Nutrition - Competing Interests

"What supplements should I consider taking for improving performance and staying healthy during competition season?"

This is a common question that I get from friends and fellow racers (running, nordic, skimo or otherwise - it doesn't matter). My answer is usually a rambling version of "it depends" as diet, training plan, and personal taste all bring a lot of variation. I started this article with the purpose of generally answering the question (and thats still how I will finish it) but quickly got sidetracked with the issue of competing interests.

While looking for a reference on a particular supplement, I came across an article posed on the Master Skier - a Cross Country Ski Journal. This is a fairly well read journal among cross country skiers and occasionally will run articles on nutrition and exercise physiology. The particular article that I stumbled across is titled Supplements for Skiers and was published in 1997. The published date should be a tipoff that some of the information may be dated but as it came up high on a google hit list on a search for "ussa supplements", it is clearly still being viewed and used. Another quick google search with the author's name and "supplements" turns up a much more recent (2011) version of almost the same article: Supplements - A Necessity for Athletes. Now the issue of conflicting interests becomes apparent. The author is employed by a supplement manufacturer. This raised another red flag for me but I kept reading. From here on, I will be referencing the earlier (1997) article unless stated otherwise.

In the article, the author makes a series of recommendations for supplementation in all cross country skiers. They are summarized below as something all skiers should take (the author specifically notes these are in order of importance):

1. A complete multivitamin
2. Additional antioxidants (grape seed extract, ginkgo biloba, superoxide dismutase, glutathione, etc...)
3. Coenzyme Q10
4. Cytochrome C
5. Whey protein
6. Additional "green food"
7. Essential fatty acids

The list is based on the premise that every athlete has some sort of macronutrient deficiency that, corrected, can improve performance. This concept is supported by a quote from Dr. Misner, PhD, stating that: 

“Athletes today ingest only 11% of the organic nutrients from their food sources that the athletes of the 1940’s enjoyed."

Unfortunately, no information or reference is provided to support this. Google again comes to the rescue and the statistic seems to be from a paper by Dr. Misner titled Food May Not Provide Sufficient Macronutrients to Avoid Deficiency. By examining the link, we know that Dr. Misner is actually also employed by the same supplement company that our author works for - more red flags. I don't want to confuse this article by critiquing Dr. Misner's but it would be appropriate to think critically about as well.

So, lets start going through the author's suggestions one by one, starting with a complete multivitamin; I think this is a generally good suggestion! While I may disagree with much of what is said, here I think is a reasonable idea. I will elaborate more below.

The author provides a list of several additional antioxidants that he believes will help contribute to fighting free radicals in an athletes body. Unfortunately there is little evidence to support antioxidant supplements as a performance enhancer. In fact, according to Gomez-Cabrera et al.,  it is possible that megadoses of antioxidants inhibit performance.

Next - Coenzyme Q10 and Cytochrome C. The author describes their functions reasonable well considering the scope of his article and summarizes them by saying that both are critical for the production of ATP (energy) and are therefore necessary. Unfortunately, contrary to popular belief, just because something is required in a step for energy production doesn't mean that consuming it will lead to improved performance. If that were the case, we would just eat ATP right?

The US Ski and Snowboard Association classifies both these nutrients as Group C - meaning they are unlikely to work and not recommended. Several recent papers on Coenzyme Q10 show that supplementation has not been found to have any effect on performance. A 2012 article in the journal Nutrition has an excellent summary of the existing literature on Coenzyme Q10. The graph below from Ostman et al. shows no change in maximal oxygen consumption among athletes taking Coenzyme Q10. 

Whey protein may or may not be beneficial. While the fact is, athletes need protein, I think getting it from a dietary source is more important than through supplementation. If an athlete is truly unable to get adequate protein intake through their diet, changes should be considered before using whey protein. If the diet cannot be improved, then go ahead.

Having read the first five recommendations, I was a bit shocked to see vegetables as number six! Vegetables don't even make my list as they are part of what I consider a normal diet, not a supplement (more on the difference between normal diet and supplement below). I don't think anyone would argue that green vegetables are an important part of our diet and I think these should be prioritized well before any pill is ingested.

Essential fatty acids are another point on which I generally agree. While the author does not present it, plenty of evidence exists showing the anti-inflammatory effects of omega-3 fatty acid supplementation. More on this below.

My final criticism about the article is a complete lack of discussion on 1) supplement dose and 2) consulting a physician. Many products sold as supplements would be harmful if consumed in large doses. Any person, athlete or otherwise, should seek professional advice on which supplements to consider and how much to consume. Both will vary between every person.

The point of all this is that we need to be wary of information we find on the internet, even if it comes from a seemingly reputable source. Be even more wary of an author that does not provided references to their sources of facts. Finally, be aware of competing interests and how they may skew presentation of information. Everyone has them (myself included) but some manage them better than others. I hope I do a good job but if I don't, please leave a comment.

What works for me?

Now, I'll circle back from my tangent and try to answer the question myself. What supplements should an endurance athlete consider taking and why?

Before considering any supplements, every athlete should ensure they are consuming a balanced diet. For me, this means limiting my sugary snacks to a reasonable level and keeping up a good intake of fruits and vegetables. By doing so, you effectively minimize the additional supplementation necessary. I have never met anyone who ate well, trained according to a reasonable plan, and still needed to take supplements.

• I take a complete multi-vitamin. Much of the time, even when I try, I can't get in every necessary serving of fruits and veggies. Having a multivitamin helps fill in the gaps. As long as the gaps are small, this is a reasonable strategy. A proper multivitamin should provide roughly the daily necessary nutrients. I avoid any that provide mega-doses.
• Omega-3 fatty acids have been shown to decrease inflammation following exercise. Reduced pain and increased recovery time following exercise is certain beneficial to an athlete training full time.

All that being said, an athlete's nutritional needs are very personal. Differences in training or any other factor could greatly affect supplement needs. For example, an anemic athlete may be so for several different reasons (gender, training load, etc...) and require iron supplementation. Any supplementation plan, no matter how safe it seems should be overseen by a physician. Even well marketed supplements from big name manufacturers could be contaminated or even dangerous on their own.

Another factor that is important to consider is the issues faced by athletes with supplements and doping control. Some supplements available for purchase may be banned for use in or out of competition. Supplement manufacturers are not regulated in the same manner as over-the-counter and prescription drugs. Supplement purity is not guaranteed so even if the substance on the label is legal, there may be a banned substance that was unknowingly mixed in the bottle. Websites such as the US or World Anti-Doping Agency provide links to sites that allow you to search for reputable supplement manufacturers and to review the banned substance list.