Calcium -Food Sources, Deficiency And Functions

Calcium

Calcium is a vital mineral that you require. It is the most abundant mineral in your body. Most of the body calcium (approximately 99%) is found in your bones and teeth while only 1% is contained in serum. It serves various critical roles such as bone metabolism, muscle contraction, and nerve impulse and transmission.

Functions Of Calcium

For muscle contraction-Calcium allows your muscles to contract.
Maintains bone structure– Calcium and phosphorus work together to ensure healthy bones and teeth. Calcium combines with other minerals including phosphorus to form hard crystals that strengthen and harden the bones.
For nerve impulse and transmission –It is important for the transmission of nerve signals from nervous system to other parts of the body.
Required for the activation of certain enzymes– Calcium is crucial in activating certain enzymes and the release of hormones such as parathyroid hormone.

Food sources

Milk and other dairy products e.g. cheese, yoghurt
Nuts
Dried beans
Green leafy vegetables
Seafood
Egg yolks

RDA

Adults (19-50 years) – 950-1000 milligrams
Adults 51 years or older- 1200 milligrams

Individuals At Risk Of Deficiency

Individuals with lactose intolerance-Calcium rich sources are mainly milk and its products; hence, individuals who are lactose intolerant frequently exhibit calcium deficiency because of the dietary limitation of calcium-containing food sources.
Adolescents– Eating disorders among female and male teenagers increase their risk of nutrient deficiencies including calcium deficiency.
The elderly– They are at risk due to low calcium intake, and the intake of medications that cause a decrease in dietary calcium absorption.

Calcium is mostly significant for the development of healthy and strong bones during periods of fast growth including infancy, childhood and puberty.

It is also key that adequate calcium sources are included in the diet even as one grows older because calcium absorption decreases with advancing age. The risk of developing osteoporosis increases among the elderly. Therefore, integrating healthy dietary practices in addition to consuming adequate calcium sources is crucial to preserve bone health during this period.

Calcium Deficiency

Calcium deficiency can result from inadequate intake of calcium sources or from conditions such as hyperthyroidism and renal failure, medications including diuretics and medical treatment procedures such as gastric bypass surgery .

Signs of Calcium deficiency:

Muscle cramping
Dry skin
Bone fractures

Hypocalcaemia (low calcium blood levels) – a severe form of calcium deficiency is common and can present as asymptomatic when mild or in the initial phases, but once it reaches a severe state, the condition can occur with more serious symptoms and can be critical.

Hypocalcaemia is linked to either Vitamin D or hyperthyroidism. Hypocalcemia resultant from vitamin D may be due to renal complications that interfere with Vitamin D utilization, inadequate Vitamin D intake or limited sun exposure. Inadequate Vitamin D stores can result in secondary hyperparathyroidism and limited calcium absorption.

A long-term calcium deficiency causes osteoporosis, which is associated with an increased risk of fractures.

Calcium Toxicity

Hypercalcaemia (high calcium blood levels) is mainly related to hyperthyroidism rather than dietary intake. Excess Vitamin D supplement intake with doses greater than 50,000 IU per day and advanced stages of cancer can also lead to hypercalcaemia.

Symptoms of Hypercalcaemia include:

Abdominal pain
Depression
Constipation
Body ache and pain
Nausea and vomiting
Anorexia
Lethargy
Frequent urination
Frequent thirst

Nutrient Interactions With Calcium

Vitamin D, sodium and phosphorus –These minerals affect body calcium levels in diverse ways. For instance, vitamin D is crucial in maintaining proper body calcium levels because it aids in the absorption of calcium from dietary sources and regulates the amount of calcium excreted in urine and removed from bones. Inadequate vitamin D in your body implies an inability for your body to form hormone calcitriol (active vitamin D) , which is necessary for calcium absorption. Consequently, this leads to reduced calcium absorption.

With sodium –a high intake causes a reduction in body calcium levels, even with adequate intake of calcium sources since calcium is required for the excretion of excess salt through the urine.

Phosphorus and calcium work together to maintain strong and healthy bones and teeth. For the proper functioning of these 2 minerals, a balance between them is essential; since an excess of either inhibits the absorption of the other. To illustrate, when there are high body calcium levels, and low phosphorus levels, phosphorus absorption is limited , and the contrary is also accurate.

Drug Interactions With Calcium

Medications linked to an increase in blood calcium levels include:

Thiazide diuretics
Lithium
Estrogens

Medications linked to a decrease in blood calcium levels include:

Diuretics
Calcimimetics
Corticosteroids such as Prednisone
Bisphosphonates
Denosumab (Prolia, Xgeva)

Depending on one’s condition in regard to body calcium status, calcium can be restricted or increased.

Calcium restriction may be recommended:
· For the management of hypercalciuria(excess calcium in urine)
· For the overall treatment for kidney stones

A calcium-restricted diet will likely be inadequate of other nutrients such as riboflavin and vitamin D; thus, a dietitian’s guidance is required, to address these potential nutrient inadequacies.
Under the guidance of a dietitian, calcium supplements can be provided for certain persons susceptible to deficiency. For example, patients who have undergone gastric bypass surgery and patients who have undergone a bilio-pancreatic diversion (BPD) procedure and have clinical steatorrhea, may require calcium supplementation.

Calcium is necessary for your bones and teeth and neuromuscular function. It works with other important nutrients such as Vitamin D and phosphorus, hence a varied diet with adequate amounts of these nutrients is integral. Obtain your calcium from its food sources unless supplementation is indicated, in which case , a dietitian should offer guidance.