What are walnuts?
Walnuts are wrinkly, globe-like nut that is the fruit of the walnut tree. They grow in a hard shell that, when opened, reveals the walnut. This is then split in two, which is why you commonly see them as flat segments. Walnuts are usually eaten raw or roasted.
Nutritional value of walnuts
A 30g serving (about 14 halves) contains approximately:
- 206 kcal / 851Kj
- 4.4g Protein
- 20.6g Fat
- 14.0g Poly-unsaturated fat
- 1.4g Fibre
- 135mg Potassium
- 48mg Magnesium
- 28mg Calcium
- 114mg Phosphorus
- 20mcg Folate
Like all nuts, walnuts are rich in fat but mainly in the form of polyunsaturated fats, as such, they are a valuable vegetarian source of the essential fatty acid omega-3.
What are the 5 main health benefits of walnuts?
1. Good for the brain
Walnuts contain important phytochemicals, as well as high amounts of polyunsaturated fats that offer potential benefits for both brain health and function. Omega-3 fatty acids play a part by helping reduce oxidative stress in the brain but also by helping to improve brain signalling and neurogenesis, which is how new neurons are formed.
As well as high levels of beneficial fats, other important nutrients such as vitamin E, folate and the protective phytochemical, ellagic acid, are all found in walnuts, and contribute to their neuroprotective and memory-enhancing properties.
Omega-3 fatty acids are important for the development and function of the central nervous system. Promising research and clinical evidence indicate that omega-3 fatty acids could well play a role in certain mood disorders.
Although a study specifically evaluating the effect of walnuts reported mixed findings, the inclusion of walnuts in the diet of non-depressed, young healthy males did appear to improve mood.
3. Heart healthy
The Journal of Nutrition reports that consumption of walnuts may reduce the risk of cardiovascular disease, and that walnut oil provides more favourable benefits to endothelial function, which is the lining of the inside of our blood and lymphatic vessels. There has also been researched into whole walnuts, and how they can improve cholesterol levels and markers for inflammation, which is also connected to a reduced risk of heart disease.
A study by the British Journal of Nutrition found that those who consumed nuts more than four times a week reduced their risk of coronary heart disease by as much as 37 per cent.
4. May support weight loss
There has been some evidence to demonstrate that consuming walnuts in the place of other foods do not cause weight gain, even though they are energy-rich, offering a great snack alternative for those looking to manage their weight.
5. Support a healthy digestive system
A recent animal study has shown consuming walnuts can enrich the gut microbiota, the community of beneficial microbes which live in our intestines, and in particular increase strains of beneficial probiotic bacteria. This has been repeated in humans with reports of increases in beneficial strains and especially those which produce butyrate, a by-product which supports the health of the gut.
Are walnuts safe for everyone?
People with an allergy to tree nuts should avoid walnuts. Allergy symptoms normally develop within minutes, and you should see your GP if you experience an adverse reaction. However, if this develops into a severe reaction, known as anaphylaxis, it is a medical emergency and immediate help should be sought.
Young children, some older people and those with a problem swallowing should avoid whole nuts due to the risk of choking.
Visit the NHS website to read more about allergies.