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ZenBodyLove

Zinc

Zinc is an essential trace mineral. Populations following vegetarian and vegan diets tend to have lower zinc intakes, and pooled studies also show lower serum zinc, largely because phytate in whole grains, legumes and seeds reduces zinc absorption; food preparation such as soaking, sprouting, fermenting and leavening reduces phytate. Trials of zinc taken during a common cold suggest shorter colds with more minor side effects, at low certainty. Excessive zinc intake over time can disrupt copper metabolism.

  • Vegan

Evidence retrieved up to

What the research shows

In randomised trials, zinc taken once a common cold had started was associated with shorter colds, while zinc taken regularly showed little or no effect on how many colds occurred; non-serious side effects were more frequent with zinc.

Low certaintyFurther research is likely to change this.
Take care: see the safety noteBenefit

Who this is about

children and adults with the common cold

Practical note

Graded low, matching the 2024 Cochrane review: duration was about 2.4 days shorter (8 trials, 972 participants) but with very high heterogeneity (I2 97 percent) and most trials at unclear or high risk of bias. Lozenge trials of zinc gluconate used 45 to 276 mg a day for 4.5 to 21 days.

Safety note

Treatment trials found more non-serious adverse events with zinc (moderate certainty); the review lists unpleasant taste, loss of smell, vomiting, stomach cramps and diarrhoea as possible zinc-related effects.

Sources

Excessive zinc exposure over weeks to years, mostly from supplements or zinc-containing denture creams in reported cases, can lower copper levels and lead to blood abnormalities such as anaemia and low white cell counts.

Very low certaintyThis is uncertain; treat it as a lead, not a finding.
Caution: see the safety noteRisk

Who this is about

people with prolonged high zinc intake

Practical note

Graded very low: the source is a 2026 systematic review of 34 case reports and series (37 cases), which shows the harm can occur but cannot estimate how common it is or at what intake it starts; reported daily elemental zinc ranged from about 50 mg to more than 1500 mg.

Safety note

In the 37 reported cases serum copper was low in every patient; most recovered after zinc exposure stopped and copper was given, but nerve symptoms improved more slowly and sometimes incompletely. High-dose or long-term zinc use belongs under the guidance of a health professional.

Sources

Food preparation methods that break down phytate, such as soaking, sprouting, fermenting and leavening, and choices such as sourdough or yeast-leavened bread and presoaked legumes, may improve zinc absorption from plant foods.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsBenefit

Who this is about

people following vegetarian or vegan diets

Practical note

Graded low: supported by a narrative review and by the mechanism (phytate lowers absorption), not by trials measuring zinc status after changes in food preparation. A 2013 meta-analysis also listed dietary practices that increase bioavailability, zinc-fortified foods and low-dose supplements as strategies to consider for vegetarians with low intakes.

Vegan note

These preparation methods are relevant to vegan diets, where phytate-rich foods supply most dietary zinc.

Sources

Populations following vegetarian diets have lower zinc intakes and, in pooled studies, lower serum zinc than non-vegetarians, with a larger difference among vegans and females.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsRisk

Who this is about

adults following vegetarian or vegan diets

Practical note

Graded low: the evidence is observational (26 studies, 48 comparisons), definitions of vegetarian diets were inconsistent, and an Australian narrative review concluded serum zinc and deficiency risk were similar between vegetarians and non-vegetarians despite lower intakes, possibly through adaptive absorption.

Vegan note

The 2013 meta-analysis found a greater impact on zinc intake and status among vegans than among vegetarians as a whole; Australian and New Zealand reference values set vegetarian zinc requirements at 150 percent of the general values.

Sources

Phytate in plant foods reduces zinc absorption: in pooled absorption studies, meals or diets with a high phytate-to-zinc ratio lowered the fraction of zinc absorbed to under half of control values.

Moderate certaintyFurther research may change the size of the effect.
No known concerns at usual amountsRisk

Who this is about

adults and older adults

Practical note

Graded moderate: a systematic review of 87 publications (30 on phytate) with meta-analysis of absorption studies found a consistent effect when the phytate:zinc molar ratio exceeded 15; downgraded one level because the outcome is fractional absorption in test meals rather than long-term zinc status.

Vegan note

Whole grains, legumes, nuts and seeds supply much of the zinc in vegan diets and are also the main sources of phytate.

Sources