Introduction:
Calcium is a mineral nutrient necessary for human health: Calcium is found in supplements, dairy, cereals, meats, spinach, kale, soybeans, white beans, and other vegetables. Calcium is primarily stored in the bones but used in other parts of the body to perform functions such as nerve conduction, muscle contraction, heart function and neurotransmitter release. Calcium helps to maintain strong bones and teeth in addition to being needed for nerve transmission, clotting, blood pressure, muscle use, enzyme activation, and hormone regulation.
Dietary supplements containing calcium are taken by about 43% of Americans. Calcium is well-known for prevention of osteoporosis. A review of major trials performed on osteoporosis by Nordin, BE supported calcium supplementation in the prevention of about a 1 % bone density loss per year (1). Research also supports that weight bearing exercise increases bone mass better than calcium supplements as long as adequate calcium intake is present.
Over the past 3 years, several studies have surfaced regarding the safety of calcium supplements. The new research has shown evidence for an increased risk of all-cause mortality and cardiovascular disease related mortality in women who consume over 1400 mg of calcium per day and in men who take calcium pill supplements. Therefore, based on recent research, the ideal amount of calcium intake for most adults is about 1000-1200 mg per day from food sources but more specific recommendations are listed below for various age, gender, and pregancy.
Vitamin D significantly enhances calcium absorption. It is important to note that calcium may interfere with thyroid replacement medication. Also, excess calcium consumption is dangerous which can cause high calcium levels, milk-akali syndrome, widespread calcium deposits and kidney failure. This may occur in individuals unaware of the calcium content in antacids such as Tums which contain calcium carbonate. A breakdown of foods containing high calcium content are listed below or may be found in more detail at the link supplied below.
Calcium Recommended Dietary Allowance:
Calcium intake recommendation by of all children, males, females, elderly, calcium intake during pregnancy and during lactation is listed below and may be accessed at: Institute of Medicine. Food and Nutrition Board. Comprehensive DRI tables for vitamins, minerals and macronutrients; organized by age and gender. Includes the 2010/2011 updated recommendations for calcium and vitamin D. Click the following links: http://www.iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/5_Summary%20Table%20Tables%201-4.pdf
or here: http://www.iom.edu/Reports/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/DRI-Values.aspx
Women’s recommended dietary allowance for calcium:
According to the standards set by the Institute of Medicine and the World Health Organization for adequate intake of calcium and vitamin D: Women age 9-18 years are recommended to intake 1300mg/d of calcium. Women age 19-50 years are recommended to receive 1000mg/d of calcium. For women age 51 years and over, 1200 mg/day of calcium is recommended.
Men’s recommended dietary allowance for calcium:
According to the standards set by the Institute of Medicine and the World Health Organization for adequate intake of calcium and vitamin D: Men age 9-18 years require 1300 mg/d of calcium. Men age 19-70 years require 1000 mg/d of calcium. For men age 71 years and over, 1200 mg/day of calcium is recommended.
Infant’s recommended dietary allowance for calcium:
Age 0-6 months are recommended to receive 200 mg of calcium and infants age 6-12 months are recommended to receive 260 mg of calcium per day.
Children’s recommended dietary allowance for calcium:
Ages 1-3 require 700 mg of calcium per day and ages 4-8 require 1000 mg of calcium per day.
Pregnant and nursing women recommended dietary allowance for calcium:
Pregnant and nursing women younger than 18 years are recommended to receive 1300 mg/day of calcium. Among pregnant and nursing women older than 18 years, 1000 mg/day of calcium is recommended.
Taking vitamin D with calcium:
Widespread evidence in various research reinforces the benefit of adequate vitamin D intake together with calcium to support absorption and assimilation of calcium in the body. For more detailed information on vitamin D, please see the section on vitamin D. According to the Food and Nutrition Board, Institute of Medicine vitamin D at a dose of 600 International Units (IUs) per day meets the needs of almost everyone in the United States and Canada. Infants need 400 IUs per day, and children need 600 IUs per day. People age 71 and older may need as much as 800 IUs per day because of potential changes in people’s bodies as they age. There is also evidence that higher intakes reduce mortality. The upper level intakes were set by the committee for both calcium and vitamin D. While these values vary somewhat by age, the committee concludes that once intakes of vitamin D surpass 4,000 IUs per day, the risk for harm begins to increase. Once intakes surpass 3,000 milligrams per day for calcium, the risk for harm also increases. Report Brief, Dietary Reference Intakes for Calcium and Vitamin D, Food and Nutrition Board, Institute of Medicine, National Academy Press, Washington, D.C., November 30, 2010. Click here: http://www.iom.edu/Reports/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/DRI-Values.aspx
Ross CA, Taylor CL, Yaktine AL, Del Valle HB, eds; Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press; 2011. Accessed at http://www.nap.edu/catalog.php?record_id=13050 on 31 May 2012.
Different forms of calcium:
Calcium contained naturally in food sources: Calcium contained naturally in food sources is believed to be the best source of calcium intake because of good absorption and the greater number of other nutrients contained in these same foods.
Calcium carbonate:
Calcium carbonate is the most common form of calcium and least expensive available which contains about 40% elemental calcium. It is better absorbed with food and an acidic environment. A good time to take this form of calcium is at the time of an acidic meal such as tomato products, citrus or foods with vinegar. The daily intake of calcium should be based upon how much elemental calcium the supplement contains and not the amount of calcium carbonate.
Calcium citrate:
Calcium citrate is absorbed better within a nonacidic environment. This form of calcium is better for patients taking antacids such as H2 blockers (Pepcid, Zantac) and proton pump inhibitors (Prilosec, Protonix, Nexium). The content of elemental calcium in this form is slightly more than 20%. Again, the daily intake of calcium should be based upon how much elemental calcium the supplement contains and not the amount of total calcium citrate.
Calcium, bone mineral density, and osteoporosis:
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 . (5)
Osteoporosis prevention and the USPSTF (United States Preventive Services Task Force):
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, and vitamin D may be emphasized early. (6)
Calcium and bone mineral density loss:
How much bone mineral density loss can calcium supplements help prevent? Nordin, BE reviewed 32 major trials done on calcium supplementation for osteoporosis. According to the author, the trials generally supported calcium supplementation for the use of preventing about a 1 % bone density loss per year (1).
Vitamin D plus calcium in various age groups:
Vitamin D plus calcium supplementation is known to increase bone mineral density of the spine and other areas starting in early age childhood, college age, postmenopausal, and in women well into old age. (6,7,8)
Exercise, bone mass, and calcium:
Exercise and calcium is better than calcium alone. The link between exercise and calcium supplementation on bone mass was examined in 104 college-aged women (mean age of 22.3). Sixty-two of the women with low bone mass were included in a 3-month study (though only 60 completed the study). These women were split into 3 groups: an exercise group (n = 21), a group that took a calcium supplement at a dose of 500 mg per day (n = 21), and a control group (n = 20). The women’s distal radius (forearm) T-scores and mid-shaft tibia (shinbone) scores were taken both before and after the interventions. Results showed that approximately 60% of the 104 participants had low bone mass. After the 3 month interventions, the women in the exercise group showed significant improvement in their distal radius SOS T-scores and mid-shaft tibia scores, compared to the other 2 groups. The calcium-supplement group also showed improvements compared to the control group. The researchers conclude that their findings show that young women who exercised had the highest improvements in their bone mass, when compared with the women in the calcium-supplement and control groups. (7)
Consumption of dairy products and bone mineral density:
A meta-analysis of dairy products and dietary calcium intake and how it affects bone mineral content (BMC, measures bone strength) in children reported that total body and lower back (lumbar spine) BMC were significantly increased (compared to placebo) in children with initially low calcium intake. Therefore, an increase in calcium intake translated to an increase of total and lumber spine BMC in children. (8)
Calcium supplementation by post-menopausal women:
Calcium supplementation (about 1 g/day) in postmenopausal women had a significant beneficial effect on bone density. This review examined 32 controlled trials of calcium supplementation with dose ranging from 700-2000 mg. Change in average annual bone mass or density was reported at -0.27% in the calcium group compared to -1.07% in the control group. Calcium supplemented at 700 mg were not effective. However, higher doses were not significantly more effective. Faster bone loss was reported at doses less than 1,150 compared to doses more than 1,350 mg. The benefical effect of calcium supplementation lasted for about 4 years. (1)
Calcium, vitamin D, osteoporotic fracture, and bone loss in older adults:
Findings from a meta-analysis of 29 randomized trials in which calcium, or calcium in combination with vitamin D, was used to prevent osteoporotic fracture and bone loss in adults over 50 years of age support the use of calcium and vitamin D supplementation. Data analysis showed supplementation had resulted in a reduction of 12% in bone fractures of all types, and a 0.54% decrease in bone mineral density loss at the hip and 1.19% in the spine. In addition, a calcium dose of at least 1200 mg plus at least 800 IU of vitamin D were optimal to achieve maximum treatment effect. (9)
Osteoporosis and hypertension:
Osteoporosis often co-exists with hypertension. One of the only blood pressure medicines known to improve bone mineral density is hydrochlorothiazide (29). Hypertension and osteoporosis are often found together and how they are associated with calcium and/or vitamin D deficiency is yet to be explained.
Calcium and cancer:
Calcium, vitamin D, and the risk of cancer: Calcium together with vitamin D supplements have been linked with a decrease in the relative risk of various cancers in women excluding skin cancers. A population-based randomized 4-year study conducted in Nebraska enrolled 1179 women aged 55 years and older, with no known cancer. Participants were randomly assigned to 3 groups: 1) Placebo (calcium placebo plus vitamin D placebo, n=266); 2) calcium-only (1400 mg calcium citrate or 1500 mg calcium carbonate plus vitamin D placebo, n=416); and Calcium + D (1000 IU [25 mcg] vitamin D plus calcium [as above], n=403). Serum samples were analyzed for levels of 25(OH)D, vitamin D, at baseline and then yearly. Study results found 50 women developed non-skin cancer during the study: 13 in the first year, and 37 during the second to fourth years. The relative risk reduction (RRR) for the calcium + D group was 0.232 (confidence interval [CI], 0.09–0.60; P<.005), and the RRR for the calcium-only group was 0.587 (95% CI, 0.29–1.21; P=.147) compared with the placebo group. Increasing the dose of vitamin D from the current standard of 400–600 IU per day to 1000 IU per day may lower future risk of cancer in women older than age 55 who do not get adequate vitamin D from sun exposure or diet. The conclusion of the author was that an improvement of nutritional status with calcium and vitamin D significantly lowers cancer risk. (10)
Calcium intake and colon cancer:
In a meta-analysis by Carroll C. et al, 3 trials showed a reduction of recurrence of colon adenomas for subjects who took 1200 – 2000 mg per day of a calcium supplement, but no decrease in risk for those with advanced adenomas. Also as part of the meta-analysis, 2 trials were found to have no benefit of calcium in those without increased risk of colorectal cancer. (11)
Shaukat A et al reviewed 3 randomized controlled trials (1,485 patients) and found that calcium supplementation was associated with a significant 20% reduction in the risk of recurrence of colorectal adenomas compared with placebo. (12)
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)
Excess calcium and prostate cancer:
Rodriguez C et al evaluated a cohort of over 65,000 men in the United States over a period of 6-7 years revealed that 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. The risk of prostate cancer was not increased with diary intake. There was also no increase in risk of prostate cancer with moderate or low levels of dietary calcium intake. (13)
Chung et al reviewed calcium and prostate cancer risk as part of a systematic review of health outcomes. He found that a number of studies reported that high calcium intakes were associated with an increased risk of prostate cancer. (14)
Consumption of dairy products, calcium, and vitamin D showed no increase in the risk of prostate cancer in this review and meta-analysis of 45 observational studies. Cohort studies demonstrated no link between dairy or milk consumption and increased risk of prostate cancer nor did case control studies of calcium intake. Additionally, dietary intake of vitamin D was not correlated with increased prostate cancer risk. The study did find that as calcium intake from food increased, the risk of prostate cancer decreased across all races. (15)
Butler LM 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)
In exploring the subject of calcium and prostate cancer, the analysis of the data becomes more complicated as more studies are included. Therefore, as an older male with the goal to reduce prostate cancer risk, an approach of maintaining an adequate calcium intake from food is supported by the majority of the research. In absence of deficiency and in presence of an adequate balanced diet, calcium supplements should be avoided by middle aged to older men.
Calcium and breast cancer:
Chung, et al reviewed a number of studies on health outcomes by subjects which consumed calcium and vitamin D. It was found that adequate calcium intakes in premenopausal women was associated with a decreased risk of breast cancer. (14)
Calcium and pregnancy:
Calcium, pre-eclampsia, eclampsia, and pregnancy-induced high blood pressure: An overview of systematic reviews was performed by Kulier R et al on nutritional interventions during pregnancy and their impact on maternal outcomes of pre-eclampsia, eclampsia, and pregnancy-induced high blood pressure. It was found that calcium supplementation for women at high risk of pregnancy hypertension reduced the rate of high blood pressure by 65% and pre-eclampsia by 78%. In women with low dietary calcium intake, supplementation was associated with a significant decrease in the rate of high blood pressure by 51% and pre-eclampsia by 68%. The benefits of calcium supplementation were small in women with low risk of pregnancy hypertension or who had enough calcium intake. Additionally, iron and folate supplementation reduced the rate of low pre-delivery hemoglobin. On the basis of this review, routine calcium supplementation for pregnant women at low risk for hypertension or with adequate calcium is not recommended. In areas where nutritional anemia is prevalent, routine iron/folate supplementation programs for all pregnant women should be introduced. (16)
A review of calcium supplementation trials and pre-eclampsia: A review of 13 trials (n=15,730 women) found supplementation with 1 g or more of calcium per day helped prevent pre-eclampsia (high blood pressure in pregnancy), preterm birth and lowered the risk of woman dying or having serious problems related to pre-eclampsia. Compared to placebo, calcium supplementation during pregnancy was associated with an average reduction risk of pre-eclampsia by 55%, with women at high-risk and low starting calcium consumption reporting a greater reduction (78% and 64%, respectively). Risk of premature birth was also reduced by 24% (and 55% in women at high-risk of pre-eclampsia) in the calcium supplemented group compared to placebo. Women were also less likely to die or have serious problems due to pre-eclampsia (20% reduced risk). (17)
Another review of calcium supplementation trials and pre-eclampsia: A review of 15 randomized contolled trials found calcium supplementation helped prevent pre-eclampsia (high blood pressure in pregnancy), preterm birth and lowered the risk of woman dying or having serious problems related to pre-eclampsia. Compared to placebo, calcium supplementation during pregnancy was associated with a 52% risk reduction of pre-eclampsia and 25% risk reduction of severe pre-eclapmsia. Risk of premature birth was reduced by 24% in the calcium supplemented group compared to placebo. Additionall, there was an 85 g gain in birthweight associated with calcium supplementation. Women were also less likely to die or have serious problems due to pre-eclampsia (20% reduced risk). (18)
Calcium deficiency, pre-eclampsia, and intra-uterine growth restriction: Pre-eclampsia and intra-uterine growth restriction has been seen in pregnant women with calcium deficiency . Calcium taken during pregnancy can reduce the possibility of low birth weight and pre-ecclampsia. (19)
Calcium and hypertension:
Systolic blood pressure improved in 47% of subjects taking calcium alone but calcium and vitamin D taken together lowered bp in 81% of subjects in a study by Pfeifer M et al. A double-blind randomized controlled trial of 148 women with a mean age of 74 years tested the effect of calcium plus vitamin D on blood pressure was compared to calcium alone. Participants received either 1200 mg calcium plus 800 IU vitamin D3 or 1200 mg calcium per day. Vitamin D level, blood pressure, and heart rate were measured before and after treatment. Results indicate that supplementation with vitamin D and calcium resulted in a significant increase in vitamin D (25-D) levels by 72% and decreased PTH levels by 17% along with significant decreases in systolic blood pressure (SBP) by 9,3% and heart rate by 5.4% compared with calcium supplementation alone. Sixty subjects (81%) in the vitamin D(3) and calcium group compared with 35 (47%) subjects in the calcium group showed a decrease in SBP of 5 mm Hg or more (p = 0.04). The authors concluded that a short-term vitamin D plus calcium regimen reduced SBP better than calcium alone. (20)
A meta-analysis of 40 trials (2,492 subjects with high blood pressure) showed significant reductions in systolic blood pressure (SBP) of 1.8 mmHg and in diastolic blood pressure (DBP) of 0.99 mmHg associated with calcium supplementation (average dose: 1,200 mg/day). Among patients who had a calcium intake of 800 mg/day or less BP reductions were greater (SBP: -2.63 mmHg, DBP: -1.30 mmHg). (21)
In a review by Chung M et al, trials including hypertensive adults showed that calcium supplementation lowered systolic, but not diastolic, blood pressure by 2-4 mm Hg. (14)
Hypertension and osteoporosis link:
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 are often found together and how they are associated with calcium and/or vitamin D deficiency is yet to be explained.
Calcium supplements and mortality:
Calcium and cardiovascular mortality: High-dose calcium supplementation was associated with greater cardiovascular (CV) mortality and all-cause mortality in women according to a prospective cohort study of 61,433 women born between 1914 and 1948. Compared with dietary calcium intakes of 600 to 1000 mg daily, daily intakes of ≥1400 mg were associated with significantly higher rates of death from all causes (40% increased risk), CV disease (49% increased risk), and ischemic heart disease (2 times higher risk), but not from stroke. Among the 6% of participant women using calcium supplements (500 mg), those who were also consuming >1,400 mg/d in their diet had a 2.5-times higher risk of all-cause death than women with similar total intakes not taking a supplement. (22)
Calcium and cardiovascular events:
Calcium supplements increased the risk of cardiovascular events, especially heart attacks, in older women. A re-analysis of data from the Women’s Health Initiative Calcium/Vitamin D Supplementation Study found that among the almost 16,718 women not taking personal supplements at the time of randomization, being randomized to new supplement use (1g calcium and 400 IU vitamin D daily) was associated with a statistically significant increase in risk of cardiovascular events (heart attack, stroke) ranging from 13%-22%. Among women already taking supplements at the start of the study, no such increase in events was seen. A meta-analysis of 3 placebo-controlled trials found that compared to placebo, calcium and vitamin D increased the risk of heart attack by 21%, stroke by 20%, and heart attack or stoke by 16%. (23)
Calcium and risk of cardiovascular disease: An analysis of 388,229 individuals aged 50 to 71 years found that high calcium intake was associated with an increased risk of cardiovascular disease (CVD) mortality in men, but not women. At study enrollment, 51% of men and 72% of women were taking some form of calcium. The study found that compared to men not taking calcium, men with calcium intake of 1000 mg/day had an elevated risk of total CVD death (20% increased risk) and heart disease death (19% increased risk) but not cerebrovascular disease. In women, there was no association between calcium supplementation and death from cardiovascular disease or cerebrovascular disease. (24)
Dietary calcium and weight loss:
Dietary calcium consumption can contribute to enhanced fecal fat excretion, which may be a relevant finding for weight loss. A meta-analysis of randomized controlled studies with consistent trial outcomes found that an increase in dairy calcium intake by 1241 mg/day leads to 5.2 g/day extra fecal fat excretion. (25)
Calcium for binding phosphorus in chronic kidney disease:
A total of 40 trials were reviewed by Navaneethan SD et al which compared risks and benefits of calcium carbonate and calcium acetate phosphorus binders with sevelamer. In patients with chronic kidney disease, treatment with the 2 mentioned calcium salts (calcium acetate and calcium carbonate) resulted in a significant decrease in phosphorus levels (often elevated due to kidney disease) and parathyroid hormone levels (regulate calcium and phosphate levels) compared to patients taking sevelamer, a drug commonly used to treat high blood levels of phosphorus in patients with kidney disease. Compared to calcium salts, treatment with sevelamer had about one half the risk of hypercalcemia. Patients taking sevelamer were found to be 39% more likely to experience gastro-intestinal side-effects than those taking calcium salts. Lanthanum decreased both calcium and phosphorus levels. (26)
Taking Calcium for Weight Loss
New research, sponsored by the dairy industry, has suggested that including calcium in the diet has a positive effect on weight loss. In fact, the dairy industry has produced an entire advertising campaign around the concept of increasing calcium through dairy products and weight loss (31). Many of the studies which the American Dairy Association rely on in their advertising have found a link between the amount of calcium an individual consumes during the day and the type of weight which is lost in the body.
Advertising campaigns point to research which showed a relationship between eating three to four servings of low-fat dairy products each day and a decrease in the amount of fat stores in the body. This research suggested that calcium increases the amount of fat in the body converts to energy by increasing the body’s core temperature. The theory is that by increasing the core temperature the body will burn more calories at a faster rate. (32)
The study also suggests that individuals who have the highest amount of stored fat will also show the lowest amount of calcium stored in the body. Conversely, popular diets that promise a quick weight loss are often very low in dairy products, the foods containing the highest amounts of calcium. These popular fad diets also affects the ability of the body to absorb calcium which can lead to bone loss and osteoporosis. Women who control their calories each day can be at risk for a number of deficiencies because they miss vital vitamins and minerals necessary for overall health.
Foods that are high in calcium include milk, cheese, yogurt, ice cream, baked beans, dried figs, broccoli and most dark leafy vegetables. The research funded by the American Dairy Association did not include vegetable sources of calcium in their study.
Dr. Reed Mangels from the Vegetarian Resource Group commented on the influence of a high amount of animal protein has on the body. Quoting a study published in the Journal of Nutrition in 2003 he states that “Some studies show that diets that are high in protein, especially animal protein, do cause increased losses of calcium in the urine…” this means that the amount of calcium in the Recommended Daily Allowance may fluctuate for individuals based on the amount of animal protein they consume. (33,34)
The current recommended dose for calcium is 800 to 1000 mg per day. Most Americans typically consume between 500 and 700 mg of calcium. Unless a diet is high in foods that contain calcium, many Americans may find that supplementation is necessary to avoid the increased loss of bone and osteoporosis while taking advantage of the potential for weight loss. However, it is also important to note that the production of bone does not rely exclusively on the amount of calcium in the body. Several other vitamins and minerals are necessary in order for the body to adequately manufacture bone.
Unfortunately, this promotion of calcium may result in a convenience to believe that increasing the amount of calcium in the diet will also increase the amount of weight that people can lose. Weight loss is always dependent on the number of calories eaten versus the number of calories burned. The number of calories burned by increasing the core temperature of the body through stored calcium may not be great enough to offset the potential risk for the development of kidney stones. The American Journal of Clinical Nutrition, April 2005, carried reports of research which contradicts the reported weight loss by calcium intake which other studies had shown. (35)
Before beginning any weight loss program, a new exercise regimen or changing your diet significantly, one should consult a physician especially for those under 18, pregnant, nursing or have a pre-existing health problem. Before increasing the amount of calcium, establish the amount of current calcium intake as well as other vital vitamins and minerals. At that point, working with a nutritionist, a specific diet may be developed that meets caloric needs, nutritional needs, in order to attain the desired goals. The current results of studies which link calcium and weight loss are not conclusive and much more research is required before a judgment can be drawn.
Common Highest Calcium Containing Foods (mg):
GENERAL MILLS, TOTAL Raisin Bran, 1 cup 1038 mg |
GENERAL MILLS, Whole Grain TOTAL, 3/4 cup 1000 mg |
Milk, canned, condensed, sweetened, 1 cup 869 mg |
Cheese sauce, prepared from recipe, 1 cup 756 mg |
Milk, canned, evaporated, nonfat, added vitamin A and vitamin D, 1 cup 742 mg |
Cheese, ricotta, part skim milk, 1 cup 669 mg |
Milk, canned, evaporated, with added vitamin D no vitamin A, 1 cup 658 mg |
Cheese, ricotta, whole milk, 1 cup 509 mg |
Cornmeal, self-rising, degermed, enriched, yellow, 1 cup 483 mg |
Milk shakes, thick vanilla, 11 fl oz 457 mg |
Yogurt, plain, skim milk, 13 grams protein per 8 ounce, 8-oz container 452 mg |
Wheat flour, white, all-purpose, self-rising, enriched, 1 cup 423 mg |
Yogurt, plain, low fat, 12 grams protein per 8 ounce, 8-oz container 415 mg |
Milk shakes, thick chocolate, 10.6 fl oz 396 mg |
Shake, fast food, vanilla,16 fl oz 383 mg |
Shake, fast food, chocolate, 16 fl oz 376 mg |
Malted drink mix, chocolate, added nutrients, with whole milk, 1 cup 368 mg |
Collards, frozen, chopped, cooked, boiled, drained, without salt, 1 cup 357 mg |
Rhubarb, frozen, cooked, with sugar, 1 cup 348 mg |
Yogurt, fruit, low fat, 10 grams protein per 8 ounce, 8-oz container 345 mg |
Leavening agents, baking powder, double-acting, straight phosphate, 1 tsp 339 mg |
Candies, white chocolate, 1 cup 338 mg |
Eggnog, 1 cup 330 mg |
Malted drink mix, natural, added nutrients, powder, whole milk, 1 cup 326 mg |
Fish, sardine, Atlantic, canned in oil, drained solids with bone, 3 oz 325 mg |
Fast foods, enchilada, with cheese, 1 enchilada 324 mg |
Macaroni and cheese, frozen entrée, 1 package 323 mg |
Fast foods, cheeseburger, double, regular patty and bun, plain, 1 sandwich 306 mg |
Milk, lowfat, fluid, 1% milkfat, with added vitamin A and vitamin D, 1 cup 305 mg |
Milk, nonfat, fluid, added vitamin A and vitamin D (fat free or skim, 1 cup 299 mg |
Cheese, pasteurized process, American, fortified with vitamin D, 1 oz 296 mg |
Sauce, homemade, white, medium, 1 cup 295 mg |
Milk, reduced fat, fluid, 2% milkfat, added vitamin A and vitamin D, 1 cup 293 mg |
Potatoes, au gratin, home-prepared from recipe using butter, 1 cup 292 mg |
Spinach, frozen, chopped or leaf, boiled, drained, without salt, 1 cup 291 mg |
Milk, chocolate, lowfat, with added vitamin A and vitamin D, 1 cup 290 mg |
Milk, buttermilk, fluid, cultured, lowfat, 1 cup 284 mg |
Rice drink, unsweetened, with added calcium, vitamins A and D, 8 fl oz 283 mg |
Milk, dry, nonfat, instant, with added vitamin A and vitamin D, 1/3 cup 283 mg |
Milk, chocolate, whole, with added vitamin A and vitamin D, 1 cup 280 mg |
Fast foods, cheeseburger; double, regular patty; plain 155 1 sandwich 279 mg |
Milk, whole, 3.25% milkfat, with added vitamin D, 1 cup 276 mg |
Yogurt, plain, whole milk, 8 grams protein per 8 ounce, 8-oz container 275 mg |
Milk, chocolate, reduced fat, with added vitamin A and vitamin D, 1 cup 273 mg |
Fast foods, nachos, with cheese, 6-8 nachos 272 mg |
Spinach, canned, regular pack, drained solids, 1 cup 272 mg |
Adapted from: Nutritive Value of Foods, United States Department of Agriculture, 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.
Summary: Low Calcium or Too Much Calcium Can Be 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)
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