Bone health

Bone health across the lifespan — our ever-changing bones

by Dr. Susan E. Brown, PhD

It’s a commonly held misconception that our bones are solid, and exist only to hold up our organs, muscles, and skin. Bones are not just a scaffold made of calcium and other minerals — they are dynamic, living tissue that serves the body in many ways. And contrary to popular belief, our bones are always changing — not just during the growth phases of childhood and adolescence, but throughout our lives. Of course we realize that bone repairs itself when broken — but did you know that new bone formation occurs well beyond the growth spurts of youth? Even when we’re full-grown and have no fractures to heal, new bone is constantly forming to replace old bone that has been broken down in a process called resorption. This coupling together of bone resorption and formation is part of a normal, daily process known as bone remodeling — a state of continual bone turnover that allows fully developed bones to maintain and renew themselves. If there is more bone formation than resorption, our bones become stronger. If the two processes occur at equal rates, our bones are stable. If resorption is greater than formation, our bones weaken.

This last situation — where bones weakness develops because of imbalance in the rate of bone resorption and formation — is a crucial factor in our concerns about osteoporosis, osteopenia, and the potential for hip and spine fractures as we age. As with any body system, our bones tend to function better as we age if they’re treated properly and given the support they need. So it’s important that we understand what our bones need, and attend to those changing needs at each stage of life. Learning about the dynamics of bone remodeling can help you create healthier bones — no matter what your age is right now.

Bone remodeling and bone loss

The living tissue of bone has many components, including three main cell types: osteoblasts, osteocytes, and osteoclasts. Osteoblasts are the cells primarily responsible for new bone formation and bone mineralization — that is, deposit of mineral complexes that make up the bone’s rigid architecture. Osteoblasts are balanced by the activity of osteoclasts, which are responsible for breaking down and recycling old, worn-out bone cells. Osteocytes are osteoblasts that have completed their bone formation function and have become entrapped in new bone tissue. In a sense, they have evolved into structural bone cells that form the building blocks of hard bone. Osteocytes sense stresses on the bone surface, assess the need for remodeling, and signal osteoblasts when and where to build new bone.

At different times in our lives, this process occurs at different rates. Remodeling to one degree or another continues throughout life to such an extent that most of the adult skeleton is replaced every ten years. When we’re young, the body makes new bone faster than it breaks down old bone, and bone mass increases until we reach our peak bone mass, typically in our late 20’s. After that, the bones aren’t quite as efficient at making new bone as they are at breaking it down, so slightly more bone is lost than is gained — which is why even healthy adults will normally see a certain degree of bone loss over time.

A crisis in bone health — and it’s not restricted to the elderly

Even knowing that some bone loss is inevitable as we age, the trends we see in bone health here in the West are disheartening. Today, more than ten million Americans have osteoporosis, and another 34 million have osteopenia (low bone density) — and it’s not just the elderly. In the US, 40% of Caucasian women age 50 and older as well as 13% of Caucasian men will experience a clinically noted, low-trauma fracture of the hip, spine, or wrist sometime during the remainder of their lifetime. The lifetime risk for non-Caucasian women and men is less than that of Caucasians, but still substantial, and rising among certain populations such as Hispanic women. Most worrisome is the fact that poor bone health and low-impact fractures are being seen more often in young adults and children. Clearly, the problem of excessive bone loss is not restricted to any age group. Why is this happening?

The risk of losing excessive bone and developing osteopenia or osteoporosis depends in large part on two factors: first, how much bone mass we attain by our late 20’s (peak bone mass), and second, how rapidly we lose bone as we age. The higher the peak bone mass, the more bone the individual has “in the bank,” making her less likely to develop osteoporosis with age — even if she loses bone relatively rapidly. If for some reason a person fails to build up an ample reserve of bone during youth (due to illness, poor nutrition, inactivity, or simply the genetics of being naturally small-boned), it’s still not necessarily the case that she’ll have excessive bone loss as she ages — the rate of bone loss in age depends on many factors.

So how do you know whether you have healthy bones at whatever age you might be today? Let’s take a look at what happens during different phases of our lives so you can think about how your bone health measures up — and what steps you can take now to prevent problems later on in life.

The origins of bone health — before birth

Bone formation begins long before birth, as early as the third week of gestation. Thus, prenatal nutrition is critical for early bone health, and pregnant mothers should eat as well now as they possibly can. Daily intake of calcium should be on the order of 1200–1500 mg, and adequate vitamin D intake is vital for calcium absorption and to maintain muscle strength. The current recommendation of 400 international units (IU) of vitamin D daily is far too low — a level of 1500–2000 IU is minimally appropriate during pregnancy, and higher amounts may be needed for optimal maternal/fetal health. A recent US study found that a dose of 4000 IU/day maintained vitamin D sufficiency in the mother and also raised vitamin D in breast milk to the point where there was no further need for infant supplementation. If the mother’s nutritional needs during this time go unmet, the baby may be born with low birth weight and low bone mass. Stress and environmental toxins may also affect fetal bone development, which is why an expectant mother is counseled to avoid smoking, alcohol, and unnecessary chemical exposure.

Obviously, you can’t do much about how well or poorly your mother ate before you were born! But we’re telling you about this to offer some perspective about where bone health begins, so you can trace your own bone health, or that of your children, back to its origins.

Bone health in infancy (ages 0-3)

During infancy we undergo a period of rapid skeletal growth. Our perinatal nutrition is vital to our later health. Thankfully, most new mothers today are encouraged to breastfeed their newborns. Not only does breast milk provide nutrients essential for physical development, it also supports the development of a strong immune system and offers emotional benefits for both mother and child that likewise convey health benefits. If the mother decides to breastfeed, her nutrition is crucial for this phase of rapid infant growth, and she will need to take in 1200–1500 mg of calcium daily until her infant is weaned. Thereafter, the child will need between 270 and 800 mg of calcium daily. Vitamin D requirement depends on sun exposure and skin pigmentation, but most 2–3-year-olds would benefit from 800–1000 IU/day.

Again, infancy is long in our past and we can’t change what we were given to eat. But you may have been told some details of your early childhood, or maybe your mother maintained a “baby book” for you — all useful information that helps build a picture of how your bones have developed.

Bone health in childhood through early adolescence (ages 4-12)

During early childhood, bone growth slows — until the well-recognized adolescent growth spurt. It is during this time that bone responds most to “mechanical loading” — in other words, if, during these years, children are physically active, the skeleton adapts by growing stronger and denser. Because at least one-quarter of all peak adult bone mass is accumulated during adolescence, this period offers a window of opportunity to strengthen bones with healthy diet and exercise.

Pre-teens should consume at least the full RDA of calcium (1300 mg/day), magnesium (240 mg/day), zinc (8 mg/day), manganese (3 mg/day), copper (700 mcg/day), vitamin C (45 mg/day), and all the other 20 key bone nutrients. We now know that vitamin D is even more important than calcium to growing bone, and that it is of tremendous significance during adolescence. On average, 1000-2000 IU vitamin D daily provide for an optimum blood level of this key nutrient.

As rapid bone growth calls on the body’s stores of all 20 key bone nutrients, it is a good idea for a pre-teenager to take a high-quality multivitamin with all the key bone nutrients daily to ensure nutrient adequacy. Sugar, processed foods, sodas, and fatty snack foods should be consumed very infrequently — these are “empty calories” because they supply calories that encourage weight gain, but provide few, if any, life-supporting nutrients.

Take a moment to look back on your childhood. Were you healthy or did illness keep you home from school? Were you a picky eater who turned down vegetables, or did you often enjoy all the foods you were offered? Did you run and play outside daily, or were many of your days spent indoors, reading or watching TV? Did you eat junk food a lot, or rarely? All these factors contribute data to the expanding portrait of how your bones developed as you grew.

Bone health in the teenage years (ages 13-19)

The teen years, are also a time of rapid bone growth and high nutrient utilization. Ideally teenagers should consume a diet high in fruits and vegetables (at least 8-10 servings a day) with dairy foods as tolerated, providing plenty of calcium (1200–1500 mg daily), magnesium (400-800 mg day), vitamin D (1000-2000 IU/day), and all of the other 20 key bone nutrients in adult doses by age 15-16.

Current national statistics, unfortunately, show that few adolescents or teenagers obtain the nutrients they need. According to the 2001-2002 National Health and Nutrition Examination Survey (NHANES), the average daily calcium intake of girls ages 9–13 was just 865 mg. While the RDA for magnesium in the mid-teens is 410 mg, the average intake of mid-teen girls was only 206 mg. Sadly, many girls in our culture suffer from eating disorders which, if left unaddressed, can have long-term consequences for their bones. Meanwhile, consumption of sugary foods and soft drinks (including diet soda) continues to rise during these years and is detrimental to bone. Cola consumption by girls, for example, has been found to increase fracture risk 300-500%.

Widespread suboptimal nutrient intake appears common among teens and sets the stage for bone problems later in life. During these growing years, exercise is also more important than ever, as is adequate sunlight and vitamin D (1000-2000 IU/day).

Again, think back to your teen years. Answer the same questions we offered in the previous section. Your answers point to whether your bones were able to build “to the max” during this time, and give you some clues as to how proactive you may need to be about bone health as you age.

Bone health in early adulthood (ages 20-45)

By our late 20’s, bone growth is generally complete. By our mid-30’s, most of us gradually begin to lose bone strength. Thus, this is a critical time to focus on bone strength maintenance. Broad-spectrum nutrition and an active lifestyle continue to be important — especially for women, whose bones will benefit from consuming all the key bone nutrients in ample amounts and significant weight-bearing exercise.

Women should also pay special attention to hormonal balance during this time, because imbalances may lead to bone loss. Irregular periods or loss of the menstrual period for any reason can jeopardize bone. Emotional disturbances have also been shown to impair hormonal balance; thus, extra steps to alleviate depression, anxiety, and stress are a worthwhile investment for not just your happiness but your lifelong bone health as well. This is easier said than done — but choosing an optimal diet, getting regular exercise, and cultivating supportive relationships can help to maintain healthy emotional states.

If you’re in this life stage, it’s a good time to begin to take a second look at your dietary patterns. Increasing your intake of alkaline-forming foods to include 10-13 servings per day of vegetables, legumes, fruits, nuts and seeds is one of the most powerful things you can do to preserve both bone and muscle during this stage of your life. And if you consume a lot of sugar or alcohol, consider the benefits of tapering off or even giving the habit up to protect your bone health.

Bone health in middle age (ages 46-53) — special concerns for perimenopausal women

In the middle-adult years, there are special concerns for women as their bodies start to undergo major hormonal shifts. Perimenopause refers to the years around the time that women stop having menstrual periods. During perimenopause, when hormone levels can vary dramatically, bone loss can occur at a very high rate. It has been reported that most perimenopausal women lose bone mass at about 2% per year during this time — and this is natural and to be expected (see my article on bone health in perimenopause) — but I have even seen a few women lose up to 20% of their bone density during the years around menopause.

Nutrition is critical during this time to slow bone loss. Studies worldwide have shown that an alkalizing diet rich in potassium, zinc, magnesium, and fiber is associated with higher bone-mineral density. In addition, higher vitamin K intake has been associated with higher bone mineral density and reduced bone resorption (breakdown) in the early postmenopausal period . Further new studies suggest women experience an increased need for vitamin K during menopause. Vitamin D is also essential for calcium absorption and the maintenance of muscle strength. Sufficient daily intake allows us to obtain an ideal blood level of 50–70 ng/mL 25(OH)D. While we can manufacture vitamin D from sunlight, how effectively we are at this varies greatly between individuals, depending upon season, where we live, skin pigmentation, and even our body mass index! So most midlife women would do well to supplement what they get from the sun with 1500-2000 IU a day.

Exercise (particularly weight-bearing exercise) is also important for maintaining bone health. To gain this benefit, middle-aged adults should participate in regular strength-building exercise at least three times a week. Several studies document how women can halt perimenopausal bone loss, and even build bone at this time, with a serious strength-training program.

If you’re in this age range and suspect that you have low bone density, it is a good idea to have a baseline bone-density measurement. Alternatively, you can have your urine tested periodically for markers of bone breakdown, which can tell you whether your bones are stable or are actively losing bone over time. In either case, you may want to seek individualized advice on how to use nutritional supplements, diet, and exercise to maximize bone health during this life stage. (For more information on bone health during the menopausal transition, see our article on menopause and bone loss.)

Bone health in mid to late adulthood (ages 54-75) — special concerns for postmenopausal women

The good news for women is that the accelerated bone loss typically experienced in perimenopause and menopause usually slows down within five to six years after the last period. After that, normal bone loss may average 0.5% to 1% per year. The concern, however, is that by the time bone loss slows down, many women have already lost an awful lot of bone. In the US, it is estimated that 37–50% of all postmenopausal women are osteopenic, and 13–18% are osteoporotic, using the World Health Organization’s definitions of these bone disorders. More recent data from the Canadian Multicentre Osteoporosis Study (CaMOS) indicate that these rates are on a par with those of women in Canada, with some 15% of Canadian women over 50 having osteoporosis by definition.

But there’s more good news, and this applies to both sexes: you can rebuild much of that lost bone through the everyday choices you make. For many postmenopausal women, stabilizing and rebuilding bone might be as easy as taking supplements that provide moderate doses of selected key bone-building nutrients.

Among these, vitamin D is paramount to healthy calcium absorption and utilization, as well as maintaining muscle strength. As we age we tend to become less efficient at generating vitamin D through sun exposure, so our risk for vitamin D deficiency increases. Our intestines cannot absorb calcium from the diet as well when we’re deficient in vitamin D, so the body responds by producing more parathyroid hormone, which draws calcium from bones to keep calcium blood levels at their critical levels. Before age 60, vitamin D intake should be at least 1000-2000 IU/day, and after age 60, vitamin D intake for most should be at least 2000 IU/day, with blood level testing to determine exact need. Some women may need more — 4000 IU/day or higher — to bring levels up to where they can halt or even reverse further bone loss.

Yet another opportunity where you have the lifelong ability to maintain and rebuild bone is with exercise. Dr. William Evans, who leads the US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, specifically studied the effects of exercise on postmenopausal women. Think of it this way: if you’re building muscle, you’re building bone. So any regular physical activity (four or more hours a week) helps to maintain bone, but strength-building (or weight-bearing) exercises are the most effective at building bone. One hour of rigorous exercise three times weekly (such as weight-training and aerobics combined) can yield great bone-strengthening benefits. And it doesn’t need to be a high-impact workout in a gym — gentle exercises like qi gong, Pilates, and yoga can be effective for building bone, muscle strength, and balance.

There are several other lifestyle factors that can influence your bones for better or worse, and this is a good time to consider their effects. Many medications, for example, can impair bone health. In particular, anti-inflammatory drugs called corticosteroids, commonly prescribed to women over 55 for conditions like asthma, auto-immune diseases, and other inflammatory conditions, are known to directly lead to bone loss. According to the American College of Rheumatology, 20% of all osteoporosis in the US is attributable to corticosteroid use!

Many women on corticosteroids are offered bone drugs like Fosamax, but there are other alternatives you can discuss with your healthcare provider. It may be possible for you to taper or stop taking these drugs altogether — it is certainly worth a trial. Even if you cannot discontinue the drugs right away, all the additional steps we’ve discussed that improve bone health remain available to you at all times — increasing your weight-training, eliminating damaging lifestyle factors to the extent you can (smoking, drinking alcohol and soda, eating sugary foods), and making sure you get good nutrition. (See our article on inflammation and bone health for an explanation of the underlying mechanisms.)

Bone health in the elder years (ages 76 and up)

From age 75 years on, bone fragility becomes much more common in both women and men, though osteoporosis is two to four times more common in older women. While most American women under the age of 50 have normal bone density, by the age of 80 about 27% are osteopenic, and 70% are osteoporotic at the hip, lumbar spine, or forearm. Regardless of bone density or sex, fracture risk increases exponentially with age. That said, we do not have to become a statistic!

While aging itself is naturally associated with bone loss, certain nutritional risks also increase with age. For one, the elderly often experience diminished appetite and under-consume calories, protein, and other bone-building nutrients. We also tend to produce less stomach acid as we grow older, dampening the fires of digestion and, consequentially, intestinal absorption. Furthermore, kidney function tends to slow as we grow older, compromising our capacity to offset chronic low-grade metabolic acidosis — another reason why an alkaline diet serves lifelong bone health. And as mentioned above, risk of vitamin D deficiency increases with advanced age. Recent research by vitamin D authority Dr. Robert Heaney reports that older individuals as a whole need at least 2600 IU supplemental vitamin D to ensure adequate blood levels of this key bone nutrient.

Nutritional supplement support is one of the simplest, most cost-effective ways to reverse bone loss and reduce hip fracture risk. Let’s take a look at just one bone-critical nutrient: vitamin D. In one large study, women with an average age of 84 who took a daily supplement containing 1200 milligrams of tricalcium phosphate and 800 IU vitamin D3 had an average 2.7% increase in hip bone mineral density, while unsupplemented women lost 4.6% bone mineral density. Most importantly, hip fractures were reduced by 43%, and all nonvertebral fractures by 32% in supplemented women. A separate, innovative study in Romania gave 5000 IU D3 to elderly nursing home residents daily, producing an astonishing 23% gain in hip and 4% gain in spine bone density.

Indeed, vitamin D deficiency is the rule among the elderly, and up to 90% of all hip fracture patients are deficient in vitamin D. Overall studies suggest from 50-60% of hip fractures could be prevented with adequate dose vitamin D supplementation. All elderly should be tested for vitamin D and supplemented to reach an ideal 50-70 ng/mL level.

In addition, we encourage the elderly to maintain optimal intake of calcium, magnesium, phosphorus, protein, and all the other key bone nutrients — at least at RDA levels. This one measure alone could improve the health and overall quality of life in older people by leaps and bounds, and at such a minimal cost.

Better bone health at any age

While the majority of bone building takes place earlier in life, it is important to understand that it’s never too late to improve your bone health. Along with sound nutrition and optimal supplementation, one of the most powerful ways for elderly people to avoid or alleviate bone loss is through exercise. Study after study has shown that even in elderly women, a program of regular exercise, particularly strength-training, helps to maintain muscle and bone mass and improves balance, reducing the risk of falls and debilitating fractures.

Beyond the benefits of exercise, the recent breakthroughs in bone health provide exciting opportunities for every woman to have strong bones throughout her lifetime. We now know that Mother Nature provided us with ample bone to last a lifetime. We have also learned that there are at least 20 nutrients that are essential for bone health, not just calcium, and that the optimal bone-protective level of vitamin D is much higher than previously recognized. We’ve seen that vitamin D in optimal doses can likely reduce hip fracture incidence by 50-60%. We’ve also found that a diet high in alkaline-forming fruits, vegetables, nuts, and seeds may well be even more important to bone than boosting calcium intake. And finally, we’ve discovered that throughout life, our bones respond to the demands placed upon them to support us and strengthen us — as long as we remember to give back. No matter what your age or fitness level, better bones are within your power, and now is the perfect time to begin.

Our Personal Program for Better Bones is a great place to start

The Personal Program for Better Bones promotes natural bone strength and regeneration with nutritional supplements, our exclusive bone builder formula, dietary and lifestyle guidance, and optional phone consultations with our Nurse-Educators. It is based on over 25 years of research and experience and has helped thousands of women reclaim their bone health.

• To learn more about the Personal Program for Better Bones, go to How it works.
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If you have questions, don’t hesitate to call us toll-free at 1-800-685-3275. We’re here to listen and to help.

Related to this article:
References & further reading on healthy bones at any age

 

Original Publication Date: 01/01/2009
Last Modified: 08/17/2009
Principal Author: Dr. Susan E. Brown, PhD