Sunday, March 4, 2007

Critical Evaluation of the Nutritional Supplement Chromium Picolinate and Its Purported Body Composition Benefits Using 3 Peer Reviewed Studies

A highly popular product sold in both health food stores and over the Internet, CrPic is best known to consumers as a ‘miracle weight-loss supplement’. Sensational marketing has also linked CrPic with many other beneficial qualities, including increasing lean body mass (LM), and virtually eliminating appetite while simultaneously melting of fat. Recently, advertisements have marketed CrPic as a ‘safe alternative to steroids’ to boost body composition changes, including enhanced energy and vigor, greater skeletal muscle (SM), strength and size, greater fat-free mass (FFM), and decreased fat mass (FM).

Backgrounder
A naturally occurring trace mineral, chromium is found in a variety of foods including whole-grains breads, fish, poultry, and meat. Although sufficient quantities of chromium are found in common foods, commercials food preparation methods strip foods of their chromium content. Subsequently, many people may have chromium deficiencies. The biochemical and physiological role of chromium is not well understood, however, it seems clear that it is involved in blood glucose transport across cell membranes.


Review of Studies
In the first double blind study, Wayne W. Campbell et al. (1999) used 18 male subjects to examine the effects of resistance training (RT) and CrPic high dose supplementation on SM in older men. Every subject was carefully screened to eliminate confounding variables, and to ensure homogeneity between groups. All volunteers selected were: 1. male 50-75 years of age; 2. had a body mass index of 27-34 kg/m2; 3. nondiabetic; 4. capable of safely completing the study protocol (e.g., RT); and 5. had normal kidney, liver, and cardiac function, and normal blood pressure as determined by an extensive medical screening evaluation. To control CrPic intake, subjects suspended all personal nutritional supplementation 3 weeks before the start of the study. Only foods from a low chromium diet provided by the researchers were consumed throughout the study. Body composition was determined before commencement of RT using muscle biopsies, and skinfold thickness (measured to 0.5 mm at the biceps, triceps, subscapular, and suprailiac sites on the right side of the body). During week 1, baseline levels for CrPic were set while subjects remained sedentary. Maximal strength baselines for each exercise were determined during the 1st week of RT. A protocol of RT and supplementation followed for the next twelve weeks, with testing/evaluation repeated at week 7 and 12 for muscle size, strength, power and whole body composition. Progressive RT protocol required all men to perform the following exercises twice weekly for 12 weeks: 1. unilateral knee extension; 2. unilateral knee flexion; 3. double leg press; 4. seated chest press; and 5. seated arm pull. Volunteers were randomly divided into the experimental and control groups (n=9) that ingested either 17.8 µmol Cr/day (924 µg Cr/day) as CrPic, or a low-Cr placebo, over a period of 12 weeks. Results indicated CrPic supplementation did not aid muscle strength increases or body composition changes generated through RT. Muscle power for arm pull and knee extension increased independent of CrPic. More muscle power was gained in the placebo group than in the experimental group. Body composition changes increased independent of CrPic
[1]. No side effects of CrPic ingestion were reported in this study.

Steven L. Nissen and Rick L Sharp (2003), the principle investigators of the second study, used a meta-analysis to determine if chromium (among various other dietary supplements) worked in conjunction with RT to increase FFM and strength gains. Meta-analysis is a vigorous quantitative statistical approach that reduces subjectivity by facilitating the interpretation of data, through the standardization of key experimental variables. The description of the various statistical methods utilized to normalize the conversion of lean mass ratios and strength changes between studies per week (i.e., meta-analysis) are beyond the scope of this paper. Determination of inclusion or exclusion of peer-reviewed studies was made with a specific predetermined set of criteria: 1. published 1967-2001; 2. employed a specific, rigorous and extensive set of experimental protocol; 3. were at least 3 weeks in length; and 4. included RT 2 times or more per week for the duration of the study. Of the ~ 250 candidate supplement studies, 48 met with Nissen and Sharp’s demanding criteria, and only 6 were supported by more than one study. 12 Chromium studies regarding supplementation and RT were analyzed. Meta-analysis of the research pool indicated a small non-significant gain of FFM (0.08%/wk, P = 0.22), and a non-significant strength gain (0.25%/wk, P = 0.41). No evidence was found to support the claim that chromium increased SM, FFM or strength gains with RT. No side effects resulting from CrPic supplementation were noted.



In the third study, Lukaski and associates (1996) examined the effects of daily chromium supplementation with RT, and its effects on the body composition and strength in a group of 36 young (age range 19-29) sedentary males. Subjects, located through newspaper ads, were medically and physically screened before admission to the study. With the exception of RT at the university facilities, all subjects continued with their normal lifestyle, and lived in their usual place of residence. Rather than use a random assignment into control and experimental groups, subjects were divided into 3 homogeneous treatment groups (n=12), to control for ability to maximize strength gains. Groups were based on specific nutritional and physical characteristics including body composition, body build, baseline strength measurements, and serum chromium concentration. Body composition was determined using skin fold thickness (measured to 0.1 mm at the biceps, triceps, subscapular, and suprailiac sites on the right side of the body), Body Mass Index, somatotype (i.e., Endomorphy, Mesomorphy, Ectomorphy), and Dual X-ray absorptiometry to determine whole-body and regional bone and soft tissue composition.



A protocol of RT and supplementation followed for 8 weeks with: 1. testing/evaluation for peak strength every 2nd week; and 2. at the end of each 3-day period, 3-day food records (including 1 weekend day) were reviewed and coded for computer calculation and dietary analysis. Questionnaires were administered to improve accuracy of food records. Progressive RT protocol required all men to perform the following exercises 5 days a week for 8 weeks: 1. leg curls; 2. lateral pull downs; 3. bench press; and 4. leg press. After a warm-up, the volunteers performed 3 sets for each exercise: 1st set 8-12 repetitions - 50-60% of 1 Repetition Maximum (RM); then 2nd set 3-4 repetitions - 70-80% 1 RM; and finish with a 3rd set with 1 repetition – 95-100% 1 RM. A double blind design was used to administer the placebo, chromium chloride (3.85 mu mol), and chromium picolinate (3.85 mu mol). Participants were instructed to take their pills every morning. Pill bottles were collected every 4 weeks, and the contents were counted to determine compliance. A statistical analysis of the data determined that chromium supplementation, either in the form of chromium picolinate or chromium chloride, in conjunction with RT, has no favorable effects on body physique, or body composition (i.e., anthropometry, physique, or strength gains)
[2]. Significant changes were noted, however, as a result of resistance training (i.e., increase in FFM of arms, legs and trunk, and strength gains for each exercise). The subjects in this study reported no adverse effects caused by the use of CrPic.


SummaryThe Internet is littered with sites hawking chromium picolinate as nature’s miracle element. It has become a wildly popular supplement used by recreational and high performance athletes, diet-obsessed weight-loss junkies, and health conscious consumers looking for the ‘magic pill’. Peer-reviewed studies were examined to determine the validity the various body composition changes attributed to chromium picolinate. Of the 2 studies and 1 Meta analysis reviewed, no beneficial effects were found in any human population.

Comments: Buyer Beware!
In a diet and weight-loss obsessed culture, people are naturally attracted to the quick fix, especially if it is advertised as a reliable, immediate and safe method. However, scientific evidence indicates that chromium picolinate is nothing of the kind. Study after study clearly demonstrates that these sensational advertisements are not reliable or quick. Chromium with RT does not decrease fat content or increase muscle mass. Furthermore, the safety of ingesting concentrated amounts this nutrient has not been determined. Nor have possible side effects, levels of toxicity or the potential ramifications of long-term supplementation been adequately investigated. Another concern for the consumer is the possible interaction of chromium and other metabolically active substances found in chromium products (e.g., bars, shakes etc.).

Bottom Line:
The adage “if it sounds too good to be true then it is” clearly applies to CrPic and the wild claims of ‘exercise in a bottle’ and ‘herbal fat burner pills’. CrPic supplementation products are a waste of money, and are of no use. The best bang for your buck is resistance training, which significantly improved both fat loss and muscle mass in every study. It is not the ‘quick fix’ consumers are looking for, but it is reliable, safe and effective.





Coach Dave

References
Campbell, Wayne W., Lyndon J.O. Joseph, Stephanie L. Davey, Deanna Cyr-Cambell, Richard A. Anderson and William J. Evans. Effects of resistance training and chromium picolinate on body composition and skeletal muscle in older men. J Appl Physiol 86(1): 29-39, 1999.

Steven L. Nissen and Rick L. Sharp. Effects of dietary supplements on lean mass and strength gains with resistance exercise: a meta-analysis. J Appl Physiol 94:651-659, 2003.

Lukaski, Henry C, Bolonchuk, William W, Siders, William A, Milne, David B. Chromium supplementation and resistance training: Effects on body composition, strength, and trace element status of men. Am J Clin Nutr 63(6): 954-957, 1996.
[1] (FFM (P<0.001)>

[2]The effects table for chromium supplementation on assessments of body physique or composition, regional body composition, and strength gains was omitted from this study.

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