HEALTH OUTCOMES OF LONG-TERM CALCIUM AND VITAMIN D SUPPLEMENTATION IN WOMEN

Medically Reviewed by Dr. Rosmy Barrios - September 04, 2024

Understanding the intricate balance between bone health and heart issues is crucial when considering long-term calcium and vitamin D supplementation, particularly in post-menopausal women. The function of calcium and vitamin D in bone health, especially in preventing osteoporosis, is well-established. However, delving deeper into extended supplementation reveals potential benefits as well as emerging concerns.

This article explains the recent findings assessing the use of calcium and vitamin D for bone health in women and alternative strategies for managing bone health alongside supplementation.

Women's Health Initiative Study

The original Women's Health Initiative (WHI) study, which took place in the early 2000s and assessed supplementation in over 36,000 post-menopausal women, found that calcium and vitamin D supplementation did not significantly impact the risk of coronary or cerebrovascular events in healthy postmenopausal women over a 7-year use period. 

The results of a recent 22-year follow-up study confirmed an elevated risk of 1-12% for cardiovascular events in postmenopausal women on calcium and vitamin D supplementation. The variance was lower than the previous observations, with the average slightly higher at 6%.

It was also found that Vitamin D with calcium supplementation reduced the risk of cancer-related mortality by 1-13%, averaging 7% across the participants. There was no significant link between supplementation and all-cause mortality rates.

While these results have intriguing implications for cardiovascular health and cancer patient outcomes, the authors of the follow-up acknowledge that the study did not take joint supplementation into account or the individual effects of calcium versus vitamin D supplementation.

It is also crucial to note that the relationship between calcium and vitamin D is complex and warrants further research. Many other investigations into the topic have given rise to contradictory results over the last two decades, identifying potential benefits, risks, and factors that influence the outcome individually.

The Benefits of Long-Term Supplementation

Calcium and vitamin D are a dynamic pair for bone health, especially crucial for women after menopause.

The long-term benefits of vitamin D and calcium supplementation are discussed below.

Improved Bone Mineral Density

Bone mineral density (BMD) is a measure of the amount of minerals, such as calcium, in your bones. A higher BMD indicates stronger bones and a lower risk of fractures.

Estrogen is vital in regulating bone remodeling and favoring bone formation, which requires calcium to sustain. It acts on receptors in osteoblasts and osteoclasts to inhibit bone resorption (breakdown). It also boosts calcium absorption directly in the gut and indirectly through kidney enzymes that promote its reuptake^[1].

During menopause, estrogen levels decline significantly. With lower estrogen, bone breakdown can outpace formation, inducing a loss of bone mass and an increased risk of osteoporosis (weak, brittle bones). The increased bone resorption leads to a rise in serum calcium in women. Declining estrogen levels also promote lower calcium absorption from the digestive tract and a higher excretion from the kidneys into urine.

Adequate calcium intake ensures enough building material for bones. 1,25-dihydroxy vitamin D, an active form of vitamin D, regulates active calcium absorption through vitamin D receptors in intestinal cells and ensures it reaches the bones.

By working together, vitamin D and calcium can help sustain optimal bone density and lower the incidence of osteoporosis after menopause. Long-term supplementation with calcium and vitamin D can improve BMD in post-menopausal women^[2], reducing their risk of osteoporosis and fractures.

Reduced Fracture Risk and Osteoporosis Prevention

The most well-known benefit of long-term calcium and vitamin D supplementation is the reduced risk of fractures and prevention of osteoporosis. Osteoporosis and fractures are especially common in post-menopausal women due to their declining estrogen levels, which are a requirement for maintaining bone mineral balance.

Studies have shown that long-term supplementation with calcium and vitamin D can help avert the onset of osteoporosis and decrease fracture risk in post-menopausal women. A 2015 study observed decreased total and hip fracture risk among women who adhered to calcium and vitamin D supplementation. Those who supplemented experienced a 15% lower risk for bone fractures and a 30% risk reduction for hip fractures.

Improved Muscle Function and Fall Prevention

Adequate vitamin D levels from supplementation can improve muscle function, which is another factor that can lower the risk of falls and fractures in women after menopause.

A study published in BioMed Central indicates that higher levels of estradiol and vitamin D share a connection with better muscle mass and function in postmenopausal women. Estrogen regulates muscle growth and function, while vitamin D has been found to have a potential direct effect on muscle health. In this regard, supplementing with more vitamin D may help preserve muscle health in postmenopausal women.

Other Potential Benefits

Emerging research suggests that vitamin D supplementation may offer additional benefits beyond bone health, including:

• Improved immune function: Vitamin D is known to modulate the immune system. It regulates the development and function of immune cells, including monocytes, macrophages, and dendritic cells. It also influences cytokine production (signaling molecules involved in the immune response)^[3].
• Lower Cancer Risk: Supplementation may lower the risk of acquiring certain types of cancers, such as colorectal, bladder cancer, and invasive breast cancer. These findings are from observational studies. Results from clinical trials reveal no link between vitamin D supplementation and a lower incidence of cancer^[4]. The results from other studies are mixed, suggesting that long-term supplementation may increase the risk for prostatic and pancreatic cancer despite posing potential protective benefits.
• Deficiency Elevates CVD Risk: Studies suggest that low vitamin D levels are typical in patients with CVD, stroke, and heart failure. Deficiency and low bone mineral density are also associated with cardiovascular disease risk factors, yet supplementation yields mixed results. Some studies show that elevated serum vitamin D levels are linked to exhibiting a lower degree of vascular calcification, which may lower the risk for atherosclerosis. More research is needed to confirm whether vitamin D supplementation can effectively reduce CVD risk.^[5]
• Low Vitamin D and Metabolic Disease: Above cardiovascular disease, 25-OH D deficiency is associated with hypertension, obesity, glucose intolerance, and metabolic syndrome.^[6]

By exploring these potential benefits, individuals can understand the holistic impact of long-term calcium and vitamin D supplementation on their overall health and well-being.

Potential Concerns and Side Effects

Following recommended dosages and consulting with a healthcare professional before starting any long-term supplementation is crucial.

The effects of excessive amounts of supplemental calcium and vitamin D:

Cardiovascular Risks

As explained, the WHI study raises concerns about a possible link between long-term calcium and vitamin D supplementation and the odds of cardiovascular events occurring in postmenopausal women^[7]. The chances of contracting a cardiovascular event, such as a heart attack, appear higher for postmenopausal women consuming over 1400 mg of calcium per day.

The findings emphasize the need for further investigation and caution when considering calcium supplementation, particularly in individuals with existing cardiovascular risks.

Calcification and Kidney Stone Formation

Excessive vitamin D and calcium intake can lead to hypercalcemia, where blood calcium levels are too high. Symptoms may include^[8]:

• Dizziness
• Frequent urination
• High blood pressure
• Digestive symptoms, such as nausea, vomiting, constipation, diarrhea, and appetite loss
• Altered mental status
• Confusion

Hypercalcemia can also result in the deposition of calcium in soft tissues, leading to complications like:

• Kidney stones
• Calcification of blood vessels
• Impaired organ function

On the other hand, vitamin D supplementation is linked with lower blood vessel calcification, kidney protective benefits (especially in those with kidney disease), lower blood C-reactive protein, and a general anti-inflammatory effect. This indicates that the balance between calcium and vitamin D is crucial for the best outcome.

Interference with Medications

Certain medications, including blood pressure-lowering drugs, antibiotics, and medications for osteoporosis, may interact with calcium supplements which might affect their effectiveness^[9]. Bile acid sequestrants can diminish vitamin D absorption and interfere with calcium absorption^[10].

It can help avoid taking the above medications and vitamin D and calcium supplements. It is vital to discuss with a healthcare professional the optimal dosage, timing, and suitability before starting any supplementation, especially if you are taking medications.

The Latest Research and Considerations

In addition to the findings from the WHI study, newer research has focused on optimizing dosage recommendations, considering individual needs and risk factors, including:

• Age
• Ethnicity
• Seasonal variance
• Altitude
• Dietary intake
• Sunlight exposure
• Specific health conditions

Genetic Influences on Vitamin D Metabolism: Researchers have been exploring the potential influence of genetic factors and baseline vitamin D levels on the effectiveness of supplementation. Genetic variations in how the body processes and absorbs vitamin D may impact the response to supplementation, making it important to consider individual genetic profiles when determining the effectiveness of supplementation.

For example, vitamin D and calcium levels are elevated in some individuals genetically predisposed to kidney stone formation^[11]. Skin type and sun tolerance also impact how the skin produces active vitamin D3, leading to variations amongst those of different ethnicities^[12].

Complementary Strategies for Bone Health Management

In the quest for comprehensive bone health management, researchers are also investigating alternative strategies to supplementation with calcium and vitamin D.

Nutritional interventions, such as incorporating a well-balanced diet rich in bone-healthy nutrients (such as potassium, vitamin K2, vitamin C, and magnesium). Specific exercise programs that focus on weight-bearing and strength-training activities have been explored as potential adjuncts to supplementation. These are essential approaches that contribute to optimal bone health.

By incorporating these suggestions into daily life, individuals can complement the effects of supplementation and promote overall bone strength.

Vitamin D Sources

While supplementation is a common strategy for increasing vitamin D levels, it is important to also focus on obtaining vitamin D from natural sources.

Spending time in the sun can stimulate the body's production of vitamin D. However, it is essential to practice proper sun protection and avoid excessive exposure.

Additionally, foods with a rich vitamin D and calcium content can help boost blood levels of these nutrients and contribute to optimal bone maintenance. Food sources include^[13]:

• Fatty fish such as salmon, sardines, mackerel, and tuna
• Leafy green vegetables, including collard greens, kale, cabbage, okra, dandelion greens, and broccoli

Should Women Take Calcium with Vitamin D?

The decision to take calcium with vitamin D should be made on an individual basis, considering various factors such as age, dietary intake, and existing health conditions. It is generally recommended for women, particularly post-menopausal women, to ensure adequate calcium and vitamin D intake for bone health.

One study revealed the following about postmenopausal women and increasing vitamin D and calcium requirements:

• Vitamin D intake of 500-800 IU daily increases bone mineral density in women around 63.
• For women over 65, 800-900 IU of vitamin D and 1200-1300 mg of calcium daily improve bone health further.

However, it is essential to confer with a qualified healthcare professional to understand your appropriate dosage and prescription period based on your individual needs and risk factors.

Lifestyle Modifications

A wholesome lifestyle plays a prime role in maintaining strong and healthy bones. Consider the following lifestyle modifications for optimizing bone health:

1. Regular Weight-Bearing Exercise: Engaging in weight-bearing exercises^[14] like walking, jogging, dancing, or strength training can stimulate bone growth, boost bone density, and enhance overall bone strength.
2. Weight Management: Bone health depends on maintaining a healthy weight. Excessive weight can strain the bones, while being underweight can lead to decreased bone density^[15]. Aim for a balanced weight that is appropriate for your body type.
3. Avoid Smoking: Smokers often display lower vitamin D levels^[16], decreased bone density, and increased fracture risk^[17]. Quitting smoking and avoiding secondhand smoke exposure can contribute to improved bone health.

Individuals can significantly improve their bone health by focusing on vitamin D sources, engaging in weight-bearing exercise, managing weight, and avoiding smoking. These lifestyle modifications and calcium and vitamin D supplementation synergistically support and maintain strong bones.

Remember, it is best to book an appointment with a healthcare professional or registered dietitian before making noteworthy changes to your diet or supplementation regimen. They can offer guidance and design a diet plan to suit your individual requirements and health conditions..

Conclusion

In conclusion, long-term calcium and vitamin D supplementation can significantly benefit post-menopausal women's bone health. However, it is crucial to consider potential concerns and limitations and alternative strategies for managing bone health. By following recommended dosages, getting vitamin D from natural sources, and making lifestyle modifications, women can support stronger bones and lower their odds of developing osteoporosis and fractures. Conferring with a healthcare expert before starting any supplementation regimen is best.

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