Calcium is a mineral most often associated with healthy bones and teeth, although it also plays an important role in blood clotting, helping muscles to contract, and regulating normal heart rhythms and nerve functions. About 99% of the body’s calcium is stored in bones, and the remaining 1% is found in bloodstream, muscle, and other tissues.
In order to perform these vital daily functions, the body works in order to keep a steady amount of calcium in the blood plus tissues. If calcium levels drop too low in the blood, parathyroid hormone (PTH) will signal the bones to release calcium into the bloodstream. This hormone may also activate vitamin D to improve the particular absorption of calcium within the intestines. At the same time, PTH signals the kidneys to release less calcium mineral in the urine. When the body has enough calcium, the different body hormone called calcitonin works in order to do the opposite: it lowers calcium amounts within the blood by stopping the release associated with calcium from bones and signaling the kidneys to rid more of it in the particular urine.
The particular body gets the calcium it needs in two ways. One is by eating foods or supplements that contain calcium supplement, as well as the other is by drawing through calcium in the entire body. If one does not eat enough calcium-containing foods, the body will remove calcium supplements from bones. Ideally, the particular calcium that is “borrowed” from the bones will be replaced at a later point. But this doesn’t always happen, plus can’t always be accomplished just by eating a lot more calcium.
The Recommended Dietary Allowance (RDA) for calcium for women 19-50 years of age is 1, 000 mg daily; for women 51+, 1, 200 mg. For pregnant and lactating ladies, the RDA is one, 000 magnesium. For men 19-70 many years of age, the RDA is 1, 000 mg; for men 71+ years, one, 200 magnesium. 
Calcium mineral and Health
The reviews below specifically looked at the effect of calcium on various health conditions. Scroll down for links to more information on the particular health effect of specific foods rich in calcium.
Several literature reviews on the topic associated with total calcium mineral intake, from food plus supplements, and blood pressure have suggested a possible link to lowering high blood pressure. However, problems with study designs in these types of analyses (small numbers of participants, differences among the people studied, plus various biases in the types of studies included) prevent a new recommendation for the treatment of hypertension that would increase calcium supplement intake above the Suggested Dietary Allowance.  Larger trials along with longer duration are needed in order to clarify whether increased calcium supplements intakes or the use of calcium dietary supplements can lower high blood pressure.
Some research has raised concerns about calcium supplements and heart health . These studies discovered that taking calcium health supplements increased the particular risk of cardiovascular events in males and females. It has been suggested that high-dose supplements can cause hypercalcemia (toxic level of calcium in the blood) that can cause bloodstream to clot or the arteries to harden, leading to cardiovascular disease. The connection is not yet clear, but a clinical guideline published after review of the particular available research from the National Osteoporosis Foundation plus the American Society with regard to Preventive Cardiology stated that calcium through food or even supplements has no relationship (beneficial or harmful) to heart problems in generally healthy adults. The guideline advises individuals not in order to exceed the particular Upper Limit for calcium mineral, that is, 2, 000-2, 500 mg daily from food and products. 
Calcium is one of the most important nutrients required regarding bone wellness. Bone will be living tissue which is usually in flux. Throughout the lifespan, bones are constantly being broken down and built up within a process known as remodeling. Bone tissue cells called osteoblasts build bone, while other bone cells known as osteoclasts break down bone tissue if calcium mineral is needed. In healthy individuals who get enough calcium supplement and physical activity, bone fragments production exceeds bone destruction up to about age group 30. After that, damage typically surpasses production. This is sometimes called “negative calcium balance, ” which can lead in order to bone loss. Women tend to experience greater bone loss than men later in life due to menopause, the condition that will lowers the amount of hormones that help in order to build plus preserve bone tissue.
Getting plenty of dietary calcium supplements at all ages may help to slow the degree associated with bone reduction, but calcium intakes at any level are not known to completely avoid bone loss.  Calcium is less easily absorbed at later ages, and therefore eating a very high quantity of calcium will not always resolve the problem.
Studies upon calcium intake and bone fragments density in postmenopausal women have mixed results. Possible reasons:
- The study only looked over calcium mineral intakes through a supplement provided to the participants, and did not account for calcium supplement from your diet or estimate the total amount of calcium from both food and supplements. 
- The research did not adjust intended for or track if women were furthermore taking junk replacement therapy or other vitamin supplements that will can lessen bone much less, such as calciferol.
Because the results of some large trials found that higher calcium supplements intakes (usually achieved with a supplement) was associated with improved bone density plus slightly lower risk associated with hip fractures, the RDA for calcium for postmenopausal women is higher than at younger age groups.  A few studies suggest that frail elderly (80 years and older living in institutions) may benefit through supplementation more than “younger” elderly who live independently in the particular community. 
A 2018 review of randomized controlled trials by the U. S. Preventive Services Task Force did not really find that dietary supplements with calcium mineral and vitamin D taken for up to 7 years reduced the incidence of bone injuries in postmenopausal women. These types of women did not have osteoporosis or a vitamin D deficiency at the start of the study plus lived individually in the community. The particular amount of calcium associated with the health supplements ranged from 600-1, 600 mg every day. 
Epidemiological studies following people over time recommend a protective role of high calcium intakes (whether through food and/or supplements) from colorectal cancer. 
However , randomized managed trials using calcium products, with our without vitamin D, have shown combined results. One reason may be a fairly short duration. Due to higher cost and difficulty with continued compliance through participants, clinical trials have a tendency to be shorter in duration compared to epidemiological research. But colorectal cancer can take 7-10 years or longer to develop, during which these tests might not reflect any changes in the particular colon.
- A Cochrane overview of two well-designed double-blind placebo-controlled studies found that will taking 1, 200 magnesium of elemental calcium daily for about 4 years caused a 26% reduced occurrence of new intestines adenomas inside participants, a few of whom had adenomas before.  An adenoma is really a non-cancerous tumor yet which could become cancerous.
- The randomized double-blind placebo-controlled trial through the Women’s Health Initiative gave 36, 282 postmenopausal women 2 doses everyday of 500 mg much needed calcium and 200 IU calciferol, or even placebo, to get about seven years. The trial failed to find a difference within incidence of colorectal malignancy between the two groups.  A follow-up to this study five yrs later (total of 11 years follow-up) also did not find a lower incidence of colorectal cancer with the same calcium supplement and vitamin D supplement regimen.  It was noted in these studies that the women already had the high calcium supplements intake in the start from the research, so additional supplements might not have made a difference.
Right after a review of both cohort plus clinical studies from the World Cancer Research Fund and the United states Institute pertaining to Cancer Study, they reported strong evidence that calcium supplements of a lot more than two hundred mg day-to-day and consumption of high-calcium dairy food items will likely decrease the risk associated with colorectal cancer.  They noted possible causes including the ability of calcium to bind to certain toxic substances in the particular colon plus prevent the growth of tumor cells. Certain bacteria in dairy foods may also be protective against the development associated with cancerous tissues within the colon. 
At one time, experts recommended that people with kidney stones limit their calcium mineral intake because the mineral makes up one of the most common types of stones, called calcium-oxalate stones. What we know now is the reverse—that not eating enough calcium-rich foods may increase the particular risk associated with stone formation. Research from large trials including the Women’s Health Effort and the Nurses’ Health Study found that a high intake of calcium meals decreased the risk for kidney stones in ladies. However the same effect is not true with supplements, as calcium supplement in pill form was found in order to increase risk. [13,14]
A benefit of calcium-rich foods (mainly from dairy) on the particular prevention associated with kidney stones was found in a cohort of 45, 619 guys. Intakes of skim or low-fat milk and cottage cheese or even ricotta cheese showed the greatest protective impact. Men that drank two or more 8-ounce glasses of skim dairy a day had 42% less danger of developing calcium oxalate stone(s) as compared along with men who else drank less than one glass a month. Eating 2 or more half-cup servings of new cheese or ricotta cheese a week was associated with 30% less risk associated with kidney gemstones as compared with men which ate much less than 1 serving a month. It will be believed that will calcium-rich foods reduce the development of rocks by lowering the absorption of oxalates, which make upward calcium-oxalate gems. Nevertheless , some other undetermined components of dairy products foods can also be responsible meant for the decreased risk. 
Calcium is usually widely available* in many food items, not just milk along with other dairy foods . Fruits, leafy greens, beans, nuts, and some starchy vegetables are good sources.
- Dairy (cow, goat, sheep) plus fortified plant-based milks (almond, soy, rice)
- Calcium-fortified orange juice
- Winter squash
- Edamame (young green soybeans ); Tofu, made with calcium sulfate
- Canned sardines, salmon (with bones)
- Leafy greens (collard, mustard, turnip, kale , bok choy, spinach)
*Bioavailability of calcium supplements
For example , dairy foods have a bioavailablity of about 30% absorption so if a food label on milk lists 300 mg of calcium mineral per cup, about 100 mg is going to be absorbed and used simply by your body. Plant foods like leafy greens contain less calcium overall but have got a higher bioavailability than dairy. For instance , bok choy contains about 160 magnesium of calcium supplement per 1 cup cooked but has the higher bioavailability of 50%, so regarding 80 mg is soaked up. Therefore , consuming a single cup associated with cooked bok choy has almost while much bioavailable calcium because 1 mug of whole milk. Calcium-fortified orange juice plus calcium-set tofu have a similar total amount of calcium supplements and bioavailability as milk products, while almonds have slightly lower total calcium and bioavailability of about 20%. This may be useful information for those who cannot eat dairy products foods or even who follow a vegan diet plan.
A downside to some plant foods is that they contain naturally occurring plant substances, sometimes referred in order to as “ anti-nutrients . ” Examples of anti-nutrients are usually oxalates plus phytates that bind to calcium and decrease its bioavailablity. Spinach contains the most calcium of all the green greens from 260 mg of calcium mineral per one cup cooked, but it is also high in oxalates, lowering the particular bioavailability so that only 5% or about 13 magnesium of calcium supplement can become used with the body. The takeaway message is not really to avoid spinach, which contains other valuable nutrients, yet not in order to rely upon spinach since a significant source associated with calcium since most of this will not be consumed by the body. You can also schedule your meals so that you do not really eat “calcium-binding” foods like spinach with the same meal as calcium-rich food items or along with supplements.
In case you are scanning foods labels to reach a specific amount of daily calcium supplements, continue to aim for the particular RDAs set for your own age group plus gender. The particular RDAs are usually established with an understanding of calcium bioavailability in food. Also keep in mind that the exact amount of calcium absorbed in the body will vary amongst individuals based on their metabolism and what other foods are eaten at the same meal. In general, eating a variety associated with calcium-rich meals can help to offset any small losses.
Signs of Deficiency and Toxicity
Blood levels of calcium are tightly regulated. Bones will launch calcium into the blood if the particular diet does not provide enough, and no symptoms usually occur. A more serious deficiency of calcium, known as hypocalcemia, results from diseases such as kidney failure, surgeries of the digestive tract like gastric bypass, or medications want diuretics that will interfere along with absorption.
Symptoms of hypocalcemia:
- Muscle cramps or even weakness
- Numbness or tingling in fingers
- Abnormal heart rate
- Poor appetite
A gradual, progressive calcium deficiency can occur in people who also do not get enough dietary calcium mineral within the long-term or whom lose the ability in order to absorb calcium supplement. The first early stage of bone loss is called osteopenia and, if untreated, brittle bones follows. Examples of individuals at risk include:
- Postmenopausal women —Menopause reduces the quantity of estrogen in the body, the hormone that helps to increase calcium assimilation and retain the mineral within bones. Sometimes physicians may prescribe hormone replacement treatment (HRT) with estrogen plus progesterone to prevent osteoporosis.
- Amenorrhea —A condition where menstrual periods stop early or are disrupted, and is usually often seen in younger women along with anorexia nervosa or athletes who physically train in a very large level.
- Milk allergy or lactose intolerance— Occurs when the entire body cannot digest the sugar in milk products, lactose, or the proteins in milk, casein or whey. Lactose intolerance can be genetic or acquired (not consuming lactose in the extensive may decrease the efficiency of lactase enzyme)
Guidelines if you are taking calcium supplements for osteoporosis
After a diagnosis of osteoporosis, your physician may prescribe over-the-counter supplements. However, there are several points to consider when using calcium dietary supplements.
- First, clarify with your physician how much total calcium supplements you should take daily. This amount includes calcium through as well as health supplements. The RDA for adults is between 1, 000-1, 200 mg daily, depending on age. Taking more compared to 2, 000 mg daily is not suggested for adults even with brittle bones, as this particular can potentially lead to additional health problems. It is not recommended to take more than 1, 200 magnesium daily, even with a diagnosis of osteoporosis.
- Taking too high an amount of calcium at one time, particularly from a supplement, can actually lower the particular absorption from the mineral. It is best to take no more than 500 mg at a single time. If you are prescribed more than that, get each dose at least 4 hours apart. So if you are prescribed 1000 magnesium of calcium daily, you might take a 500 mg supplement along with breakfast and then again at night with dinner.
- The two most common types associated with calcium supplements are within the form of calcium carbonate and calcium mineral citrate. The particular carbonate form needs to be broken down by stomach acid before it can end up being absorbed, so it can be usually used with meals; the citrate form does not require stomach acidity and can be taken without food.
- If you are unsure about how much calcium you are getting from the diet, consult with a registered dietitian. You would subtract the estimated amount of calcium through food from the RDA or prescribed amount by your doctor; the remaining can be taken as a supplement. If you are usually eating the very high calcium diet plan f (e. g., several servings associated with dairy milk or fortified milk, cheese, tofu, etc . daily), inform your doctor so they can estimate that amount into your calcium mineral prescription.
Too much calcium supplement in the blood is called hypercalcemia. The Upper Limit (UL) for calcium is 2, 500 mg daily through food and supplements. People over the age of 50 should not take more than two, 000 magnesium daily, especially from dietary supplements, as this can increase risk of some conditions like kidney stones, prostate cancer, and constipation. Some research has shown that in certain people, calcium can accumulate in blood vessels along with long-term higher doses plus cause heart problems. Calcium is also a large mineral that can block the absorption of other minerals like iron and zinc.
Symptoms of hypercalcemia:
- Weakness, fatigue
- Nausea, vomiting
- Shortness of breath
- Chest pain
- Heart palpitations, irregular coronary heart rate
Did A person Know?
Certain nutrients plus medications may increase your need for calcium supplements because they either lower the particular absorption associated with calcium inside the gut or cause more calcium to be excreted in the urine. These include: corticosteroids (example: prednisone), excess sodium in the diet, phosphoric acid such as found in dark cola sodas, excess alcohol, and oxalates (see Are anti-nutrients harmful? ).
- Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Ross AC, Taylor CL, Yaktine AL, et al., editors. Dietary Reference Intakes for Calcium mineral and Vitamin D. Washington (DC): National Academies Press (US); 2011. 5, Dietary Reference Content for Adequacy: Calcium and Vitamin Deb. Available from: https://www.ncbi.nlm.nih.gov/books/NBK56056/ Accessed 12/16/2019.
- Dickinson HO, Nicolson DJ, Cook JV, Campbell F, Beyer FR, Ford GA, Mason J. Calcium supplement supplementation with regard to the management of primary hypertension in adults. Cochrane Database Syst Rev . 2006 Apr 19; (2): CD004639.
- Kopecky SL, Bauer DC, Gulati M, Nieves JW, Singer AJ, Toth PP, Underberg JA, Wallace TC, Weaver CM. Lack associated with evidence linking calcium with or without vitamin D supplementation to cardiovascular disease within generally healthy adults: a clinical guideline from the National Osteoporosis Foundation plus the American Society regarding Preventive Cardiology. Annals of internal medicine . 2016 Dec 20; 165(12): 867-8.
- Tang BM, Eslick GD, Nowson C, Smith Chemical, Bensoussan A. Use of calcium or calcium inside combination along with calciferol supplements to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. The Lancet . 2007 Aug 25; 370(9588): 657-66.
- Yao P, Bennett M, Mafham Meters, Lin X, Chen Z, Armitage J, Clarke R. Vitamin G and calcium mineral for the prevention of fracture: a systematic review and meta-analysis. JAMA network open . 2019 Dec 2; 2(12): e1917789-.
- Kahwati LC, Weber RP, Pan H, Gourlay Michael, LeBlanc E, Coker-Schwimmer M, Viswanathan Meters. Vitamin D, calcium supplement, or combined supplementation intended for the main prevention associated with fractures in community-dwelling adults: evidence report and systematic review for that US Preventive Services Task Force. JAMA . 2018 Apr 17; 319(15): 1600-12.
- Wactawski-Wende M, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O’sullivan MJ, Margolis KL, Ockene JK, Phillips L, Pottern T, Prentice RL. Calcium plus vitamin D supplementation plus the risk of colorectal cancer. New England Journal of Medicine . 06\ Feb 16; 354(7): 684-96.
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- World Cancer Research Fund/American Institute pertaining to Cancer Research. Continuous Update Project Expert Report 2018. Diet, nutrition, physical activity and colorectal cancer. https://www.wcrf.org/sites/default/files/Colorectal-cancer-report.pdf . Accessed 12/21/2019.
- Song Michael, Garrett WS, Chan AT. Nutrients, foods, and colorectal cancer avoidance. Gastroenterology . 2015 May 1; 148(6): 1244-60.
- Curhan GC, Willett WC, Speizer FE, Spiegelman D, Stampfer MJ. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the particular risk meant for kidney stones in women. Life of inner medicine . 1997 Apr one; 126(7): 497-504.
- Sorensen MD, Kahn AJ, Reiner AP, Tseng TY, Shikany JM, Wallace RB, Chi T, Wactawski-Wende J, Jackson RD, O’Sullivan MJ, Sadetsky N. Impact associated with nutritional factors on incident kidney stone formation: a report from the WHI OS. The Journal of urology . 2012 May; 187(5): 1645-50.
- Curhan GC, Willett WC, Rimm EB, Stampfer MJ. A prospective study of dietary calcium and other nutrients and the risk associated with symptomatic kidney stones. New England Journal of Medicine . 1993 Mar 25; 328(12): 833-8.
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