Breast Cancer Basics: Improving Bone Health

People who undergo cancer treatments have an elevated risk of bone loss and fractures due to bone depleting therapies (i.e aromatase inhibitors, androgen deprivation therapy, steroids), nutritional deficiencies, reduced physical activity and other factors.

A few years ago, a scientific investigation produced shocking results: In this study, doctors treated 115 men for prostate cancer using a commonly prescribed hormonal treatment called androgen deprivation therapy (ADT.) ADT is known to reduce bone density in patients, which is why anyone on ADT should have their bone density assessed before starting treatment, and every year thereafter. So – how many men were tested? None!

Hopefully your doctor will remember to assess your bone health before you begin treatment. If not, we provide in-depth information here on how you can protect your bones from the potentially damaging effects of cancer treatment.

Who is at risk of bone loss and fractures?

Many cancer treatments can weaken bone density, but there are other bone-loss risk factors, too, as this list shows:

  • Women who have undergone menopause due to cancer treatment
  • People who have had their ovaries or testes removed
  • People receiving hormonal therapies for cancer (i.e., anti-estrogen and anti-androgen therapies)
  • People with inadequate calcium intake
  • People with vitamin D deficiency
  • People who don’t exercise (especially weight bearing/resistance exercise)
  • People who smoke
  • People who drink substantial amounts of alcohol
  • People with a family history of hip fractures
  • People who use proton pump inhibitors, anticoagulants, and certain antidepressants
  • …and numerous other medical conditions.

Are you taking hormonal therapy for breast or prostate cancer?

The longer you are on hormonal therapies for breast and prostate cancer the greater your risk of osteoporosis and bone fractures. Not only are fractures painful and can impinge on your quality of life, they have also been shown to increase your risk of dying prematurely.

Our bone mineral density (BMD) peaks in our thirties, and from our forties onward, we gradually begin to lose bone mass. However, this decline occurs much more rapidly in people undergoing hormonal therapies for cancer. Studies show that significant bone loss can be detected as soon as six months after starting hormonal therapy. Thus, while healthy men lose 0.5% of their lumbar spine bone density each year, men on androgen deprivation therapies (i.e. Lupron, Firmagon, Zoladex) for prostate cancer can lose 4-5% over the same time span.

Meanwhile, healthy postmenopausal women lose 1-2% of their lumbar spine bone density each year, but women taking aromatase inhibitor therapy (i.e. Tamoxifen, Letrozole, Anastrozole) for breast cancer lose 2-3% annually, and potentially even more if they are also receiving androgen deprivation therapies.

How to measure bone-mineral density

The most common BMD test is called a DEXA scan. Typically, this measures your bone density at the hip or spine, which is where most osteoporosis-related fractures occur. DEXA scan results are reported as T-scores. The lower your T-score, the lower your bone density.

  • A T-score of -1.0 or above is normal.
  • A T-score between -1.0 and -2.5 indicates low bone density, called osteopenia.
  • A T-score of -2.5 or below is an indication of more severe bone loss, or osteoporosis.

You may also be given a “Z-score”, which compares your bone density to what is expected for someone of your age, gender, weight, ethnicity, and race.

Anyone who is about to start taking a drug that depletes bone density needs bone density testing. A bone density test should be done before you start the drug treatment, and then every 12 months thereafter to monitor for bone loss.

How to decrease your risk of osteoporosis and fractures

Osteoporosis and fractures don’t have to be your fate; there are many highly effective ways in which you can prevent or slow down bone loss.

  • Exercise: Aim to do at least 30 minutes of moderate physical activity five to seven days per week. This should include a mix of aerobic and weight bearing exercises. Research indicates that the best exercise for your bones is the weight-bearing kind, which forces you to work against gravity (i.e. weight training, walking, hiking, jogging, climbing stairs, tennis, and dancing). Swimming and bicycling are not weight-bearing. Although these activities help build and maintain strong muscles and have cardiovascular benefits, their effects on bone loss are minimal.
  • Yoga: Yoga can be particularly helpful in preventing or slowing bone loss; please read this New York Times article about yoga for bone health. And here’s a video showing the 12 poses mentioned in the NYT article.
  • Avoid smoking: Tobacco use reduces bone density.
  • Limit alcohol intake. Drinking alcohol is associated with lower bone density.
  • Optimize your vitamin D status:  Vitamin D is involved in numerous bone-related functions, such as increasing calcium absorption from the intestines, maintaining bone density, and reducing systemic inflammation. Most adults (70-95%) are deficient in vitamin D, so it is very important to have your blood levels 25(OH)D tested.
  • Optimize your calcium intake: Calcium is important in maintaining bone. Start by trying to obtain as much of your daily calcium requirements as possible from food (such as tofu, kale, spinach and other green leafy vegetables, nuts, seeds, canned bone-in sardines, home-made bone broth and dairy foods), and only use supplements to make up for any shortfall. Taking more calcium than the daily recommended amount has not been shown to be beneficial and may, in fact, be harmful.
  • Vitamin K2, which is needed for adequate calcium metabolism and is linked to a lower risk of bone loss. (Found in foods like egg yolks, grass-fed butter and meat, liver and fermented foods.)
  • Reduce inflammation: Like so many health problems, bone loss is increasingly understood to have inflammatory origins. Stress reduction, regular physical activity, healthy sleep habits and anti-inflammatory foods and supplements can help here.
  • Lower your stress levels, and don’t eat on the run: Stress causes urinary excretion of calcium, magnesium and iron which can lead to bone mineral loss. Moreover, stress hormones such as cortisol block the absorption of calcium in the intestines, restricting the amount of calcium available for bone growth. Lastly, eating on the run makes it hard for your body to break down and absorb bone-building nutrients efficiently.
  • Whole-body vibration devices: Numerous studies have found that standing on a vibration plate device that creates low-magnitude whole-body vibration bone loss can be slowed. These devices are commercially available (REF).


Diet plays an important role in bone health, and studies have found the Mediterranean diet to be particularly bone-protective. Here’s how a healthy diet can support your bones:

  • Consume adequate amounts of calcium each day: Women under age 50 need 1,000 mg, and 50 and older (or any woman who is not menstruating) need 1,200 mg per day. Men under age 71 need 1,000 mg, and 71 and older need 1,200 mg per day (REF).
  • Keep blood-sugar levels steady. This means not skipping meals, and eating small, healthy snacks in-between meals if you’re feeling hungry. When you let blood sugar levels drop too low, your adrenal glands produce cortisol (a stress hormone) to boost your blood-sugar level. However, chronically elevated cortisol in the bloodstream reduces the activity of osteoblasts (bone-building cells), lowers bone-mineral density ad increases fracture risk.
  • Reduce sugar and grains: A diet high in sugar and grain-based foods such as pasta, bread and cereal can weaken the bones. Elevated blood glucose can lead to osteoporosis by increasing inflammation, hyperinsulinemia, increased renal (kidney) acid load, reduced calcium intake, and increased urinary calcium excretion (REF) Limit grains to 1-2 times/day. Consider using xylitol as a sweetener – it’s been shown to have a beneficial effect on bone!
  • Eat calcium-rich vegetables every day: Examples include collard greens, broccoli, turnips, kale, soy beans, bok choy, dandelion greens, okra, mustard greens.
  • Foods high in oxalate are not great sources of calcium: Oxalate (oxalic acid) prevents the absorption of calcium. Foods high in oxalate include spinach, rhubarb, certain beans and beet greens.
  • Limit intake of foods high in sodium: Eating salty foods can cause your body to excrete calcium. Try to limit your daily sodium intake to 2,400 mg or less.
  • Eat moderate amounts of high-quality animal protein, such as wild-caught seafood, pastured poultry, and lean, grass-fed beef. This is very important for the construction of bone matrix. Lysine is an amino acid that’s particularly important for bone health as it helps the body absorb and conserve calcium and is needed for the formation of collagen. Lysine is mostly found in animal protein, which is why vegetarians can get lysine deficient.
  • Omega-3 fats: These reduce inflammation. Eat oily fish 2-3 times a week. Flax seeds are useful too; they not only contain omega-3s, but also lignans, plant compounds that help maintain bone health.
  • Omega-9 fats: Monounsaturated fats e.g. in olive oil, almonds, hazelnuts, avocados with anti-inflammatory properties. Omega-9s contain polyphenols that reduce inflammation and have been shown to reduce the risk of osteoporosis.
  • Soak your legumes (e.g. lentils, chickpeas, beans): Beans are high in calcium, but they also contain substances called phytates which interfere with calcium absorption. By soaking your beans in water for several hours and then cooking them in fresh water, you can significantly reduce their phytate levels.
  • Avoid eating wheat bran with calcium: Wheat bran contains phytates and can reduce calcium absorption when consumed with calcium-rich foods or calcium supplements. This is mainly an issue with 100% wheat bran products. If you eat 100% wheat bran, take your calcium supplements (or eat calcium-rich foods) 2 or more hours before or afterwards.
  • Cook bone broth and use it to make soups, stews or to cook rice: Bones (e.g. beef, chicken) contain nutrients that are needed to build strong collagen matrix; they also support intestinal health (which leads to better nutrient absorption) and are rich in bone-building minerals.
  • Avoid hydrogenated oils: They fuel inflammation.
  • Limit your caffeine consumption: Caffeine in coffee, tea and soft drinks may contribute to bone loss by decreasing calcium absorption. Drinking more than two cups a day may accelerate bone loss
  • Limit alcohol intake: Consuming more than 2-3 drinks per day can lead to bone loss.

What to do if you have low bone density (osteopenia) or bone loss (osteoporosis)?

Depending on the degree and rate of bone loss, your doctor may recommend that you take medication to reduce bone loss.

There are two main types of osteoporosis medications: Those that slow the loss of bone, and those that increase the rate of bone formation. Both can have negative side-effects, such as gastrointestinal irritation, certain types of bone cancer, fracture of the femur and damage to the jaw bone (rare). (Read about potential osteoporosis drug side -effects here.)

Since the choice of medication can be complicated and depends on numerous factors, ask your doctor to help you weigh up the pros and cons of osteoporosis medication.