Why we don't include zinc

Why not Zinc?

Despite commonly being used as a daily supplement to prevent illness, the findings suggest that zinc supplementation has no effect on the prevention of colds, with an increase in adverse events among those who use the supplement daily. There is some low-quality evidence to show that high doses of zinc at the onset of the cold/viral symptoms can reduce the length of illness by 1-2 days… which is a fairly positive outcome.

However, these doses of zinc are extremely high and well above the recommended daily intake, and would not be recommended in a regular use hydration drink, as it could lead to significant side effects (i.e. Headache, Nausea, Vomiting, Diarrhea). 

When considering Zinc toxicity, the recommendation for adults is no more than 15mg per day. Those studies that found reduction of cold/illness symptoms by 1-2 days, were patients who were receiving 75mg! or above "after onset of symptoms" (for a duration of 4-7 days after onset of illness).

So basically, the dosing of zinc that would be required to reduce cold symptoms by 1-2 days, would lead to zinc toxicity if they were included in a daily hydration drink.

This is an example of one of the things that we are trying to do at Juice Doctor… sort through the data to provide a rationale for why we are selecting ingredients. You may not always agree with what we include (magnesium), or choose not to include (Zinc), but we will try to provide our rationale for those decisions. Why include zinc in a daily hydration drink when we know the only evidence of potential benefit is around huge doses right at the onset of an illness.

Interested in a summary of the studies that have looked at Zinc? 

(Check out the table below summarized by the Cochrane Review)