Category Archives: Nutrition

Selenium and Brazil Nuts and Testosterone

Can brazil nuts and selenium increase testosterone?

There seems to be a lot out in the popular press or online material that incresing selenium intake will increase a healthy man’s testosterone production (example and example II from Forbes Magazine: what were they thinking?), but little, if anything, in the scientific literature to support that idea. (I like the scientificky approach used by that website, especially the graph that shows no effect, and no indication of variability in the data points). There has also been recent emphasis on consumption of brazil nuts as a natural source of selenium that will boost testosterone and increase virility.

Can brazil nuts and selenium increase testosterone?

What do we know about selenium and Brazil nuts?

Selenium is protective against prostate cancer, and good for testicular development (fetal period . . . sorry guys) and possibly protective against other oxidative-stress-induced ailments, testicular or not. On the other hand, selenium, at high concentrations can result in DNA damage, and thus increase risk of cancer. The problem with supplementing, either through tablets, or through consumption of a natural product high in selenium, is that we do not know where the lines of good and evil cross.

As for Brazil nuts, selenium concentrations in any plant should be dependent on the concentration of selenium in the soil in which it grows, therefore, the concentration of selenium in Brazil nuts probably varies. This turns out to be the case, with nuts grown in Manaus-Belem more than ten times higher in selenium than those grown in Acre-Rondia. Someone consuming Brazil nuts may or may not be making a significant increase in selenium intake.
Chang, J. (1995). Selenium content of Brazil nuts from two geographic locations in Brazil Chemosphere, 30 (4), 801-802 DOI: 10.1016/0045-6535(94)00409-N

ATIF, F., YOUSUF, S., & AGRAWAL, S. (2008). Restraint stress-induced oxidative damage and its amelioration with selenium European Journal of Pharmacology, 600 (1-3), 59-63 DOI: 10.1016/j.ejphar.2008.09.029

Brozmanová J, Mániková D, Vlčková V, & Chovanec M (2010). Selenium: a double-edged sword for defense and offence in cancer. Archives of toxicology, 84 (12), 919-38 PMID: 20871980
Henderson, B. (2000). Hormonal carcinogenesis Carcinogenesis, 21 (3), 427-433 DOI: 10.1093/carcin/21.3.427

Crossfit and the Ketogenic Diet. And a little about Crossfit Vegetarians

Ketogenic diets have proven helpful to people with uncontrolled epilepsy and may be of benefit to epileptics in general, to victims of stroke and other forms of brain injury and possibly cancer. They come with other effects that may not be worth the discomfort or unintended risks to healthy people.

Ketogenic Diets for Healthy People

Some of the problems that may show up along with Ketogenic Diets are kidney stones and, in women and girls, amenorrhea. Amenorrhea is associated with bone loss, increasing risk of osteoporosis, and indicates problems in hormone balance. Supplementation with calcium may help with this, but then again, it might not. Physiology can be quite complex, and consumption does not necessarily indicate absorption is occurring. It is quite possible that something that causes hormonal imbalance in women may also cause hormonal imbalance in men. Playing with one’s physiology, when we don’t know the unintended outcomes of such play, may be inadvisable, especially long-term.

womens shirt crossfit or kettlebell shirt
Birth of Venus and her Kettlebells in Blue: Athletic shirt for crossfit women, kettlebell enthusiasts, and crossfit vegetarians

I have been a vegetarian for 30 years and an athlete all my life. I have excellent bone density, low blood pressure, low resting heart rate, low fasting blood sugar, excellent blood lipid profile and great strength to body weight ratio. I’m happy and healthy, even though I thoroughly understand I represent but a single data point. I do get a lot of advice from well-meaning crossfit friends that I need to eat meat and would be much healthier if I followed a ketogenic diet.  Vegetarians are often described by some Crossfit participants as weak and “skinny-fat”. I will leave it at this: The “optimal diet” for one person may not be the “optimal diet” for another, nor the optimal diet for all conditions. Humans are omnivores and physiologically polymorphic and adaptable. This has given us tremendous abilitity to survive in wildly different climes and environments, and has made us such a resilient species. It is also quite possible, that our individual resilience allows our bodies to adjust to dietary and environmental change.

The current state of research indicates no harm though, from short-term ketogenic diets. I have not found much in the way of research on the risks and benefits of long-term ketogenic diets in healthy adults. Anyone who wishes to add a citation, please feel free.

Kossoff, E., Zupec-Kania, B., & Rho, J. (2009). Ketogenic Diets: An Update for Child Neurologists Journal of Child Neurology, 24 (8), 979-988 DOI: 10.1177/0883073809337162

Bergqvist AG, Chee CM, Lutchka L, Rychik J, & Stallings VA (2003). Selenium deficiency associated with cardiomyopathy: a complication of the ketogenic diet. Epilepsia, 44 (4), 618-20 PMID: 12681013

Brinkworth GD, Buckley JD, Noakes M, Clifton PM, & Wilson CJ (2009). Long-term effects of a very low-carbohydrate diet and a low-fat diet on mood and cognitive function. Archives of internal medicine, 169 (20), 1873-80 PMID: 19901139