Zinc benefits

Perhaps zinc hasn’t been on your radar before, or perhaps it has because of its significant immune-supportive benefits.* Articles on how to supplement with zinc and how zinc benefits immune function are popular on our Take 5 Daily blog.

Zinc is not just for immune support and should not just be on your radar during the winter months. Zinc is in every cell in our bodies and is a necessary co-factor in more than 200 enzymatic reactions. A sampling of zinc’s key functions in the body includes the following:

  • White blood cell production (to make natural killer cells, T-lymphocytes, and B-lymphocytes) for support of a healthy immune response
  • Testosterone production
  • Skin health and repair
  • Eye health, particularly the macula
  • Normal growth and development
  • Taste and smell

What is zinc bisglycinate?

Zinc bisglycinate – a well-tolerated and well-absorbed zinc chelate – is composed of one zinc molecule bound to two (bis = two) molecules of the amino acid glycine. Because this form of zinc is absorbed intact (that is, bound to glycine) it does not compete with other minerals for absorption in the intestinal tract. Several studies demonstrate its superior absorption - so keep reading.

Zinc bisglycinate benefits start with superior absorption

The form of the mineral – including the compound it is bound to – matters, and zinc is no exception. One factor that is always an issue when supplementing minerals is that, by their very nature, they are not particularly well absorbed by the human body. In addition, various dietary, lifestyle, and health factors can have a negative impact on mineral absorption.

Factors that interfere with mineral absorption. There are numerous dietary, health, and medication factors that can interfere specifically with mineral absorption:

  • oxalic acid (found in high amounts in spinach, rhubarb, and black tea)
  • phytic acid (found in whole grains, nuts, seeds, beans, and potatoes)
  • caffeine
  • antacids, acid-blocking medications
  • malabsorption syndromes

The obstacle to absorption can be easily overcome by optimizing the form the mineral comes in. This is simple chemistry – certain forms of minerals are better absorbed than others, and zinc bisglycinate is the star in the zinc world.

Zinc bisglycinate vs. zinc gluconate vs. zinc picolinate

Better absorption translates to greater efficacy so what does the science say about the absorption of several zinc supplement forms available on the market?

Zinc bisglycinate vs. zinc gluconate. A small crossover study examined the absorption of 15 mg of elemental zinc bound to bisglycinate or gluconate in 12 healthy volunteers. A single dose of each was followed by a seven-day washout period, then followed by a dose of the other form. Zinc bisglycinate resulted in 43% higher zinc blood levels compared to zinc gluconate.1

 

Zinc bisglycinate vs. zinc gluconate vs. placebo. In another comparative absorption study, 30 healthy females were randomly assigned (10 in each group) to: (1) zinc bisglycinate (60 mg of elemental zinc), (2) zinc gluconate (60 mg of elemental zinc), or (3) a maltodextrin placebo – all daily for six weeks.

Participants who took the zinc bisglycinate supplement had more significant increases in blood levels of zinc compared to the zinc gluconate and placebo groups. Zinc bisglycinate resulted in significant increases in blood levels of zinc in all 10 subjects, while 6 of 10 women in the zinc gluconate group had no significant increase or even had a decrease in zinc blood levels.2

Zinc bisglycinate vs. zinc picolinate vs. zinc gluconate vs. zinc oxide. In a third study, 12 healthy women were given single doses of zinc bisglycinate, zinc picolinate, zinc gluconate, or zinc oxide. With blood levels being tested every hour for four hours, zinc bisglycinate resulted in the highest plasma zinc levels. In addition, zinc in red blood cells (RBC) was measured over the same four-hour period. At the end of the study, RBC levels of zinc were in this order from highest to lowest: zinc bisglycinate > zinc picolinate > zinc gluconate > zinc oxide.3 

Better absorption means better efficacy and tolerability

Obviously, the more of a mineral you absorb into your bloodstream, the less of it ends up in your stool, and the greater the opportunity for it to do its work in your body. This is demonstrated in a study of mineral differences in exercise performance.4 A double-bind, placebo-controlled trial looked at the effect of three different protocols in 42 aerobically fit women (ages 18-30).

Aerobic fitness was tested before and after one month of three test protocols: (1) 36 mg of iron (as ferrous sulfate), 15 mg zinc (as zinc gluconate), 2 mg copper (as copper gluconate), 2 grams of carnitine (as Carnipure®), and 400 mg of phosphatidylserine (SerinAid®); or (2) 36 mg iron (as iron bisglycinate; Ferrochel®), 15 mg of zinc (as zinc bisglycinate), 2 mg copper (as copper bisglycinate) – the bisglycinates all from Albion®, 2 grams of carnitine (as Carnipure), and 400 mg of phosphatidylserine (SerinAid); or (3) placebo corn starch. The only differences between the test materials in groups 1 and 2 were the differences in mineral forms – group 2 taking all mineral chelates as bisglycinates. 

After one month on the test protocols, the women in the group who took bisglycinate chelate minerals showed significantly decreased three-mile run time and significantly further 25-minute stationary bike distance compared to baseline (before supplementation) and compared to the other two groups.

In most instances, the better that a mineral is absorbed, the fewer the side effects, which are often GI symptoms such as constipation or diarrhea. In the case of zinc, whatever its form, it’s best to take it with food because zinc is notorious for causing nausea on an empty stomach, although in the studies cited above, zinc bisglycinate was well-tolerated.

Explore Thorne’s zinc bisglycinate and zinc picolinate supplement offerings.

References

  1. Gandia P, Bour D, Maurette J-M, et al. A bioavailability study comparing two oral formulations of zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers. Int J Vitamin Nutr Res 2007;77(4):243-248.
  2. DiSilvestro R, Koch E, Rakes L. Moderately high dose zinc gluconate or zinc bisglycinate: effects on plasma zinc and erythrocyte superoxide dismutase in young adult women. Biol Trace Elem Res 2015;168(1):11-14.
  3. DiSilvestro R, Swan M. Comparison of four commercially available zinc supplements for performance in a zinc tolerance test. FASEB J 2008;22:693.3.
  4. DiSilvestro R, Hart S, Marshall T, et al. Enhanced aerobic exercise performance in women by a combination of three mineral chelates plus two conditionally essential nutrients. J Int Soc Sports Nutr 2017;14:42.