Brazil Nuts

Brazil Nuts in more detail

Brazil nuts are the only food in this encyclopedia where the sensible advice is to eat fewer of them. At 254 µg of selenium per 100 g — about 339% of the adult reference intake — two or three nuts cover a day's requirement, and a large handful eaten daily can genuinely push you past the safe upper limit.

The selenium comes from the soil of the Amazon basin, and the tree, Bertholletia excelsa, is exceptionally good at concentrating it. Because soil selenium varies enormously by region, so does the content of individual nuts — the figure on this page is an average, and a particular nut might carry several times more or less. That variability is precisely why using Brazil nuts as a deliberate daily selenium supplement is a worse idea than it sounds.

Chronic excess selenium causes selenosis: brittle hair and nails, hair loss, a garlic odour on the breath, and in severe cases nerve damage. The NHS advises against taking more than 350 µg a day from food and supplements combined. A handful of Brazil nuts is roughly that on its own.

Worth knowing about the supply chain, because it is genuinely unusual: Brazil nuts cannot be farmed successfully. The tree depends on large-bodied orchid bees for pollination and on agoutis to open the fruit and disperse the seeds, and neither survives in a plantation. Essentially all commercial Brazil nuts are wild-harvested from standing rainforest — which makes the trade one of the few that gives an intact forest direct economic value.

Nutrients worth knowing about

Per 100 g, this page's panel shows Selenium at 254 µg (about 339% of the adult reference intake), Vitamin E at 7.18 mg (180%), Copper at 1.76 mg (147%), Magnesium at 410 mg (137%), Phosphorus at 590 mg (107%), Manganese at 1.2 mg (86%), Vitamin B1 (Thiamin) at 0.67 mg (67%), Zinc at 4.2 mg (44%), Calcium at 170 mg (24%), Vitamin B6 (Pyridoxine) at 0.31 mg (22%), Potassium at 660 mg (19%) and Iron at 2.5 mg (17%).

Two other figures set Brazil nuts apart from the rest of this section. They are the most energy-dense entry here at 683 kcal per 100 g, and at 17.41 g of saturated fat per 100 g they are much more saturated than Hazelnuts or Almonds — roughly a whole day's reference intake for a woman in 100 g.

Other nuts

• Almonds
• Hazelnuts
• Macadamia Nuts
• Cashew Nuts
• Pistachio Nuts
• Pumpkin Seeds