by Jack Norris, RD • Last updated February 2014
- Dietary Reference Intakes for Zinc
- Zinc Content of Plant Foods
- Zinc Deficiency
- Zinc Absorption and Status of Vegetarians
- Zinc Supplements
Zinc is not found in large amounts in plant foods, but as far as can be detected, vegetarians have similar zinc status to non-vegetarians (1). Zinc is important for immunity and if you find you’re easily catching colds, a modest zinc supplement of about the Dietary Reference Intake (DRI) might solve the problem.
Dietary Reference Intakes for Zinc
See Daily Needs for the zinc DRI.
Zinc Content of Plant Foods
The common plant foods highest in zinc are legumes, nuts, seeds, and oatmeal. The table below shows the zinc content of selected plant foods (2).
|Zinc in Plant Foods|
|Tofu||firm, raw||1/2 cup||2.0|
|Cashews||dry roasted||1/4 cup||1.9|
|Sunflower seeds||roasted||1/4 cup||1.7|
|Garbanzo beans||boiled||1/2 cup||1.3|
|Kidney beans||boiled||1/2 cup||1.0|
|Chia seeds||dried||1 oz||1.0|
|Peanut butter||2 tbsp||0.9|
|Corn||yellow, boiled||1 cup||0.9|
|Pinto beans||boiled||1/2 cup||0.8|
|Broccoli||boiled, chopped||1/2 cup||0.4|
Symptoms of zinc deficiency include poor growth and delayed sexual maturation in children, poor wound healing, hair loss, impaired immune function, and dermatitis—especially around body orifices (3).
Zinc Absorption and Status of Vegetarians
Phytates, which are commonly found in plant foods, reduce zinc absorption, and some researchers have suggested that this increases the zinc needs of vegetarians by up to 50% (4).
In contrast, a 2013 meta-analysis showed vegans to have only a slightly lower serum zinc level than non-vegetarians, a difference of 1.17 ± 0.45 µmol/l (1). Average serum zinc levels are from 10 to 15 µmol/l (5), so it’s doubtful that the differences are meaningful (absolute values for serum zinc were not given in the analysis).
Protein increases zinc absorption. Because of this, foods high in protein and zinc, such as legumes and nuts, are good choices (6). The leavening of bread (most bread is leavened) and fermenting of soyfoods (tempeh and miso) also enhances zinc absorption (6).
A modest zinc supplement up to 100% of the Dietary Reference Intake (DRI) should be safe for those who are concerned or having symptoms of zinc deficiency. See Daily Needs for the DRI and Upper Limit for zinc.
Some people do not absorb zinc oxide (7).
Zinc gluconate may be the best choice due to lower levels of cadmium (9).
4. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. (2001) Food and Nutrition Board, Institute of Medicine. Accessed 12/28/2010.
7. Wegmüller R, Tay F, Zeder C, Brnic M, Hurrell RF. Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide. J Nutr. 2014 Feb;144(2):132-6.