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!
What the researchers found
In this 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.
At the same time, their ‘good’ HDL-cholesterol increased 6 hours after eating the Brazil nuts and reached a stable level at 5 days.
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.
What’s going on?
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.
The monounsaturated and polyunsaturated fats have beneficial effects on cholesterol production in the liver, soluble fibre binds cholesterol to slow its absorption, while phytosterols 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:
| Biona Organic Dark Chocolate Brazil Nuts come in a handy, 80g bag. Enough for two healthy snacks if you have the willpower to stop half-way through!
Available from Amazon.co.uk
Similar products are available via Amazon.com
Home-Made Dark Chocolate Brazils
You 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.
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.