Take Zinc or you may sink

Details: Created on Tuesday, 30 December 2014 14:07

This is a fascinating new report about the effects of giving supplemental zinc to African women. Read it first, then my comments follow:

A randomized, double-blind trial reported online on October 16, 2014, in Nutrition Research found a protective effect for zinc supplementation against DNA strand breaks. This type of genetic damage is caused primarily by reactive oxygen species and can lead to further damage and consequent disorders if not repaired.

The study included 40 Ethiopian women believed to be of low zinc status due to decreased meat intake and high dietary phytate levels, which reduce zinc absorption. Plasma zinc levels were measured in blood samples collected at the beginning of the study. The women were given 20 milligrams zinc from zinc sulfate or a placebo daily for seventeen days. Comet assay of intracellular DNA strand breaks was conducted in cells collected at the beginning and end of the trial.

While plasma zinc levels were not significantly changed by the end of the study, comet tail measurement of DNA strand breaks decreased from an average of 39.7 to 30.0 in the supplemented group.

"Zinc deficiency in both in vitro and in vivo models is associated with increased oxidative stress and increased DNA damage," note Maya L. Joray of the University of Colorado Health Sciences Center and colleagues in their introduction to the article. "As a result of this relationship between cellular zinc levels and DNA damage, the comet assay, a method that measures DNA strand breaks in cells, may represent a sensitive functional tool to assess response to zinc supplementation."

"Plasma zinc comprises a very small percentage of the total body zinc, and plasma zinc may not be a priority pool for repletion in chronically deficient adults," the authors remark. "Because of zinc's essential role in maintaining DNA integrity, the comet assay may be a useful tool to assess cellular impacts of alterations in zinc intake and possibly zinc status."

Note that they mentioned that the women were eating low-meat/ high phytate diets. Phytic acid is an acid distributed widely in plants, and it binds minerals, such as zinc, making them unavailable. And it has also been found in Western populations that the high phytic acid in plant-based diets can compromise zinc status.

Zinc is involved in taste perception, and it has been found that vegans perform less well on taste perception tastes, suggesting the possibility of zinc deficiency.

Besides the phytic acid, also the oxalic acid in fruits and vegetables may bind zinc into a non-useable oxalate form. Then lastly, the high fiber content of plant-based diets may impede zinc absorption to some extent. There is a good side but also a bad side to all that fiber.

Note that overall, plant-based diets are very healthy and offer huge benefits. But, it's possible that they are marginal when it comes to maintaining optimal zinc status. Not major, but subtle degrees of zinc deficiency may be occurring widely among unsupplemented vegetarians and vegans. And that's why I prefer, for insurance reasons, to include a zinc supplement in my diet. I would rather be on the safe side.

And here is another consideration: As people age, their natural ability to absorb zinc goes down- way down. Dr. Walter Pierapaoli, a prominent Italian physician, believes that a significant amount of the decrepitude of old age results from poor zinc nutriture. There are over 200 enzymes that are zinc-dependent. This is way too important to leave to chance. I recommend including a zinc supplement in your health program- especially if you are eating a vegan or mostly vegan diet.