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Calcium in Human Digestive System

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Calcium in Detail

Calcium is a nutrient that is required by all living things, including humans. It is the body's most prevalent mineral and is essential for bone health. Humans require calcium to produce and maintain strong bones and it has been estimated that bones and teeth contain 99 percent of the body's calcium. It's also required for keeping the brain and other sections of the body in good working order. It helps with muscle activity and cardiovascular health. Many foods naturally contain calcium, and some food producers add it to their products. There are other supplements available.

Vitamin D, which helps with the digestion of calcium, is required in addition to calcium. Fish oil, fortified dairy products, and sun exposure are all good sources of vitamin D. Before moving on, let us take a brief look at the Human Digestive System.

Human Digestive System

The gastrointestinal tract, as well as the digestive organs that support it, make up the human digestive system (the tongue, liver, pancreas, salivary glands, and gallbladder). Food is broken down into smaller and smaller components during digestion until it could be taken and incorporated into the body. The cephalic phase, the stomach phase, and the intestine phase are the three stages of digestion.

Gastric secretions are produced in reaction to the sight and smell of food in the initial stage of digestion, known as the cephalic phase. The mechanical breakdown of food through chewing and the chemical breakdown of food via digestive enzymes both occurs in the mouth during this stage.

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Importance of Calcium in Body

Calcium has a variety of functions in the body. The following are some of them:

Bone Health

  • The bones and teeth contain nearly all of the calcium throughout the human body. Calcium is required for bone formation, growth, and maintenance.

  • Calcium aids in the growth of children's bones as they grow. Calcium managed to help strengthen bones and slow down bone density loss, which seems to be a natural part of the ageing process, even after a person has stopped growing.

  • Males and younger adults lose bone density at a faster pace than women who have previously gone through menopause. They are more likely to develop osteoporosis, and a doctor might advise calcium supplements.

Muscle Contraction

  • Calcium aids in the control of muscular contractions. The body produces calcium when a neuron stimulates a muscle. Calcium aids muscular contraction by assisting the proteins in the muscle.

  • The muscle relaxes as the calcium is pumped out of it by the body.

Cardiovascular System

  • Calcium is essential for blood coagulation. Clotting is a multi-step operation that requires a lot of patience. A variety of substances, including calcium, are involved.

  • Calcium's role in muscular function involves keeping the cardiac muscle in action. The smooth muscle which surrounds blood arteries relaxes when calcium is present. Several studies have found a correlation between high calcium consumption and decreased blood pressure.

  • Vitamin D is also important for bone health because it aids calcium absorption.

Other Roles

Many enzymes require calcium as a cofactor. Certain important enzymes cannot function properly without calcium.

Calcium deficiency has also been linked to the following outcomes in studies:

  • During pregnancy, there is a lesser risk of acquiring high blood pressure issues.

  • Young people's blood pressure stays lower.

  • Those whose mothers received enough calcium throughout pregnancy had reduced blood pressure.

  • cholesterol levels get improved.

  • colorectal adenomas, a form of non-cancerous growth, are less likely to occur.

Calcium-rich Foods

Sources of calcium may include:-

  • cheese, milk, and several other dairy foods

  • fish wherein one eat the bones – such as pilchards and sardines

  • soya drinks with added calcium

  • green leafy vegetables, including turnip leaves, okra, broccoli, curly kale, spinach and watercress

  • bread and anything that is prepared using fortified flour

  • many fortified breakfast cereals

  • legumes and grains

  • cornmeal and corn tortillas

  • nuts and seeds, particularly sesame, almonds, and chia

  • fortified fruit juices

Calcium Digestion

The circumstances in the small intestine lumen have an impact on calcium absorption. The calcium is converted to salt by the stomach's acid secretion, which is collected largely in the duodenum. Calcium that is not absorbed is precipitated within the ileum and eliminated in the stool. Excessive fatty acid and high amounts of magnesium and oxalates hinder calcium absorption, but lactose, the sugar in milk, improves it.

A process that demands energy absorbs calcium all across the brush boundary of the enterocyte cell membrane. Vitamin D is required for this activity, and when it is low, active calcium transport is halted. Calcium absorption is further influenced by parathyroid hormone (parathormone) and pituitary growth hormone. A typical meal comprises 1,200 mg of calcium, with about a third of it being absorbed. 99 percent of the calcium in the blood is reabsorbed when it passes through the kidneys. As a result, significant calcium losses occur in both kidney failure and malabsorption states. Calcium is reabsorbed from the bone in calcium shortage, weakening and softening the skeletal structure.

Calcium Deficiency

Low calcium levels, commonly known as hypokalemia, can be caused by the following conditions or lifestyle habits:

  • Bulimia, Anorexia, and a few other eating disorders

  • Overconsumption of Magnesium

  • Chelation Therapy Used For Metal Exposure

  • Mercury Exposure

  • Elongated Use of Laxatives

  • Prolonged Use of Few Medicines, Including Corticosteroids Or Chemotherapy

  • Lack Of Parathyroid Hormone

  • People who intake a lot of sodium or protein might face excretion of calcium.

  • High consumption of soda, caffeine, or alcohol

  • Various Cancers

  • Certain conditions, like Inflammatory Bowel Disease, Celiac Disease, Crohn’s Disease, and few other digestive diseases

  • Some surgical procedures, including removing the stomach

  • Vitamin D Deficiency

  • Kidney Failure

  • Phosphate Deficiency

  • Pancreatitis

Calcium is excreted by the body via urine, sweating, and faeces. Calcium levels in the body might be reduced by foods and activities that promote such functions.

Calcium Supplements:

Calcium supplements might be recommended by a doctor if you have a calcium shortage. The supplement users should do the following:

  • Check with their doctor to see whether they require supplements.

  • Follow the doctor's instructions for the dose.

  • Take the supplement with meals for optimal absorption and to reduce the risk of side effects.

  • The supplements should be taken at regular intervals, normally two or three times each day.

As per the ODS, approximately 43% among all adults in the United States, particularly 70% of older females, use calcium supplements. Consuming calcium supplements might boost daily calcium intake by roughly 300 mg on average.

Vitamin D is found in far too many calcium supplements. Vitamin D aids in the absorption of calcium and promotes protein synthesis in the body.

Types of Supplement

Supplements come in a variety of forms. A doctor can advise you on the best course of action. This will be determined by the individual's demands and preferences, as well as any medical problems and drugs they are taking.

Although elemental calcium is a pure mineral, it does coexist with various compounds in its natural state.

  • Calcium Carbonate: This is made up of 40% elemental calcium. This style is widely available, as well as inexpensive and convenient. It should have been taken with meals since stomach acid aids absorption.

  • Calcium Lactate: This comprises 13% elemental calcium.

  • Calcium gluconate: This comprises 9% elemental calcium.

  • Calcium Citrate: This has a calcium content of 21% elemental calcium. It can be taken with or without a meal. Achlorhydria, Inflammatory bowel disease, and various absorption diseases can all benefit from it.

Risks of Supplements

Supplement use has been linked to a variety of benefits and downsides, according to research. The majority of specialists think that getting nutrients through natural food sources is preferable, albeit this is not always achievable. Calcium supplementation, on the other hand, has been linked to health risks in several studies.

Side Effects: 

When taking calcium supplements, some persons have gastrointestinal symptoms including bloating, gas, constipation, or a mixture of all three.

Calcium citrate, on the other hand, has fewer and milder adverse effects than calcium carbonate. Using the supplements alongside food or throughout the course of the day might assist in reducing the occurrence or severity of adverse effects.


High consumption of calcium supplements may lead to:

  • kidney problems

  • kidney stones

  • calcification of soft tissues and blood vessels

  • constipation

As per the ODS, these serious adverse effects are more frequently the result of cancer and thyroid disorders than of excessive calcium levels caused by taking too many supplements.

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FAQs on Calcium in Human Digestive System

Q1. What Foods Stop Calcium from Being Absorbed?

Ans. Food ingredients such as oxalic acid and phytic acid, which are naturally found in certain plants, get attached to calcium and therefore can prevent it from being absorbed. Sweet potatoes, spinach, rhubarb, collard greens, and beans are examples of foods rich in oxalic acid.

Q2. Can One Take Calcium Tablets on a Daily Basis?

Ans. It's possible that you'll need to divide the dose. It's critical to evaluate the calcium tablets content of the supplement you purchase. It's impossible for your body to absorb big amounts of it all at once. In supplement form, specialists advise consuming no more than 500 mg at once.

Q3. What Happens if Serum Calcium Levels in Your Blood are Low?

Ans. Hypocalcemia, popularly called calcium deficiency disease, is a condition in which the serum calcium levels are abnormally low. Long-term calcium insufficiency can cause dental problems, brain abnormalities, cataracts, and osteoporosis, which causes bones to become weak.