Moderate walnut consumption improved lipid profile, steroid hormones and inflammation in trained elderly men: a pilot study with a randomized controlled trial

Abstract

The present study aimed to investigate the effect of walnut consumption on lipid profile, steroid hormones and inflammation in trained elderly men performing concurrent (resistance and endurance) training. Twenty healthy elderly males were divided into two matched groups, in a randomized controlled trial, that trained three sessions per week: concurrent training + dietary walnut consumption (15 g/day for six weeks, CTW: n = 10); concurrent training + control diet (CT: n = 10). Fasting blood samples were taken 48 hours before and after intervention for biochemical assessments. levels of high-density lipoprotein (HDL) increased only in CTW compared to baseline (19.8%, p < 0.01). Total cholesterol (TC), low-density lipoprotein (LDL) and triglyceride (TG) levels significantly decreased only for CTW (i.e., 13%, 18%, and 18.5% at p < 0.01 for all). Testosterone (T) increased after the training compared to pre-training for CTW and CT (10.3%, p < 0.01, 4.27% p < 0.05, respectively), but the increase was significantly higher in CTW (p < 0.05). Serum cortisol (C) was lower for CTW compared to CT (p < 0.01). C-reactive protein (CRP) decreased in CTW in comparison with CT. The present study revealed that 6-week moderate walnut supplementation (15 g/day) improved lipid profile, steroid hormones and systematic inflammation in aged men performing concurrent training. These findings could be attributable to the potential effect of polyunsaturated fatty acids (PUFA) contained in walnut (linoleic acid, n-6; linolenic acid, n-3).

Walnut consumption and health outcomes with public health relevance—a systematic review of cohort studies and randomized controlled trials published from 2017 to present

“…Characteristics of the RCTs can be seen in Table S4 in the Supporting Information online. Eight of the RCTs were parallel group studies, 63 , 64 , 78 , 79 , 82–89 , 92–94 and 5 employed a crossover design. 65 , 80 , 81 , 90 , 91 , 95–97 RCTs were conducted in Australia, Cyprus, Germany, Iran, South Korea, Spain, Tunisia, Turkey, and the United States.…”

“…Two RCTs exclusively enrolled older adults. 78 , 92 No RCTs involved children. One RCT was in chronic kidney disease patients.…”

“…Nine RCTs compared walnut consumption with a walnut- (or nut)-free diet. 63 , 64 , 78 , 79 , 81–83 , 85 , 86 , 88–90 , 92 , 94 In 1 RCT the comparator was oily fish, 87 in 2 RCTs the comparator was white bread, 91 , 95 and in another the comparator was a diet that replaced the amount of ALA contributed by walnuts with oleic acid. 65 Included RCTs providing additional interventions alongside walnut consumption also contained a group that received the additional interventions without walnuts, which served as the comparator group for the purposes of this review.…”

“… 65 Included RCTs providing additional interventions alongside walnut consumption also contained a group that received the additional interventions without walnuts, which served as the comparator group for the purposes of this review. In 1 RCT exercise classes were provided (with or without walnuts), 92 1 RCT prescribed an energy-restricted diet alongside advice to consume walnuts (or not), 87 and 2 RCTs supplied dietary counseling, advice to increase physical activity, and psychological coaching with the aim of inducing weight loss, with or without walnuts. 64 , 94 In total >190 unique outcomes that were relevant to the review were reported across the RCTs (summarized in Table S2 in the Supporting Information online).…”

Walnut N-Acetylserotonin Methyltransferase Gene Family Genome-Wide Identification and Diverse Functions Characterization During Flower Bud Development

“…Compared to other nuts, walnuts are richer in melatonin (Verde et al, 2022). The available studies have mainly focused on pathological experiments or nutritional value evaluation of melatonin in walnuts (Bonomini et al, 2018;Cheng et al, 2021;Kamoun et al, 2021;Steffen et al, 2021). However, systematic reports on the mechanism of melatonin synthesis and inheritance in walnut are still lacking.…”