In an ideal world, none of us would have deficiencies of any nutrient. In an ideal world, we’d all be consuming the optimal amount of every one of the 13 vitamins, 7 major minerals, 9 trace minerals and essential amino acids that contribute to our health.
But many of us don’t manage to achieve that ideal amount. In fact, some of us might not even come close. And while not getting the optimal amount of any nutrient is a concern for everyone, not getting enough of these particular nutrients is especially concerning for athletes.
If you’re an athlete, here are seven nutrients to be especially aware of.
Athletes use up iron much faster than people who don’t work out. If you train less than four hours a week, you likely have no more risk for iron deficiency than someone who doesn’t train at all. But if you train a lot – say six hours or more per week – you may have a much greater risk of being deficient. This is especially true of women who are menstruating regularly and losing iron on a monthly basis.
Iron deficiency can impact energy, thyroid, reproductive function and bone health in women. The RDA for iron for adults over 18 years old depends on your age and sex, but ranges from 8 to 18 mg daily (more if you’re pregnant). This amount is pretty easily gotten from food, though more difficult if you’re a vegan or vegetarian. (The iron in spinach is not nearly as absorbable as the heme iron in beef.) Iron supplements can help and should be considered.
Note: I do not recommend iron supplements for men, or for post-menopausal women, except if recommended by your personal health care provider. That’s because men and postmenopausal women have no way to get rid of excess iron, and the excess iron, a condition called hemochromatosis, can lead to life-threatening conditions like liver failure.
Athlete or non-athlete, many people do not get enough magnesium. According to a national report, a whopping 48% of folks do not get near the optimal level.
Magnesium is needed for more than 300 biochemical operations, making it essential for everybody. But it’s especially important for athletes for two reasons: One, it’s involved in relaxation – of the muscles and the arteries. And two, it’s one of the two main minerals that may be missing when you get leg cramps (the other is potassium).
Magnesium is found throughout the plant kingdom in fruits, vegetables and nuts. The literature is also filled with examples of studies where magnesium was effective with daily supplemental doses ranging from 125mg a day to 2500 mg a day for specific conditions. The Recommended Daily Allowance is a paltry 310 to 420 mg for adults over 18 years, depending on age and gender. I recommend to my clients, especially my athletes and athletically inclined, that they double that (to 800 mg a day).
Potassium is one of those “goldilocks” nutrients for athletes – you definitely don’t want too little, but you also don’t want too much. It’s lost through urine and sweat. One study showed that athletes running even 40 minutes at a reasonably balm temperature of 70 degrees lost what was calculated at 435 mg of potassium per hour. In general, athletes will lose through the skin approximately 200mg of potassium per kg of body weight during an hour of exercise. According to my friend and naturopathic physician, Alan Christianson, NMD, author of The Thyroid Reset Diet, athletes should supplement with just that amount post-workout (i.e. 200mg of potassium per kg (2.2 pounds) of body weight.
I believe that most athletes can tolerate 150 mg of supplementation per hour of exercise. But use caution as a lot of potassium consumed too quickly can, in rare cases, cause cardiac arrest.
Supplementing with potassium while training does not increase performance. But it does increase markers of recovery.
There’s no controversy about the importance of calcium for athletes. But there is some misunderstanding about how much of this nutrient they actually need. There’s no real data showing that athletes need more calcium than the recommended daily allowance (about 1000mg). But lots of folks don’t get that much, and that’s a particular problem for athletes.
Here’s why. You need calcium for bone health and to help prevent osteoporosis. The last thing a competing or recreational athlete needs is porous, weak bones. And athletes can easily lose calcium through sweat, making it all the more important that they replenish via food or supplements.
Calcium is especially important in the diet of young female athletes, who can be vulnerable to the loss of bone strength. And female athletes are more likely to be calcium deficient in the first place. Female athletes under about 25 need to be the most careful about their calcium intake, since those are the years when you’re basically “building” your calcium bank. The recommended daily allowance of calcium from ages 9 to 18 is 1300 mg, for both boys and girls. Starting at 19, the RDA goes down to 1000 mg for those up to age 70.
Even so, some research shows that about 90% of female athletes may not get adequate calcium (and over 40% may not get enough vitamin D). This significantly increases the risk of bone stress fractures (not to mention osteoporosis later on).
Foods are a great source of calcium, particularly dairy, but supplements are also fine.
In light of all the anti-sodium messages we get from the media, you may be surprised to find sodium on a list of essential nutrients for athletes, but consider this. A study compared athletes doing a triathlon (approximately two to four hours) with athletes doing an Ironman, a grueling event that lasted anywhere from nine to 17 (!) hours. While none of the triathlon athletes had low sodium – a condition known as hyponatremia – 27% of the Ironman athletes required medical attention for the condition.
This, by the way, is why you see food stands with salty snacks all along the 26.2 mile route of any marathon in the country. If you’re working out for one or two hours a day, no problem, but once you start doing events lasting five hours, or any number of hours in high heat, pay attention. I suggest that athletes aim for 80 to 100 mg sodium per quart of hydrating beverage and 100-300 mg of sodium per hour from other sources.
Selenium is a wonderful nutrient for athletes that has all kinds of benefits. But it’s often woefully lacking in our diet. (Best food source: Brazil nuts!) Here’s why selenium is especially important to athletes.
Let’s string a few facts together and connect the dots. Firstly, athletes may be subject to large amounts of oxidative stress and even cellular damage during the course of strenuous exercise. Secondly, one of the most powerful weapons we have against oxidative damage is a compound called glutathione, also known as the master antioxidant, which we make in our bodies. Lastly, selenium is necessary to make glutathione.
This means that selenium is important to help mitigate the cellular and oxidative damage of exercise. One study in France found that among athletes, 23% of males and 66% of females had selenium intakes below the French RDA. Another study looked at healthy nonsmoking males exercising to exhaustion. Half the group took 240 mcg of selenium while the other half took a placebo. The selenium takers showed a significant decrease in enzymatic activity, suggesting less cellular damage.
The RDA for selenium is only 55 mcg for people 14 years and over, an amount easily gotten with a couple of Brazil nuts. However, I agree with many functional medicine practitioners who recommend between 100 and 200 mcg a day from supplements. That’s the amount found in many quality mineral supplements.
Compared to sedentary folks, athletes can have lower blood levels of this key nutrient. And that goes for both males and females. In one carefully controlled study, twelve volleyball players and twelve non-athletic control subjects performed progressive bicycle ergometer tests on stationary bikes on two occasions, once in October, once in December. On the first occasion, both the volleyball players and the control group showed a similar measure of zinc in their sweat and urine after the intense testing. But in December, after the volleyball players had spent two months training and competing, there was a significant increase in the loss of zinc through sweat and urine from the players after the bicycle tests compared to that lost by the control group. Dr. Christianson suggests that immune system compromise due to zinc depletion may be one of the reasons endurance athletes (like marathoners) often get sick shortly after completing their event.
I would recommend that athletes consider taking 30 to 60 mg of zinc a day. (Zinc picolinate supplements are generally well-tolerated and very absorbable).
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