Tuesday, July 12, 2016

Could a Multivitamin Be Counterproductive?

By: Andrew Jagim

A lot athletes or active individuals usually supplement with a multivitamin to help provide some anti-oxidant support, in addition to several other health benefits of course. However, if we look at the concept of oxidative stress and why people recommend an anti-oxidant rich diet versus what drives several physiological adaptations, it just gets more and more confusing.

For example, some of that oxidative stress from reactive oxygen species (ROS) production make actually be a good thing and therefore interrupting this mechanism could be counterproductive.

During strenuous exercise, the production of free radicals (aka ROS) is increased. These free radicals, collectively referred to as oxidative stress can lead to cell apoptosis (death) if levels are chronically elevated. By consuming foods or vitamins that specifically contain a high degree of anti-oxidants, or substances that help reduce oxidative stress, it's thought that we can reduce the potential damaging effects of strenuous exercise.  With that being said, these free radicals may also serve as a necessary evil when it comes to triggering adaptive responses within the muscle. The reason why we train is to expose our bodies and specific physiological systems to a certain stressor, with continuous exposure we combat these stresses by adapting (i.e. increase energy production, improve blood flow, increase muscle size, strength, etc.).  If we remove or attenuate some of the acute stressors, we may also be minimizing the acute physiological stimulus needed to elicit said adaptations over time. 

There are several publications that suggest not only to high-dose multivitamins NOT improve performance, they may actually hinder certain training adaptations (1).  Initially, a lot of the research suggested that certain antioxidants (i.e. Vitamin C, E and CO-Q10) may hinder endurance performance in aerobically trained athletes when consumed at relatively high doses for several weeks. Recent evidence suggests that this maladaptation may actually occur with resistance training outcomes as well with evidence supporting the idea that antioxidants blunt a lot of the cell-signaling required to elicit muscle growth. Below is a direct quote from such a publication:

A significant number of both healthy and sick individuals are taking antioxidant supplements in the belief that these will improve their health and prevent or ameliorate diseases (1). Moreover, a large proportion of athletes, including elite athletes, take vitamin supplements, often large doses, seeking beneficial effects on performance (16). The complete lack of any positive effect of antioxidant supplementation on physiological and biochemical outcomes consistently found in human and animal studies raises questions about the validity of using oral antioxidant supplementation in both health and disease. The vast majority of experimental evidence clearly advises against this supplementation. Thus, we unreservedly confirm the conclusions derived from our previous research (4, 14) and disagree with Higashida et al. In our opinion, antioxidant supplements are, at the least, useless."
Now, keep in mind this is only one publication but you may be asking yourself: "Wait a minute, I thought you guys believe in vitamin supplementation and often recommend people to take vitamins?!" The answer to your question would be yes, we do believe that vitamins and antioxidants are important for long-term health. My opinion on the matter is that if you are not adequately consuming enough vitamins and anti-oxidants in your diet than supplementing with a multivitamin is probably a good idea. Is more better? Will it make you bigger, faster stronger? Probably not. How much is too much? Unfortunately we don't really have the answer as it is likely different for everyone based upon, body size, age activity level etc. More research is definitely needed in this area. For the time being, there are certain blood tests that can be done to assess your levels for certain vitamins and minerals from which you could then conclude whether or not you are deficient in certain areas.

1. Gomez-Cabrera, M. C., Ristow, M., & ViƱa, J. (2012). Antioxidant supplements in exercise: worse than useless?. American Journal of Physiology-Endocrinology and Metabolism, 302(4), E476-E477.

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