Brazil Nuts Have Miraculous Effects On Cholesterol Balance

Brazil nuts are one of my favourite snacks, and I’ve just discovered a reason to eat more of them. A single ‘dose’ of just 4 Brazil nuts can significantly improve cholesterol balance – an effect that starts within 6 hours and lasts for at least 30 days!

Click here to see my recommended Brazil nuts on Amazon.

Brazil nuts lower cholesterol

In a fascinating study from the Journal of Nutrition and Metabolism, ten adults aged 23 to 34 years, were asked to eat different quantities of Brazil nuts on 4 separate occasions. They followed a balanced diet and fasting blood samples were taken at several points during the first day, at 48 hours, then 5 and 30 days after eating either no Brazil nuts, 5g Brazil nuts, 20g Brazil nuts or 50g Brazil nuts.

While their total cholesterol levels did not change, there was a rapid improvement in overall cholesterol balance after eating the 20g or 50g ‘doses’. Their circulating levels of ‘bad’ LDL-cholesterol levels fell significantly after 9 hours and reached a steady level at 48 hours.

LDL cholesterol

At the same time, their ‘good’ HDL-cholesterol increased 6 hours after eating the Brazil nuts and reached a stable level at 5 days.

HDL cholesterol

Astonishingly, both these beneficial changes were still present after 30 days and may have been sustained for longer as the study design meant testing was stopped at that point.

After another 30 day ‘wash out’ period, the next dose of Brazil nuts was tested in each volunteer and, by this stage, their cholesterol balance had returned to its baseline value.

This study seems to suggest that eating a single dose of 4 Brazil nuts might be enough to improve cholesterol balance for at least 30 days, and could reduce the risk of a heart attack or stroke by 20% or more.

How do Brazil nuts lower cholesterol?

Brazil nuts provide numerous nutritional goodies that are known to moderate cholesterol balance, including monounsaturated fats, polyunsaturated fats, antioxidants (selenium, polyphenols, vitamin E), plant sterols and soluble fibre.

Monounsaturated and polyunsaturated fats both have beneficial effects on cholesterol production in the liver, soluble fibre binds cholesterol to slow its absorption, while plant sterols block cholesterol absorption in the small intestines. Selenium, vitamin E and the polyphenols also prevent oxidation of circulation LDL-cholesterol so it is more readily carried back to the liver for processing.

Together, these effects could be expected to improve cholesterol balance, but for the action to remain statistically significant for 30 days or more seems extraordinary.

Brazil nuts and selenium

One thing I did note was that the researchers focussed in on selenium as Brazil nuts are the richest dietary source. A single Brazil nut supplies between 50mcg and 300mcg selenium depending on the selenium content of the soil in which the tree grows. Eating one or two Brazil nuts therefore provides the recommended daily amount (55mcg selenium per day in the EU and 70 mcg in the US).

Because of this focus, the study volunteers were asked to follow a balanced diet that excluded all other selenium-rich foods from their diets such as eggs, garlic, additional Brazil nuts and whole-wheat cereals. It’s possible that the sustained beneficial changes in cholesterol balance were due to these other changes to their normal diet – for example if they swapped wheat products for oat, barley or rye products.

Having said that, however, when the same people ate no Brazils, or only 5g Brazil nuts, their cholesterol balance did not significantly reduce despite the fact that they presumably maintained the same controlled diet. On the face of it, eating 20g or 50g of Brazil nuts was the only significant factor to change.

Brazil nuts reduce inflammation

Low grade inflammation is one of the leading causes of hardening and furring up of the arteries, and other age-related conditions. Another study based on these same adult volunteers, and published in the journal, Nutrition, showed that eating a single portion of brazil nuts (20 to 50 grams) also produced a significant decrease in the levels of inflammatory chemicals (eg IL-1, IL-6, TNC-alpha) – an effect that again lasted for at least 30 days after a single serving.

These findings need to be tested in a larger group of people. In the meantime, however, there are countless reasons to eat Brazil nuts regularly as a healthy snack – not just once a month, but several times a week.

Brazil nuts that are enrobed in dark chocolate will provide even greater health benefits. These are my current favourites – organic because these tend to provide higher levels of selenium and polyphenol:

 Home-Made Dark Chocolate Brazils

Chocolate brazil nutsYou can make these really easily at home, too.

30 large organic Brazil nuts, as fresh as possible

300g dark chocolate (at least 70% cocoa solids)


Crack the Brazil nuts and discard the shells.

Break the dark chocolate into squares and melt in a bain marie, over a pan of simmering water, stirring occasionally.

Add the Brazils to the melted chocolate and mix gently until thoroughly coated. Remove the Brazils one at a time, using two forks.

Place each nut on a silicone sheet or a tray lined with greaseproof paper.

Refrigerate for 30 minutes so the chocolate sets. Store in an airtight container and eat within a week (if you can make them last that long!)

Harvesting Brazil nuts

Brazil nuts are tree seeds from the South American rain forest. These trees can grow up to 50 metres in height and live for as long as 700 years.

A mature tree produces up to 300 fruit pods per year whose thick, woody outer shell and heavy weight (2.5kg or more) make them resemble a cross between a coconut and a cannon ball. Inside each pod are 10 to 25 delicious, creamy, Brazil nuts, each encased in a dark, thin shell.

Click here to see my recommended Brazil nuts on Amazon.

Watch a Brazil nut pod being opened here:

NB A note of warning – Brazil nuts are the second most frequent cause of nut allergy in the UK, after peanuts.

Image credits: gadini/pixabay;  ron wilson/;

About Dr Sarah Brewer

QUORA EXPERT - TOP WRITER 2018 Dr Sarah Brewer MSc (Nutr Med), MA (Cantab), MB, BChir, RNutr, MBANT, CNHC Cert IoD qualified from Cambridge University with degrees in Natural Sciences, Medicine and Surgery. After working in general practice, she gained a master's degree in nutritional medicine from the University of Surrey. Sarah is a registered Medical Doctor, a registered Nutritionist and a registered Nutritional Therapist. She is an award winning author of over 70 popular self-help books and a columnist for Prima magazine.

Please leave a comment or ask me a question ...

7 thoughts on “Brazil Nuts Have Miraculous Effects On Cholesterol Balance

    • DrSarahBrewer

      Sensible intakes are not associated with selenium toxicity. You may safely eat normal amounts of Brazil nuts without worrying. I like mine coated in dark chocolate. 🙂

    • DrSarahBrewer

      Hi James, Good question!
      Each Brazil nut weighs around 5g, so 30 = 150g.
      100g Brazil nuts contains 682 kcals, so 150g = 1023 kcals.
      300g dark chocolate provides 3 x 510kcals = 1530 kcals.

      The total for the recipe is 2553 kcals, which means that each thickly-chocolate coated Brazil provides around 85kcals, 34 kcals from the nuts itself. Chocolate and nuts both have a satiating effect, and you will tend to eat less at a later meal after indulging.

      You can read my overview of a cholesterol-friendly diet on my blood pressure site via this link:

  • Terri

    You haven’t mentioned the potential dangers of selenium overdose. Please edit the above to make it clear that more than 4 a day could be problematic.

    • DrSarahBrewer

      Hi Terri, Thanks for your comment. Those who watch the popular TV medical drama, House, may have seen Dr Gregory House diagnose a case of selenium toxicity from the overconsumption of Brazil nuts. In reality, no cases of selenosis from eating Brazil nuts has ever been reported in the medical literature (or not that I can find – do you know of any?). Selenium toxicity is usually associated with industrial accidents or taking excessive amounts in the form of supplements.

      One study looked for evidence of selenosis from populations eating a selenium-rich diet in the Brazilian Amazon where Brazil nuts are a staple, and where other crops are harvested/grown on selenium rich soils. Researchers found no clinical evidence of toxicity (brittle hair/nails, skin rash, garlic breath odour) despite high blood selenium levels. This is largely due to the fact that the selenium naturally present in Brazil nuts is in the form of selenomethionine (an amino acid) which is less toxic than the inorganic selenium salts found in some food supplements.

      High intakes of selenomethionine, the major form of selenium in food, can ‘escape’ into the tissue through the random incorporation of selenomethionine into proteins in place of methionine to delay the onset of toxicity. In contrast, inorganic selenium salts in some supplements cannot ‘escape’ by entering the methionine pool and cause toxicity at much lower tissue concentrations. With long term intakes, however, excessive intake of Brazil nuts could, theoretically lead to selenium toxicity.

      In one study, volunteers ate around 11 nuts (45g) Brazil nuts every day for 15 days. Their plasma selenium levels increased to 208 mcg/L. Although this was a short-term study, the blood levels achieved were significantly lower than the 1000 mcg/L concentrations associated with endemic selenosis.

      I doubt many people will eat 11 Brazil nuts or more per day, every day, long-term in the Western world, but a dailiy intake of 4 to 6 nuts is unlikely to lead to harm. I have emailed Prof Margaret Rayman the leading selenium researcher in the UK for her comments.

      The EU Scientific Committee on Food derived the Upper safe level for selenium taken as supplements based on two studies in which no adverse events occurred at an intake of 819mcg or 850mcg per day. It was decided to use an uncertainty factor of 3 to allow for the remaining uncertainties of the studies used in deriving a tolerable upper intake level of 300mcg per day for adults (from all sources of food, including supplements).

      I must admit that just eating 4 Brazil nuts seems a bit measily as a snack!

      • Terri

        Hi Sarah

        I’m glad you take this issue seriously and I will read the references you’ve posted with interest. It was actually a conversation with Prof Rayman that made me think that there should be a little caveat to your article, although it may have been the other minerals (barium, strontium and radium) that she was referring to, rather than selenium itself.

        I think when it’s possible for selenium (and other minerals) to accumulate in tissues, an excess of caution may be worthwhile as reversal may be more difficult.

        Four does seem rather measly, and of course depends on exactly where they were grown because of the great variation in selenium content. I think I will stick to the random allocation I get in my muesli, as I have no reason to think I’m deficient (and dark chocolate covered ones are far too moreish).