The Skinny on Bone Thinning and Why Milk Isn’t Enough

Kelsi Auld Fact Checked
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Since our childhood days of Skip-Its and snap bracelets, millennial women have been told to drink eight ounces of milk a day to build strong bones. We probably never heard, however, that out of the estimated 10 million Americans with osteoporosis, about 8 million are women.  


What happens to our bones between childhood and old age? And as women in our 20s, 30s and beyond, what can we do now to avoid joining this statistic? Susan Williams-Judge is an osteoporosis prevention nurse at UW Medicine's Strong Bones Clinic.

Williams-Judge shares her decades of experience treating and preventing bone loss and fractures by giving us a 101 course on our 206 bones.

What exactly is osteoporosis?

Osteoporosis literally means “porous bone.” It’s a disease where bone mass and density progressively decrease, resulting in an extremely fragile structure—hollow like a honeycomb and susceptible to fractures (cringe).

It was once believed that osteoporosis was an inevitable part of aging, but now we know there are many things you can do to build strong bones to reduce your risk of developing osteoporosis later in life.

When does bone loss occur?

Although we tend to think of bones as static structures that support out body, Williams-Judge explains that “bones are living tissues and are continually being remodeled, torn down and built anew.” 

In general, when we are young we tend to build bone. 

“We accrue 90 percent of the bone mass we will ever have by age 19, and the remainder of it by age 30,” Williams-Judge says.

How much you accrue while you are young will affect how much bone you will have later in life. Our bodies begin to lose bone mass faster than it is rebuilt, which is why bone loss is more and more common as we age. This also means that at age 30, our bones are at their strongest. So it’s important to do what we can in our 20s and 30s to promote strong bones for life.

What causes bone thinning?

Although some loss of bone is natural as we age, Williams-Judge says there are other major factors that can cause bone thinning. These include: inadequate nutrition (whether inadvertent or from eating disorders), low levels of vitamin D, a sedentary lifestyle, malabsorption disorders like celiac or Crohn’s disease and a family history of osteoporosis. 

Estrogen also plays an important role in building and maintaining bone, which is why after menopause women are at much greater risk of osteoporosis.  

How can women in their 20s and 30s prevent extensive bone loss?

Eat a calcium-rich diet. 

“Calcium is the most abundant mineral in our body,” says Williams-Judge. And, fun fact, 99 percent of the body’s calcium is found in our bones and teeth.  But because our bodies do not produce it naturally, we must ingest it. The recommended daily dose of calcium for adults is 900 to 1,200 milligrams. 

Want to know if you’re getting enough? Calculate your daily intake here.  

If you do not reach the recommended amount, Williams-Judge suggests adding a 500 to 600 milligram calcium supplement, though dietary calcium is best. 

Aside from milk or dairy products, some dark leafy vegetables, legumes, nuts and seeds also have calcium in them. There are also some types of bread, orange juice and other calcium-fortified foods available.

But what about people who are lactose intolerant and vegans? Are they at a higher risk of bone thinning and fractures?

“Not necessarily,” Williams-Judge explains. “The important thing is to make sure you get enough supplemental calcium if you cannot get adequate intake in through your diet.” 

If you need a supplement, calcium citrate is the one best absorbed by your body.  All other forms of calcium should be taken with food for best absorption, she says.  

Get enough Vitamin D.

While you may reach the daily calcium dosage, if you are low or deficient in Vitamin D, you may be inadvertently thwarting your valiant efforts. This is because Vitamin D helps our bodies absorb calcium, which is why it’s commonly found in calcium-fortified food and supplements. 

It’s difficult to get enough Vitamin D  from foods alone (fish and egg yolks have the most), and although our skin produces Vitamin D when exposed to sunlight, there are many factors (like where you live and the time of day) that can affect how much our bodies create.  

Because there is some debate over whether or not supplements can reduce the risk of osteoporosis, have a discussion with your provider about what it right for you. 

Keep moving. 

“Exercise is one of the best things we can do for our bones,” Williams-Judge says. “Physical activity helps new bone tissue form, which helps bones stay strong.” 

Does yoga count? 
Non-weight-bearing movements like yoga, tai chi and swimming don’t necessarily increase bone density, but they do promote muscle strength and balance, which help prevent falls. 

“Fall prevention is one of the most important things you can do to prevent a fracture,” says Marti McGinley, a physical therapy specialist for osteoporosis. 

Don’t smoke. 

Aside from its many other health risks, smoking reduces your estrogen levels which can accelerate bone loss and lead to early osteoporosis

To keep your bones strong and healthy, embrace a healthy lifestyle filled with a calcium-rich diet and regular weight-bearing exercise routine. And definitely don’t smoke.