November 2003

Previous issues

Each month we offer a new article by Kitty Consolo, Ph.D.   Kitty is a veteran runner and exercise physiologist.  She has been running and racing since 1975, and has won over 400 road races ranging from the mile to the marathon and went to the first women's Olympic marathon trails in 1984. Kitty has a PR of 2:42.46 for the marathon and 35:02 for the 10km,  She now enjoys shorter races and masters running.

Enjoy, and please let us know your thoughts about the Runner's Corner!

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Click here for a short 'thank you' from a long time admirer of Kitty!

Guidelines for Runners in Taking

Vitamin and Mineral Supplements

     We all tend to be in a hurry these days and taking time to eat nutritious meals often becomes a challenge.  I’ve met many runners who try to make up for a poor diet by popping vitamin pills and mineral supplements.  This article will help guide you as to what to take, what not to take and how.

     First of all, our bodies function best if we eat foods containing the vitamins and minerals we need.  Vitamins and minerals should never be taken to supplement a poor diet or on an empty stomach.  However, even if one does eat nutritiously, being a runner can deplete one of certain vitamins and minerals more than the average person coupled with the fact that some minerals are difficult to absorb from food alone. 

Vitamins to Consider Supplementing Your Diet With

     Let’s focus on vitamins first.  Years ago it was thought that taking vitamin supplements just gave you rich urine.  However work done by Ken Cooper at the Aerobics Center in Dallas discovered that those who exercised more than 20 miles a week had a greater need for the antioxidant vitamins.  These vitamins help destroy substances called free radicals which come about from exposure to various things in our environment as well as heavy exercise and if allowed to accumulate, can result in cancer.  Hence, the recommendation is to include these three antioxidant vitamins in these amounts:

1.  beta carotene  3 -20 mg per day

2.  vitamin E  100- 400 IU per day

3.  vitamin C 250-500 mg per day

(note RDA is only 60 mg per day)

Is more better?

     If you read the labels of vitamin supplements you will often see the words RDA—recommended daily amount.  Many companies pride themselves in selling vitamins that are 500-1000% over the RDA.  This can be dangerous to your liver.  In most cases except with vitamin C as seen above, it is best to stay no more than 150% above the RDA or you may encounter gastric distress and liver damage.

Dangers of Excess Intake of Fat Soluble Vitamins

    Not only can excess amounts of a multiple vitamin be dangerous, but there are fat soluble vitamins which tend to be stored in our body fat and thus can accumulate to toxic levels.  The following are our fat soluble vitamins:

E, A and K.  Be sure to stay within 100-400 IU for vitamin E unless recommended otherwise by your physician, avoid vitamin A altogether and take beta carotene instead and avoid a vitamin K supplement—we usually get enough in food.

Dangers of Excess Intake of Water Soluble Vitamins

     It used to be thought that excess amounts of water soluble vitamins, Bs and C were safe because any excess could just be passed out through our urine.  However, people who consume large amounts of vitamin C (excess of 500) can develop kidney stones.  Also if a woman is pregnant and takes high doses of vitamin C, her baby can develop scurvy, a vitamin C deficiency when it is born because it has been used to the higher levels of C.  Also, vitamin C in sensitive individuals, since it is ascorbic acid, can exacerbate acid reflux and cause diarrhea.

      Excess amounts of vitamin B6 which were recommended to women for PMS have now been shown to cause nerve damage and in some cases, it has been irreversible. 

Summary for vitamin supplements:

When in doubt, stay within the RDAs only take the antioxidant vitamins as a supplement.

Guidelines for Mineral Supplements

     As with vitamins, most minerals should be gotten from ones diet rather than from reliance on a supplement.  There are however, three minerals which are not always absorbed well and that many Americans are found to be deficient in.  They are calcium, magnesium and iron.

Calcium is easily found in dairy products, broccoli and salmon, however the RDA is quite high,  we need 1200-1500mg per day.  It is best taken with magnesium which is found in milk, yogurt, dried beans, nuts, green leafy vegetables, avocadoes and sunflowers seeds.  The RDA for magnesium is 420 mg per day for men and 320 mg per day for women.  These minerals are not only important for bone health, but for muscle contraction and our heart health.  Though we need a large amount of calcium daily, limit the amount you take in supplement form to 600 mg per day and break it down into no more than 400mg at a time as the body can not absorb more than that amount!  I went to the store and noticed that most calcium supplements are way above the 400mg that can be absorbed!

Avoid Caffeine and Iron with your Calcium

     One of the biggest culprits in hurting our calcium and magnesium stores in the consumption of caffeine.  Caffeine robs our body of calcium and magnesium so it you when you are consuming your calcium and magnesium sources, avoid caffeine for at least 4 hours.  Caffeine should be limited to no more than 300 mg per day—a cup of coffee is about 150mg.  Also, iron supplements and foods containing iron such as red meat, also prevent the absorption of calcium.  Thus avoid your red meat with dairy and other calcium containing foods.

Iron—must test for Ferritin

     Iron, an important mineral in helping our blood carry oxygen, can also be very toxic if your body does not need it.  Usually, men do not need an iron supplement and most men should avoid iron as it increases risk of heart disease.  However, if you are male and a very heavy sweater, you may lose lots of iron in your sweat.  For women, at least 20% of women runners tend to be iron deficient.  Before taking iron, both men and women should have a blood test which looks at serum ferritin stores.  Do not settle for hemoglobin as this test is not a as sensitive and will not show low iron stores until you are in a very low state of low iron called anemia.  Serum ferritin will tell you when your stores are getting low.  Your levels should be above 60 or you will start to feel very tired as a runner.  Rather than try to supplement your iron with an over-the counter choice, ask your doctor to prescribe trinsicon, a very easy to absorb iron capsule with few side effects.  Be sure to take with food but not with calcium.  Have your blood tested every 6 months for serum ferritin to be sure you are within normal ranges.

Summary

     Like vitamins, minerals are best gotten in our food with care taken to avoid caffeine and also putting iron and calcium together.  Most mineral supplements are not necessary with the exception of calcium, magnesium and iron if a blood test shows low ferritin.

Take the time to eat healthy frequent meals and the care to be very selective as to what if any supplements you decide to add to your body.  One last word of advice, place your vitamin/mineral supplements in a glass of water.  If they are still there after 30 minutes, they probably will not be absorbed into your body either.  The cheaper the supplement, and the more additives, the less likely they will end up in your body.

Best wishes to a healthy diet and see you on the roads.

Kitty