Selenium & Deficiency On A Paleo Diet?

Despite following a healthy Paleo Diet, if not enough attention is paid to getting a wide variety of different foods, deficiencies are still possible. I've been looking into a number of the more common deficiencies to understand how to tweak your Paleo diet to ensure deficiencies don’t occur. This week, I've been looking into Selenium.

What is Selenium?

It is a trace mineral that is only needed in small amounts but it is essential for good health. Some of the functions selenium performs include helping regulate the thyroid gland, assisting the immune system and protecting our cells from the damage caused by free radicals. In dietary terms the selenium content of plant foods are proportionate to the soil concentration of selenium where the food was grown.

These days severe selenium deficiency in adults is very rare, particularly when following a healthy Paleo diet, but minor deficiencies do occur and that can have some rather unpleasant effects on our health.

Some of the selenium deficiency symptoms include polyneuropathy and muscle damage that can look a lot like the side effects of statins. Selenium supports the synthesis of the thyroid hormone and is needed for the conversion of the T4 thyroid hormone into the active T3 hormone. As a result deficiency can look like hypothyroidism.

So, how do you become Selenium deficient?

It can be as simple as just not eating enough Selenium rich foods, or if you suffer from an intestinal disorder such as Celiac, Chron’s disease or an ulcerative colitis these can all reduce the body’s absorption of selenium from foods.  While deficiency does not cause those illnesses it can make the body more susceptible to illnesses caused by biochemical or infectious stress due to the role selenium plays in the immune system.

It can also be due to a lack of selenium in the soil where your food has been grown. Just like other minerals, it must be in the soil or it won’t be present in the food grown in the soil.

Where can you get it from, in keeping with the Paleo diet?

You can find good sources of selenium in lamb, turkey, prawns, salmon, cod, crimini and shiitake mushrooms, kidney’s,  egg yolks and halibut.

Keeping your thyroid healthy is important with many people dealing with thyroid conditions such as hypothyroidism. There have been many research studies that have shown the benefits of selenium supplements when treating some thyroid conditions. One such study has found that selenium supplements have reduced the inflammation damage to the thyroid tissues. While studies have shown that selenium supplements can help prevent thyroid tissue damage there is more research needed to determine the long-term effects.

Making sure that your selenium intake is at its peak may give both your thyroid and immune system that little boost it needs to help function better. Whether you use supplements or include more selenium-rich foods in your diet it is important for those who are managing a thyroid condition to make sure their selenium intake is adequate.

As important as it is not to be deficient, it’s also important not to go over board. Over increasing your intake of selenium over long periods of time can lead to complications including garlic breath odour, hair loss, mild nerve damage, gastrointestinal upsets, white blotchy nails, irritability and fatigue.

The best option is to include selenium rich foods in your diet. While high in omega-6 fats it takes just a couple of Brazil nuts a day to boost your immune function and improve the amount of selenium in your diet.

Have you given much consideration to your Selenium intake? Which minerals and vitamins are you most concerned about, in your Paleo diet?

How Much Selenium Do You Actually Need?

The recommended daily intake for selenium varies slightly between countries, but for adults in Australia, the National Health and Medical Research Council recommends 70 micrograms per day for men and 60 micrograms per day for women. Pregnant and breastfeeding women may require slightly more. Since it's a trace mineral, you don’t need huge quantities – but consistency matters.

The Best Paleo-Friendly Sources of Selenium

While Brazil nuts are famously rich in selenium (just one or two nuts can provide well over 100% of the daily requirement), they aren’t your only option. For those following a more varied or strict Paleo approach, it’s helpful to include a mix of selenium-rich options:

• Wild-caught fish – Tuna, sardines, salmon, and especially cod are excellent sources.
• Shellfish – Oysters, prawns, and mussels contain respectable selenium levels.
• Grass-fed meats – Lamb liver, beef kidney, and muscle meat offer both selenium and other vital micronutrients.
• Pasture-raised eggs – Especially the yolks, which are rich in selenium and choline.
• Crimini and shiitake mushrooms – A great option for those after more plant diversity.

Rotating these foods through your weekly meals can help ensure you stay on top of your selenium intake without relying too heavily on just one source.

Selenium Absorption and Synergy with Other Nutrients

It’s not just how much selenium you eat – it’s how well you absorb and utilise it. Selenium works synergistically with other nutrients, particularly:

• Iodine – Both are essential for thyroid function. If you’re low in one, the other may not be as effective.
• Vitamin E – Helps reduce oxidative stress alongside selenium. Good fat sources like almonds and sunflower seeds (if tolerated) can help.
• Protein – Since selenium is incorporated into selenoproteins, an adequate protein intake helps support this function.

If you're supplementing or relying on specific foods, consider whether you're supporting those nutrients in a broader context, too.

Soil Depletion and Selenium Content in Australia

Australia’s soils are known to be naturally low in selenium – particularly in the southern and eastern regions. This means produce grown in these areas may have lower levels, even if they would normally be a good source. For example, broccoli grown in selenium-rich soil may provide a decent amount, whereas the same broccoli from another farm may contribute very little.

Because of this, it’s a good idea to diversify the origins of your food when possible or choose animal products where the feed is fortified with selenium (common in ethical Australian livestock farming). Buying from farmers who can tell you about their soil quality and animal diets can make a meaningful difference.

What About Supplementing?

If you suspect your intake is low – perhaps due to autoimmune thyroid issues, absorption problems, or limited food variety – a low-dose selenium supplement may help. But proceed with caution. Supplements often provide 150–200 micrograms per dose, which can be excessive if you're already consuming selenium-rich foods.

Ideally, work with a health practitioner to test your selenium levels before supplementing long term. Hair mineral analysis and blood serum tests can both provide useful data.

Signs You May Be Getting Too Much

Although rare, selenium toxicity (known as selenosis) can happen – particularly from supplements or eating large quantities of Brazil nuts daily. Some symptoms to watch for include:

• Brittle hair or nails
• Digestive discomfort
• Fatigue or irritability
• Unusual breath odour (often described as “garlic-like”)

Again, balance is key. Aim to meet your needs through whole foods, monitor symptoms, and seek testing if you’re unsure.

How to Add More Selenium-Rich Foods to Your Paleo Meals

Here are a few simple, Paleo-friendly ideas to boost selenium naturally in your week:

• Breakfast: Add two eggs with sautéed mushrooms and spinach in ghee or olive oil.
• Lunch: A salad with grilled salmon, avocado, and a boiled egg. Top with a citrus olive oil dressing and a sprinkle of sesame seeds.
• Dinner: Grass-fed lamb chops with roasted root vegetables and a side of steamed broccoli.
• Snacks: One or two Brazil nuts, or a small portion of prawns with lemon and herbs.

Takeaway

While selenium deficiency isn’t especially common on a nutrient-dense Paleo diet, it’s still worth being aware of – especially if you’re dealing with thyroid issues or have limited variety in your meals. Focus on diverse, whole food sources, be mindful of soil quality and absorption, and only supplement if there’s a genuine need.