Which nut is the healthiest? As royal nutritionist swears by Brazil nuts for hair loss, experts reveal the type you should eat every day

Nuts have long had a reputation as diet wreckers – too fatty, too calorific, too moreish. But Gabriela Peacock, nutritionist to the royals, is turning that idea on its head. 

If you want a quick and easy way to boost your health, look no further than the humble Brazil nut, she says. 

These nuts pack impressive benefits, from bolstering the immune system and protecting cells from damage to warding off heart disease – as one of the richest dietary sources of essential vitamin selenium. 

But according to Ms Peacock, whose clients include Princess Beatrice, one of their most coveted benefits is their potential to promote healthy hair growth and prevent breakage.

And Brazil nuts are just the beginning. A recent study found that eating 50g of walnuts at breakfast can help young adults perform better on memory tests. 

Other studies have linked nuts to lower rates of diabetes and depression, as well as boosted fertility and improved brain function in later life.

But the average Briton only eats 6g of nuts daily. As a result, warn experts, we could be missing out on essential vitamins and minerals, healthy fats and a daily protein boost. 

To find out which varieties deliver the most benefits, and how much we should really be eating, we asked top nutritionists for advice…

Why nuts won’t make you fat 

At first glance, it makes sense to be cautious. A small handful of almonds contains more than 150 calories, while Brazil nuts are among the fattiest plant foods you can buy.

But research shows those calories don’t behave in the same way as the empty kind found in biscuits or crisps.

Studies by the US Department of Agriculture have shown that we don’t absorb all the fat in nuts. Around a fifth of the calories in almonds and walnuts never make it into the bloodstream, because the fat remains locked inside their fibrous cell walls and passes straight through the digestive system.

‘Nuts are incredibly nutrient-dense, but the body doesn’t utilise every calorie they contain,’ says registered nutritionist Grace Kingswell. ‘That’s why they don’t have the same impact on weight gain as other high-fat foods.’ 

Their unique mix of protein, fibre and unsaturated fat also keeps hunger in check and stabilises blood sugar – meaning people are less likely to reach for snacks later.

A review of weight-loss trials last year even found that participants who included nuts in their diets sometimes lost more weight than those who cut them out.

In other words, far from being diet-wreckers, nuts can actually support weight control when eaten in sensible portions – roughly 30g a day, or a small handful.

 Walnuts boost brainpower

Walnuts are especially rich in omega-3 fatty acids, protein and polyphenols – which is why they are often referred to as ‘brain food’. 

A University of Reading study found that when young adults added just 50g of walnuts to breakfast, they experienced faster reaction times and sharper memory throughout the day. 

Omega-3 fats are already thought to help shield against Alzheimer’s disease and stroke, and the Reading trial was the first to show even a single serving of walnuts could deliver a measurable mental boost.

Brazil nuts pack a punch

Brazil nuts are one of the richest sources of selenium, a key nutrient for thyroid health. 

Ms Peacock said: ‘Selenium is a really good antioxidant. It’s another kind of mineral which you need in your diet. It’s very important for your hair.’ 

According to the NHS, men need around 75mcg per day, while women need 60mcg.  

Just one to two nuts per day provide a full day’s requirement – but Ms Kingswell warns it’s important not to overdo it, as too much selenium can be toxic. 

Despite being high in saturated fats, Brazil nuts also contain magnesium, copper and phosphorus, and a small study even suggested a single monthly serving could lower cholesterol faster than statins. 

Public health nutritionist Dr Emma Derbyshire adds that older adults in particular often fall short on selenium, making Brazil nuts a useful addition in moderation.

Almonds help the gut

Almonds stand out for fibre, with a 30g serving providing around 4g – helping to boost gut health, immunity and digestion. 

This creates a more diverse gut microbiome which helps promote regular bowel movement and proper digestion. Adequate fibre intake also helps us feel fuller for longer, lowering the risk of over-eating. 

Almonds are also rich in vitamin E, with a 30g portion containing just over 7mcg – almost double the daily recommended intake for adults. 

Several studies have even linked higher vitamin E intake to lower rates of heart disease, Alzheimer’s and cancer, although more research is needed to confirm these findings. 

Pecan nuts   

Pecans can help keep heart disease at bay, by lowering levels of so-called ‘bad’ cholesterol that builds up in the arteries and increases the risk of heart attack and stroke. 

One study, published in the journal Nutrients – which examined more than two decades of research – found that those who regularly ate between 30g to 60g of pecans a day had lower (LDL) cholesterol.

This is partly thanks to the nut’s high vitamin E content, which helps prevent LDL cholesterol from becoming toxic and proinflammatory. 

Nut butters under scrutiny

Nut butters have surged in popularity. Almond, hazelnut and pistachio butters are marketed as healthier swaps for peanut butter, and indeed they provide protein, fibre and good fats. 

But not all spreads are equal. ‘There are a lot of nut butters on the market that are full of palm oil or sugar,’ says Ms Kingswell. 

‘It’s important to look for one that’s 100 per cent nuts, with maybe just a pinch of salt.’ 

Whole nuts, she adds, remain slightly higher in fibre and may be better for blood sugar control.

Because nut butters are so concentrated, it’s easy to eat far more than you realise – a tablespoon can contain the equivalent of several handfuls of nuts, meaning calories mount quickly. 

Easy ways to add them in

Still, for most people, the benefits far outweigh the drawbacks. 

Dr Derbyshire says: ‘Nuts are great as they are, but they can be paired to further improve nutrient absorption and balance.’ 

Pairing them with berries or oranges, she explains, enhances the iron absorption from nuts, while sprinkling them on top of yogurt can provide ‘an array of complementary amino acids, known as protein synergy’.

Ms Kingswell added that activating nuts – which involves soaking them overnight and then slowly dehydrating them in the oven – can make the nutrients more bioavailable and easier to digest. 

Because they are naturally low in carbohydrates but high in fibre and healthy fats, nuts also make an ideal snack for people looking to manage blood sugar or improve their diet.

‘Despite decades of diet advice and campaigns, we are still not better off when it comes to our nutrition and this includes brain and immunity nutrients,’ says Ms Kingswell. 

‘We need to get back to the basics of snacking on and cooking nutrient-dense fresh foods and minimising sugary, fatty snacks. 

‘In an ideal world, people should be able to get all the nutrients they need from their diets.’