Marshalls Health Shop - Selenium Blog



Selenium is an essential trace mineral for good health and one which most people living in New Zealand are deficient in!”

Consuming enough naturally occurring selenium has a multitude of benefits that include defending against oxidative stress, heart disease, cancer, boosting immunity against viruses and other invading pathogens, regulating thyroid function, protecting against cognitive decline, reducing the risk of autoimmune diseases and boosting fertility.

Studies have shown that most people in New Zealand do not get the recommended daily intake of selenium naturally. Studies have also shown that countries with higher levels of selenium intake have lower rates of cancer and other common diseases.

What is Selenium? 

Selenium is an essential trace mineral found naturally in soil, certain foods and small amounts in water. It is a major contributor to the body’s production of the cellular enzyme glutathione and is a component of selenoproteins.

Glutathione supports the body’s natural detoxification mechanism which subsequently takes part in antioxidant activity that defends against free radical damage, inflammation and maintaining a healthy metabolism.

Selenoproteins supports the body’s physiological processes such as DNA synthesis and reproductive health.

What happens when you have a Selenium deficiency?

Based on the many functions that glutathione and selenoproteins perform in the body, your metabolism, heart, brain and the production of thyroid hormones can all suffer when sub-optimal levels of these enzymes and proteins exist. The body’s natural immune system cannot defend against diseases, viruses and infections.

The most common selenium deficiency symptoms include:

  • Reproductive issues
  • Muscle weakness
  • Fatigue
  • Brain fog
  • Thyroid dysfunction
  • Mood-related issues including depressed mood, anxiety and hostile behaviours
  • Hair loss
  • Weak, brittle nails
  • Susceptibility to illnesses due to a weakened immune system
  • Confusion and cognitive changes

Having low selenium status is also correlated with an increased risk of some major health problems such as, mortality as a result of inflammation, infertility and certain types of cardiovascular diseases and cancers. Cells also become more prone to oxidative stress and negative effects of exposure to heavy metals (such as lead, cadmium, arsenic, mercury, etc.) Brain health deprivation can lead to cognitive decline, potentially Alzheimer’s disease, depressed moods and hostile behaviour.

What factors contribute to Selenium deficiency?

Certain groups of people are more likely to be deficient in selenium than others. Local soil quality, medical history, genetics, individual absorption ability and diet are all contributors.

1/ Low selenium content in soil.

The amount of selenium in soil differs considerably depending on location. Contributing factors include rainfall, evaporation and pH levels.

Equally, the amount of selenium in food is largely dependent on soil conditions where crops are grown. Therefore, within the same food groups, levels of selenium can vary widely. Higher selenium concentrations are found in crops grown in certain locations more so than others. For example, selenium levels in New Zealand soils, especially in the South Island are very low and subsequently, crops grown in these soils are commonly low in selenium.

In a study of New Zealanders, where soil selenium levels are low, found sub-optimal levels of the selenium-dependent enzyme, glutathione peroxidase and subsequently, the subjects were six times more likely to have asthma.

2/ Low selenium intake from food sources.

Not eating selenium rich food regularly, such as, meat, fish and poultry also increases the risk of having selenium deficiency. Diets such as vegetarian and vegan may potentially be at an increased risk of low selenium intake.

3/ Health conditions that affect levels of selenium.

Undergoing kidney dialysis, living with HIV, having a digestive disorder, Crohn’s disease, colitis or liver cirrhosis can increase the risk of selenium deficiency.

Natural solutions to Selenium deficiency.

It is believed that if you regularly include natural food sources of selenium in your diet and are generally healthy, there is only a small chance you will suffer from selenium deficiency. There are several ways you can help prevent and treat selenium deficiency.

1/ Eat selenium rich foods.

Some of the top selenium rich foods to include in your diet are:

  • Brazil nuts
  • Eggs
  • Liver
  • Fish (specifically Tuna & Cod)
  • Shellfish
  • Sunflower and Chia seeds
  • Poultry (Specifically Chicken & Turkey)
  • Beef
  • Pork
  • Barley
  • Mushrooms

Whole foods are the best sources of selenium, especially when these foods are handled and prepared in a delicate way, since selenium may be destroyed during processing and very high-heat cooking methods. Getting selenium from foods is the safest way to prevent low levels.

Marshalls Health Shop - Selenium Blog

2/ Take selenium specific supplements.

Selenium deficiency is predicted to increase under future climate change suggesting that natural sources of selenium are depleting and why supplementary sources are important regardless of one’s current health status.

Research shows that humans require 300mcg – 400mcg (micrograms) of selenium per day, for optimal health. Selenium is found in most multivitamin supplements. Read the label and/or check with our experts  to ensure the supplement you are taking is right for you. Marshalls Health recommends the NOW brand of high-quality selenium specific supplement to directly target selenium deficiency.

The benefits of optimum Selenium intake, explained.

1/ Selenium acts as an antioxidant and defends against oxidative stress.

Selenium helps fight the aging process by reducing free radical damage. It has a synergistic effect with other antioxidants like vitamin E enabling the body to defend against oxidative stress. Stress contributes to many conditions, including heart disease, neurological conditions and some cancers.

2/ May help defend against Cancer.

Taking optimum doses of selenium has been shown to potentially have anti-cancer effects by protecting DNA synthesis.

3/ Can help boost immunity against viruses.

Selenium supports immunity because it’s required for the correct functioning of the immune system. It is also a key nutrient in counteracting the development of viruses, including HIV.

4/ Improves blood flow and may lower the risk of heart disease.

Selenium deficiency is associated with an increased risk of developing cardiovascular disease and potentially suffering from a stroke or heart attack. Supplements, or an increase of selenium-rich foods may be able to help prevent coronary heart disease by protecting arteries against plaque build-up and damage.

5/ Helps regulate thyroid function.

Selenium acts as a catalyst to produce active thyroid hormones. Research now suggests that there is a direct link between thyroid metabolism and selenium deficiency. Having too little selenium in your diet can impair how your thyroid functions and therefore metabolism suffers. One study even found that selenium helps protect against obesity.

6/ May help health into older age.

Certain studies have investigated the use of selenium supplements for the treatment of dozens of conditions that range from asthma, arthritis, thyroid disorder and Alzheimer’s. There’s a risk of these conditions increases as we age, but with a high-antioxidant intake (selenium) and consumption of essential vitamins and minerals, the body can naturally defend against these conditions and may contribute to a longer life.

7/ Helps reduce asthma symptoms.

According to studies, when people with asthma take selenium supplements, they experience less asthma-related symptoms than those who take placebos.

8/ Can help boost fertility.

Selenium benefits fertility because it is required for proper sperm motility and increases blood flow. These are two key components involved in conception and beating infertility.

Note: Excessive levels of selenium can be toxic. An overdose of selenium may cause reactions like bad breath, fever, nausea and potentially liver, kidney and heart complications. These only occur at very high levels of selenium where a “poisoning” status is reached.



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