What is a "Bone Density Test?"

A bone density test, also known as a DEXA scan or DXA, stands for Dual Energy X-Ray Absorptiometry. DEXA scans are the most widely used test to measure bone mineral density.

This measurement reflects the fact that the denser the bone, the less x-rays pass through it.

Usually, the denser your bone, the stronger it is, and the less likely it is to fracture. (Although this isn’t always the case, as we’ll cover a little further down the page!)

If you’ve ever had an x-ray, the process is very similar.

A DEXA machine uses low-energy x-rays and sends two different sources (thus the ‘D’ for “dual” in the name) through the bone in question. The two x-ray sources double the accuracy in measuring your bone density. So, your bone blocks some of the x-rays. And the more dense your bone is, the less x-rays pass through to the detector.

Then, the amount of x-rays passing through the bone is sent to a computer that calculates an average score for the density of your bone.

A DEXA scan is more accurate than a regular x-ray or CAT scan and requires less radiation exposure. More on this in a moment.

But first, let’s go over the different types of DEXA scans!

There are two DEXA scan variations:¹

1. 1. Central DEXA looks at your whole skeleton, paying special attention to your spine and hips. These machines are usually found in hospitals and medical centers, but some doctors’ offices have them too.
   2. Peripheral DEXA (also called screening tests) are smaller, and focus on your extremities, like your fingers, ankles, and wrists. You often find peripheral DEXA machines in a doctor’s office or smaller medical exam facility. Sometimes, you’ll also see them at health fairs or even bigger shopping malls!

Both Central and Peripheral scans are done on an “outpatient” basis, meaning you aren’t admitted to the hospital to take this test. Central DEXA scans usually take less than 30 minutes, depending on the equipment used and the parts of your body being examined.

In the Central DEXA, you lie comfortably on a padded table. No need to remove your clothes— just make sure there are no zippers that might block the x-rays of your hips and spine. Below the bed is the x-ray generator, and above you is the imaging device.

The person who performs the test will usually place a small pillow to support your legs. This helps your spine lie flat on the table to help get the greatest image. Also, you may find your foot placed in a brace. This keeps your hip nice and still during the procedure. The technician will help you prepare, before walking behind a protective wall. (Remember, the x-ray dose is minimal. But this person takes dozens of x-rays every day, so they need extra protection!)

The imaging detector will pass slowly over your body. During this time you need to hold your breath, but only for a few seconds. Don’t worry, the technician will guide you through it. The scan will produce an image that looks like this:

DEXA scans are the best method to diagnose and monitor osteopenia and osteoporosis. The National Osteoporosis Foundation’s guidelines state you should get a DEXA scan if:

• • you are a woman age 65 or older
  • you are a man age 70 or older
  • you break a bone after age 50
  • you are a woman of menopausal age with risk factors
  • you are a postmenopausal woman under age 65 with risk factors
  • you are a man age 50-69 with risk factors

There are numerous factors that can increase your risk of osteoporosis. Below are a few to watch out for. If you say, “That’s me” to two or more items on this list, it may be a good idea to ask your doctor about a DEXA scan!

• • Gender: Women are at higher risk of developing osteoporosis. This is because estrogen decreases sharply during menopause which accelerates bone loss. In fact, in the five to seven years following menopause, a woman can lose up to 20% of her bone density.²
  • Age: In your lifetime, you increase bone mass from childhood to about your mid-thirties, when you reach your peak bone mass. Then, after age 40, you lose about 1% bone density every year.³
  • Lack of Exercise: Weight-bearing exercise is one of the best things you can do to strengthen your bones. This type of exercise places stress on your bones, which helps them become stronger. On the other hand, if you don’t exercise, your bones will become weaker over time.
  • Diet: A diet lacking in essential nutrients plays a major role in the development of osteoporosis. As you’re no doubt aware, calcium is crucial for healthy bones. But you also need 12 other minerals and three vitamins to support your bone health! Learn more about diet and nutrition here.
  • Family History: Having a family member with osteoporosis puts you at greater risk because osteoporosis has a strong genetic component.⁴
  • Body Size: Women and men who have small body frames tend to have a higher risk for osteoporosis.⁵

A DEXA scan involves lying down— generally fully clothed— on a scanning table. A scanning arm painlessly and non-invasively scans your spine, and then your hips, to determine the quantity of bone you have. The results are calculated in a computer, and you’re told your T-score; one of the results of the bone density test.

If your score is -1.0 or above, your bone density is considered normal. If it’s between -1.0 and -2.5, you have osteopenia. If it’s -2.5 or below,, you have osteoporosis. If you’re diagnosed with osteoporosis, don’t worry!

There are things you can do to reverse your bone loss. In fact, several studies suggest that with a healthy lifestyle and the right combination of nutrients, you can increase your bone density. But prevention is the best medicine, so if you have any concerns about your bone health, it’s in your best interest to get a DEXA scan!

Many people worry about whether they should stop taking calcium before a DEXA scan. That’s because they wonder whether the calcium might overstate their DEXA results. But this fear is largely unfounded…

Undissolved calcium could influence your DEXA scan reading— if you take calcium tablets.⁶ Calcium tablets contain binders that can delay dissolution of the tablets in your gut. However, if you take calcium capsules with powder inside like AlgaeCal Plus, this won’t be an issue.

In fact, AlgaeCal arranged a clinical test to observe the dissolution of AlgaeCal raw powder in stomach acid conditions. The test revealed that 96% of the calcium dissolved within 30 minutes. So, if you take AlgaeCal Plus as your calcium supplement, you never have to worry about DEXA scan overstatement.

Okay, but what if you do take calcium tablets?

Even then, taking your calcium supplement before a DEXA scan will have minimal to no effect on your DEXA results. But there are two groups of people who might want to hold off on their calcium for 24 hours before their scan: Those who have poor digestion and those who have poor calcium absorption.

Either group will have trouble absorbing calcium. And that means any unabsorbed calcium can sit in their digestive tract— and be picked up by the DEXA machine. Now, this unabsorbed calcium in the digestive tract could affect the DEXA reading. But if it did, the effects would be minimal!

That said, if you’re in either of these groups, and you’re concerned about DEXA scan overstatement, don’t take supplemental calcium for 24 hours before your scan. Anything longer than 24 hours is unnecessary and could harm your bone health!

In short, no! As you can see from the chart below, there’s very little exposure when compared to numerous other types of medical imaging procedures. For perspective, the amount of radiation emitted during a DEXA scan (0.001) is less than you’d be exposed to on a flight from New York to L.A.

If you go back a few decades, the only place to measure your bone health was at a hospital using a full body machine. But to meet the demands of the ever-increasing cases of osteoporosis, more efficient machines to test bone density were invented. Today, thanks to the wonders of technology, DEXA machines can safely, quickly, and painlessly spot a bone density issue on the distant horizon— before a bone fracture alerts you to the problem.

Imaging Procedures and Radiation Doses:⁷

The best way to measure your bone density progress is to track the percentage change in your BMD from your previous DEXA scan. Your T-score is a useful indicator of how your bones compare to someone with peak bone density.

But unfortunately, there isn’t a standard scoring system for T-score values, so they vary from one clinic to the next. What’s more, T-score percentages can be a little broad, so your T-score may not change, even though your bone density increased!

So the percentage change in your BMD is the best indicator of your progress. Remember, BMD stands for bone mineral density— a measure of the mineral content in a certain volume of your bone. So if you see an increase in your BMD, your bones are getting denser and stronger. A BMD decrease means your bones are becoming more porous and weak.

Because different clinics use slightly different equipment and scoring methods, it’s best to have all your DEXA scans at the same clinic. This way, you’ll be able to track your progress accurately.

Note: It’s a good idea to have a DEXA scan before you start a new bone health regimen like AlgaeCal (within 30 days ideally). When you have a recent baseline reading, you can more accurately monitor the impact of the new regimen. If your baseline DEXA scan is older than 30 days, you won’t have an accurate starting point for comparison.

You may have heard of a newer measurement called trabecular bone score (TBS).⁸ The trabecular bone score analyzes the internal texture of your bones, their “micro architecture”. A higher TBS means the internal structure of your bones is stronger, while a lower score means it’s weaker.

So, your TBS tells you about the quality of your bones, and your BMD tells you about their density! And these are the two main factors that contribute to bone strength and reduce fracture risk. That’s why BMD alone isn’t always a reliable predictor of fracture risk. There’s another factor to take into account, and that’s bone quality.

Bones can be mineral-dense, and still be brittle. Basically, you end up with a lot of low-quality bone, that’s still prone to fracture.

So, the real test of a program to increase bone density is whether it also reduces fracture risk. The AlgaeCal studies are a perfect example of the power of increased bone density and quality. In all three studies, not one participant suffered a fracture! That’s zero fractures across a total of 802 participants. So if you’re taking AlgaeCal Plus and Strontium Boost (our Bone Builder Pack), your bone quality is certain to benefit just as your bone density increases.

All this to say, it’s worth asking your medical professional whether you can get your TBS score. Since it’s calculated using your DEXA results, it’s possible to run this test after your scan.

First of all, don’t despair! Of course, a low bone density reading isn’t what anyone wants to receive. But it’s not a done deal. There are things you can do to improve your bone health and even see an increase in your bone density on your next DEXA scan. So, think of a low bone density reading as a wake-up call to incorporate bone-healthy practices into your daily routine!

Here’s some information on changes you can make to improve your bone health:

• • Exercise: Exercise is a crucial aspect of bone health. For more information on the most beneficial forms of exercise for bone health and exercise tutorials, click here to visit our exercises page.
  • Lifestyle Changes: Both dietary and environmental toxins can contribute to bone loss. To discover more about toxins that cause bone loss, and what you can do to limit them, visit this page.
  • Bone-healthy Diet: Fuelling your bones the nutrients they need to stay strong and healthy is incredibly important. And it’s just as essential to avoid the foods that will cause chronic, low-grade inflammation… an underlying cause of bone loss! Find out which foods to include in your diet and which to try to avoid on our diet and nutrition page.
  • Supplementation: Your bones require 13 minerals and 3 vitamins, in particular, to stay strong and healthy. Calcium, magnesium, boron, strontium, zinc, selenium, potassium, phosphorus, copper, nickel, vanadium, silicon, manganese, vitamin C, vitamin D3, and vitamin K2. You could try to plan your grocery shop to include enough foods that contain all of those nutrients. Or you could take 16 separate supplements. Or you could take the only supplement duo that includes all of them, and is clinically supported to increase bone density…

AlgaeCal’s Bone Builder Pack consists of AlgaeCal Plus and Strontium Boost.AlgaeCal Plus is a natural calcium supplement derived from a unique species of marine algae. It contains all the vitamins and minerals your bones need to stay strong, healthy, and fracture-free.

And Strontium Boost supports the bone-building of AlgaeCal Plus by providing a little extra safe and natural strontium citrate.

Clinical studies show that the Bone Builder Pack can increase bone density… in as little as six months!

Remember, it’s never too early to start taking care of your bones! So, if you have any concerns about your bone health, be sure to talk to your doctor about a DEXA scan.