Please note:
Any dietary or drug treatment with high doses of micronutrients may override the body's own control mechanisms; therefore, micronutrient therapies may be associated with potential side effects and toxicities. High-dosed micronutrients should not be used without medical supervision.

 

High blood pressure

An analysis of 23 large observational studies found a reduction in systolic blood pressure of 0.34 millimeters mercury (mm Hg) per 100 mg calcium consumed daily and a reduction in diastolic blood pressure of 0.15 mm Hg per 100 mg calcium (25). A large review of 42 randomized controlled trials examining the effect of calcium supplementation on blood pressure compared to placebo found an overall reduction of 1.44 mm Hg in systolic blood pressure and a reduction of 0.84 mm Hg in diastolic blood pressure (26). Calcium supplementation in these trials ranged from 500–2,000 mg/day, with 1,000–1,500 mg/day being the most common dose.

 

In the DASH (Dietary Approaches to Stop Hypertension) study, 549 people were randomized to one of three diets for eight weeks (27): a combination diet (rich in fruits, vegetables, and low-fat dairy products) reduced systolic blood pressure 5.5 mm Hg and diastolic blood pressure 3.0 mm Hg more than the control diet (low in fruit, vegetables, and dairy products), while a fruit/vegetable-rich diet reduced systolic blood pressure 2.8 mm Hg and diastolic blood pressure 1.1 mm Hg more than the control diet. The combination diet represented an increase of about 800 mg of calcium/day over the control and fruit/vegetable rich diets for a total of about 1,200 mg calcium/day. Among those participants diagnosed with abnormal high blood pressure ('hypertension'), the combination diet reduced systolic blood pressure by 11.4 mm Hg and diastolic pressure by 5.5 mm Hg more than the control diet, while the reduction for the fruit/vegetable diet was 7.2 mm Hg systolic and 2.8 mm Hg diastolic compared to the control diet (28).

 

This research indicates that a calcium intake at the recommended level (1,000–1,200 mg/day) may be helpful in preventing and treating moderate hypertension (29).

 

Premenstrual syndrome (PMS)

PMS refers to a cluster of symptoms, including fatigue, irritability, moodiness/depression, fluid retention, and breast tenderness, that begins sometime after ovulation (mid-cycle) and subsides with the onset of the monthly period ('menstruation') (30). Low dietary calcium intakes have been linked to PMS in several studies, and supplemental calcium has been shown to decrease symptom severity (31).

 

In randomized controlled trials, supplemental calcium (1,000–1,200 mg/day) for three menstrual cycles was associated with a 48% reduction in total symptom scores, compared to a 30% reduction observed in the placebo group (32, 33, 34).

 

A case-control study in women participating in the Nurses' Health Study II found that those who consumed the most calcium (median of 1,283 mg/day) from foods had a 30% lower risk of developing PMS compared to those with the lowest calcium intake (median of 529 mg/day from foods) (35). However, calcium intake from supplements had no effect on PMS in this study.

 

Large-scale clinical trials are needed to determine whether increasing dietary calcium intake or taking calcium supplements has therapeutic benefits in treating and preventing PMS.

 

Weight loss

Diets with higher calcium density (calcium per total calories) have been associated with a reduced incidence of being overweight or obese in some studies. It has been suggested that low calcium intakes could result in hormonal and metabolic changes that increase the tendency of fat cells to accumulate fat (36).

 

In a two-year trial, higher dietary calcium intakes were associated with weight loss whether participants were in an exercise group or the control group (37). A placebo-controlled calcium supplementation trial found significantly greater weight loss in elderly women supplemented with 1,200 mg calcium/day compared to a control group (38).

 

In a 1-year dairy product intervention trial in healthy young women, only in the high-dairy group (1,300 to 1,400 mg calcium/day) a slight reduction in body fat mass was observed at the 6-month follow-up (39).

 

Controlled feeding studies where calories remain fixed are needed to quantify the likely small effect of calcium, if any, on body fat and body weight.

 

High cholesterol

Preliminary studies in animals and humans suggest that calcium supplements, in the range of 1,500 to 2,000 mg per day, may help to lower blood cholesterol slightly (40). From these studies it appears that calcium supplements, along with exercise and proper diet, may be better at keeping cholesterol at normal levels than at lowering them once cholesterol is already high.

 

More research in this area is needed to confirm any beneficial effects in treating high cholesterol with calcium supplements.

 

Rickets

Rickets causes softening and weakening of the bone in children. Although virtually eliminated in developed countries where milk consumption is common, it still occurs in many parts of the world.

 

Researchers have thought that rickets is caused by a lack of vitamin D; however, one study showed that calcium supplementation may be an effective treatment (41).