Chromium

 

Chromium Introduction

Amongst the entire trace element grouping, chromium may be the most popular and widely used dietary mineral supplement. This may be due, in large part, to its use in the nutritional supplementation of individuals involved in strenuous exercises. First discovered in the late 1950’s, this mineral has seen tremendous exposure during the past two decades in both the medical and non-medical community. Chromium benefits not only those persons looking for performance enhancement in physical activities, but also in the core factors that dictate our overall health and well being.

Chromium is considered and essential mineral in the human body. However, some 90 percent of humans have lowered or deficient chromium levels. In order to achieve proper daily intake we must first recognize the different forms of this significant mineral. Chromium is an exacting trace mineral that exists in two distinct forms: the trivalent and the hexavalent form. Higher organisms, such as humans, utilize the trivalent form of chromium (primarily obtained from whole food sources). Chromium was once thought of as a toxic mineral in higher organisms. We now know that it provides for many important biochemical processes, paramount to our survival.

This fundamental mineral is a component of the compound, “glucose tolerance factor” (GTF) in humans. GTF is critical for the maintenance of proper serum levels of blood glucose, or insulin metabolism, and its many diverse actions. GTF plays integral roles in the metabolism of other nutrients as well. Fatty-acids and carbohydrates are metabolized by this compound. GTF is also necessary for the activation of enzymes that aid in the digestion of various food sources, and in cholesterol synthesis, which results from daily food consumption.

Chromium is found in the highest concentrations in those organs that provide for metabolic activity. These include the liver, kidney, spleen and even bone tissue(s). Many medical practitioners label chromium as an “ultra” trace mineral because it is found in such diminutive concentrations throughout the body. The amount of chromium stored in the body is in direct correlation to one’s diet. It is estimated that Americans store approximately 6 milligrams of chromium in various metabolic tissues.

Chromium is made available in numerous commercial forms. Most of the chromium not included in the diet is obtained from multi-vitamin and mineral supplements. The most available forms of chromium are;

  • Chromium chloride
  • Chromium nicotinate
  • Chromium-enriched yeasts
  • Chromium picolinate

Chromium picolinate stands atop the list of all commercially available forms of chromium. It is, by far, the most popular, absorbable, and publicized form.

Chromium Food Sources

Many food sources have not been analyzed or defined in concerns to the amount of chromium they contain, due to body’s minute needs for fulfilling biochemical activities. Brewer's yeast contains the highest concentrations of this mineral. Organ meats, and whole grains also contribute a large portion of chromium to our overall diets. Vegetables, fruits, and most processed and refined foods contain trace amounts of chromium.

The bioavailability of chromium for use in the body is dependant upon a number of factors. For example, processed food sources (except organ meats) contain very little chromium. The following table lists common whole food sources that contain high amounts of chromium:

Food Amount per serving Micrograms(mcg)
Broccoli 1 cup 22.0
Turkey, dark meat/cooked 3 oz. 10.4
Juice (grape) 1 cup 7.5
Waffle or egg 1 med. 6.7
Ham 3 oz. 3.6
English muffin 1 whole 3.6
Cookies (chocolate chip) 1 large 3.4
Potatoes 1 cup 2.7
Bagel 1 whole 2.5
Juice (orange) 1 cup 2.2
Green beans, cooked 1 cup 2.2

It should be noted that chromium absorption is minimal in the digestion process. Organic forms of chromium, which act in the GTF, are better absorbed than their counterparts - inorganic chromium salts. Figures for inorganic chromium salt assimilation range anywhere from 0.5 - 3 %, as opposed to the 10 - 20 % absorption rate of the organic complexes of chromium. It is estimated that nearly half of our recommended daily intake of this trace mineral may be fulfilled, simply, by drinking hard water sources.



Chromium Uses

The Glucose Tolerance Factor (GTF) in association with the nutrients niacin, B3, glycine, cysteine, and glutamic acid, provide an enhancement of insulin levels in the blood. This hormone-affiliated agent assists sugars (i.e. glucose) into cells for energy and metabolic productions; and is also considered a key component in the regulation of cholesterol levels of the blood. [1] The supplementation of chromium, in its various forms, may provide a means for individuals suffering from hypertension to lower total LDL (’bad’) serum cholesterol levels, while elevating HDL (’good’) cholesterol levels. [2, 3]

The effect of chromium upon blood glucose levels has been documented in the clinical application with diabetics. The National Institute of Health (NIH) is currently studying the potentiality of chromium supplementation in persons suffering from diabetes. In past study, chromium has provided reductions in both blood sugar levels and the amount of insulin needed to support the intolerance of sugar in diabetics. [4, 5] Because of chromium’s ability to enhance the metabolism and utilization of sugars within the body, it supplementation may prove integral in the prevention and treatment of not only diabetes mellitus, but also hypoglycemia. [6]

Chromium in its chelated form, chromium picolinate, may prove beneficial in improving muscle and skeletal mass in persons involved in strenuous activities and/or resistance training. [7, 8] More research is, however, necessary to determine its overall effect on muscle gain (improved body composition via lean muscle mass) and strength. In regards to body composition, chromium may possess the ability to reduce the overall body weight and fat percentages in both men and women. [9]

The nutritional supplementation of chromium may also be important in reducing the occurrence of certain chronic diseases and conditions, such as coronary heart disease, atherosclerosis, and glaucoma. [10, 11, 12]



Chromium Dosages

To date, there remains no established recommended dietary allowance (RDA) for chromium by the USDA. Safe and adequate dietary intakes have been established (in micrograms), and are as follows:


Age Group Infants Children Adolescents Adults
Under 6 months 0.2 mcg
7-12 months 5.5 mcg
1-3 years 11 mcg
4-8 years 15 mcg
9-13 years 21-25 mcg
14-18 years 24 mcg (females) 35 mcg (males)
19 years to 50 years 25 mcg (females) 35 mcg (males)
Older than 50 years 20 mcg (females) 30 mcg (males)
Pregnancy 29-30 mcg 29-30 mcg
Lactation 44-45 mcg 44-45 mcg

[13]

Chromium Toxicities and Deficiencies

Chromium Deficiencies

Because of the minute amounts needed for the various processes within the body, a deficiency of chromium is extremely rare. This is not to say that it is impossible for one to develop a deficiency. Research has indicated that those most at risk for the development of a deficiency are the elderly. Chromium levels in tissues dissipate with age, and this deficiency may be an underlying factor in the development of such diseases as adult-onset diabetes mellitus (type II diabetes).

Metabolic processes also decline with age and could also be an influential factor in the development of abnormal conditions originating from the malabsorption of chromium. Also at risk are individuals receiving long-term paternal nutrition in which there are insufficient amounts of chromium added to the solution. Those who participate in strenuous exercise, and individuals who lose large amounts of bodily fluids either through exercise or illness, should also be aware of the danger for the development of a chromium deficiency.

The development of a deficiency is usually characterized by diabetes-like symptoms. These may include insulin resistance, hyperglycemia, and blood lipid abnormalities.

Chromium Toxicities

There have no reported cases of chromium toxicity or overdose from dietary, or trivalent, sources. Chromium supplements, taken in excess over a long period of time, have been accounted for human overdose. This is extremely rare due to the inability for humans to absorb chromium efficiently and affectively, and its very high excretion rates. Chromium salts account for all documented cases of overdose and toxicity. Overdose may result in persons developing dermatitis, gastrointestinal ulcers, and in cases of prolonged and excessive intakes of chromium-containing supplements, possible irreversible liver and kidney damage.

References

1. Gordon JB. An easy and inexpensive way to lower cholesterol? West J Med. 1991 Mar;154(3):352.

2. Press RI, Geller J, Evans GW. The effect of chromium picolinate on serum cholesterol and apoliprotein fractions in human subjects. Western J Med. 1993;152:41-45.

3. Wang MM. Serum cholesterol of adults supplemented with brewer’s yeast or chromium chloride. Nutr Res. 1989;9:989-998.

4. National Institutes of Health. NIH Program Announcement. Chromium as adjuvant therapy for type 2 diabetes and impaired glucose tolerance. NIG Guide. 2001. Accessed at http://www.nccam.nih.gov/nccam/fi/concepts/pa/pa-01-114.html on March 5, 2002.

5. Anderson RA, Cheng N, Bryden NA, et al. Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes. Diabetes. 1997;46:1,786-1,791.

6. Anderson RA. Chromium in the prevention and control of diabetes. Diabetes and Metabolism. 2000;26(1)22-27.

7. Campbell WW, Joseph LJ, Davey SL, Cyr-Campbell D, Anderson RA, Evans WJ. Effects of resistance training and chromium picolinate on body composition and skeletal muscle in older men. J Appl Physiol. 1999;86(1):29-39.

8. Lukasi HC, Bolonchuk WW, Siders, WA, Milne DB. Chromium supplementation and resistance training: effects on body composition, strength, and trace element status of men. Am J Clin Nut. 1996;663:954-965.

9. Anderson RA. Effects of Chromium on Body Composition and Weight Loss. Nutr Rev. Sept 1998;56(9): 266-70.

10. Newman HA, et al. Serum Chromium and Angiographically Determined Coronary Artery disease. Clin Chem. Apr 1978;24(4):541-44.

11. Canonaco F, et al. Chromium and Atherosclerosis. Pediatr Med Chir. May 1986;8(3):415-16.

12. Lane BC. Diet and Glaucomas. J Am Coll Nutr. 1991;10(5):536.

13. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Chromium, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academies Press. 2002. http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml (Chapters 1, 2, and 8)