Low Calcium or Too Much Calcium is Dangerous

Obtain the recommended calcium intake from food sources and adequate vitamin D intake from foods or sun exposure as expressed above. Use the following food list provided to increase dietary calcium intake to an average of 1000 mg daily. Add the total calcium content consumed in foods and supplements for the day. The total calcium requirement to meet should be 800 to 1200 mg daily. Here is the list of foods with the highest calcium sources by the USDA: high calcium foods.

Avoid calcium intake over 1400 mg per day including food sources and supplements. Attempt to increase calcium intake by food sources to the RDA (recommended daily allowance) instead of supplements unless required to replace a deficiency gap in the recommended intake. Compared with dietary calcium intakes of 600 to 1000 mg daily, higher daily intakes of ≥1400 mg were associated with significantly higher rates of death from all causes, cardiovascular disease, and ischemic heart disease, but not from stroke. This is why too much calcium should be avoided. These findings were observed in 2 cohort studies on women (22,23). Another cohort study found the mortality rate to be increased in men but not women (24). Higher calcium intakes are also associated with an increased risk of prostate cancer in men-see below (13,14, 28).

If a calcium supplement is required, and the patient is taking an H2 blocker (Pepcid, Zantac), or proton pump inhibitor (Prilosec, Protonix, Nexium) calcium citrate is a better choice. Calcium citrate will be better absorbed than calcium carbonate in this case. Calcium carbonate is otherwise appropriate but requires an acid environment and this form should be taken with food.

According to an article by Christopher Nordin, MD, the recommendation by the USPSTF (United States Preventive Services Task Force) to begin screening for osteoporosis at the age of 65 appears to neglect the fact that 25% of a women’s bone mass has already been lost by that time. He recommends that women have bone density screening at menopause so that lifestyle changes such as exercise, calcium intake, and vitamin D intake may be emphasized early.

Adequate calcium intake should be part of the treatment for osteoporosis. An ideal treatment regimen for osteoporosis supported by mainstream physicians and the study by Sosa et al consists of weight bearing exercise, adequate calcium intake, optimal vitamin D from sun or supplement, avoidance of smoking, abstaining from alcohol, assessment of bone mineral density and seeking medication options from the primary physician.

A review of major trials was performed on osteoporosis by Nordin, BE who determined that calcium supplementation translates to the prevention of about a 1 % bone density loss per year. In a meta-analysis of 29 trials, elemental calcium dose of at least 1200 mg plus at least 800 IU of vitamin D was optimal to achieve maximum treatment effect (9). Again, dietary sources of calcium are recommended over supplements.

For osteoporosis, weight bearing exercise was shown to improve bone mineral density better than a calcium supplement at a dose of 500 mg per day.

Total body and lower back (lumbar spine) bone mineral content was significantly increased with calcium supplements (compared to placebo) in children with initially low calcium intake.

The conclusion of a study by Lappe JM stated that an improvement of nutritional status with calcium and vitamin D significantly lowers cancer risk (10).

In a meta-analysis by Carroll C. et al, 3 trials showed a reduction of recurrence of colon adenomas (a type of colon polyp) for subjects who took 1200 – 2000 mg per day of a calcium supplement, but no decrease in risk for those with advanced adenomas (11). Shaukat A et al reviewed 3 randomized controlled trials (1,485 patients) and found that calcium supplementation resulted in a 20% reduction in the risk of recurrence of colorectal adenomas compared with placebo. (12) For those desiring to decrease colon cancer or polyp risk, dietary sources of calcium are recommended over supplements. Palacios C et al found that subjects with a median of 1180 mg per day of calcium whether from dietary calcium intake or calcium from supplements as opposed to a median of 1036 mg per day had less colorectal neoplasia (30).

For the subject of calcium and prostate cancer, the analysis of the data becomes more complicated as more studies are included. Rodriguez C et al found that the intake of calcium over 2000 mg per day in the form of dietary and supplement intake was associated with a moderate increase in risk of prostate cancer (13). Chung et al also found that a number of studies reported that high calcium intakes were associated with an increased risk of prostate cancer (14). Huncharek M et al found an opposing outcome that as calcium intake from food increased, the risk of prostate cancer decreased across all races (15). Butler LM further complicated the understanding of the calcium and prostate cancer link when the study outcome found that moderate intakes of calcium from vegetables resulted in a moderately higher prostate cancer risk for subjects with a body mass index below 22.9 (28). Therefore, as an older male with the goal to reduce prostate cancer risk, an approach of maintaining an adequate (but not excessive) calcium intake from food is supported by the majority of the research but calcium supplements should be avoided by older men until further research is done.

Adequate calcium intake in premenopausal women appears to be associated with a decreased risk of breast cancer.

Compared to placebo, calcium supplementation of at least 1 gram per day during pregnancy was associated with an average reduction risk of pre-eclampsia by 55%, with women at high-risk and low calcium consumption reporting a greater reduction (78% and 64%, respectively) and calcium reduced mortality from pre-eclampsia by 20% (17). Calcium can also reduce the possibility of delivering an infant with low birth weight (19).

Hypertension and osteoporosis often co-exist. One of the only blood pressure medicines known to improve bone mineral density is hydrochlorothiazide (29). Hypertension and osteoporosis may be partially related to calcium and/or vitamin D deficiency.

If diagnosed with hypertension, consider increasing calcium intake in the diet to adequate levels. If unable to reach adequate calcium by the diet, a supplement can be considered to increase the calcium enough to the recommended allowance. Calcium appears to lower systolic bp by 2-4 mm Hg, but not diastolic blood pressure, and calcium 1200 mg, with vitamin D, 800 IU appears to lower systolic blood pressure by about 9%. Vitamin D plus calcium reduced SBP better than calcium alone.

Dietary calcium consumption can contribute to weight loss by enhanced fecal fat excretion.

For patients with chronic kidney disease and high phosphorus, calcium acetate and calcium carbonate lowered phosphorus levels and parathyroid hormone levels better than sevelamer, but sevelamer had about half the risk of hypercalcemia. Sevelamer use had more gastro-intestinal side-effects than calcium. Lanthanum decreased both calcium and phosphorus levels.(26)

Nutrition, Supplements and Exercise for Optimal Health