As the season quickly progresses and training/racing demands increase, so do your nutritional needs. Calcium is an important essential mineral that is typically low in women athletes, as foods containing Calcium are often sacrificed to meet training weight and performance demands. Your present and future health could be at risk. Don’t jeopardize the longevity of your racing profession by cutting essential nutritional corners. Make sure you are getting enough Calcium at the right times to optimize absorption. Here’s how…..
Calcium’s daily job:
99% of our bodies Calcium is dedicated to forming and maintaining bone- the important skeletal structure that continues to develop until about 30 years old. At about 30 years, our skeleton has reached its peak development and begins to decline in strength throughout the rest of our lives, making it extremely important to get enough Calcium during the bone’s developing years!
Calcium isn’t only working daily to maintain bone, but also acts in a variety of other essential ways- enzyme activation (allowing for basic and complex cell activity to give us life); vascular contraction and vasodilation (which allows different amounts of blood to flow throughout our body and to our muscles for use and repair); nerve impulse and transmission (which allows us to feel and sense how tight our cycling shoes are for example); and muscle contraction/function- super important for us cyclists (need I say more?)!!!
How much makes all this possible?
Aim for at least ~1200mg/day and limit your Calcium intake to ~25-50% Daily Value (DV) each time you eat it. Why? …Like many things, more is not always better! Research indicates that the body can only absorb ~250-500mg of Calcium at a time. Therefore, it’s essential to get small amounts of Calcium frequently throughout the day in order to maximize your absorption.
Your Calcium source actually does matter!
By source I mean- where is the calcium coming from? For example, dairy products naturally contain Calcium in them, whereas orange juice and almond milk are “fortified” with Calcium (meaning that they don’t naturally exist within the product and Calcium from a different source is added to the product). For most people, a greater percentage of Calcium is absorbed and used from the dairy derived sources (milk, kefir, yogurt, and cheeses) than from other Calcium sources (supplements and vegetables). However, it is good to get Calcium from many sources, and especially those that are Lactose Intolerant or allergic to dairy need to consider non-dairy sources such as kale, bok choy, Chinese cabbage, broccoli, collards, and fortified foods like soymilk, almond milk, and orange juice….
Dairy- milk, yogurt, kefir, cheeses (yes- even low-fat cheese is a fantastic source of Calcium for those that are watching their weight!), ice cream and frozen yogurt
Milk Alternatives- Soymilk, Almond milk, Coconut milk – look to see if they are fortified with Calcium such that 8oz or one cup has at least 25% DV
Vegetables- kale, bok choy, Chinese cabbage, broccoli, collards, and turnip greens
Fruits- Fortified orange juice and other fortified juices
Other- Sardines, canned salmon, tofu, fortified grains like Total Cereal
How much food-containing Calcium should I eat at one time?
Aim for 3-4 servings of dairy or dairy alternative per day
1 serving of Calcium ~250mg =
~1 cup dairy or soy/coconut/almond alternative
~ ½ cup fortified tofu with Calcium
~ >2 cups kale or >1 cup boiled turnip greens
~ 1 cup Total cereal
What if I don’t get enough Calcium?
If you are not getting enough Calcium (either in your diet or if Calcium is poorly absorbed), your body takes the Calcium from stores within your bones causing your bones to weaken, thin, and become brittle. This loss of bone can increase your risk of fractures and stress fractures, and if continued eventually lead to Osteopenia (low bone density) and eventually Osteoporosis- a serious condition of very low bone density. Bone loss occurs naturally with the aging process, but a loss can also be induced by restricting too many Calories or by having very high training/racing demands and not eating enough Calcium to match your needs.
Making the most of your daily Calcium- A few things that help and hinder absorption…
#1- Vitamin D has been shown to improve Calcium absorption, so aim to eat vitamin D with your Calcium (found naturally in dairy foods), take a vitamin D supplement when you eat your Calcium, or eat your ice cream in the sun (a good source of vitamin D)!
#2- Some components in foods can bind to Calcium and can inhibit its absorption. Two of these food components that limit Calcium absorption are oxalic acid and phytic acid. Both oxalic acid and phytic acid are found naturally in selected plant foods like spinach, collard greens, sweet potatoes, rhubarb, beans, and in fiber-containing foods with wheat bran, seeds, nuts, and soy isolates. For those eating a variety of foods this interaction with Calcium isn’t a problem since the extent of interaction with Calcium varies. But for those with a limited variety in their diet- beware! Carefully look at your meals and snacks to make sure you are getting enough total daily Calcium.
#3- Another important mineral for athletes that inhibits or limits Calcium absorption is Iron. Iron and Calcium seem to “cancel each other out”. So, try and eat Calcium and Iron at separate times by at least one hour. This means don’t take your Iron containing multivitamin with your yogurt at breakfast!
Try eating a good dose of Calcium in your post-training/race recovery snack by blending together yogurt, whey protein, or milk/nut-milk with fruit in a cold smoothie for a quick recovery on these hot days…
1 cup plain non-fat or low-fat yogurt*
1 cup frozen mixed berries
8-12 ounces coconut water
Handful of ice cubes
Pinch of salt
Directions: Put all ingredients in a blender. Blend together and enjoy!
*Yogurt is a fantastic source of Calcium, but it can be substituted for Calcium enriched whey protein or milk of choice.
Questions or Comments?
What are your favorite Calcium sources or recipes with Calcium? Post on Facebook to share….
Image courtesy of www.bcm.edu
National Institutes of Health (http://ods.od.nih.gov/factsheets/Calcium-Consumer/)
Written by Sarah Weber, RD, LD
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