Selenium is an essential trace mineral that helps us with fertility and cognitive function. People need this mineral for many vital bodily functions and also plays a role in protection for stress, thyroid health, healthy brain function, and it’s also essential for metabolism. How much selenium is gets consumed depends on where someone lives. When switching over to a low carb diet, people on the ketogenic diet, in particular, can get their selenium from seafood and other animal products. That’s good news considering we discuss how important it is to eat fatty meats and seafood while on the keto diet in the Body Reboot book. Let’s continue to learn about selenium, it’s benefits, and why it’s essential to get enough of while on a low carb diet. 

Medical News Today explains what the recommended daily value of selenium should be and even though you can take a selenium supplement, it’s best to get this mineral from food. 

The recommended Daily Value (DV), or daily allowance, for selenium is 55 micrograms (mcg) per day for adults.

During pregnancy, a woman should consume 60 mcg, and lactating women should consume 70 mcg a day.

Selenium deficiency is rare worldwide. It often takes years to develop, and it usually only occurs in regions with severely low selenium content in the soil.

Several regions in China have low soil selenium content, but deficiencies in the population have been eradicated through supplementation programs.

Selenium supplements are available, but it is best to obtain any vitamin or mineral through food.

1. Protects against certain cancers 

Ketovale tells us that selenium can help protect you from getting cancer. In the past studies showed that cancer patients showed improvements when they took selenium supplements. 

Selenium has the outstanding ability to reduce DNA damage and to protect against certain cancers, such as breast cancer, lung cancer, and prostate cancer, among others.

Additionally, studies have concluded that selenium supplementation, if selenium status wasn’t adequate, could help cancer patients in their recovery from the illness and from treatment, and when combined with radiotherapy, it helped them manage radiotherapy side effects better and improved their overall quality of life.

Poor selenium content in soil in some parts of the world is also associated with higher cancer risk, compared to places where the soil is rich in selenium.

A study by Radiat Oncol. 2014 revealed that adding more selenium to a person's diet can offer many benefits for cancer patients who are going through chemotherapy. However, you should carefully manage the dose of selenium as taking too high of an amount may cause side effects over time. 

Abstract: 

To establish guidelines for the selenium supplementation in radiotherapy we assessed the benefits and risks of selenium supplementation in radiotherapy. Clinical studies on the use of selenium in radiotherapy were searched in the PubMed electronic database in January 2013. Sixteen clinical studies were identified among the 167 articles selected in the initial search. Ten articles were observational studies, and the other 6 articles reported studies on the effects of selenium supplementation in patients with cancer who underwent radiotherapy. The studies were conducted worldwide including European, American and Asian countries between 1987 and 2012. Plasma, serum or whole blood selenium levels were common parameters used to assess the effects of radiotherapy and the selenium supplementation status. Selenium supplementation improved the general conditions of the patients, improved their quality of life and reduced the side effects of radiotherapy. At the dose of selenium used in these studies (200–500 μg/day), selenium supplementation did not reduce the effectiveness of radiotherapy, and no toxicities were reported. Selenium supplementation may offer specific benefits for several types of cancer patients who undergo radiotherapy. Because high-dose selenium and long-term supplementation may be unsafe due to selenium toxicity, more evidence-based information and additional research are needed to ensure the therapeutic benefits of selenium supplementation.

Conclusion:

This paper summarized 16 clinical studies on selenium and radiotherapy conducted from 1987 to 2012. The studies included 1303 cancer patients. To assess the selenium status in patients before and after radiotherapy, the plasma, serum or whole blood selenium level was a common parameter used to assess the effect of radiotherapy on selenium status and the effectiveness of selenium supplementation. Selenium supplementation increased the blood selenium level, improved the general condition of patients, improved quality of life, prevented or reduced the side effects of radiotherapy and did not reduce the effectiveness of radiotherapy or cause any toxicity.

The results of our summary suggest that selenium supplementation in the form of sodium selenite at doses ranging from 200–500 μg daily by oral administration may offer benefits for head and neck cancer; head and neck cancer with lymphedema; and oral, cervical and uterine cancer patients who undergo radiotherapy and have low selenium levels. In the future, further research and additional evidence of the benefits of selenium supplementation in patients during radiotherapy are required to clarify optimal dosing strategies in specific types of cancer and the associated risks, to ensure therapeutic efficacy before it can be recommended for broad clinical use.

2. May help prevent and treat depression 

Another benefit of selenium, according to Nutrition Advance, is that it may help prevent and treat depression. This study found that for the adults who struggled with depression at the time, their symptoms lessened and they felt better by taking selenium. 

Research suggests that selenium may lower the risk of depression.

While it is important to remember that associations are not proof of causation, numerous studies show that higher selenium status has links to better mood;

In a study featuring 978 young adults, an optimal range of selenium (not too high or too low) was associated with reduced symptoms of depression.

A case-control study based on food questionnaires demonstrated a higher risk of depression when selenium intake is low.

In addition to the epidemiological research, randomized controlled trials also show potential benefits for treating depression.

For example, in one clinical trial, selenium supplementation during early pregnancy reduced the risk of post-natal depression.

Another study, this time from The Journal of Nutrition, explained how even though more reviews should take place concerning the topic, for now, studies are very promising concerning how selenium may help treat depression. 

Background: There is evidence that low, and possibly high, selenium status is associated with depressed mood. More evidence is needed to determine whether this pattern occurs in young adults with a wide range of serum concentrations of selenium.

Objective: The aim of this study was to determine if serum selenium concentration is associated with depressive symptoms and daily mood states in young adults.

Conclusions: In young adults, an optimal range of serum selenium between ∼82 and 85 μg/L was associated with reduced risk of depressive symptomatology. This range approximates the values at which glutathione peroxidase is maximal, suggesting that future research should investigate antioxidant pathways linking selenium to mood.

3. Can keep the brain healthy 

Ketovale says that selenium can improve brain function, and since the keto diet can help with brain function and energy as well, it’s easy to see how having selenium is essential. 

The antioxidant properties of selenium might also play a role in preventing cognitive decline in older people; oxidative stress is one of the contributing factors to diseases such as Alzheimer’s, Parkinson’s, multiple sclerosis and others.

In studies, normal levels of selenium and other micronutrients (such as DHA, folate, vitamin E, C, and B12) were associated with a lower incidence of Alzheimer’s disease.

Although the connection between the two is not yet fully understood, and therefore selenium supplementation is, again, not advised as a preventive strategy, getting enough micronutrients from your food is essential for minimizing the risk of various age-related diseases.

Science Direct did a study on Alzheimer’s disease and discovered that not only can this powerful mineral help prevent the disease, but it can also improve brain function. 

Abstract

Introduction

Alzheimer's disease (AD) patients are at risk of nutritional insufficiencies because of physiological and psychological factors. Recently, we showed the results of the meta-analyses indicating lower plasma levels of vitamins A, B12, C, E, and folate in AD patients compared with cognitively intact elderly controls (controls). Now, additional and more extensive literature searches were performed selecting studies which compare blood and brain/cerebrospinal fluid (CSF) levels of vitamins, minerals, trace elements, micronutrients, and fatty acids in AD patients versus controls.

Methods

The literature published after 1980 in Cochrane Central Register of Controlled Trials, Medline, and Embase electronic databases was systematically analyzed using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines to detect studies meeting the selection criteria. Search terms used are as follows: AD patients, Controls, vitamins, minerals, trace elements, micronutrients, and fatty acids. Random-effects meta-analyses using a linear mixed model with correction for age differences between AD patients and controls were performed when four or more publications were retrieved for a specific nutrient.

Conclusion

The current data show that patients with AD have lower CSF/brain availability of DHA, choline, vitamin B12, folate, vitamin C, and vitamin E. Directionally, brain nutrient status appears to parallel the lower circulatory nutrient status; however, more studies are required measuring simultaneously circulatory and central nutrient status to obtain better insight in this observation. The brain is dependent on nutrient supply from the circulation, which in combination with nutrient involvement in AD-pathophysiological mechanisms suggests that patients with AD may have specific nutritional requirements. This hypothesis could be tested using a multicomponent nutritional intervention.

4. Supports thyroid health 

If you’ve been struggling with keeping your thyroid healthy or are concerned that the keto diet may affect it, Medical News Today explains how selenium may be able to help with that. 

Selenium has an important role in producing and metabolizing thyroid hormone.

There is some evidence that women with higher selenium levels have fewer thyroid problems, but this has not been proven for men, and other studies have produced mixed results.

More studies are under way to decide whether selenium supplements might support thyroid health.

Low carb selenium options: 

Now that you know all about the many benefits selenium has to offer and how combined with the keto diet it can provide many health benefits, you should learn about what food sources contain selenium. Ketovale provides a great list below: 

These good sources of selenium that are also low in carbs which you can add to your meal plan are:

Brazil nuts

Fish and seafood, such as tuna, halibut, sardines, shrimp, mussels

Meat, such as pork (and ham in particular), beef steak, beef liver, ground beef

Poultry – chicken and turkey meat

Eggs

Mushroom

Spinach

Other sources of selenium, that are higher in carbs, include brown rice, oatmeal, grains, and beans, among others.

To learn more about the keto diet and what other minerals you should consider taking or making sure you’re getting enough, check out the Body Reboot book. The keto diet is helping dieters make new and positive health habits, and you can do the same! Get a free copy by helping us cover shipping. Visit this page to get a copy — you won’t regret it! 

Sources: Ketovale, NCBI: Radiat Oncol. 2014, Science Direct: Alzheimer's & Dementia: Translational Research & Clinical Interventions, September 2017, Medical News Today, Nutrition Advance, The Journal of Nutrition, January 2015