BLOG

Bone remodeling is a process that persists throughout our lives, involving a continuous cycle of breaking down old bone tissue and replacing it with new bone. Bone building is most active during adolescence when the body is in a growth phase. In fact, peak bone mass is achieved around the age of 15 to 20 in women and between 25 and 30 in men.

After this point, bone turnover gradually decreases. As we age, our bones begin to lose more tissues than they gain, leading to a net loss of bone density. This shift can eventually lead to osteoporosis, a condition marked by fragile bones that are highly susceptible to fractures. For older adults, these fractures can have serious consequences, including prolonged disability or even fatal outcomes. Osteoporosis is particularly prevalent in postmenopausal women, where hormonal changes exacerbate bone loss.

While factors such as age, sex, and genetics are pivotal in determining bone health, there are several proactive strategies that can help mitigate bone loss. Engaging in regular weight-bearing exercise, ensuring adequate intake of calcium and vitamin D, and adopting a balanced diet rich in bone-supportive nutrients are all effective measures to maintain bone density and reduce the risk of osteoporosis as we age.

Exercise

Weight-bearing exercise, which includes walking, running, and resistance training (weightlifting), places stress on bones, stimulating osteoblasts (the cells that produce bone) and leading to increased bone density and strength. This is defined by Wolff’s Law, which states that bones will adapt to the forces placed upon it, becoming stronger in response to increased load. Not only does exercise strengthen bones, but it also strengthens the muscles that support them. Stronger muscles improve balance and coordination, reducing the risk of falling, which is the leading cause of fractures in older adults. According to the U.S. Department of Health and Human Services, all adults should aim for at least 150 minutes a week of moderate-intensity exercise or 75 minutes a week of vigorous-intensity exercise, including aerobic and weight bearing exercises).

Calcium

Calcium is the most abundant mineral in the human body with over 99% of it stored in our bones and teeth. It is vital for bone remodeling, as it is required for the mineralization of the newly formed bone matrix by osteoblasts. Calcium is essential not only for building and maintaining strong bones but also for crucial physiological processes such as nerve transmission, muscle contraction, and blood clotting. When calcium intake is insufficient, the body prioritizes these vital functions by drawing calcium from the bones, which can lead to a reduction in bone density. This challenge becomes more pronounced with age, as the body’s ability to absorb calcium from dietary sources diminishes.

The National Institutes of Health state that women ages 19 to 50 need 1,000 milligrams of calcium each day, and 1,200 milligrams if they’re 51 or older. Men ages 19 to 70 need 1,000 milligrams, or 1,200 if they’re older. Calcium-rich foods include milk, yogurt, beans, tofu, sardines, and leafy green vegetables like kale and collard greens. For perspective, one cup of low-fat Greek yogurt provides about 25% of the daily calcium requirement for most adults.

Although calcium is best absorbed through food and beverages, some individuals may struggle to meet their calcium needs through diet alone—particularly those who are lactose intolerant, have gastrointestinal issues, or follow a vegan diet. In such cases, calcium supplements may be necessary to ensure adequate intake.

Vitamin D

Vitamin D promotes bone health by helping the body absorb the calcium we ingest. Individuals between the ages of 1 and 70 should aim to consume 600 IU (international units) of vitamin D per day, while those aged 70 and older require 800 IU daily.

The most effective way to obtain vitamin D is through exposure to sunlight, particularly the sun’s ultraviolet B (UVB) rays. Even brief exposure can lead to significant production of vitamin D. However, certain groups are at greater risk of vitamin D deficiency due to limited sun exposure. For instance, disabled individuals and infants may spend less time outdoors, while people over 70 have reduced skin efficiency in synthesizing vitamin D. Additionally, those with darker skin have higher levels of melanin, which acts as a natural sunscreen, reducing UV light absorption and requiring longer sun exposure to produce sufficient vitamin D compared to individuals with lighter skin.

To compensate for insufficient sun exposure, incorporating vitamin D-rich foods into the diet is essential. Foods and beverages such as salmon, tuna, egg yolks, milk, and orange juice are examples. For those who may not get enough vitamin D from sunlight or diet, supplements such as vitamin D2 and vitamin D3 are available, but it is not clear whether it helps with bone health. Recent research suggests vitamin D supplements may not significantly reduce fracture risk. Therefore, consulting with a healthcare provider is advisable to determine whether supplementation is appropriate for your individual health needs.

Protein

Proteins make up about 50% of bone volume, with collagen being the most prevalent. Collagen provides a flexible structure allowing for strength while enabling the bones to withstand stress without breaking. Protein is also vital for bone remodeling, as it is required for the formation of new bone tissue.

The importance of protein is illustrated in a 2021 study involving over 7,000 older adults residing in senior living centers in Australia. Participants who consumed 3.5 servings of dairy per day—rich in both calcium and protein—experienced a 33% reduction in fractures over two years compared to those who consumed only two servings daily. The study’s authors noted that this reduction in fracture risk is comparable to the effects of certain osteoporosis medications designed to prevent fractures.

Federal guidelines recommend that most adults consume 0.36 grams of protein per pound of body weight daily. For someone weighing 185 pounds, this equates to approximately 67 grams of protein each day. However, research suggests that adults aged 65 and older might benefit from a higher protein intake—around 0.45 to 0.54 grams per pound of body weight per day, which would be about 84 to 101 grams of protein daily for a 185-pound individual. Protein-rich foods that can help meet these needs include Greek yogurt, salmon, chicken, beef, eggs, almonds, beans and lentils. There is good evidence that a sufficient intake of plant-based proteins can meet daily requirements.

Other Vitamins and Minerals

Magnesium and phosphorus are two essential minerals for maintaining bone health. Magnesium supports bone density, calcium metabolism, and the balance of bone remodeling, while phosphorus is crucial for bone mineralization and structural integrity. Leafy greens, fruits, nuts and legumes, for example, are rich in both magnesium and potassium.

A balanced diet, such as a Mediterranean-type diet that includes a variety of vitamins and minerals is crucial for maintaining strong and healthy bones. Along with calcium, vitamin D, phosphorus, and magnesium, other nutrients work synergistically to support bone formation, maintenance, and overall skeletal health. These include zinc, manganese, copper and vitamin C. Importantly, regular physical activity, particularly weight-bearing exercise, complements these dietary efforts to optimize bone health throughout life. Adhering to these guidelines will add a significant component to healthy aging related to bone health.