What are nuts?
Tree nuts are nutrient-dense, edible seed kernels encased in a hard shell – the most popular being almonds, hazelnuts, walnuts and pistachios as well as cashews, pine nuts, pecans, macadamias and Brazil nuts.
Although chestnuts (Castanea sativa) are tree nuts, they are different from all other common nuts because they are starchier and have a different nutrient profile. Often thought of as a ‘nut,’ peanuts are technically legumes just like peas and beans.
A 30g serving of mixed nuts provides:
- 174Kcal /722KJ
- 7.1g protein
- 14.7g fat
- 8.2g mono-unsaturated fat
- 3.5g poly-unsaturated fat
- 3.5g carbohydrate
- 1.9g fibre
- 28mg calcium
- 67mg magnesium
Each type of nut has different nutritional credentials, with some nuts being richer in certain nutrients – for example, Brazil nuts are especially rich in the mineral selenium.
Check out our top 10 healthiest nuts guide for more essential nutritional information.
Top 5 health benefits of nuts
1. Rich in protective antioxidants
Nuts contain compounds called polyphenols which have a protective effect in the body – they do so by helping to neutralise unstable molecules called free radicals which can cause damage.
2. Supports gut health
Nuts are a good source of fibre, with almonds, hazelnuts, pistachios and pecans being among the richest. Evidence suggests that a diet rich in fibre is associated with a lower risk of a number of chronic diseases including heart disease and diabetes. Increasing fibre in your diet can also support and regulate your digestive function.
The polyphenols in nuts also help to keep our guts healthy by benefiting the good bacteria that reside there – they do this by fuelling the bacteria, helping them grow and increase in number. In turn certain bacteria produce short chain fatty acids which provide numerous benefits for both our gut and our wider health.
3. May aid weight management
Nuts contain a number of nutrients and phytochemicals that we find difficult to digest, and this results in us being unable to absorb approximately 5 -15% of the calories in nuts. This explains why consuming a modest amount, such as a small handful of nuts, is inversely associated with body mass index (BMI).
This was illustrated by research which found that consuming nuts, in this case 55g of almonds, as part of a healthy diet had limited risk of weight gain. A study from 2013 also concluded that almonds, when consumed as a snack, help to reduce hunger.
4. High in fats
With the exception of chestnuts, nuts are a high fat food, with levels ranging from 46% in cashews and pistachio to 76% in macadamias. However, the type of fats are those which have proven benefits to health, being low in saturated fat, with higher levels of the heart-friendly mono-unsaturated fats and poly-unsaturated fats.
Walnuts are worthy of special mention because they have the highest content of the short chain omega-3 essential fatty acid, alpha lipoic acid (ALA), of all edible plants, making them a useful inclusion for those following a plant-focused diet.
5. Supports heart health
Including nuts in your diet has been associated with improved heart health. This is because consuming nuts helps maintain the health of the lining of the arteries, balances cholesterol and reduces the build-up of deposits called plaques, while also lowering the risk of blood clots.
The reasons why nuts support heart health are numerous, and include their beneficial fat profile being predominantly mono and poly-unsaturated, their fibre content, the existence of phytosterols as well as contributions of proteins such as l-arginine, which help relax blood vessels and lower blood pressure.
Are nuts safe for everyone?
Although a beneficial food for many, tree nuts are one of the eight most common food allergens and as a result can cause allergic reactions, including severe anaphylaxis. Cross contamination is a particular concern for those with a nut allergy and requires extra caution when eating away from home. Whole nuts may pose a choking risk, especially for the under-fives.
This article was last reviewed on 6 October 2021 by Kerry Torrens.
Kerry Torrens is a qualified nutritionist (MBANT) with a postgraduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the past 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.
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