Walnut
| Walnut |
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| Scientific classification |
A walnut is an edible seed of any tree of the genus Juglans, especially the Persian walnut, Juglans regia. Broken nutmeats of the eastern black walnut are also commercially available in small quantities, as are foods prepared with butternut nutmeats.
Contents |
Medical benefits and claims
Raw walnuts contain glyceryl triacylates of the n-3 fatty acid alpha-linolenic acid (ALA),[1] which is not as effective in humans as marine n-3 fatty acids,[2] and (mostly insoluble) antioxidants.[3][4][5][6][7] Roasting reduces antioxidant quality.[8] In 2010, a report[citation needed] published in the Journal of the American College of Nutrition said that walnuts and walnut oil improve reaction to stress.[9]
A study has suggested that consumption of walnuts increases fat oxidation and reduces carbohydrate oxidation without affecting total consumption, suggesting that walnut consumption may improve the use of body fat in overweight adults.[10] Walnuts have been shown to decrease the endothelial dysfunction associated with a high-fat meal.[11] Aged rats fed diets containing 2% to 6% walnuts showed reversal of age-associated motor and cognitive function, but a 9% walnut diet impaired performance, suggesting a J curve.[12]
On October 11, 2006, ScienceDaily published a report[13] which stated "New research shows that consuming a handful of raw walnuts along with meals high in saturated fat appears to limit the ability of the harmful fat to damage arteries," and attributed the result to a 2006 article in the Journal of the American College of Cardiology. The lead researcher, Emilio Ros, MD, PhD, was quoted as saying "People would get the wrong message if they think that they can continue eating unhealthy fats provided they add walnuts to their meals."[13] Funding for the study was provided by the California Walnut Commission, an industry marketing agency.
Medicinal Uses
Scientists are not yet certain that walnuts do not act as a cancer chemopreventive agent, due to the fruits high phenolic content, antioxidant activity, and potent in-vitro antiproliferative activity.[14]
Compared to certain other nuts, walnuts (especially in their raw form) contain the highest level of antioxidants.[15]
References
- ^ "Omega-3 Fatty Acids". Tufts University. http://www.tufts.edu/med/nutrition-infection/hiv/health_omega3.html. Retrieved 4 April 2011.
- ^ Charles, Deborah (21 April 2009). "Want to reduce breast cancer risk? Eat walnuts". Reuters. http://www.reuters.com/article/2009/04/21/us-cancer-breast-walnut-idUSTRE53K52820090421. Retrieved 4 April 2011. ""Scientists have been unsure whether the types found in nuts and leafy green vegetables work as well as the omega-3 fatty acids found in fish oil.""
- ^ "Antioxidant capacity of walnut ( Juglans regia L.): contribution of oil and defatted matter". 25 August 2007. http://www.springerlink.com/content/6150735721q44814/. Retrieved 4 April 2011.
- ^ "Walnuts Are Top Nut for Heart-Healthy Antioxidants". 28 March 2011. http://www.sciencedaily.com/releases/2011/03/110327191040.htm. Retrieved 4 April 2011.
- ^ "Ask the Expert: Omega-3 Fatty Acids". Harvard University. 21 April 2009. http://www.hsph.harvard.edu/nutritionsource/questions/omega-3/index.html. Retrieved 4 April 2011. ""Omega-6 fatty acids lower LDL cholesterol (the "bad" cholesterol) and reduce inflammation, and they are protective against heart disease. So both omega-6 and omega-3 fatty acids are healthy. While there is a theory that omega-3 fatty acids are better for our health than omega-6 fatty acids, this is not supported by the latest evidence. Thus the omega-3 to omega-6 ratio is basically the "good divided by the good," so it is of no value in evaluating diet quality or predicting disease.""
- ^ "Cholesterol: Top 5 foods to lower your numbers". Mayo Clinic. http://www.mayoclinic.com/health/cholesterol/CL00002. Retrieved 4 April 2011.
- ^ Park, Alice (29 March 2011). "The Supernut: Walnuts Pack a Powerful Dose of Antioxidants". Time (magazine). http://healthland.time.com/2011/03/29/the-supernut-walnuts-pack-a-powerful-dose-of-antioxidants/. Retrieved 4 April 2011.
- ^ "Walnuts are the healthiest nut, say scientists". BBC News. 27 March 2011. http://www.bbc.co.uk/news/health-12865291. Retrieved 28 March 2011.
- ^ "Eating Walnuts With High-Fat Meals Helps To Protect Arteries Against Short-Term Damage". 4 October 2010. http://www.sciencedaily.com/releases/2010/10/101004101141.htm. Retrieved 4 April 2011.
- ^ Tapsell L, Batterham M, Tan SY, Warensjö E (2009). "The effect of a calorie controlled diet containing walnuts on substrate oxidation during 8-hours in a room calorimeter". JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 28 (5): 611–617. PMID 20439557.
- ^ Cortés B, Núñez I, Cofán M, Gilabert R, Pérez-Heras A, Casals E, Deulofeu R, Ros E (2006). "Acute effects of high-fat meals enriched with walnuts or olive oil on postprandial endothelial function". JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY 48 (6): 1666–1671. PMID 17045905.
- ^ Willis LM, Shukitt-Hale B, Cheng V, Joseph JA (2009). "Dose-dependent effects of walnuts on motor and cognitive function in aged rats". THE BRITISH JOURNAL OF NUTRITION 101 (8): 1140–1144. PMID 18778529. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=5465528.
- ^ a b "Eating Walnuts With High-Fat Meals Helps To Protect Arteries Against Short-Term Damage". 11 October 2006. http://www.sciencedaily.com/releases/2006/10/061010022750.htm. Retrieved 4 April 2011.
- ^ Negi AS, Luqman S, Srivastava S, Krishna V, Gupta N, Darokar M., "Antiproliferative and antioxidant activities of Juglans regia fruit extracts." Pharm Biol. 2011 Jun;49(6):669-73 http://www.ncbi.nlm.nih.gov/pubmed/21554010
- ^ Black, Debra (28 March 2011). "Raw walnuts fight free radicals more than other nuts". The Star (Toronto). http://www.thestar.com/living/article/962981--raw-walnuts-fight-free-radicals-more-than-other-nuts.
