Are Brazil Nuts Good for Erectile Dysfunction?

Brazil nuts may support vascular health through their selenium content, but there is no clinical evidence that eating them improves erectile dysfunction. The link is plausible in theory, but it has never been tested directly in men with ED. Think of them as a sensible addition to your diet, not a treatment.

Why selenium gets mentioned alongside ED#

Selenium is a trace mineral that helps protect blood vessel walls from oxidative damage. Healthy blood vessels are essential for an erection, which depends on adequate blood flow and nitric oxide production. When oxidative stress impairs endothelial function (the inner lining of blood vessels), erections become harder to achieve and maintain.

The UK is one of the worst places in Europe for dietary selenium. British soils are naturally low in selenium, so crops grown here contain very little. Average selenium intake for men in the UK is around 55 mcg per day, below the EU reference intake of 70 mcg. This is genuinely relevant: UK men are more likely to fall short of adequate selenium than men in North America, where most of the nut-and-ED articles originate.

Brazil nuts are the richest food source of selenium by a significant margin. A single nut contains roughly 68–90 mcg, though this varies considerably depending on where the nuts were grown. Bolivian-sourced Brazil nuts tend to contain less selenium than those from Brazil itself, and UK food labelling does not require selenium content to be listed, so you cannot easily verify what you are buying.

How many Brazil nuts is safe to eat?#

The tolerable upper intake for selenium in adults is 400 mcg per day (European Food Safety Authority). Eating 2 to 3 Brazil nuts provides roughly 140–270 mcg, which comfortably covers your daily requirement with a reasonable safety margin. Four or more per day consumed regularly starts to push intake towards the upper limit, and chronic overconsumption can cause selenosis: hair loss, brittle nails, fatigue and nerve damage.

So the practical portion is 2 to 3 nuts a day, not a handful. They are not a food you eat in large quantities.

The SELECT trial and why selenium supplements are a different story#

Some men assume that if Brazil nuts might help, a selenium supplement would work better. The opposite is likely true for men with adequate selenium levels. The SELECT trial, a large US randomised controlled trial, found that selenium supplementation did not reduce prostate cancer risk and may have increased it in men who already had sufficient selenium. SELECT did not measure erectile function or cardiovascular outcomes, so it cannot tell us whether selenium helps or harms in those areas. What it does show is that taking extra selenium when you are not deficient is not a guaranteed benefit and may carry risks.

Food sources carry lower risk than supplements because the dose is harder to overshoot. Unless a blood test shows you are genuinely selenium deficient, Brazil nuts as a food are the safer and more practical route.

Which nuts have stronger evidence for ED?#

Pistachios are the only nut with a small dedicated clinical trial. A 2011 study by Aldemir and colleagues, published in the International Journal of Impotence Research, found that men with ED who ate 100 g of pistachios daily for three weeks showed improved erectile function scores and better lipid profiles. The study was small (17 men) and unblinded, so the results cannot be taken as definitive, but they are at least direct.

A 2019 randomised controlled trial of 83 men, by Salas-Huetos and colleagues and published in Nutrients, found that 60 g of mixed nuts per day (walnuts, almonds and hazelnuts) over 14 weeks improved self-reported sexual function compared to a Western diet without nuts. Again, this was a healthy population, not men with established ED, and the outcome measure was a questionnaire rather than a physiological test.

Brazil nuts have no equivalent trial. Their relevance to ED is extrapolated from selenium's role in vascular biology, which is not the same as clinical evidence.

A note on medication interactions#

If you are already taking sildenafil or tadalafil, eating a handful of Brazil nuts will not interfere with how those medicines work. Nuts are not contraindicated with PDE5 inhibitors. If you take warfarin, note that Brazil nuts are not a meaningful source of vitamin K, so they are not a recognised cause of INR changes. The foods that matter are those rich in vitamin K, such as leafy green vegetables. Keep your overall diet consistent, and tell your anticoagulation clinic or pharmacist about any major dietary changes.

Men on nitrate medicines for angina should not take PDE5 inhibitors regardless of diet. ED in that group warrants a conversation with a GP to explore safe options.

What actually moves the needle on ED#

ED is often an early warning sign of cardiovascular disease. NICE Clinical Knowledge Summaries on erectile dysfunction advise assessing cardiovascular risk in men presenting with ED, including checking blood pressure, cholesterol and blood glucose. Addressing those underlying risks, alongside regular exercise and not smoking, has more evidence behind it than any dietary supplement.

For men who want effective treatment, licensed options such as sildenafil and tadalafil have a large body of RCT evidence behind them. NHS GPs can prescribe generic sildenafil, making it far more affordable than many men realise.

If you are exploring the broader role of diet in sexual health, our guide on foods that can help boost your libido naturally covers the wider evidence, and our erectile dysfunction treatment hub explains the licensed options available in the UK.