Selenium – The Lesser Known but Important Mineral

Margaret Hudson
President, Burnbrae Farms
4^th Generation Farmer

There are many nutrients in eggs that lend to its stellar nutrition profile, including protein, iron and vitamin D. But there’s a lesser-known mineral in eggs that’s beginning to make headlines for its health benefits: selenium.

You may not have heard of selenium, since it’s a mineral that humans require in only trace amounts. It’s not top of mind like calcium or iron. But emerging research shows that selenium is a powerful antioxidant, and may play a role in reducing the risk of heart disease, cancer and cognitive decline. It’s certainly one to watch.

What is selenium?

Selenium is a trace mineral that’s naturally present in many foods and drinks. It’s also available as a dietary supplement, but today we’ll just focus on dietary sources rather than pills. Selenium plays a role in thyroid gland function, DNA production and protecting the body from damage caused by oxidation.

Dietary guidelines recommend 55 micrograms of selenium daily for adults. It’s easy to get enough selenium if your diet includes eggs, fish and poultry. Here are some dietary sources of selenium (from Food Data Central ):

Selenium content (mcg):

Brazil nuts, 1 ounce (6–8 nuts) - 544 mcg

Tuna, yellowfin, cooked, 3 ounces - 92 mcg

Halibut, cooked, 3 ounces - 47 mcg

Sardines, canned, 3 ounces - 45 mcg

Macaroni, enriched, cooked, 1 cup - 37 mcg

Beef steak, bottom round, roasted, 3 ounces - 33 mcg

Eggs, 2 large - 30 mcg

Chicken, light meat, roasted, 3 ounces - 22 mcg

Bread, whole wheat, 1 slice - 13 mcg

Yogurt, plain, 1 cup - 8 mcg

Lentils, boiled, 1 cup - 6 mcg

A serving of two eggs – whether hard-boiled, scrambled or in an omelette - provide just over half of your daily requirement for selenium. You’ll note that Brazil nuts are super-high in selenium, and you may be wondering if it’s possible to get too much of a good thing. It certainly can be problematic, and the tolerable upper intake level for selenium is set at 400 mcg/day. If you love Brazil nuts, cap your portion at just 2-3 nuts per day so you don’t get too much selenium from all of the foods that you eat throughout the day.

Health benefits of selenium

Deficiencies in selenium have been linked to several possible disease outcomes. Selenium plays a vital role in regulating the thyroid gland, and low levels of selenium may be associated with thyroid problems.

Studies show that selenium may play a role in cancer prevention. It’s likely because selenium has antioxidant effects, which quell the harmful effects of free radicals. Plus, selenium plays a role in DNA repair, apoptosis (killing harmful cells) and in immune health, which also play a role in cancer prevention.

In a review of studies on selenium and cancer prevention, those with sufficient selenium intake had a 31 percent lower cancer risk and 45 percent lower cancer mortality risk compared to those who were deficient in selenium. The study also found no clear benefit from selenium supplements on preventing cancer risk, meaning that getting selenium from food is likely your best bet.

Likewise, studies show that low levels of selenium have also been linked to an increased risk of developing heart disease, showing the importance of getting enough selenium daily. It is thought that selenium helps prevent the oxidation of fats and reduces inflammation, which helps reduce heart disease risk.

As we age, the levels of selenium in our blood naturally decline, and some researchers think this may be linked to cognitive decline . More research is needed to determine if there is a link between selenium status and cognitive decline or Alzheimer’s disease in older adults.

Getting enough selenium is as easy as eating a balanced diet . Including eggs is an easy, tasty and reliable way to include this important trace mineral.

Margaret Hudson

President and CEO, Burnbrae Farms