It is well established that adequate calcium intake is important to prevent osteoporosis. Since osteoporosis is a disease that most commonly affects the elderly, they are typically the subject of clinical studies on calcium.

In a 1997 study, 318 volunteers over the age of 65 participated in a double-blind, placebo-controlled study. This three-year study found that total body bone mineral density was improved in the group receiving calcium and vitamin D.However, it did not show a significant difference in the bone mineral density at the hip and femoral spine between the two groups. The placebo group exhibited a higher fracture rate, at 12.9% compared to 5.9% for the group receiving calcium and vitamin D.

An even larger study on 1,765 elderly women found similar results to the trial mentioned above. This 1992 study found 32 percent fewer non-vertebral fractures and 43 percent fewer hip fractures in a group receiving vitamin D and calcium versus the placebo group. After 18 months, the group receiving vitamin D and calcium also experienced a 2.7% increase in bone density at the proximal femoral region, while the placebo group had a 4.6% decrease. This study did not show any changes in serum creatinine, phosphorus, osteocalcin, and total protein concentrations. The studies above were on the elderly, and more studies should be performed on a wider group of the population.

A double-blind, placebo-controlled study with 930 volunteers gave participants 1,200mg of calcium or a placebo for 4 years. Subjects were monitored over the course of the study and for several years after.. During the course of treatment, only 15 participants experienced fractures from minimal trauma in the treatment group, compared to 29 participants from the placebo group. The benefit of the calcium was only found during the supplementation period. In the years after the treatment had ended, no benefit was found.

In 2010, a data analysis was performed on 68,517 participants to prove the effects of calcium and vitamin D. Seven randomized studies were included in the data analysis, which included over 1,000 participants. This meta-analysis reported: “trials using vitamin D with calcium showed a reduced overall risk of fracture and hip fracture. For vitamin D alone in daily doses of 10 micrograms or 20 micrograms, no significant effects were found.” This data supports the synergistic effect of calcium and Vitamin D.

Post-menopausal women, who have the highest rate of osteoporosis, were selected for a 2009 clinical study on the effects of Vitamin K on bone health. 244 healthy postmenopausal women were given 180mcg per day of vitamin K2 or a placebo for three years, and their bone strength and density was measured each year. Vitamin K2 reduced age-related decline in bone mineral content and bone mineral density at the lumbar spine and femoral neck, but not at the total hip. Bone strength was affected positively by vitamin K2 and a decrease in the loss of vertebral height in the lower thoracic region was found.

In a 1991 study, blood samples were taken from two groups in order to review the levels of vitamin K2. The subjects in the first group had osteoporosis and had experienced a recent fracture; those in the second group were healthy and did not have osteoporosis. Vitamin K2 levels were significantly higher in the group without osteoporosis. In the osteoporosis group, only two of the 29 patients were getting sufficient levels of vitamin K2.

Calcium has been shown to be beneficial for gestational hypertension. A double-blind, placebo-controlled study was performed on 189 pregnant subjects from 20-weeks’ gestation until delivery. The rate of pregnancy-induced hypertension was 8.24% in the calcium group and 29.03% in the placebo group. The incidence of gestational hypertension was 6.18% in the calcium group and 17.20% in the placebo group. The rate of preeclampsia was also lower for the calcium group, at 2.06%, compared to 11.82% in the placebo group.

A 1999 clinical trial on 456 pregnant Australian women also examined the effect of calcium on gestational hypertension. This study concluded that calcium reduced the risk of preeclampsia and pre-term birth, but did not decrease the frequency of pregnancy-induced hypertension.

In 2010, a meta-analysis reviewed 13 high-quality studies involving a total of 15,730 pregnant women. Twelve of the 13 studies including 15,470 subjects suggest that calcium supplementation reduces the risk of hypertension during pregnancy. The analysis also concluded that calcium reduces the risk of preterm birth. Most of the women in the trials were low-risk for pre-term birth and had a low calcium diet.

Excessive alcohol consumption inhibits calcium absorption and has been shown to obstruct the production of vitamin D, which is needed for calcium absorption. People who drink alcohol daily should consider calcium supplementation.

Studies have shown that smoking is harmful to your bones. If you are a smoker, it is important to get enough calcium and vitamin D through diet or supplementation.

Studies have shown that smoking is harmful to your bones. If you are a smoker, it is important to get enough calcium and vitamin D through diet or supplementation.

Vitamin D is found in our diet, but we also produce it through exposure to sunlight. Research suggests that daily sun exposure without sunblock, particularly between the hours of 10 a.m. and 4 p.m, may support vitamin D synthesis.

A number of regional factors impact the ability for people to get necessary levels of vitamin D through sun exposure alone, including cloud cover patterns, smog, and the angle with which the sun hits the earth. In cities north of 37 degrees latitude (imagine a line drawn between San Francisco and Richmond, VA), it’s hard for people to produce enough vitamin D from sun exposure, especially between the months of November and March. The ability for skin to absorb light also impacts how well people can produce vitamin D, as does the use of sunscreen and the number of hours per day spent inside. It should be noted that UVB rays necessary to produce vitamin D do not penetrate glass, so sitting near a window indoors won’t help you produce sufficient vitamin D.

Because vitamin D is an essential nutrient, it is recommended that individuals with limited sun exposure increase dietary intake of vitamin D either through foods high in vitamin D or through dietary supplementation.

Vitamin D is found in our diet, but we also produce it through exposure to sunlight. Research suggests that daily sun exposure without sunblock, particularly between the hours of 10 a.m. and 4 p.m, may support vitamin D synthesis.

A number of regional factors impact the ability for people to get necessary levels of vitamin D through sun exposure alone, including cloud cover patterns, smog, and the angle with which the sun hits the earth. In cities north of 37 degrees latitude (imagine a line drawn between San Francisco and Richmond, VA), it’s hard for people to produce enough vitamin D from sun exposure, especially between the months of November and March. The ability for skin to absorb light also impacts how well people can produce vitamin D, as does the use of sunscreen and the number of hours per day spent inside. It should be noted that UVB rays necessary to produce vitamin D do not penetrate glass, so sitting near a window indoors won’t help you produce sufficient vitamin D.

Because vitamin D is an essential nutrient, it is recommended that individuals with limited sun exposure increase dietary intake of vitamin D either through foods high in vitamin D or through dietary supplementation.