The Health Benefits of Walnuts

September 1, 2008

walnutsWalnuts are believed to have originated in Persia or France where petrified shells of roasted walnuts have been discovered dating back 8,000 years from the Neolithic period.

Walnuts (Juglans) were considered food for the gods in ancient Rome and named Juglans regia (Jupiter’s royal acorn ) in honor of Jupiter. Juglans is derived from Jovis glans, meaning Jupiter’s acorn, and regia meaning royal.

Walnuts should not be shelled until ready to use, and once shelled can be refrigerated in a tightly sealed container for up to one year

The United States is the world’s top producer of walnuts, with California providing more than 50% of worldwide walnut supply.

Health Benefits of Walnuts

Nutrients in Walnuts

Walnuts are an excellent source of antioxidants and the minerals manganese, copper, phosphorus, and magnesium. Walnuts are a very good source of protein, dietary fiber, the amino acid arginine, omega-3 fatty acids and alpha-linolenic acid (ALA). Walnuts are unique because they are rich in n-6 (linoleate) and n-3 (linolenate) polyunsaturated fatty acids.

Reduced Risk of Heart Disease

Alpha-linolenic acid (ALA) is an n-3 polyunsaturated fatty acid found mainly in plant sources, especially walnuts. There have been numerous clinical studies that suggest that alpha-linolenic acid (ALA) intake reduces the incidence of coronary heart disease. Alpha-linolenic acid (ALA) in walnuts may reduce cardiovascular risk through a variety of biologic mechanisms, including platelet function, inflammation, endothelial cell function, arterial compliance, and arrhythmia.

Walnuts also contain other potentially cardioprotective constituents including phytosterols, tocopherols, squalene and the amino acid arginine.

Walnuts are rich in the antioxidant ellagic acid, and in a preliminary study, it has been suggested that the ellagic acid present in walnuts has a high anti-atherogenic implicating the beneficial effect of a walnut-enriched diet on cardio protection.

Cholesterol Reduction

A diet supplemented with walnuts has been shown to significantly reduce total and LDL cholesterol levels.

Reduced Risk of Alzheimer’s Disease

Fibrillar amyloid beta-protein (Abeta) is the principal component of amyloid plaques in the brains of patients with Alzheimer’s disease. Over 90% inhibition of Abeta fibrillization from walnut extract was observed in a laboratory study, suggesting that walnuts may reduce the risk or delay the onset of Alzheimer’s disease by maintaining Abeta in the soluble form.

Weight Loss

There is some concern amongst dieters about incorporating walnuts into a weight loss program due to the high fat content. A 12-month study of 90 participants has demonstrated that weight gain from daily consumption of walnuts has been shown to be insignificant.

Moderate amounts of oxalate are found in walnuts, and should be consumed in moderation by individuals with a history of oxalate-containing kidney stones. References:
1. The Encyclopedia of Healing Foods by Michael Murray, Joseph Pizzorno, and Lara Pizzorno.
2. Benders’ Dictionary of Nutrition and Food Technology.
3. USDA National Nutrient Database for Standard Reference.
4. Abbey M, Noakes M, Belling GB, Nestel PJ. Partial replacement of saturated fatty acids with almonds or walnuts lowers total plasma cholesterol and low-density-lipoprotein cholesterol. Am J Clin Nutr. 1994 May;59(5):995-9. PMID: 8172107.
5. Olmedilla-Alonso B, Granado-Lorencio F, Herrero-Barbudo C, Blanco-Navarro I, Blázquez-García S, Pérez-Sacristán B. Consumption of restructured meat products with added walnuts has a cholesterol-lowering effect in subjects at high cardiovascular risk: a randomised, crossover, placebo-controlled study. J Am Coll Nutr. 2008 Apr;27(2):342-8. PMID: 18689569.
6. Maguire LS, O’Sullivan SM, Galvin K, O’Connor TP, O’Brien NM. Fatty acid profile, tocopherol, squalene and phytosterol content of walnuts, almonds, peanuts, hazelnuts and the macadamia nut. Int J Food Sci Nutr. 2004 May;55(3):171-8. PMID: 15223592.
7. Anderson KJ, Teuber SS, Gobeille A, Cremin P, Waterhouse AL, Steinberg FM. Walnut polyphenolics inhibit in vitro human plasma and LDL oxidation. J Nutr. 2001 Nov;131(11):2837-42. PMID: 11694605.
8. Lanzmann-Petithory D. Alpha-linolenic acid and cardiovascular diseases. J Nutr Health Aging. 2001;5(3):179-83. PMID: 11458289.
9. Mozaffarian D. Does alpha-linolenic acid intake reduce the risk of coronary heart disease? A review of the evidence. Altern Ther Health Med. 2005 May-Jun;11(3):24-30; quiz 31, 79. PMID: 15945135.
10. Papoutsi Z, Kassi E, Chinou I, Halabalaki M, Skaltsounis LA, Moutsatsou P. Walnut extract (Juglans regia L.) and its component ellagic acid exhibit anti-inflammatory activity in human aorta endothelial cells and osteoblastic activity in the cell line KS483. Br J Nutr. 2008 Apr;99(4):715-22. Epub 2007 Oct 5. PMID: 17916277.
11. Ros E, Núñez I, Pérez-Heras A, Serra M, Gilabert R, Casals E, Deulofeu R. A walnut diet improves endothelial function in hypercholesterolemic subjects: a randomized crossover trial. Circulation. 2004 Apr 6;109(13):1609-14. Epub 2004 Mar 22. PMID: 15037535.
12. Feldman EB. The scientific evidence for a beneficial health relationship between walnuts and coronary heart disease. J Nutr. 2002 May;132(5):1062S-1101S. PMID: 11983840.
13. Sabaté J, Cordero-Macintyre Z, Siapco G, Torabian S, Haddad E. Does regular walnut consumption lead to weight gain? Br J Nutr. 2005 Nov;94(5):859-64. PMID: 16277792.
14. Chauhan N, Wang KC, Wegiel J, Malik MN. Walnut extract inhibits the fibrillization of amyloid beta-protein, and also defibrillizes its preformed fibrils. Curr Alzheimer Res. 2004 Aug;1(3):183-8. PMID: 15975066.
15. Photograph by Fir0002 used with permission under the under the terms of the GNU Free Documentation License

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One Comment

  1. mohamed bin smeir

    October 3, 2011 at 4:03 am

    Effects of walnuts on blood pressure, how much is enough ?

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