Selenium on Keto: Brazil Nuts and Beyond

The ketogenic diet shifts how we obtain essential micronutrients, with selenium being particularly crucial for thyroid function and antioxidant defence. Brazil nuts stand out as one of the most concentrated food sources, but their high carb content requires careful portioning.

Why selenium matters

Selenium supports over two dozen selenoproteins, including glutathione peroxidase, which protects cells from oxidative damage. A 2013 meta-analysis found that very-low-carbohydrate diets may alter mineral requirements compared to standard diets (Bueno et al., 2013). Those restricting carbs often consume fewer selenium-rich grains and legumes, making Brazil nuts a strategic choice.

Brazil nuts by the numbers

Two medium Brazil nuts (about 8g) provide roughly 200% of the UK Reference Nutrient Intake (RNI) for selenium. At Tesco, a 200g pack costs £3.50, working out to 14p per daily serving. The nuts contain 3.5g net carbs per 100g, so portion control matters when staying under 20-50g daily carbs. keto electrolyte balance also depends on proper mineral intake.

What this means in practice

For UK keto followers, Brazil nuts offer a practical solution:

Buy from Lidl (£2.99 for 200g) or Sainsbury’s (£3.25)
Store in the freezer to prevent rancidity
Consume 1-2 nuts 3x weekly to avoid excess

Alternatives include:

Tuna (50μg per 100g)
Eggs (20μg each)
Chicken liver (40μg per 100g)

Potential risks

Exceeding 400μg daily selenium long-term may cause selenosis, with symptoms like hair loss and brittle nails. A 2017 review noted that nutrient-dense keto diets typically provide adequate minerals without supplementation (Kosinski & Jornayvaz, 2017). Those with thyroid conditions should consult their GP before adjusting intake.

Frequently asked questions

Can I get enough selenium without Brazil nuts?

Yes. A 150g portion of salmon provides about 40μg selenium, while two eggs offer 20μg. Most UK meats contain 10-30μg per 100g.

Are Brazil nuts too high in carbs for keto?

Not in moderation. Two nuts contain under 1g net carbs. Spread consumption across the week to minimise impact.

Do roasted Brazil nuts lose selenium?

Dry roasting at 160°C causes minimal selenium loss. Avoid oils or high temperatures above 200°C.

The bottom line

Brazil nuts provide a cost-effective selenium solution for keto diets when consumed in controlled portions. Pair them with eggs, seafood, and organ meats for balanced mineral intake. If you’d rather not do the macro maths yourself, the Keto Dieting app does it for you on Google Play and the App Store.

Educational only — not medical advice. This article is for general information. Speak to your GP before changing your diet, especially if you have type 1 or type 2 diabetes, kidney or liver disease, are pregnant or breastfeeding, or take medication for blood pressure, cholesterol, or blood glucose.

References

Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T (2013). Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. British Journal of Nutrition. https://doi.org/10.1017/S0007114513000548
Kosinski C, Jornayvaz FR (2017). Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies. Nutrients. https://doi.org/10.3390/nu9050517