According to A.J. Schenkman:
“… if Washington did cut down a cherry tree it was most likely to make room for planting a walnut tree, and if he did have wooden teeth his real teeth likely were ruined breaking walnuts. One thing is true, confirmed by sources both foreign and domestic: General Washington, whether at home in Mount Vernon or at his headquarters in Newburgh, always had plenty of walnuts on hand."
Washington's personal papers are littered with references regarding purchases of [nuts] he was, in fact, fond of nuts of all kind. Walnuts, however, were his favorite. He "planted several varieties," including black and English walnuts, on his Virginia plantation, Mount Vernon. ….. English walnuts seemed to be a particular favorite of Washington—he planted some 30 trees at Mount Vernon in just 1763 alone; between 1790 and 1799 he planted at least eight more that we know of from his writings.”1 This being the case, one would think that National Walnut Day would somehow be connected to some important Washington commemorative date but instead it is celebrated on May 17th and apparently has been since 1949. It wasn’t until 1958 that Eisenhower, then President, made it official.
In recent years there seems to have been an upsurge of scientific research on the health benefits of eating nuts and in particular on walnuts. Thus it feels appropriate to take a few minutes and to remind ourselves about some of these newer papers.
Walnuts contain a number of nutritive compounds including:
“… vitamin E and polyphenols. Among common foods and beverages, walnuts represent one of the most important sources of polyphenols, hence their effect over human health warrants attention. The main polyphenol in walnuts is pedunculagin, an ellagitannin. After consumption, ellagitannins are hydrolyzed to release ellagic acid, which is converted by gut microflora to urolithin A and other derivatives such as urolithins B, C, and D. Ellagitannins possess well known antioxidant and anti-inflammatory bioactivity, and several studies have assessed the potential role of ellagitannins against disease initiation and progression, including cancer, cardiovascular, and neurodegenerative diseases.”2
There are some very intriguing walnut studies. In December 2018, Freitas-Simoes et al reported a trend that eating walnuts may preserve telomere length in elderly people. Preserving telomere length is the Holy Grail of longevity research.3
People have this thing about eating nuts - they worry that nuts will make them fat. Over the years we’ve lost count of all the studies that suggest this is nonsense. A September 2018 reaffirmed this, that supplementing the diet with nuts, in this case walnuts, doesn’t add either pounds or inches.4
Eating walnuts (45 grams or about 1.5 ounces/day for 16 weeks) improved metabolic syndrome, increasing HDL cholesterol and lowering fasting blood sugar, A1c and adiponectin.5 Adding in a similar amount of walnuts into daily smoothies over 5 days reduced the bad LDL cholesterol fractions and increased the good HDL fractions in a placebo-controlled trial that was published May 14, just in time for Walnut Day.6
In a paper published last December, eating walnuts was associated with lower risk of depression, especially among women.7 Eating nuts improves the gut microbiome, an admirable goal that more and more people who come to see us seem to be fixated on of late.8 A number of studies are suggesting that eating walnuts might lower risk of specific cancers9 including breast,10,11 colon,12 prostate,13 and lung.14
There are some great walnut recipes on Walnuts.org, the website of The California Walnut Board and Commission.
- Sánchez-González C, Ciudad CJ, Noé V, Izquierdo-Pulido M. Health benefits of walnut polyphenols: An exploration beyond their lipid profile. Cln Rev Nutr. 2017 Nov 2;57(16):3373-3383. https://www.tandfonline.com/doi/abs/10.1080/10408398.2015.1126218?journalCode=bfsn20
- Freitas-Simoes TM, Cofán M, Blasco MA et al. Walnut Consumption for Two Years and Leukocyte Telomere Attrition in Mediterranean Elders: Results of a Randomized Controlled Trial. Nutrients. 2018 Dec 4;10(12). pii: E1907. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316673/
- Bitok E1,2, Rajaram S3, Jaceldo-Siegl K, et al. Effects of Long-Term Walnut Supplementation on Body Weight in Free-Living Elderly: Results of a Randomized Controlled Trial. Nutrients. 2018 Sep 18;10(9). pii: E1317. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6163338/
- Hwang HJ, Liu Y, Kim HS2, Lee H, Lim Y, Park H. Daily walnut intake improves metabolic syndrome status and increases circulating adiponectin levels: randomized controlled crossover trial. Nutr Res Pract. 2019 Apr;13(2):105-114. https://synapse.koreamed.org/DOIx.php?id=10.4162/nrp.2019.13.2.105
- Tuccinardi D1,2, Farr OM1, Upadhyay J, et al. Mechanisms Underlying the Cardiometabolic Protective Effect of Walnut Consumption in Obese Subjects: A Cross-Over, Randomized, Double-Blinded, Controlled Inpatient Physiology Study. Diabetes Obes Metab. 2019 May 14. https://onlinelibrary.wiley.com/doi/abs/10.1111/dom.13773
- Arab L, Guo R, Elashoff D. Lower Depression Scores among Walnut Consumers in NHANES. Nutrients. 2019 Jan 26;11(2). pii: E275. https://www.mdpi.com/2072-6643/11/2/275/htm
- Bamberger C, Rossmeier A, Lechner K et al. A Walnut-Enriched Diet Affects Gut Microbiome in Healthy Caucasian Subjects: A Randomized, Controlled Trial. Nutrients. 2018 Feb 22;10(2). pii: E244. doi: 10.3390/nu10020244. https://www.mdpi.com/2072-6643/10/2/244
- Jahanbani R, Ghaffari SM, Salami M, et al. Antioxidant and Anticancer Activities of Walnut (Juglans regia L.) Protein Hydrolysates Using Different Proteases. Plant Foods Hum Nutr. 2016 Dec;71(4):402-409. https://link.springer.com/article/10.1007/s11130-016-0576-z
- Hardman WE, Primerano DA, Legenza MT, Morgan J, Fan J, Denvir J. Dietary walnut altered gene expressions related to tumor growth, survival, and metastasis in breast cancer patients: a pilot clinical trial. Nutr Res. 2019 Mar 10. pii: S0271-5317(18)31190-4. https://www.ncbi.nlm.nih.gov/pubmed/30979659
- Soriano-Hernandez AD, Madrigal-Perez DG, Galvan-Salazar HR, et al. The protective effect of peanut, walnut, and almond consumption on the development of breast cancer. Gynecol Obstet Invest. 2015;80(2):89-92. https://www.karger.com/Article/Abstract/369997
- Nakanishi M, Chen Y, Qendro V et al. Effects of Walnut Consumption on Colon Carcinogenesis and Microbial Community Structure. Cancer Prev Res (Phila). 2016 Aug;9(8):692-703. http://cancerpreventionresearch.aacrjournals.org/content/9/8/692
- Kim H1, Yokoyama W, Davis PA. TRAMP prostate tumor growth is slowed by walnut diets through altered IGF-1 levels, energy pathways, and cholesterol metabolism. J Med Food. 2014 Dec;17(12):1281-6. https://www.ncbi.nlm.nih.gov/pubmed/25354213
- Zhang XB, Zou CL, Duan YX, Wu F, Li G. Activity guided isolation and modification of juglone from Juglans regia as potent cytotoxic agent against lung cancer cell lines. BMC Complement Altern Med. 2015 Nov 3;15:396. https://www.ncbi.nlm.nih.gov/pubmed/26530090