June 2022. About this episode: Nutrition is a crucial foundation for performance. It underpins everything from preparation via fuelling and…
Like all tree nuts, walnuts are packed with vitamins, minerals, antioxidants and phytochemicals beneficial to health. Regularly eating nuts has been shown to contribute to heart health, reduce overall mortality and the risk of developing type 2 diabetes, assist with weight management, reduce the risk of cancer, improve sperm quality, reduce depression and overall promote good health.
A 30g serve is around 10 whole walnuts.
|Nutrient||Per 100g||Per 30g|
|Total fat (g)||69.2||20.8|
|Saturated fat (g)||4.4||1.32|
|Monounsaturated fat (g)||12.1||3.63|
|Polyunsaturated fat (g)||49.6||14.9|
|Omega 3 ALA||6280||1884|
|Dietary fibre (g)||6.4||1.92|
|Niacin (mg eq)||5||1.5|
|Folate DFE (ug)||70||21|
|Vitamin B6 (mg)||0.4||0.12|
|Vitamin E (mg)||2.6||0.78|
In addition to the health benefits that all tree nuts provide, walnuts nuts have been associated with:
- Moderate to highly consistent favourable effects on total cholesterol, LDL cholesterol and LDL:HDL cholesterol ratio .
- Better results in tests measuring cognitive function, attention capacity and working memory in children whose mothers ate more nuts (including walnuts) during the first trimester of pregnancy .
- Supporting brain health: via protecting against death of specific types of brain cells important for memory, and also improve learning and memory formation [3-5]. Associations have also been found for lowering the prevalence and frequency of depression symptoms .
In a US-based randomised controlled trial, with crossover design, published in 2022, 90 participants received a control diet or a walnut-supplemented diet (where walnuts made up around 12% of daily energy intake) for a 6-month period, then switched (8). Diets in the walnut period had significantly higher plant protein, total fat, total PUFA, linoleic acid, alpha-linoleic acid, and dietary fibre. Most mineral levels were also higher, particularly calcium, phosphorus, magnesium and zinc. The study also found walnuts partially displaced non-alcoholic beverages, desserts, candy, sugar and sweets in the diet.
What makes walnuts unique?
- Walnuts are one of the few plant sources of omega-3 fats, in the form of alpha-linolenic acid (ALA). Research has shown that ALA can reduce inflammation – an important factor in the development of chronic disease .
- They are rich in polyphenols – powerful antioxidants that protect the body’s tissues from damage due to oxidation .
- Walnuts contain predominantly polyunsaturated fats.
- Walnuts are a source of polyunsaturated fats and omega 3 ALA’s, and are naturally low in sugar and sodium.
- They are a source of copper, magnesium, manganese, niacin and folate.
Where they are grown?
Walnuts are grown more widely (geographically) across Australia than some other tree nuts, and particularly thrive in cool-temperate and semi-arid regions. Major production areas are largely in south-east Australia in:
- New South Wales: the Riverina near Griffith and Leeton
- Tasmania: on the east coast of Tasmania
- Victoria: the Goulburn Valley near Shepparton and the Murray Irrigation near Kerang and Swan Hill.
Small-scale orchards are scattered in the Ovens Valley, Gippsland and Central region of Victoria; Southern Highlands and Central Tablelands (New South Wales); the Adelaide Hills and Riverland regions (South Australia); and in the south west (Western Australia).
In 2021, Australia produced more than 6,350 tonnes of walnut kernel (around 12,700 tonnes in shell), from more than 1.2 million walnut trees. The walnut industry is very young in Australia, with 90% of our walnut trees planted within the last 15 years.
A native of the northern hemisphere, major supplies to Australia come from California, USA and China, but they are also grown in Chile and Eastern Europe.
Forms and best eaten with…
- Walnuts are usually available either in their shell, or as raw, unsalted nuts.
- They make great additions to muffins and cakes, like banana bread, carrot cakes and zucchini loafs
- Walnuts also make great pesto when combined with basil, garlic, olive oil and parmesan cheese.
Remove nuts from plastic bags and store them in an airtight container in the refrigerator or freezer. Nuts can be refrigerated for up to four months and frozen for up to six months.
Remember, bringing nuts back to room temperature before eating can help them taste nuttier.
- Neale, E., et al., The effect of nut consumption on heart health: an updated systematic review of the literature. 2018. Nuts for Life, unpublished.
- Gignac, F., et al., Maternal nut intake in pregnancy and child neuropsychological development up to 8 years old: a population-based cohort study in Spain. Eur J Epidemiol, 2019.
- Carey, A.N., et al., The ability of walnut extract and fatty acids to protect against the deleterious effects of oxidative stress and inflammation in hippocampal cells. Nutr Neurosci, 2013. 16(1): p. 13-20.
- Hicyilmaz, H., et al., The effects of walnut supplementation on hippocampal NMDA receptor subunits NR2A and NR2B of rats. Nutr Neurosci, 2017. 20(3): p. 203-208.
- Pribis, P., et al., Effects of walnut consumption on cognitive performance in young adults. Br J Nutr, 2012. 107(9): p. 1393-401.
- Arab, L., R. Guo, and D. Elashoff, Lower Depression Scores among Walnut Consumers in NHANES. Nutrients, 2019. 11(2).
- Zhao, G., et al., Dietary alpha-linolenic acid reduces inflammatory and lipid cardiovascular risk factors in hypercholesterolemic men and women. J Nutr, 2004. 134(11): p. 2991-7.
- Natto, Z.S., et al., Food and nutrient displacement by walnut supplementation in a randomized crossover study. Nutrients, 2022. 14:1017.
- Amen, R., et al. The effect of walnut supplementation on dietary polyphenol intake in the Walnuts and Healthy Aging Study (WAHA). Curr Developments Nutr, 2022. 6(Supp 1):265. https://doi.org/10.1093/cdn/nzac053.006
Published July 17, 2019