Calcium is a type of body mineral that is extremely important for our health. It is the most abundant mineral in the body with more than 99% in the form of calcium phosphate complexes that mainly builds up our bones and teeth and contributes to the formation of nerve cells, body tissues, and fluids. It serves a whole lot of functions in the body so its deficiency can harm the body greatly and since our bodies can not produce calcium naturally and get its supply mainly from the diet or through calcium supplements it is essential to make sure that you incorporate foods that contain sufficient amounts of calcium in our diets to avoid these harmful effects and keep our bones and teeth healthy.
Calcium deficiency :
Calcium deficiency is also known as hypocalcemia is a very dangerous condition in which there is not enough calcium in the blood usually at a level of less than 2.1 mmol/l or ionized calcium level below 1.15 mmol/l if this condition occurs during essential times of high calcium requirements like during childhood and adolescence, pregnancy and lactation, and postmenopausal period it can lead to harmful health consequences, cause severe bone density loss and increase the risk of fractures it is mostly due to:
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- parathyroid hormone deficiency owing to an autoimmunedisease or idiopathically
- genetic cause like pseudohypoparathyroidism where there is a resistance to parathyroid hormone
- Digeorge syndrome where you are born without a parathyroid gland due to a mutation in chromosome 22
- most commonly following total thyroidectomy surgery since there is no further parathyroid hormone production
- post-radiation to the thyroid gland that affects the parathyroid gland as well
- vitamin D deficiency due to decreased intake, problem in absorption, and mainly due to not getting enough sun exposure
- Chronic kidney disease leads to an increased rate of calcium excretion and defects in vitamin D production in the body
- Liver failure that interferes with vitamin Dproduction
- poor calcium intake and too little dairy products or calcium-rich foods consumption
- taking medications that suppress the absorption of calcium like rifampin, phenytoin, phenobarbital,and chemotherapy like alendronate
- hyperphosphatemia and hypomagnesemia associated with excessive alcohol consumption that reduces the function of parathyroid hormone
- critical illness like toxic shock syndrome, tumor lysis syndrome, and rhabdomyolysis
- After massive blood transfusions since citrate in the blood reduces calcium absorption
- pancreatitis where the calcium gets deposited in the abdominal cavity due to the inflammation and gets lower in the blood
- Post Para thyroidectomy where there is a condition known as hungry bones syndrome where your bones absorb most of the calcium in the body leading to hypocalcemia
Food elements rich in calcium
1. Milk:
One cup of milk contains 122 calories,4.8 grams of fat, 12 grams of carbs, 8.1 grams of protein.
Without a doubt milk has always been the number one go-to drink that supplies you with the highest amount of calcium than any other food ingredient there is about 23% of the daily requirements of calcium in just one cup of milk that helps protect you against all the bad side effects of low calcium that is why it is very important to start from an early age to begin and finish the day with a cup of milk to keep healthy for as long as possible and age gracefully with strong bones that can help you avoid getting osteoporosis in the future.
2. Cheese:
5 grams of parmesan cheese contains 21 calories, 1.4 grams of fat, 0.7 grams of carbs, 1.4 grams of protein
Parmesan cheese is one of the oldest cheeses that has been used all over the world especially in Mediterranean countries mainly Italy. they are great sources of calcium with almost 3.3% of the daily requirements of calcium that keeps your bones and teeth healthy and strong, it has a strong salty and nutty flavor that enhances any dish it is added to, and it is high on protein for Lacto vegetarians and provides the body with medium-chain fatty acids that are more easily absorbed, it is also lactose-free what makes it extra special for people who suffer from lactose intolerance.
3. Yogurt:
100 grams of fat-free greek yogurt contains 59 calories, 0.4 grams of fat, 3.6 grams of carbs, 10 grams of protein
Yogurt is one of the best sources of calcium that supplies the body with almost 8.5% of the daily calcium requirements not only is it rich in calcium but it is also full of high-quality protein and vitamins and choosing the fat-free types makes it even better for your health with its great content of probiotics that are very beneficial for gut health and increase the healthy gut flora diversity so it is basically good for all body systems from bones and heart to the gut, it makes a marvelous, light, sour, snack with some fruits, seeds, or nuts and it can be a healthy start for the day as a simple breakfast.
4. Sardines:
12 grams serving of sardines contains 25 calories, 1.4 gm of fats, 0 gm of carbs, 3 gm of protein.
Sardines are very neglected sources of calcium although it contains roughly 3.5% of the daily requirements of calcium, sardines are great small fishes that can add saltiness to almost any dish they are full of omega 3 fatty acids that are good for heart health and prevention of many neurodegenerative diseases, They are also high on iron and magnesium. they can be prepared in a lot of ways either grilled, smoked, or even salted on top of pizzas and bagels.
5. Edamame:
100 grams of edamame contain 122 calories, 5 grams of fat, 10 grams of carbs, 11 grams of protein
This type of beans is basically immature soybeans, they are ones of the best sources of proteins that vegetarians can depend on and they are low on carbs which makes them great for people who are trying to lose weight and buff up and for diabetics as well since it doesn’t raise their blood sugar levels as it is full of fiber along with their high calcium content that equals to almost 5% of daily calcium requirements they protect you from osteoporosis as you get older.
6. Dried Figs:
One dried fig of 8.4 grams contains about 21 calories, 0.1 grams of fat, 5.4 grams of carbs, 0.3 grams of protein
Figs are marvelous fruits that contain a lot of health benefits, they contain a lot of fiber that helps soften stool and promote gut health, they improve blood pressure and the lipid profile that lowers the risk of having cardiovascular diseases, they have been shown to exert some anti-cancer properties through their antioxidant content and they improve skin health and lower the rate of collagen destruction along with 1% of the daily calcium requirements that you can get from just eating one dried fig. it is great in granola bars or just on their own as a healthy sweet snack.
7. Salmon:
100 gram serving of salmon contains 206 calories, 12 grams of fat, 0gm of carbs, 20 gm protein
Salmon is one of the best fatty fishes with not only high content of omega 3 fatty acids that help you sustain your brain health, have better gut motility, and reduce the risk of many chronic diseases, it is also full of calcium with 1.2% of the daily requirements that help you keep your bones and teeth healthy so make sure to add salmon to your diet at least twice every week.
8. Chia seeds:
A 12 gram serving of chia seeds contains 58 calories, 3.7 grams of fat, 5.1 grams f carbs, 2 grams of protein
Chia seeds are known for their slimy texture when soaked in water they can supply you with a whole lot of calcium almost about 5.8% of your daily requirements, chia seeds are also very high in iron, and are great sources of antioxidants and anti-inflammatories such as quercetin and kaempferol that has protective effects on heart and liver, they also potentially have anticancerous properties. you can add daily to your meals just sprinkle some on top of baked goods or add a teaspoon to your water to get some of its wonderful health effects.
9. Almonds:
100 grams of almonds contain 579 calories, 50 grams of fat, 22 grams of carbohydrates, 21 grams of protein
Almonds are the healthiest of nuts with their high content of antioxidants and vitamins, they are very rich in protein and fiber which aids people who want to lose weight in achieving their goal, and control blood sugar and insulin levels, they are also full of magnesium that helps lower blood pressure and decreases the risk of heart attacks and strokes along with 21% of the daily requirements of calcium that is easy to get as almonds are very tasty and simple snacks to have around all the time
The function of calcium in the body:
1. Building bones and teeth:
Bone is a complex tissue made up of 70% minerals and 30% organic content. This 70% of mineral content is made up of 95% hydroxyapatite which is a compound made up through the bonds between calcium and phosphorus Crystals and other ions like magnesium and fluoride, and the osteoid content is composed of 98% collagen fibers and a cellular matrix of glycoproteins and proteoglycans.
Calcium is a part of two different types of bone and is present in different concentrations according to the function of the bone there is :
- cortical bone or compact bone that is the structural strong bony part of the skeleton with 80_90% of calcium.
- trabecular bone or cancellous bone that serves mainly a metabolic function with 15_20% of calcium only.
While bone mass and density are determined by various factors like genetics, hormones, physical activity, and nutrition calcium is needed to maintain strong dense bones.
2. Muscle contraction:
Calcium is a major ion that plays a role in muscle contraction when an action potential is generated in the neuromuscular junction and propagates through the muscle fiber it activates voltage-gated calcium channels and this influx of calcium diffuses in the cytoplasm between actin and myosin filaments of the muscle which makes them glide over each other triggering muscle contraction and as the action potential fades the calcium ions get stored back to be released again with the new action potential.
3. Vascular caliber:
Calcium with its action on smooth and striated muscle leads to vasoconstriction of blood vessels which is the main idea behind the use of calcium channel blockers as antihypertensive drugs since they stop the influx of calcium ions and inhibit muscle contraction leading to vasodilation, lowering the resistance and subsequently lowering blood pressure
4. Nerve impulse transmission:
High calcium levels or hypercalcemia blocks sodium movements through voltage-gated sodium channels causing reduced depolarization and impaired action potential propagation which causes low muscle tone, cognitive impairment, and fatigue.
5. Cardiac contractility and conduction:
Calcium balance is also important for cardiac contractility as it is necessary for calcium to be influxed In large amounts during systole to trigger muscle contractility by the sliding of troponin filaments in relation to the propagated action potential from the Sa node and it should be effluxed from the heart during diastole to help the cardiac muscle to relax and fill with blood. in contrast, low calcium levels hypocalcemia facilitate sodium transport as there is no inhibition of the sodium channels leading up to hyperexcitability and if the calcium levels exceed 50% below normal it can lead to the spontaneous firing of nerve impulses giving tetanic muscle contraction
6. Coagulation cascade:
Calcium ions are essential to the coagulation cascade as it helps activate some of the clotting factors like factors 2, 8,9 10 it also plays a role in platelet activation resulting in the formation of a fibrin clot to stop bleeding which is very essential for the maintenance of hemostasis.
7. Hormone secretion:
The parathyroid gland is one of the main glands of the body that help regulate calcium, vitamin D, and parathyroid hormone levels in the blood through the interaction between bones, kidneys, and the intestine. parathyroid hormone is mainly controlled by the negative feedback of calcium as low calcium levels stimulate the release of parathyroid hormone to cause an increase in blood calcium levels by stimulating calcium release from large bones to the bloodstream, lowering its excretion rate through the kidneys, and increasing its absorption through the intestine, as well as stimulating the production of active vitamin D.
Hypercalcemia
Having too much calcium isn’t ideal as well as it serves no benefit and only causes harm to the body that is why it is not a good idea to have too much calcium supplementation and to supplement only when needed, hypercalcemia is diagnosed at a level of 2.63 mmol/l or urinary calcium excretion above 250 mg/day and is mainly due to:
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- excessive calcium supplements intake
- excess parathyroid hormone production due to adenoma or hyperplasia of the parathyroid gland
- malignancy mainly
- Leukemia, lymphoma,lung, breast, renal carcinoma
- Excess vitamin D either due to excessive supplementation or secondary to granulomatous diseases like tuberculosis and sarcoidosis
- Endocrine diseases such as Hyperthyroidism, Addison’s disease, pheochromocytoma
- Some medications such as lithium and thiazide diuretics
- Taking too many drugs that have high concentrations of calcium in them like antacids
Symptoms of too much calcium:
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- Musculoskeletal system: Bone pain, otitis fibrosis cystica, bone fractures,
- Poor dentition and erosions in the lamina of the teeth
- Renal system: kidney stones, polyuria (excessive urination) ,polydipsia (excessive thirst)
- Gastrointestinal system: pain, nausea,and vomiting related to peptic ulceration and acute pancreatitis along with constipation
- Neuropsychiatric: lethargy, depression,confusion, memory loss
- Headache, Fatigue, myalgia, muscle weakness
- Cardiac arrhythmias and arrest
So in order to avoid having all of these harmful outcomes it is best to rely on nutritious food to get the daily requirements of calcium and take supplementation only in times of high calcium need to get the most out of it since it offers no additional protection to your bones and it has even been associated with the development of prostate cancer in men and make sure to drink enough fluids to avoid dehydration which can exacerbate the hypercalcemia.
Dietary requirements:
- During the first 3 years 700 mg per day
- 4-8 years 1000 mg per day
- 9-18 years 1200 mg per day
- 18-50 years 1000 mg per day
- >50 years 1200 mg per day
- Pregnant and lactating females 1000:1300 mg per day
- With the upper limit being 1500:2000 mg per day and no more to avoid hypercalcemia
Advantages of supplements:
Calcium supplements are present in many forms but most commonly calcium carbonate and calcium citrate with the latter being easily absorbed through the GIT and don’t have to be taken with food but have lower amounts of elemental calcium than the former.
calcium is essential for special populations for example:
- Women after starting menopause since the rapid decline in estrogen levels can lead to bone resorption in rates higher than bone formation and compromise bone density, lead to osteoporosis and increase the risk of fracture, especially in vertebrae, hips, forearm so taking 1000 mg of calcium per day can decrease bone loss by 1% and with some exercises and sun exposure it can help you have healthy dense bones for longer and avoid having fractures.
- If you are on a vegan diet you usually don’t consume as manydairy products and foods with high calcium content so it is best to rely on supplements to protect your bones and teeth
- If you are on a high protein diet since proteins usually lead to excretion of calcium through urine leading to high loss rates of calcium this also happens if you consume too much salt in your diet since the sodium enhances calcium excretion by the kidneys
- If you are lactose intolerant and avoid having dairy products that have the highest amount of calcium we need but you can depend on lactose-freedairy products to make sure you get enough calcium through the diet
- If you have a health condition where you are unable to absorb calcium from your diet like inflammatory bowel disease so it is best to take supplements
- If you have been on medications that suppress calcium absorption or cause osteoporosis like corticosteroids and some types of immunotherapeutic drugs
- If you are suffering from low bone density and osteoporosis
- It can help reduce the incidence of some cancers like colon and rectum cancers
- It has been shown to reduce cardiovascular risk through its binding to fatty acids and reducing lipid absorption and it has shown lower ratesof hypertension so it decreases the two main causes of heart disease
- Some studies have shown that taking calcium supplements during pregnancy lowers the rate of developing preeclampsia
- Calcium has been shown to reduce weight gain and aid in weight loss as well as reduce the risk of getting metabolic syndrome