Bone Health

Bone Health 101

Rebecca Youngs, MS, RD, LD

Fit For Life Physical Therapy

Bone health becomes increasingly important as individuals get older, but athletes need to pay much closer attention as they are at an increased risk for bone density issues and injury as they play sports or participate in exercise.  Exercise, specifically weight bearing exercise, has been proven to be protective and important for bone health as the natural “pounding” and strain that comes with running and jumping signals the body to generate bone cells to reinforce the area that is put under strain, but if an athlete is at risk for injury due to under eating or nutrient deficiencies, exercise can put them at a greater risk.

Peak bone mass is reached by the early-mid 20s for men and women, so focusing on activities and nutrients that support and protect bone density as early as possible is incredibly important as natural bone loss occurs with age.

Below is a list of nutrients that play a role in bone health.  Consuming a variety of these sources is key to supporting overall health and reinforcing bone strength during times of stress. 

The above table is not an all-inclusive list, but these are the factors and nutrients most heavily studied to play a role in bone maintenance. Let’s focus further on two main nutrients: Vitamin D and Calcium. 

Vitamin D

This is a nutrient important for many athletes, but especially those who are vegan, vegetarian, or dairy- free.  Vitamin D is the sidekick to Calcium.  It plays critical roles in protein synthesis, calcium regulation, immune response, and hormone synthesis. Vitamin D is a key part of vitamin D-dependent calcium binding proteins in the small intestine.  These proteins help get calcium from the diet and transport it across the small intestine to be absorbed and used in our body.  Vitamin D is needed for this protein to work, so this is why you commonly hear how important vitamin D is for bone health as well as calcium, and how the two must be consumed together.  Those at risk for lower vitamin D levels are athletes who play indoor sports, have a darker skin tone, get little sun exposure, or have liver or kidney problems.  Some studies followed athletes for a year and noticed that athletes were more at risk for vitamin D deficiency in the months of January and February, and in those living at higher latitudes with little sunlight.  The nice thing is that we can get this nutrient from both the sun and food. Vitamin D is found in salmon, sardines, egg yolks, fortified milk, fortified cereal, and other fortified grain products. 

Calcium

Calcium is needed to promote bone formation, allow for proper muscle contraction, and nerve conduction, and plays a role in blood clotting.  99% of the calcium in our body is found in bone and teeth, so by keeping our bones strong with calcium consistently, athletes can help deter any detrimental bone density issues and help reinforce the strength of bones.  Alongside calcium, meeting your daily caloric needs plays a key role in keeping your bones strong and maintaining proper hormone function.  When there is a disruption in hormonal function, specifically a decrease in estrogen, individuals are at a higher risk for lower bone mineral density since estrogen plays a role in inhibiting bone resorption, or the breaking of bone.  In some cases, calcium can be lost in sweat during activities of long duration. At its extreme, the loss of calcium in sweat could be enough to decrease calcium levels in the blood.  If this happens, the body will secrete a hormone that will trigger the body to break down calcium in bone leaving one at higher risk for bone injury. Calcium needs specifically will differ between age and sex but focus on increasing sources of calcium from food first before adding a supplement.  This will help ensure adequate calorie intake to support hormone function and deliver a source of calcium to the body- two things key for bone health.  Dairy products like milk, yogurt, and cheese are common sources of calcium.  Non-dairy sources include sardines, dark leafy greens, tofu, and fortified orange juices or grains.  Calcium intake is especially important for athletes who are injured or who undergo surgery on a bone. 

Recommended amounts by age and gender

Note: these amounts are for those with no deficiencies or those who do not have increased needs You may need more than what is recommended.

Source: RDI, National Academy of Sciences

Supplementation

Supplementation of calcium and vitamin D may be needed for those who do not consume dairy or have higher needs, such as those with a bone injury or a history of an eating disorder.  It is more common to supplement with Vitamin D than calcium as Vitamin D can be more difficult to get in the diet, but for some, getting the recommended amounts of each may be difficult from diet alone.  There are various forms of calcium such as calcium carbonate and calcium citrate, so work with a qualified healthcare professional before starting a supplement as some forms may be better absorbed than others or work better with other medications an individual may be taking.  Additionally, consuming smaller amounts of calcium supplements at various points throughout the day versus one large, such as two 500 mg doses as opposed to one 1,000 mg dose, is safer and better absorbed since it mimics calcium intake from food. Calcium supplements should also be consumed alongside Vitamin D. 

Food sources

The amount of calcium and vitamin D is often listed on the nutrition facts of a product, but if not, use the information below as a rule of thumb when estimating the amounts in foods:

• ~300 mg of calcium for each serving of dairy, calcium fortified soy milk, or orange juice
• ~300 mg of calcium in:
  • 1 cup of yogurt
  • 2 ounces of cheddar cheese
  • 8 cups of cooked spinach
  • 2 cups of cooked kale
  • 2.5 cups of cooked broccoli
    
    

Other calcium rich foods include:

• Bone in fish (sardines, canned salmon)
• Fortified orange juice
• Fortified grains
• Whey protein
• Seeds 
• Dark leafy greens
• Fortified cereal

Resources

Li et al. 1998

Farrokhvar et al, 2015

Khosla, Oursler, and Monroe 2012

Bary et al. 2011

PMID: 31139653

Registered & Licensed Dietitian, Rebecca Youngs, is an avid marathoner, loves to work out, and has specialized her practice in gastrointestinal health, as well as sports nutrition and fueling athletes of all levels.  She is available for individual consultations at Fit For Life Physical Therapy or through FFL zoom video conference.

Fit For Life Physical Therapy cares for people of all activity levels - to help prevent, recover from, or rehabilitate sports & orthopedic injuries.  We are proud to move people every day.  Please visit our website https://www.fitforlifephysicaltherapy.com/, email us at info@fitforlifephysicaltherapy.com, or call or text us at any of the phone numbers for our three convenient locations inside Fleet Feet+FrontRunner stores:

Polaris:  1270 East Powell Road Lewis Center, Ohio 43035 ~ 614-981-2065

Upper Arlington:  1344 West Lane Avenue, Columbus, Ohio 43221 ~ 614-981-1979

New Albany:  5792 North Hamilton Road, Columbus, Ohio 43230 ~ 614-581-7441