Minerals // Calcium
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). In the DASH (Dietary Approaches to Stop Hypertension) study, 549 people were randomized to one of three diets for eight weeks (26): 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 (27).
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 (27).
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') (29). Low dietary calcium intakes have been linked to PMS in several studies, and supplemental calcium has been shown to decrease symptom severity (30).
In a randomized controlled trial, supplemental calcium (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 (31).
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.
Authored by Dr Peter Engel in 2010, reviewed and updated by Dr Igor Bendik-Falconnier on 17.10.17