Vitamin A Is More Than Just Easy on the Eyes

The more vitamin A you eat, the more impact on your testosterone levels and prostate health.

For most of our lives, we’ve been told that vitamin A is good for our eyes. It’s the excuse our mothers used to make us eat steamed carrots or a pile of spinach. However, vitamin A is good for so much more than healthy eyes. It’s also vital for your teeth, skeletal system, soft tissue, skin, and mucous membranes. (The name vitamin means vital amine, which is proof of how important it really is).

But, a 2016 study from the University of Illinois at Urbana-Champaign makes vitamin A even more important. According to the research, the enzyme that digests vitamin A could also be responsible for regulating testosterone levels. Bco1 is the enzyme responsible for splitting beta-carotene into the two molecules that make up vitamin A. It’s a highly important enzyme, as it plays a role in the absorption and utilization of vitamin A in the body.

A group of mice was put on a beta-carotene-free diet. They derived vitamin A from other non-carotene sources. The mice with lower Bco1 enzymes ended up with lower testosterone levels than the mice with higher levels of this important enzyme. Their prostates were also significantly smaller, which is a bad thing in this case, given that testosterone plays a role in prostate development.

The seminal vesicles and prostate of the Bco1-lacking mice were 20-30% smaller than their counterparts. They also had 44% fewer of the Leydig cells that turn cholesterol into testosterone. The mice without Bco1 suffered from reduced androgen receptor signaling, causing reduced cellular growth and function of their prostates.

The human body is designed to produce enzymes according to the food we eat. By eating more vitamin A-rich foods, we encourage our bodies to produce the Bco1 enzyme needed to absorb vitamin A. The lack of vitamin A foods may be more than a minor problem to those with a genetic predisposition to reduced Bco1 production.

For this reason, it’s vital that you consume enough vitamin A in your daily diet. The National Institutes of Health recommend around 3,000 IU of vitamin A for adult and adolescent men and 2,300 IU for adult and adolescent women. This means it’s time to start eating more vitamin A-rich foods: carrots, sweet potatoes, beef liver, spinach, mangoes, and apricots. The more vitamin A you eat, the less risk a genetic predisposition to reduced Bco1 enzyme production will impact your testosterone levels and prostate health.


1. Joshua W. Smith, Nikki A. Ford, Jennifer M. Thomas-Ahner, Nancy E. Moran, Eric C. Bolton, Matthew A. Wallig, Steven K. Clinton, John W. Erdman. “Mice lacking β-carotene-15,15’-dioxygenase exhibit reduced serum testosterone, prostatic androgen receptor signaling, and prostatic cellular proliferation.” American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, 2016; Dec 2016, 311 (6): R1135-R1148; DOI:10.1152/ajpregu.00261.2016.