“I can’t eat that…I’m on a diet”. 

“I’d kill for a solid meal right now, but I’m counting calories and trying to lose weight.” 

Ever utter those words or allow them to run through your head?  You’re not alone!  So much energy is put into focusing on the foods that we can’t or shouldn’t eat that we forget about the awesome power of food.  We need to remember that food is good for us!  Aside from mere survival, there are many other reasons why we need food.  These “reasons” are called nutrients.  They are key participants in the myriad of chemical reactions that is a functioning human body.  Let’s consider our skeletal structure, the foundation of our house, so to speak.  Through a delicate balance of hormones and chemical reactions, our bones continually renew themselves throughout our entire life cycle.  We need a lot of different nutrients in order for this to happen. 

Why should I worry about my bones?

Before we get into the nutrients that influence bone health, we need to understand why bone health is even an issue.  Because our bones go through a lifelong cycle of formation and breakdown (known as bone turnover), a ready supply of the necessary nutrients is essential for maintaining strong bones throughout this entire process.  With age, bone mass declines as the amount of minerals in our bones decreases.  Starting at age 35, women lose 0.5-1% of their total bone mass each year.  The first 5 years of menopause can lead to a loss of as much as 15-35% of bone mass.  This loss of bone mass, known as osteopenia in the early stages and osteoporosis in advanced stages, can lead to spinal deformities, loss of height, and increased susceptibility to fractures.  But, ladies, you need not despair; while there is no cure for this disease, it is largely preventable.  Adequate intake of the bone-building nutrients can help to reverse and delay these losses and strengthen weak bones!  And so we shall discuss these all-important bone defenders:  

Calcium

Calcium is the main structural mineral in bone; 99% of the body’s calcium is found here making it one of the two most important nutrients related to bone health.  Our bodies cannot produce calcium, so it must be obtained from food.  Studies show that U.S. women don’t do a very good job of taking in adequate calcium; their intake levels are considerably lower than the recommended amount.  But consuming enough calcium need not be a challenge; there are many excellent sources of calcium readily available in our grocery stores. 

At the very top of the list are dairy products: milk, yogurt, cheese, and, yes, even ice cream (though ice cream should be consumed with caution – excessive intake has been known to lead to thunder thighs!).  Aim for non-fat or low-fat dairy products when possible as calcium content is unaffected by a change in fat content.  What if you’re a vegetarian or lactose intolerant?   Although dairy products are a great source of calcium, there are plenty of non-dairy sources as well. 

Sources of Calcium

Each of the servings listed below provides ~10-15% (110-150mg) of the daily calcium needs for adults.  Aim for 8 or more servings per day:

• Cow’s milk or yogurt or fortified soy milk = ½ cup (125ml)
• Cheese ¾ oz (21g)
• Tempeh or tofu = ½ cup (125ml)
• Almonds = ¼ cup (60ml)
• Almond butter or sesame tahini = 2 tbsp (30ml)
• Cooked soybeans = ½ cup (125ml)
• Soynuts = ¼ cup (60ml)
• Bok choy, broccoli, collards, Chinese cabbage, kale, mustard
• greens or okra = 1 cup (250ml) cooked OR 2 cups (300ml) raw
• Fortified tomato juice = ½ cup (125ml)
• Fortified fruit juice = ½ cup (125ml)
• Figs = 5

(information courtesy of the American Dietetic Association)

Vitamin D

Vitamin D is the second of the primary bone health nutrients.  Its job is to help with calcium absorption and to direct it to the bones; it is required for normal bone metabolism.  We can consume all the calcium we want but if our vitamin D levels are inadequate, that calcium won’t be able to make it to our bones where it’s needed.  So how do we make sure that we get in enough vitamin D?

Dietary Sources

There aren’t many foods that contain significant amounts of vitamin D, so adequate dietary intake can be a challenge.  

• fortified milk, orange juice, and some cereals
• canned salmon and sardines
• liver
• eggs

Fortunately, our bodies have a backup plan available: sunshine!

Sunshine

Our bodies can produce vitamin D internally from just 10-15 minutes of sun exposure to the arms and legs at least 3 times a week from 11am-2pm.  The activating element here is the sun’s UVB rays, which are normally considered the bad guys when it comes to skin cancer and aging.  Use of sunscreen can get in the way of vitamin D synthesis because it blocks the sun’s UV rays, so what are we to do?  Not to worry; a brief amount of sun exposure a few times a week on unprotected skin is not harmful, just watch the clock and limit your exposure to 10-15 minutes.  If you are fair-skinned, sensitive to the sun, or prone to skin cancer and want to limit your exposure to direct sunlight, vitamin D supplementation may be the way to go for you. 

The intensity of the sun’s rays can influence the amount of vitamin D produced through sun exposure.  In northern climates, the strength of the sun’s wintertime rays is inadequate for vitamin D synthesis; populations living in these northern latitudes cannot rely on the sun as a source of vitamin D during this time.  Darker-skinned populations are another “at-risk” group; they need more exposure than their fair-skinned counterparts to produce the same amount of vitamin D.  In these populations, vitamin D supplementation may also be necessary.

Supplementation

Your doctor can check your vitamin D level with a simple blood test and let you know if a supplement is needed.  For women over 50 years of age, the recommendation for vitamin D is at least 400 IU per day, but recent research is suggesting that vitamin D is even more important than we realized and this number may soon be raised. The importance of vitamin D’s role, both in bone health and in the prevention of many other chronic diseases, has been a subject of increased awareness in recent years; however, not all doctors remember to check this important level, so don’t be afraid to ask for this test to be done.

Vitamin K

Vitamin K plays a role in the binding of calcium to bone; thus, adequate levels are important for maintaining the structural integrity of our bones. 

Our bodies can produce their own supply of vitamin K (synthesized by bacteria in our digestive tracts), but dietary sources of vitamin K are also important. 

Sources of Vitamin K

Vitamin K is found in many foods and can be easily incorporated into your diet. 

• Leafy green vegetables (i.e. spinach, collard greens, kale, Swiss chard)
• Broccoli
• Asparagus
• Brussels sprouts
• Green beans
• Peas
• Cauliflower
• Cabbage
• Tomatoes

Magnesium

Magnesium is stored in bones and acts to regulate calcium and other bone-related hormones; thus, it plays a significant role in bone metabolism. 

Sources of Magnesium

Magnesium is readily available in many foods and can easily be incorporated into a regular diet.  It can be found in fruits, vegetables, nuts, and low-fat dairy products.  Some of the best sources include milk (a bone health over-achiever because it also contains calcium and vitamin D!), green leafy vegetables, whole grains, almonds, and peanuts.

Vitamin B12

Vitamin B12 plays a role in DNA formation and repair, and since bones are continually being broken down and rebuilt, this nutrient is especially important for bone health. 

Sources of Vitamin B12

Adequate B12 intake is not really an issue for meat eaters as this vitamin is widely available in animal products.  Vegetarians and vegans must get B12 from fortified foods or supplements.  The body’s ability to absorb B12 decreases as we age, so supplementation is often necessary for people later in life.  Ask your doctor to test your B12 level in order to determine if supplementation is needed.    

Iron

Iron has been shown to play a role in bone formation, acting as a participant in the synthesis of collagen.  Adequate iron intake is important for strong bones. 

Sources of Iron

• Beef
• Poultry
• Fish
• Beans
• Spinach

Iron absorption has been shown to be inhibited by the presence of calcium, so it’s best to consume these two nutrients in separate meals. 

Exercise

Last but not least is exercise; not a nutrient, but a hugely important factor in bone health nonetheless and worthy of brief mention here.  Weight-bearing exercise strains the muscles, which actually helps to strengthen them.  So activities such as walking, jogging, and strength training have been shown to have a positive effect on bone density.  Exercises such as swimming and cycling are very healthy for your heart but not as beneficial for your bones because they are non-weight bearing. 

Eating a diet full of a variety of fruits, vegetables, whole grains, and low-fat dairy products and including weight-bearing exercise in your regular workout routine are two of the most important things you can do for your bones.  As an added bonus, these are two of the best things you can do for maintaining a healthy weight as well!