by Jack Norris, RD
Contents
- Summary
- Dietary Reference Intakes for Zinc
- Zinc Content of Plant Foods
- Zinc Deficiency
- Zinc Absorption and Status of Vegetarians
- Zinc Supplements
- References
Summary
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 | |||
---|---|---|---|
Food | Preparation | Serving | mg |
Oatmeal | cooked | 1 cup | 2.3 |
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 |
Lentils | boiled | 1/2 cup | 1.3 |
Peanuts | raw | 1/4 cup | 1.2 |
Almonds | whole | 1/4 cup | 1.1 |
Pecans | halves | 1/4 cup | 1.1 |
Tempeh | raw | 1/2 cup | 1.0 |
Kidney beans | boiled | 1/2 cup | 1.0 |
Peas | boiled | 1/2 cup | 1.0 |
Chia seeds | dried | 1 oz | 1.0 |
Walnuts | chopped | 1/4 cup | 0.9 |
Peanut butter | 2 tbsp | 0.9 | |
Corn | yellow, boiled | 1 cup | 0.9 |
Pinto beans | boiled | 1/2 cup | 0.8 |
Pistachios | 1/4 cup | 0.7 | |
Miso | 1 tbsp | 0.4 | |
Broccoli | boiled, chopped | 1/2 cup | 0.4 |
Zinc Deficiency
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).
Zinc Supplements
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.
Zinc gluconate and zinc citrate are two forms that are well-absorbed (7). There’s evidence, though weak, that zinc picolinate is also absorbed well (8).
Some people do not absorb zinc oxide (7).
Zinc gluconate may be the best choice due to lower levels of cadmium (9).
References
Last updated February 2014
1. Foster M, Chu A, Petocz P, Samman S. Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans. J Sci Food Agric. 2013 Apr 17.
2. USDA National Nutrient Database for Standard Reference.
3. Groff J, Gropper S. Advanced Nutrition and Human Metabolism, 3rd ed. Wadsworth: 2000.
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.
5. Dietary reference intakes: the essential guide to nutrient requirements. National Academy of Sciences. 2006.
6. Messina V, Mangels AR. Considerations in planning vegan diets: children. J Am Diet Assoc. 2001 Jun;101(6):661-9.
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.
8. Barrie SA, Wright JV, Pizzorno JE, Kutter E, Barron PC. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions. 1987 Jun;21(1-2):223-8.
9. Krone CA, Wyse EJ, Ely JT. Cadmium in zinc-containing mineral supplements. Int J Food Sci Nutr. 2001 Jul;52(4):379-82.
Also Reviewed
Singh M, Das RR. Zinc for the common cold. Cochrane Database Syst Rev. 2013 Jun 18;6:CD001364.
6 thoughts on “Zinc”
Dear Jack! This article https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/ states “The percentage of elemental zinc varies by form. For example, approximately 23% of zinc sulfate consists of elemental zinc; thus, 220 mg of zinc sulfate contains 50 mg of elemental zinc.”
So I started to think about the real amounts on zinc in popular suplements on Iherb. I found only 1 explicit statement “Country Life always labels minerals in elemental weight.”
Others just put it like “Zinc (zinc gluconate, zinc citrate) 15 mg = 136% of daily value” (By the way, different DV are used: some use 11 mg, some 15 mg as 100%)
Could you please comment on all that?
Hi Nikita – The amount of zinc listed on the Nutrition Facts panel should be the amount of elemental zinc. The daily value for zinc has recently been changed to 11mg.
I’ve been taking a 50mg chelated zinc pill that I got from an OTC health provider. I thought it was safe. But now reading the comments it iffy at best.
We recommend staying under the Upper Limit unless otherwise indicated by your medical provider.
Where do you find zinc supplements that (a) are around the DRI, and (b) have enough copper to offset the extra zinc?
All of the ones I have found so far either have (a) 50 mg, which is over the safe upper level, and or (b) have no copper. \
I know you used to take Deva’s Calcium Magnesium Plus, but I am trying to get rid of multis altogether, and it has calcium carbonate, which gives me terrible GI symptoms, consistently.
Daniel,
I’ve found many zinc supplements with less than 50 mg, I’m surprised you haven’t been able to. The average vegan shouldn’t need to worry about copper when taking a modest zinc supplement. See here: https://veganhealth.org/cadmium/