Vitamin-D: Need of an hour for strenghtening immunity!

Nutrition Expert: Sana Saiyed, practicing clinical nutritionist, Mumbai.

Calcium is the most abundant mineral in the body, with about 99 percent of it stored in the bones and teeth.

Your immune system begins in your gut, all the different bacteria that live there are called the gut-micro biome. When your gut is healthy, it’s full of good bacteria which helps to strengthen your immune system.

Role of calcium in immunity:

Calcium plays a significant role in activation of immune cells to fight the viruses and bacteria. Damaged tissue activates and attracts the first white blood cells to the wound which is the first stage in the healing process. 

However, researchers from the University of Bristol’s School of Biochemistry in collaboration with a team from the University of Bath, have shown that the very first trigger in this process is a flash of calcium which spreads like a wave back from the wound edge through gap junctions that connect all the cells.

Risks due to calcium deficiency:

Lack of a desirable amount of calcium can lead to some health problems related to weak bones, as bones are the major storage unit for calcium.

Due to severe deficiency, some children won’t attain the height of their age whereas adults may have low bone mass which can put them at higher risk for osteoporosis.

Osteoporosis is characterized with fragile and porous bones. It is most associated with fracture of hip, vertebra, wrists, pelvis, ribs and other bones. (1)

When calcium intake is low or ingested calcium is poorly absorbed, bone breakdown occurs as the body uses its stored calcium to maintain normal biological functions.

Many factors increase the risk of developing osteoporosis, including being inactive, or of advanced age; smoking cigarettes; drinking excessive amount of alcohol; and having a family history of osteoporosis.

Can supplementation help overcome the deficiency?

In supplement form, the best type of calcium is calcium lactate, followed by calcium citrate.

Calcium lactate is called ionizable calcium because it is one chemical reaction away from becoming calcium bicarbonate (which is ionized calcium, a term referred to in many of the studies below).

Ionized calcium is the usable form of calcium in our bodies (and by our immune systems). Alongside calcium, people also need vitamin D, as this vitamin helps the body absorb calcium. Vitamin D comes from fish oil, fortified dairy products, and exposure to sunlight.

A recent systematic review of 26 randomized controlled trials found that calcium supplements, with or without vitamin D, modestly but significantly reduced the risk of total and vertebral fractures, but not fractures of the hip or forearm salts (2)

In a follow-up study to the Calcium Polyp Prevention Study, supplementation with calcium carbonate led to reductions in the risk of adenoma (a non-malignant tumor) in the colon, a precursor to cancer. Even as long as 5 years after the subjects stopped taking the supplement. (3)

A doctor may recommend additional calcium for people who have started menopause, stopped menstruating due to anorexia nervosa or excessive exercise, have lactose intolerance or a cow’s milk allergy and follow a vegan diet.

Foods that are rich in calcium include: raw milk and raw milk products, green leafy vegetables (especially collard greens, spinach and kale), sardines and other seafood with bones in them, sesame seeds and almonds, and amaranth.

Recommended dietary allowance for men and women is mentioned below: (4)

MenDaily RDADaily Upper Limit
19-50 years1000 mg2500 mg
51-70 years1200 mg2000 mg
71 and older1200 mg2000 mg
WomenDaily RDADaily RDA
19-50 years1000 mg2500 mg
51 and older1200 mg2000 mg






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