Walnuts were introduced to the Americas by Spanish explorers in the 1700s¹ and are now the second largest nut crop produced in the U.S. (second only to almonds). Walnuts have been found to help control blood sugar levels² and promote eye health.³

 

Now a new study⁴ has started to find that an amino acid in walnuts, L-arginine, may help walnuts maintain blood vessel health.

 

Previous research has shown that walnuts “improve [blood vessel] function in patients [with high cholesterol]”.⁵  Building upon these findings, researchers had 12 patients with high cholesterol and 12 healthy patients eat two high-fat meals containing either 25 grams of olive oil or 40 grams of walnuts.  Both meals contained 80 g fat and 35% saturated fatty acids. Consumption of each meal was separated by one week, during which they consumed the standard Mediterranean diet.⁶  The researchers then drew blood and assessed blood vessel function in a fasting state (5 hours after their last meal) and then 4 hours after the meals.

 

They found that while blood vessel function was “impaired” after the olive oil meal in both groups (decreasing by 17% in the control group and 36% in the high-cholesterol group), it increased by 24% after the walnut meal in the high cholesterol group and was unchanged in the healthy group. 

 

Although blood flow was decreased in the olive oil group, both meals decreased levels of inflammatory proteins that can harm blood vessel health.  As a result the researchers concluded that “both walnuts and olive oil preserve the protective [structure] of [blood vessel] cells” and that this study “further supports the beneficial effects of walnuts on cardiovascular risk.”

 

Greg Arnold is a Chiropractic Physician practicing in Danville, CA.  You can contact Dr. Arnold directly by emailing him at mailto:ChiroDocPSUalum@msn.com or visiting his web site www.CompleteChiropracticHealthcare.com

 

Reference:

 

¹  “Commodity Highlights: Walnuts” posted on the USDA Website http://www.ers.usda.gov/Briefing/FruitAndTreeNuts/fruitnutpdf/Walnuts.pdf#search=%22walnut%20consumption%20in%20the%20united%20states%22

 

²  Gillen LJ.  Structured dietary advice incorporating walnuts achieves optimal fat and energy balance in patients with type 2 diabetes mellitus. J Am Diet Assoc. 2005 Jul;105(7):1087-96

 

³  Progression of age-related macular degeneration: association with dietary fat, transunsaturated fat, nuts, and fish intake.  Arch Ophthalmol. 2003 Dec;121(12):1728-37

 

⁴  Cortes B.  Acute Effects of High-Fat Meals Enriched With Walnuts or Olive Oil on Postprandial Endothelial Function.  Jou Am Coll Cardiol 2006; 48(8):1666-1671

 

⁵  A. Pérez-Heras et al., A walnut diet improves endothelial function in hypercholesterolemic subjects A randomized crossover trial, Circulation 109 (2004), pp. 1609–1614

 

⁶  S. Muñoz et al., Substituting walnuts for monounsaturated fat improves the serum lipid profile of hypercholesterolemic men and women A randomized crossover trial, Ann Intern Med 132 (2000), pp. 538–546