ZINC
Role
 Required for the structure and activity of hundreds of enzymes
 Variety of physiological functions
o Required for the activity of several enzyme in energy metabolism
 Maintaining normal carbohydrate, lipid, and protein metabolism
(Cordova & Alvarez-Mon, 1994)
o Reproduction
o Immunity
 Helps the immune system
o Taste
o Hormone metabolism
o Wound healing
 Important in wound healing (injuries) (Rosenbloom, 2013)
o Skeletal development
o Behavior
o Gastrointestinal function
Recommended intake of zinc
 RDA is 15 mg/day for adults (male and non-pregnant females)
 Average plasma zinc concentrations:
o This is the most common used index of zinc status
o Normal range: 80-130 ug/dL (Grosshauser, Becker, Riemann, Langer,
Stangl, & Eder, 2006)
o 75-125 ug/dL (Cordova & Alvarez-Mon, 1994)
 Athletes general consume less zinc than recommended, 8 and 11 mg/day for
women and men, respectively (Lukaski, 2004)
o Less than optimal intake is more common among athletes who restrict
food intake (Lukaski, 2004)
Zinc status and exercise
 Short term effects of exercise on zinc metabolism
o Serum zinc concentrations can increase significantly during strenuous
exercise (Cordova & Alvarez-Mon, 1994)
 Increase is thought to be caused by muscle leakage of zinc into the
extracellular fluid following muscle damage
o Plasma zinc levels return to normal value following 30 minutes of rest
 May be due to high urinary excretion of zinc coupled with a shift in
the distribution of zinc from the serum into the liver (Cordova &
Alvarez-Mon, 1994)
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Long-term endurance training has been show to significantly decrease resting
serum zinc levels in both male and female athletes compared to sedentary
controls (Cordova & Alvarez-Mon, 1994)
o Endurance runners may have lower serum zinc concentrations than others
(Grosshauser, Becker, Riemann, Langer, Stangl, & Eder, 2006) (Lukaski,
2004)
o Caused by: inadequate intake of dietary zinc, redistribution of plasma zinc
to other tissues induced by physical stress, and increased losses of zinc in
both urine and sweat (Grosshauser, Becker, Riemann, Langer, Stangl, &
Eder, 2006)
 Avoidance of animal products and consumption of low-zinc, high
carbohydrate foods
 Dietary zinc and plasma zinc levels
 Dietary zinc was low in athletes with decreased circulating
zinc (Lukaski, 2004)
 When athletes consume at least 70% of the RDA, plasma
zinc concentrations are within the range of normal values
(Lukaski, 2004)
o Related to inadequate dietary zinc intake, increase losses (in sweat, skin,
and urine) (Cordova & Alvarez-Mon, 1994)
In athletes, a zinc-deficient diet would have adverse effect on performance and
immune-function due to its association with metabolic, neuroendocrine, and
immune alterations
o Low zinc levels could result in a reduction in muscle zinc concentrations
and lead to a reduction in endurance capacity (Cordova & Alvarez-Mon,
1994)
 Gastrocnemius muscle collected from rats fed on supplemental zinc
took longer to reach fatigue than did muscle collected from control
animals (Cordova & Alvarez-Mon, 1994)
 However, the verdict is not out. Others claim low serum zinc
concentrations do not comprise muscle function (Cordova &
Alvarez-Mon, 1994)
o Low serum zinc may be involved with fatigue, susceptibility to infectious
disease, immune system alterations (Cordova & Alvarez-Mon, 1994)
 Zinc deficiency is associated with a marked functional and
structural impairment of the immune system (Cordova & AlvarezMon, 1994)
Foods with Zinc
 Mineral found mostly in animal foods
o Meat, fish, poultry, and dairy foods
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Also present in whole-grain breads and cereals, dried beans and peas (legumes),
and nuts.
Absorbed more readily from animal proteins than plant sources (Cordova &
Alvarez-Mon, 1994)
Phytates, inorganic phosphorus, and oxalic acid inhibit absorption (Cordova &
Alvarez-Mon, 1994)
Better to get zinc from foods rather than supplements. High-dose zinc
supplements can cause nausea and vomiting.
Supplementation
 Take caution w/ zinc supplementation, because excessive zinc supplements can
inhibit the absorption of copper, even when not taking at the same meal
(Cordova & Alvarez-Mon, 1994)
o Supplements >50mg/day have been linked to copper deficiency in
humans (Cordova & Alvarez-Mon, 1994)
o 160 mg/day for 16 weeks resulted in significant reduction in HDLcholesterol (Cordova & Alvarez-Mon, 1994)
o Supplements of <50mg/day have not been reported to result in copper
deficiency or affect lipoprotein metabolism (Cordova & Alvarez-Mon, 1994)
 Suggested that supplements are not >15 mg/day (which is the current RDA for
adults) (Cordova & Alvarez-Mon, 1994)
 Zinc supplementation (20mg/day Zn {taken as zinc-DL-aspartate} for 6 weeks) in
36 highly trained athletes (Grosshauser, Becker, Riemann, Langer, Stangl, &
Eder, 2006)
o Associated with an increase in plasma zinc concentration and a decrease
of zinc binding capacity in athletes with initial plasma zinc concentration
<80 ug/dL (but not in athletes with >80 ug/dL)
o Increases the number of monocytes (provide protection against
pathogens)
o No significant increase in number of lymphocyte subpopulations, such as
natural killer cells, T cell subspecies, and B cells
 Zinc supplementation with 3mg zinc sulfate/kg body weight for 4 weeks in
comparison to athletes who did not receive zinc supplement (Kilic, Baltaci, &
Gunay, 2004)
o Increased erythrocyte count, hemoglobin, hematocrit, and leukocyte
values
Bibliography
Cordova, A., & Alvarez-Mon, M. (1994, April). Behaviour of Zinc in Physical Exercise: A Special Reference
to Immunity and Fatigue. Neuroscience and Biobehavioral Reviews, 19(3), 439-445.
Grosshauser, M., Becker, K., Riemann, D., Langer, J., Stangl, G., & Eder, K. (2006). The Effect of Daily Zinc
Supplementation on Immune System of Athletes. Trace Elements and Electrolytes, 23(2), 79-85.
Kilic, M., Baltaci, A. K., & Gunay, M. (2004, January 30). Effect of Zinc Supplementation on Hematological
Parameters in Athletes. Biological Trace Element Research, 100, 31-38.
Lukaski, H. C. (2004). Vitamin and Mineral Status: Effects on Physical Performance . Nutrition, 20, 632644.
Rosenbloom, C. (2013, November ). Eating for Strength and Recovery . Retrieved November 12, 2014,
from Academy of Nutrition and Dietetics :
http://www.eatright.org/Public/content.aspx?id=6442478898