg1d1
Alkaline phosphotase (IUL1)Pre 77.7 6.5 76.8 9.7 72.8 5.3Post 82.7 6.9 81.2 5.4 78.4 5.4
SGOT (IUL1)Pre 22.1 2.9 18.4 1.3 16.7 1.4Post 27.1 6.0 19.6 2.2 19.2 1.2
SGPT (IUL1)Pre 20.5 3.1 17.6 2.6 15.7 1.8Post 19.3 3.2 19.1 2.6 15.3 1.4
LDH (IUL1
)Pre 131.0 6.8 133.2 6.6 131.4 4.3Post 140.0 8.7 136.3 5.2 136.1 4.0
SGOT, aspartate aminotransferase; SGPT, alanine aminotransferase; LDH, lactate de-hydrogenase.Values are mean SE.
TABLE 2. Pre- and post-supplementation leukocyte levels; values are mean SE.
0 mgkg1d1 38 mgkg1d1 76 mgkg1d1
Total WBC (103L1)Pre 6.3 0.4 6.6 0.4 6.0 0.2Post 6.0 0.3 6.6 1.1 6.8 0.7
Polyosinophils(103L1)Pre 3.4 0.4 3.3 0.1 3.2 0.1Post 3.0 0.2 3.2 0.2 3.8 0.6
Lymphocytes (103L1)Pre 2.1 0.1 2.4 0.2 2.1 0.2
Post 2.2 0.1 2.5 0.1 2.1 0.2Monocytes (103L1)
Pre 0.5 0.0 0.6 0.0 0.6 0.1Post 0.5 0.1 0.5 0.0 0.6 0.1
Eosinophils (103L1)Pre 0.2 0.0 0.2 0.0 0.2 0.0Post 0.3 0.0 0.4 0.0 0.3 0.0
Basophils (103L1)Pre 0.08 0.01 0.07 0.01 0.09 0.02Post 0.08 0.02 0.11 0.02* 0.06 0.02
* Significantly greater increase from pre value (time).
HMB, HEMATOLOGY, AND HEPATIC AND RENAL FUNCTION Medicine & Science in Sport s & Exercise
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significant increase in basophils pre- to post-study (P 0.05).
However, all group mean leukocyte values, including ba-
sophils, were within normal limits at all time points throughout
the investigation.
Blood lipid profile. The blood lipid profile pre- andpost-supplementation is reported in Table 3. All blood lipid
variables were normal and no differences were noted in lipid
levels at any time point among the three groups.
Blood chemistry. No differences were observed in
blood glucose, hemoglobin, or BUN levels pre- to post-
supplementation among the three groups (Table 4). All
mean values were within normal limits and no differences
were observed at any time point throughout the
investigation.
Urine analysis. No differences among the three groups
were observed in urine pH, or glucose, protein, and ketone
excretion levels pre- to post-supplementation and all urinedata were within normal limits. The mean pre- and post-
supplementation urine pH values were 6.2 0.4 and 5.9
0.3 for the placebo group, 5.2 0.2 and 5.6 0.3 for the
38 mg·kg·d-1 group, and 5.6 0.2 and 5.5 0.3 for the 76
mg·kg·d-1 group. Throughout the study the urine glucose,
protein, and ketone assessments were negative for all but a
few individuals with no established patterns.
DISCUSSION
The intent of this investigation was to examine the effects
of different amounts of HMB supplementation (0, 38, and76 mg·kg·d-1) on hematology and hepatic and renal function
during an 8-wk resistance training study. To our knowledge,
this is the first study investigating whether adverse effects
occur during HMB ingestion greater than 38 mg·kg·d-1 in
humans. No alterations in blood and urine markers of phys-
iology were observed. The present study demonstrates that
short-term oral ingestion of HMB, up to 76 mg·kg·d-1, does
not alter hematology hepatic or renal function.
Similar to previous investigations (8), no harmful effects
of HMB supplementation were observed in any of the sub- ject’s plasma enzyme markers (Table 1). There were no
differences in LDH, ALP, SGOT, or SGPT over time or
among the placebo and HMB supplemented groups.
The mean leukocyte values were within normal limits
throughout the supplementation period (Table 2). Two sub-
jects, one in the placebo group and the other in the 38
mg·kg·d-1, displayed consistently greater (0.5–1.1 10-
3·l-1) than normal levels (0.0 – 0.4 10-3·l-1) of eosino-
phils throughout the investigation. However, no differences
in group mean total white blood cells, polysinophils, lym-
phocytes, monocytes, or eosinophils were displayed during
the entire the investigation. Although the 38 mg·kg·d
-1
group exhibited a significant increase in basophils pre- to
post-supplementation (P 0.05), the values were still
within normal limits (0.0–0.2 10-3·l-1).
It has been suggested that HMB supplementation causes
an alteration in cholesterol synthesis via conversion to
HMG-CoA (8). -hydroxy--methylglutaric acid has been
shown to produce an inhibition of liver cholesterol synthesis
(1). Thus, the changes in cholesterol synthesis could elicit an
alteration in blood cholesterol levels. Previous research in
both humans and animals has demonstrated that HMB sup-
plementation causes a lowering of LDL cholesterol (8,10).
However, the current investigation does not support theprevious findings as no differences were observed in any
lipoprotein cholesterol values over time or among groups.
One explanation may be that the intensity and quantity of
exercise elicited a greater demand of HMB (and HMG-
CoA) then previous studies, thus attenuating the inhibition
of liver cholesterol synthesis. It could be suggested that the
ingested HMB was excreted in the urine; however, it has
been shown that less HMB is excreted than consumed (see
part I (3)).
Similar to previous investigations, no differences were
observed in blood glucose, hemoglobin, or BUN levels
among the placebo and HMB supplemented groups. Twosubjects, one in the placebo group and the other ingesting 38
mg·kg-1·d-1 HMB, displayed slightly higher (111–163
mg·dL-1) than normal (65–109 mg·dL-1) glucose values
before and sporadically throughout the supplementation pe-
riod; however, there was no consistent pattern to these
values.
Urine was analyzed to assess whether HMB supplemen-
tation has any adverse effects on renal function. No changes
were observed in excretion of glucose, proteins, ketones, or
hydrogen ions in any of the subjects. Based on the excretion
levels of these compounds, it can be assumed that HMB
does not adversely affect the kidney.
TABLE 4. Pre- and post-supplementation blood urea nitrogen, blood glucose, andhemoglobin levels; values are mean SE.
0 mgkg1d1 38 mgkg1d1 76 mgkg1d1
Blood urea nitrogen (mgdL1)Pre 12.5 0.5 11.8 0.7 14.4 0.6Post 13.5 0.8 13.3 1.0 14.1 0.7
Glucose (mgdL1)Pre 97.8 2.7 97.2 1.5 90.8 1.9Post 92.3 3.1 95.5 4.8 90.4 2.5
Hemoglobin (mgdL1)Pre 15.1 0.2 15.8 0.2 14.9 0.3Post 15.3 0.2 15.6 0.2 15.1 0.2
TABLE 3. Pre- and post-supplementation plasma lipid profile.
0 mgkg1d1 38 mgkg1d1 76 mgkg1d1
Total cholesterol (mgdL1)Pre 160 7 173 5 168 13Post 154 8 160 9 172 12
HDL (mgdL1)Pre 47 3 43 2 45 3Post 50 3 42 1 46 4
LDL (mgdL1)Pre 92 7 106 4 98 21Post 82 8 96 8 98 8.5
VLDL (mgdL1
)Pre 19 2 22 2 18 3Post 21 4 20 2 18 2
Triglycerides (mgdL1)Pre 99 8.5 150 27 95 13Post 108 19 106 12 162 69
HDL, high-density lipoprotein; LDL, low-density lipoprotein; VLDL, very low-densitylipoprotein.Values are mean SE.
2118 Official Journal of the American College of Sports Medicine http://www.acsm-msse.org
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In summary, all of the examined variables were within
normal limits and no differences were observed among the
three groups in any variables, except for basophils. Thus,
based on the results of present investigation, it appears that
short-term (8-wk) HMB supplementation (up to 76 mg·kg-
1·d-1) is safe and does not alter or adversely affect hema-
tology, hepatic or renal function in young male adults.
This study was supported, in part, by a grant from MetabolicTechnologies, Inc. (Ames, IA) and Experimental and Applied Sci-
ence, Inc. (Golden, CO). Address of correspondence: Scott Trappe, Human Performance
Laboratory, Ball State, University, Muncie, IN 47306; E-mail:[email protected].
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HMB, HEMATOLOGY, AND HEPATIC AND RENAL FUNCTION Medicine & Science in Sport s & Exercise
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