Selenium 4


Summary

Selenium is an essential mineral that is needed in very small (trace) amounts. Selenium is involved in protection from oxidative damage, reproduction, DNA synthesis, and thyroid hormone metabolism. The selenium content of plant foods depends on the selenium content of the soil where the foods were grown (1).

Vegans in the U.S. appear to have adequate intakes of selenium (2). Low intakes and lower blood concentrations have been reported in vegans and vegetarians in other areas of the world where soil selenium is low (2, 3, 4, 5).

Dietary Reference Intakes for Selenium

The Recommended Dietary Allowance (RDA) for selenium is 55 micrograms per day for adolescents and adults, 60 micrograms per day during pregnancy, and 70 micrograms per day when breastfeeding (6). Most Americans get more than the RDA and over 99% of participants in a large survey of people in the U.S. had serum selenium in the normal range (6).

Selenium Content of Plant Foods

The selenium content of plant foods depends on the amount of selenium in the soil the plants were grown in as well as on other factors including soil pH and fertilizer use (1). The amount of selenium in soil varies by geographic location.

The lowest selenium intakes in the world are in some parts of China where soil selenium is very low (2), while other regions of China have a very high soil selenium and high selenium intakes (1). Areas of Europe also have low soil selenium (1) although not as low as in China. New Zealand soil is low in selenium but selenium intakes are adequate because of the use of imported high-selenium wheat (2).

In the U.S and Canada, selenium intakes, even in areas with lower soil selenium, are generally adequate (7, 8, 9). This is, at least in part, due to the food distribution system which usually makes it possible for even those living in areas with lower soil selenium to get enough selenium.

Selenium values in food composition tables may or may not reflect the actual selenium content of foods eaten by an individual. For example, the USDA Food Composition Database reports that Brazil nuts have 544 micrograms of selenium per ounce but other sources report values ranging from 45 to 566 micrograms/ounce (10, 11, 12).

In addition to Brazil nuts, foods that are relatively high in selenium include whole grains (whole-wheat bread and pasta, oatmeal, barley), brown rice, soy products, and beans. The table below shows the selenium content of selected plant foods from the USDA’s nutrient database (12). Note that selenium content will vary depending on soil selenium.

Selenium in Plant Foods in the United States
Food Serving Size Selenium
(micrograms)
Brazil nuts 1 ounce (about 6 nuts) 544
Couscous, cooked 1 cup 43
Whole-wheat pasta, cooked 1 cup 42
Sunflower seed butter 2 tablespoons 33
Wheat bagel 1 bagel 28
Sunflower seeds, dry roasted 1 ounce 23
Wheat germ, toasted 1 ounce 18
Chia seeds 1 ounce 16
Whole-wheat tortilla 1 tortilla 15
Barley, pearled, cooked 1 cup 13.5
Soybeans, cooked 1 cup 13
Oatmeal, cooked 1 cup 13
Firm tofu ½ cup 12.5
Brown rice, cooked 1 cup 12
Soymilk 1 cup 12
Pinto beans, cooked 1 cup 11
Tahini 2 tablespoons 10
Lima beans, cooked 1 cup 8.5
Whole-wheat bread 1 slice 8
Great northern beans 1 cup 7

Selenium Intakes and Status of Vegans

Vegans in the U.S. appear to have adequate intakes of selenium (2).

Depending on food choices, vegans in Europe may have lower intakes of selenium. Lower soil selenium in European countries affects the selenium content of locally-grown grains, fruits, and vegetables.

In Denmark, both vegans and the general population had median selenium intakes that were lower than recommendations; the vegans had significantly lower selenium intakes than the general population (4).

One brief report from 1997 found lower selenium status in UK vegans than in UK non-vegetarians (3).

A more recent study in the U.K. found lower mean selenium intakes in lacto-ovo and lacto vegetarians compared to meat or fish eaters. Vegans’ mean selenium intakes were lower than those of meat/fish eaters but higher than lacto-ovo/lacto vegetarians (13).

Almost half of vegan women and one-third of vegan men in the U.K. had selenium intakes below recommendations (13).

In Finland, vegans had lower selenium intakes and lower blood selenium compared to non-vegetarians (14). Both groups, however, had selenium intakes that met or exceeded recommendations and serum selenium was in an acceptable range (14). Finland is unique in that it adds selenium to fertilizers (15).

As of January 2019, information on selenium intakes and status of vegans in other areas of the world was not found.

Recommendations

Vegans in the U.S. and other areas eating a variety of foods including whole grains and beans are likely to get enough selenium. Vegans in low selenium areas should eat Brazil nuts regularly and/or to use a supplement supplying a moderate amount of selenium.

The tolerable upper intake level (UL) for selenium is 400 μg/day for adolescents and adults and includes both selenium obtained from food and selenium from supplements (6). Long-term use of high amounts of selenium can cause health problems including hair and nail loss or brittleness, nausea, diarrhea, fatigue, and neurologic disorders (16).

References

Last updated January 2019

1. Rayman MP. Selenium and human health. Lancet 2012;379:1256-68.

2. Mangels R, Messina V, Messina M. The Dietitian’s Guide to Vegetarian Diets, 3rd ed. Sudbury, MA: Jones & Bartlett Learning, 2011.

3. Judd PA, Long A, Butcher M, Caygill CP, Diplock AT. Vegetarians and vegans may be most at risk from low selenium intakes. BMJ. 1997 Jun 21;314(7097):1834.

4. Kristensen NB, Madsen ML, Hansen TH, et al. Intake of macro- and micronutrients in Danish vegans. Nutr J. 2015 Oct 30;14:115.

5. Sobiecki JG. Vegetarianism and colorectal cancer risk in a low-selenium environment: effect modification by selenium status? A possible factor contributing to the null results in British vegetarians. Eur J Nutr. 2017 Aug;56(5):1819-1832.

6. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Vitamin C, Vitamin E, Selenium, and Carotenoids. National Academy Press, Washington, DC, 2000.

7. Niskar AS, Paschal DC, Kieszak SM, et al. Serum selenium levels in the US population: Third National Health and Nutrition Examination Survey, 1988-1994. Biol Trace Elem Res 2003;91:1-10.

8. Kafai MR, Ganji V. Sex, age, geographical location, smoking, and alcohol consumption influence serum selenium concentrations in the USA: third National Health and Nutrition Examination Survey, 1988-1994. J Trace Elem Med Biol 2003;17:13-8.

9. Thompson JN, Erdody P, Smith DC. Selenium content of food consumed by Canadians. J Nutr. 1975 Mar;105(3):274-7.

10. Thomson CD, Chisholm A, McLachlan SK, Campbell JM. Brazil nuts: an effective way to improve selenium status. Am J Clin Nutr. 2008 Feb;87(2):379-84.

11. Parekh PP, Khan AR, Torres MA, Kitto ME. Concentrations of selenium, barium, and radium in Brazil nuts. J Food Comp Anal 2008; 21:332-335.

12. US Department of Agriculture (USDA), Agricultural Research Service, Nutrient Data Laboratory. USDA National Nutrient Database for Standard Reference, Legacy. Version Current: April 2018.

13. Sobiecki JG, Appleby PN, Bradbury KE, Key TJ. High compliance with dietary recommendations in a cohort of meat eaters, fish eaters, vegetarians, and vegans: results from the European Prospective Investigation into Cancer and Nutrition-Oxford study. Nutr Res. 2016 May;36(5):464-77.

14. Elorinne AL, Alfthan G, Erlund I, et al. Food and nutrient intake and nutritional status of Finnish vegans and non-vegetarians. PLoS One. 2016 Feb 3;11(2):e0148235.

15. Alfthan G, Eurola M, Ekholm P, et al. Effects of nationwide addition of selenium to fertilizers on foods, and animal and human health in Finland: From deficiency to optimal selenium status of the population. J Trace Elem Med Biol. 2015;31:142-7.

16. NIH Office of Dietary Supplements. Selenium – Fact Sheet for Health Professionals. Updated September 26, 2018.

Also Reviewed

Higdon J. Selenium. Linus Pauling Institute, Oregon State University. Updated November 2014.

Stoffaneller R, Morse NL. A review of dietary selenium intake and selenium status in Europe and the Middle East. Nutrients. 2015 Feb 27;7(3):1494-537.


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4 thoughts on “Selenium

  • Radha Sahar

    Kia Ora from New Zealand
    An increasing number of New Zealanders, including vegans, are eating gluten-free, (due to IBS sugars rather than Celiac gluten allergy – though most folk don’t know why gluten-free quells their symptoms). Might it be that we need more selenium, even though brown rice & beans, etc, are in our diets? Many people here cannot afford Brazil nuts, plus they are a high food-mile item, often involving child labour in Brazil. Perhaps our recommended level needs to be re-considered …

    • Reed Mangels

      Since imported high-selenium wheat is an important source of selenium for those living in New Zealand, those who avoid wheat due to eating gluten-free are likely to need other sources of selenium. It may be that beans and rice are imported and supply selenium but without analyzing these foods, we don’t know how much selenium they provide. This is a circumstance where using a supplement that provides the RDA for selenium seems prudent.

    • Reed Mangels

      Selenium adequacy will depend on individual food choices. For example, vegans in the UK who eat Brazil nuts regularly may have adequate selenium status based on one study that found that eating Brazil nuts can normalize selenium status (https://www.ncbi.nlm.nih.gov/pubmed/18258628) . According to the USDA National Nutrient Data Base, one Brazil nut supplies 95.8 mcg of selenium. The RDA for non-pregnant, non-lactating adults is 55 mcg/day.
      Generally speaking, the UK is a low selenium area so crops grown in the UK are likely to be markedly lower in selenium than those grown in the US or other areas with higher soil selenium (https://www.ncbi.nlm.nih.gov/pubmed/22381456). This would affect foods commonly eaten by vegans such as locally-grown grains, fruits, and vegetables. One brief, older (1997) report finds lower selenium status in UK vegans than in UK non-vegetarians (https://www.bmj.com/content/314/7097/1834.2.long).