Selenium / Brazil Nuts

 

• In RCTs, a decreased risk of all cause mortality was seen with antioxidant mixtures when selenium was part of the mix  (RR: 0.90; 95% CI: 0.82, 0.98; P = 0.02).

• A single intake of Brazil nuts (20 or 50 g) caused a significant decrease in inflammatory markers such as serum IL-1, IL-6, TNF-α, and IFN-γ levels (P < 0.05). Improved lipid profile of healthy volunteers.

• Selenium supplementation decreased serum CRP (SMD = −0.48; 95% CI, −0.96 to 0; p = 0.049) and increased glutathione peroxidase (SMD = 0.5; 95% CI, 0.36–0.64; p < 0.001).

• Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice.

• Selenium supplementation mitigates the toxic effects of environmental mercury, lead, arsenic, and cadmium by forming an insoluble complex (chelate) with these metals and reversing the oxidative damage.

• Selenium supplementation improved semen parameters in males.

• 2 Brazil nuts per day provide optimal intake (there is ~96 µg of selenium per Brazil nut).

A Single Consumption of High Amounts of the Brazil Nuts Improves Lipid Profile of Healthy Volunteers, 2013

Background. This study investigates the effects of Brazil nut ingestion on serum lipid profile in healthy volunteers. Methods. Ten healthy subjects were enrolled in the study. Each subject was tested 4 times in a randomized crossover in relation to the ingestion of different serving sizes of the Brazil nut: 0, 5, 20, or 50 g. At each treatment point, peripheral blood was drawn before and at 1, 3, 6, 9, 24, and 48 hours and 5 and 30 days. Blood samples were tested for total cholesterol, high- and low-density lipoprotein cholesterol (HDL-c and LDL-c, resp.), triglycerides, selenium, aspartate and alanine aminotransferases, albumin, total protein, alkaline phosphatase, gamma GT, urea, creatinine, and C-reactive protein. Results. A significant increase of the plasma selenium levels was observed at 6 hours within the groups receiving the nuts. Serum LDL-c was significantly lower, whereas HDL-c was significantly higher 9 hours after the ingestion of 20 or 50 g of nuts. The biochemical parameters of liver and kidney function were not modified by ingestion of nuts. Conclusions. This study shows that the ingestion of a single serving of Brazil nut can acutely improve the serum lipid profile of healthy volunteers.

1 brazil nut = 5 grams

Brazilian nut consumption by healthy volunteers improves inflammatory parameters, 2014

Results: Consumption of nuts did not affect biochemical parameters for liver and kidney function, indicating absence of hepatic and renal toxicity. A single intake of Brazil nuts (20 or 50 g) caused a significant decrease in serum IL-1, IL-6, TNF-α, and IFN-γ levels (P < 0.05), whereas serum levels of IL-10 were significantly increased (P < 0.05).

Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice, 2021

Methionine restriction (MR) dramatically extends the healthspan of several organisms. Methionine-restricted rodents have less age-related pathology and increased longevity as compared with controls, and recent studies suggest that humans might benefit similarly. Mechanistically, it is likely that the decreased IGF-1 signaling that results from MR underlies the benefits of this regimen. Thus, we hypothesized that interventions that decrease IGF-1 signaling would also produce MR-like healthspan benefits. Selenium supplementation inhibits IGF-1 signaling in rats and has been studied for its putative healthspan benefits. Indeed, we show that feeding mice a diet supplemented with sodium selenite results in an MR-like phenotype, marked by protection against diet-induced obesity, as well as altered plasma levels of IGF-1, FGF-21, adiponectin, and leptin. Selenomethionine supplementation results in a similar, albeit less robust response, and also extends budding yeast lifespan. Our results indicate that selenium supplementation is sufficient to produce MR-like healthspan benefits for yeast and mammals.

Efficacy of selenium and/or N-acetyl-cysteine for improving semen parameters in infertile men: a double-blind, placebo controlled, randomized study, 2008

468 infertile men with idiopathic oligo-asthenoteratospermia who were randomized to receive 200 microg selenium orally daily (selenium group of 116), 600 mg N-acetyl-cysteine orally daily (N-acetyl-cysteine group of 118), 200 microg selenium plus 600 mg N-acetyl-cysteine orally daily (selenium plus N-acetyl-cysteine group of 116) or similar regimen of placebo (control group of 118) for 26 weeks, followed by a 30-week treatment-free period. These patients provided blood samples for the measurement of serum testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolactin, inhibin B, selenium and N-acetyl-cysteine. Semen samples were also obtained for routine semen analysis, and the measurement of seminal plasma selenium and N-acetyl-cysteine.

Results: In response to selenium and N-acetyl-cysteine treatment serum follicle-stimulating hormone decreased but serum testosterone and inhibin B increased. All semen parameters significantly improved with selenium and N-acetyl-cysteine treatment. Administering selenium plus N-acetyl-cysteine resulted in additive beneficial effects. A significant positive correlation existed between the seminal plasma concentrations of selenium and N-acetyl-cysteine, and semen parameters. A strong correlation was observed between the sum of the selenium and N-acetyl-cysteine concentrations, and mean sperm concentration (r = 0.67, p = 0.01), sperm motility (r = 0.64, p = 0.01) and percent normal morphology (r = 0.66, p = 0.01).

Conclusions: These results indicate that supplemental selenium and N-acetyl-cysteine improve semen quality. We advocate their use for male infertility treatment.

Selenium mitigates the toxic effects of environmental mercury, lead, arsenic, and cadmium by forming an insoluble complex (chelate) with these metals and reversing the oxidative damage (link)

Selenium mitigates the toxic effects of environmental mercury, lead, arsenic, and cadmium by forming an insoluble complex (chelate) with these metals and reversing the oxidative damage. [10],[11],[12],[13],[14] Maintaining a steady supply of selenium is important, because low plasma selenium levels exacerbate the health risks associated with mercury and other heavy metals.[15] In mercury-exposed residents of Wanshan, China, for instance, supplemental selenium decreased oxidative damage, reduced the mercury burden in the body, and increased mercury excretion.[16]

Selenium also safeguards against organic pollutants and toxicants such as herbicides,[17] bisphenol A (BPA),[18] and mycotoxins (mold toxins) such as ochratoxin A.[19],[20] Last but not least, animal studies have shown that selenium supplementation could prevent the oxidative stress and cardiovascular inflammation induced by air pollution particulates (PM2.5).[21]

Selenium, antioxidants, cardiovascular disease, and all-cause mortality: a systematic review and meta-analysis of randomized controlled trials, 2020

Results: The meta-analysis identified 9423 studies, of which 43 were used in the final analysis. Overall, no association of selenium alone or antioxidants was seen with CVD and all-cause mortality. However, a decreased risk with antioxidant mixtures was seen for CVD mortality when selenium was part of the mix (RR: 0.77; 95% CI: 0.62, 0.97; P = 0.02), with no association when selenium was absent. Similarly, when selenium was part of the antioxidant mixture, a decreased risk was seen for all-cause mortality (RR: 0.90; 95% CI: 0.82, 0.98; P = 0.02) as opposed to an increased risk when selenium was absent (RR: 1.09; 95% CI: 1.04, 1.13; P = 0.0002).

Conclusion: The addition of selenium should be considered for supplements containing antioxidant mixtures if they are to be associated with CVD and all-cause mortality risk reduction. 

All-cause mortality risk for studies with and without selenium:

The effect of selenium supplementation on coronary heart disease: A systematic review and meta-analysis of randomized controlled trials, 2017

A total of 16 eligible RCTs with 43998 participants were included. Significant effects were observed for serum CRP (SMD = −0.48; 95% CI, −0.96 to 0; p = 0.049) and GSH-PX (SMD = 0.5; 95% CI, 0.36–0.64; p < 0.001) after selenium supplementation. However, selenium supplementation was not statistically associated with CHD mortality and an aberrant lipid profile.

Conclusion

Selenium supplementation decreased serum CRP and increased the glutathione peroxidase level, suggesting a positive effect on reducing oxidative stress and inflammation in CHD. However, selenium supplementation is not sufficient to reduce mortality and to improve the lipid status.

[TOO OLD] Effects of selenium supplements on cancer prevention: meta-analysis of randomized controlled trials, 2011

This meta-analysis aimed to investigate the preventive effect of selenium supplements alone on cancer as reported by randomized controlled trials (RCTs). We searched PubMed, EMBASE, and the Cochrane Library in July 2009. Of the 461 articles searched, 8 articles on 9 RCTs, which included 152,538 total participants, 32,110 in antioxidant supplement groups, and 120,428 in placebo groups, were included. In a random-effects meta-analysis of all 9 RCTs, selenium supplementation alone was found to have an overall preventive effect on cancer incidence [relative risk (RR) = 0.76; 95% confidence interval (CI) = 0.58-0.99]. Among subgroup meta-analyses, the preventive effect of selenium supplementation alone on cancer was apparently observed in populations with a low baseline serum selenium level (<125.6 ng/mL) (RR = 0.64; 95% CI = 0.53 to 0.78; I(2) = 45.5%; n = 7) and in high-risk populations for cancer (RR = 0.68; 95% CI = 0.58 to 0.80; I(2) = 41.5%; n = 8). The meta-analysis of randomized controlled trials indicates that there is possible evidence to support the use of selenium supplements alone for cancer prevention in the low baseline serum selenium level population and in the high-risk population for cancer.

How To Obtain Optimal Benefits From Selenium (link)

By protecting DNA, eliminating toxins, boosting immunity, and optimizing thyroid function, the proper forms of selenium have been shown to impede heart disease, certain cancers, immune senescence, and premature death.  [200 micrograms per day]

[​ According to the USDA, there is 96 µg of selenium per Brazil nut.]

[NEGATIVE] Selenium Supplementation and Prostate Cancer Mortality, 2015

In multivariable analyses, men who consumed 1 to 24 μg/day, 25 to 139 μg/day, and 140 or more μg/day of supplemental selenium had a 1.18 (95% confidence interval [CI] = 0.73 to 1.91), 1.33 (95% CI = 0.77 to 2.30), and 2.60-fold (95% CI = 1.44 to 4.70) greater risk of prostate cancer mortality compared with nonusers, respectively, P trend = .001. There was no statistically significant association between selenium supplement use and biochemical recurrence, cardiovascular disease mortality, or overall mortality.

Selenium supplementation of 140 or more μg/day after diagnosis of nonmetastatic prostate cancer may increase risk of prostate cancer mortality. Caution is warranted regarding usage of such supplements among men with prostate cancer.