vitamin D calcium

Vitamin D & Calcium Absorption Issue

Our body requires plenty of nutrients and minerals to work smoothly. Vitamin D and calcium are two such nutrients and minerals that it needs throughout its lifetime. In this article, we will discuss the vitamin D & calcium absorption issue. It is significantly related to bone health as adequate calcium absorption results in stronger bones.

Both vitamin D and calcium are primarily responsible for bone building and maintaining strong bones. Since bones provide structure to our body and ensure it moves effortlessly, keeping them healthy is crucial. Degrading bones is a serious health issue for both children and adults, irrespective of their sex.

The deficiency of either vitamin D or calcium may make the bones soft, weak, and prone to fractures. Various surveys and studies show that many people do not get enough vitamin D and calcium through their diet. This happens due to various reasons, and we will talk about them in a while.

As vitamin D and calcium help our body in significant ways, these two are also interrelated.

Even if someone takes ample amounts of calcium and misses out on their daily dose of vitamin D, their calcium absorption may be pointless. The reason behind that being, vitamin D enhances calcium absorption in the body.

Whenever the body has inadequate amounts of calcium, it fulfills its calcium quota through bones. Prolonged calcium deficiency may result in weaker bones and reduced mass. Therefore, one must understand the significance of the vitamin D and calcium absorption issue for healthier bones and lifestyle. Now, let’s explore and learn more about the issue.

What is Vitamin D? What is its significance for the Human Body?

Vitamin D is also known as calciferol, and it is primarily responsible for keeping the bones strong. As vitamin D is fat-soluble, it can be found in various foods, and its other sources are sunlight and supplements. Vitamin D helps the body to obtain calcium from the food and in the regulation of phosphate levels.

Apart from maintaining bone health, vitamin D helps in keeping away harmful bacteria and viruses. Moreover, vitamin D plays a crucial role in helping nerves transmit signals to the brain and body. Another significance of this essential nutrient is, it also helps in the movement of our muscles.

What is Calcium? What is its significance for the Human Body?

Calcium is an essential mineral that the human body needs to operate efficiently. Available in abundance, about 99% of the body’s calcium is stored in teeth and bones. The reason for such a high amount of calcium saturation in bones and teeth is, it helps to strengthen both of them.

Additionally, our body requires the rest of calcium (approximately 1%) to ensure muscle movement, secreting hormones, and data transmission through nerves to the entire body. The body’s primary source of calcium is green vegetables, dairy products, and fish. Moreover, if someone’s body cannot fulfill their calcium requirement from the food they eat, they may take calcium supplements.

How are Calcium and Vitamin D Interrelated?

It is clear, our bones store about 99% of the total calcium, and it is the primary mineral required for strong bones. Apart from helping the body extract calcium from the food, vitamin D also supports bone growth and remodeling. That’s not all; calcium and vitamin D, when combined, can also help the body prevent Osteoporosis and Rickets.

Osteoporosis is classified as a chronic disease that impacts bone health in the elderly and is more significant in women. A person who has Osteoporosis has weak bones, and they become prone to bone fractures. On the other hand, Rickets is also a bone disease but is prevalent in children and causes their bones to become soft.

As per studies and surveys, many adults and children don’t consume adequate calcium from their diet. One of the primary reasons behind this is not consuming enough vitamin D daily. Therefore, it becomes essential for the body to adequately consume vitamin D and calcium to prevent bone health problems.

What are the Sources of Vitamin D?

Our body gets vitamin D from a variety of foods. Apart from food, the other sources of vitamin D are sunlight and supplements.

Foods rich in Vitamin D

Fishes are a great source of vitamin D; however, one must note that not all fishes have the nutrients’ high concentration. Vitamin D is found in great amounts in a handful of oily fishes like Tuna, Trout, Mackerel, Salmon, etc. Particularly, the oil from the liver of these fishes provides significant amounts of vitamin D.

Other than oily fishes, red meat, egg yolk, and the livers of various animals also provide vitamin D in small amounts. For vegetarians, fortified foods and milk especially contain small amounts of vitamin D. If you follow a vegan diet, you may also consume mushrooms for your daily dose of vitamin D along with supplements if needed.


Sunlight is a significant natural source of vitamin D. Upon skin’s direct contact with the sunlight; it absorbs UVB radiation which is then converted into vitamin D3. However, the process of vitamin D synthesis from the sunlight gets slowed down due to multiple factors. These include amounts of skin melanin, season, sunscreen, overcast conditions, etc.

Such factors might reduce the skin’s ability to produce or absorb vitamin D from sunlight. As per experts, one must expose their skin to the sunlight for about 5 minutes to half an hour at least every three days. Studies suggest sunlight exposure for about 30 minutes twice a week can help individuals maintain their vitamin D levels. 

Dietary Supplements

Dietary supplements work as a substitute for sources and foods containing a particular vitamin or nutrient. Generally, vitamin D supplements are made using the process of UV irradiation in yeast. The process provides us with vitamin D3, and it helps fight bone diseases like Rickets in children.

Studies show consumption of vitamin D supplements can help an individual maintain their levels of the nutrient and absorb calcium. Though one may find many vitamin D supplements on the shelf, we advise our readers to consult their doctor before consuming one themselves.


Recommended Vitamin D Doses For Various Age Groups

Health experts measure the recommended dietary allowance or RDA of vitamin D in milligrams or mcg and International units or IU. 40 IU is equal to 1 mcg of vitamin D. The recommended dose of vitamin D to maintain adequate amounts of calcium and bone health is given below.

For male and female infants, 0-12 months old, the RDA is 400 IU or 10 mcg.

For male and female kids, 1-13 years old, the RDA is 600 IU or 15 mcg.

For male and female teenagers, 14-18 years old, the RDA is 600 IU or 15 mcg.

For male and female adults, 19-50 years old, the RDA is 600 IU or 15 mcg.

For male and female adults, 51-70 years old, the RDA is 600 IU or 15 mcg.

For male and female adults, 71+ years old, the RDA is 800 IU or 20 mcg.

What factors lead to Vitamin D Deficiency?

The first and foremost reason behind any nutrient or mineral deficiency is not adding adequate amounts to your diet. Therefore, if you don’t consume enough foods rich in vitamin D, you might face its deficiency in the long run. One may have vitamin D deficiency even if they’re a vegan.

A large proportion of vitamin D is produced through our skin in its inactive form, which is then converted to its active form. If your skin has limited direct contact with the sunlight or has

dark shade, you may be prone to vitamin D deficiency. The reason being the body might not be able to receive enough vitamin D from sunlight.

In case you’re someone who finds it difficult to digest dietary fats, you might need vitamin D supplements to avoid its deficiency. Moreover, obesity also leads to vitamin D deficiency as obese people tend to have lower amounts of inactive vitamin D or 25(OH)D. Such people might also need supplements or increase their intake of vitamin D-rich foods. 

Some infants may not get enough vitamin D from their mother’s milk, and they may also face vitamin D deficiency. Studies show, breastfeeding mothers with low vitamin D can provide only 0.6 to 2.0 mcg/L of the nutrient to the baby. Whereas the recommended dose is up to 10mcg for babies up to 12 months.

It has been found that breastfeeding mothers consuming vitamin D supplements can better help their baby fulfill the daily quota of the nutrient. Moreover, aging may also lead to vitamin D deficiency, as with age, the body’s ability to absorb nutrients gets reduced.

What if I consume more than the required amount of Vitamin D?

Consuming more than the recommended dose of vitamin D may cause various health complications in the long term. Excess amounts of vitamin D in the body may cause nausea, kidney stones, vomiting, weakness, dehydration, and even neurological problems. Extremely overconsumption of vitamin D may also result in renal failure and death.

What are the Sources of Calcium?

Calcium is among the vital minerals that the human body needs to perform various functions like bone remodeling. The mineral is found in a plethora of foods. Moreover, one may also consume calcium via supplements and other medicines.

Foods rich in Calcium

Yogurt, Orange Juice, Sardines, Cheddar Cheese, Milk, and Fortified Soymilk can provide up to 415 milligrams of calcium in one serving. Other than these, Salmon, Tofu, Cereals, Kale, Chia Seeds, Broccoli, etc., can also provide calcium up to 180 milligrams in a single serving. Interestingly, vanilla ice cream, bread, and cream cheese can also provide up to 84 milligrams of calcium to the body.

Dietary Supplements

Doctors often advise individuals with severe calcium deficiency or health complications to consume calcium via dietary supplements. Supplements offer calcium in two primary ways, better known as calcium carbonate and calcium citrate. The significant difference between the two forms of calcium supplements is that calcium carbonate is readily available, pocket-friendly, and easy to consume.

It does not mean that calcium citrate is not helpful or should not be consumed. Calcium citrate is more advantageous for individuals with achlorhydria and inflammatory bowel disease. Moreover, evidence shows that calcium citrate is also beneficial for individuals with absorption disorders.

As per experts, calcium carbonate uses stomach acid to be digested adequately, and these supplements work best when consumed with food. Calcium citrate, on the other hand, may or may not be consumed with food and, it would still be consumed adequately. Another key difference between the two types of calcium supplements is their calcium weight.

For instance, calcium carbonate has approximately 40 percent calcium, whereas calcium citrate is only 21 percent calcium. You may also split your daily dose of calcium supplements into two or more equal portions for best results. The reason behind this is, elemental calcium is adequately absorbed when consumed in smaller amounts.

While the markets are flooded with various calcium supplements, you should consult with your doctor to avoid any complications.


One may also absorb calcium in smaller amounts through various antacids. As antacids contain significant amounts of calcium carbonate, they neutralize stomach acids and provide up to 400 milligrams of calcium.

Recommended Calcium Doses For Various Age Groups

As per health experts and medicine institute, the recommended dietary allowance or RDA of calcium is given below:

For male and female infants, 0-6 months old, the RDA is 200 mg.

For male and female infants, 7-12 months old, the RDA is 260 mg.

For male and female babies, 1-3 years old, the RDA is 700 mg.

For male and female kids, 4-8 years old, the RDA is 1000 mg.

For male and female kids, 9-13 years old, the RDA is 1300 mg.

For male and female teenagers, 14-18 years old, the RDA is 1300 mg.

For male and female adults, 19-50 years old, the RDA is 1000 mg.

For male adults, 51-70 years old, the RDA is 1000 mg.

For female adults, 51-70 years old, the RDA is 1200 mg.

For male and female adults, 71+ years old, the RDA is 1200 mg.

What factors lead to Calcium Deficiency?

As per surveys, the most common reason for calcium deficiency in most adults is the lack of vitamin and mineral-rich balanced diet. Inadequate calcium consumption for a long time may lead to its deficiency. Apart from an imbalanced diet, menopause also leads to significant calcium deficiency in women.

When women hit menopause, their body reduces estrogen production, and it leads to low calcium absorption. Increasing the calcium intake can slow down bone loss in such women and reduce the risk of Osteoporosis. However, if a woman’s condition is severe, her doctor may also recommend hormone replacement therapy to reduce her bone loss.

Reduced amounts of estrogen in athletic women result in a condition called Amenorrhea, and it directly impacts the body’s calcium balance. These women tend to have a high rate of urinary calcium excretion and reduced bone mass. For their betterment, these women must consume recommended amounts of vitamin D and Calcium.

Additionally, lactose intolerance also leads to calcium deficiency as individuals with dairy products allergies may not be consuming enough calcium. To meet their calcium requirements and maintain healthier bones, individuals must take other foods rich in calcium or supplements.

What if I consume more than the required amount of Calcium?

Excess consumption of any nutrient or mineral is good for nothing, and such is the case with calcium. Over-consuming calcium than the recommended dose may cause soft tissue calcification, constipation, kidney stones, and hypercalcemia. Moreover, in some cases, overconsumption of calcium supplements may also lead to prostate cancer.

However, the vital thing to note is, these complications are more prevalent when calcium is consumed via supplements.


Vitamin D deficiency and calcium deficiency may trigger the vitamin D and calcium absorption issue and cause various bone health problems. Consuming enough amounts of vitamin D and calcium helps individuals lead a healthy life and maintain strong bones. Moreover, one must also be mindful about not overconsuming both vitamin D and calcium for better health.