Fight Corona

The Importance of Adequate Vitamin D for Covid 19

Alpa Momaya

April 6, 2022

Covid 19 is a deadly virus that entered the world in 2020. It spread into a pandemic and is still a threat to us. The report of its first case was in Wuhan, China. It has been testing and challenging for the whole world as it came to a halt. Since the effective means of spreading this virus were through body contact and air, the most common emotion everyone faced was fear. It made people anxious and panicky. However, panicking is not the solution to fighting Covid. On the other hand, building immunity is the right solution to stay fit during these trying times. Studies show that vitamin D supplementation can decrease the severity of Covid 19 infection. 

Healthy eating habits play a significant role in building our immunity in all of this. Since the extent of Infection this virus can cause in our body is immunity dependent, doctors advise consuming a healthy diet to build immunity. Low vitamin D levels increase inflammatory cytokines and a significantly increased risk of pneumonia and viral upper respiratory tract infections in Covid patients. Therefore, adding vitamin D to your diet came as one of the most effective solutions.

Vitamin D: A Brief

Vitamin D is a fat-soluble vitamin present in some foods, added to others, and available as a dietary supplement. It occurs in two primary forms- D2 (ergocalciferol) and D3 (cholecalciferol). They differ chemically only in their side-chain structures. In general, vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations. It further enables normal bone mineralisation and prevents involuntary contraction of muscles, leading to cramps and spasms. Moreover, it is also essential for cells for bone growth and bone remodelling.

The best natural source of vitamin D is the sun. Sun is enough to meet requirements but a person may not get adequate sunlight daily to meet requirements. Therefore, it becomes essential to consume vitamin D in our diet. You can consume foods and dietary supplements which are well absorbed in the small intestine.

Vitamin D for Covid 19: How do we fight Infections

Due to its numerous health benefits, vitamin D is an essential nutrient for the body’s proper functioning, not only during Covid but otherwise too.

Evidence suggests that vitamin D aids in the treatment of Covid infections. It boosts the functioning of your immune system and deals with pathogens to protect your respiratory system. It is also helpful for Omicron and the other variants. In addition, patients with vitamin D deficiency have 14 times more chances of severe cases of Covid 19. As a result, the mortality rates are also comparatively higher.

1. Boosts Immunity and Eases Inflammation

Evidence states that low levels of vitamin D increase inflammatory cytokines, cells that promote inflammation. COVID-19 infection results in myocarditis, microvascular thrombosis and cytokine storms. These conditions lead to inflammation. The primary role of vitamin D is to boost immunity and ease inflammation. Therefore, doctors suggest increasing vitamin D intake to prevent COVID-19.

2. Protection from Respiratory Infections

Some studies show that people with vitamin D deficiency have a 12% reduced risk for respiratory infections after taking supplements. However, there is not enough research to back up this claim.

3. Prevents Cancer

Scientists have been researching vitamin D’s possible role in preventing cancer. Several studies analysed a potential connection between vitamin D, colon cancer, ovarian cancer, and prostate cancer. It yielded promising results, suggesting that it may be an easy and low-cost way to help reduce cancer risk.

Vitamin D was not found to overall reduce the risk of cancer. However, those who developed cancer had a 25% lower death rate when taking it. Also, findings suggested vitamin D reduces cancer risk for African Americans. However, people with dark skin tones have higher amounts of skin pigment melanin, which acts as a natural sunscreen. However, the researchers have said that further study is crucial on this.

In addition, cancer weakens the immune system. Therefore, the patients can be at a higher risk of contracting COVID-19. 

4. For Pregnancy

Some studies show that vitamin D deficiency in pregnant women can put them at a greater risk of developing preeclampsia and giving birth preterm. Moreover, a lack of vitamin D can cause gestational diabetes because it stimulates your pancreas to make insulin and bacterial vaginosis in pregnant women. Similarly, pregnant women are more at risk to contract any infection, and COVID-19 is not an exception.

5. Blood Pressure Management

Vitamin D decreases the production of a hormone named renin, which plays a role in hypertension. However, more concrete studies need to prove its effectiveness in the area. The death figures show that among the deceased from COVID-19, a significant portion was suffering from hypertension. 

Vitamin D: Other Significant Benefit

Helps Maintain Healthy Bones and Teeth

Vitamin D maintains adequate calcium and phosphorus levels in the blood. It aids in the absorption of calcium. Without sufficient vitamin D, the body will not form the hormone calcitriol. Calcium and phosphorus promote the growth and maintenance of healthy and strong bones. Therefore, it is essential to maintain their levels. Children need vitamin D to prevent rickets. On the other hand, older adults need it to prevent osteomalacia and osteoporosis.

Vitamin D Sources

The most significant and most commonly available source of vitamin D is the sun. It is present in an inactive, prohormone form in our body. When sunlight strikes the skin, UV rays present in it convert the prohormone into its active form. That’s how our body makes vitamin D. However; sunlight may not always be enough to provide for the vitamin D requirements of the body. Therefore, it is essential to consume sufficient amounts in your diet. Some rich sources of vitamin D include:


Salmon is a fatty fish and a good source of vitamin D. Besides this, sockeye salmon is rich in protein and omega-3 fatty acids. There are two types of salmon fishes available in the market, i.e., farmed or wild salmon. Farmed salmon contains less amount of vitamin D as compared to the wild variety. However, farmed salmon has a lower content of environmental contaminants, while wild salmon has a higher content of omega-3 fatty acids.

  • 100g of sockeye salmon or farmed Atlantic salmon contains 526 IU of vitamin D. This is 66% of the daily recommended value.
  • 100g of wild salmon contains around 988 IU of vitamin D. This is 124% of the daily recommended value.
  • Other fishes like tuna, sardines, mackerel and herring are also good sources of vitamin D. 

Cod Liver Oil

Cod liver oil is the extract from the liver of codfish. Traditionally it was for children with vitamin D deficiency to prevent rickets, a consequence of this deficiency. In addition to vitamin D, it is a good source of vitamin A and omega-three fatty acids. However, because of the high amount of retinol, pregnant women should consult a doctor before consuming cod liver oil.

A 100 g of cod liver oil contains 250 mcg of vitamin D. This provides for your daily dietary requirement. However, one needs to be cautious when consuming cod liver oil. It can cause vitamin A and D toxicity in the body if taken in large amounts daily.


Whole eggs are an excellent source of vitamin D and are also a powerhouse of nutrients. Most of the protein in an egg is found in the egg white, while its fat, vitamin and mineral content are found mainly in the yolk. A 100 g provides 4% of the daily recommended value for vitamin D.

Eggs are an excellent source of protein. In addition, they contain a good amount of iron, vitamin A, vitamin E, selenium and choline. For most healthy adults, it is safe to consume 1–2 eggs per day, depending on their cholesterol intake through other meals in their diet. For people who do not consume seafood or animal meat, eggs can be a great source of vitamin D.


Like humans, mushrooms can synthesise vitamin D on exposure to UV light. Though mushrooms don’t naturally offer a very high amount of vitamin D, pure vegetarians and vegan can consume them and vegans as an alternative for seafood. 100g of mushrooms contain 3 IU of vitamin D, which is 1% of the daily recommended value.


The most commonly consumed milk is cow’s milk. Milk is usually known as a complete food. It is a rich source of calcium and phosphate, necessary to maintain bone and tooth health. It is an excellent source of vitamin D for children and adults. In addition, it also contains vitamins A, B6, B12, C, K and E.

Plant-based milk substitutes like soy milk and almond milk fortified with vitamin D and other vitamins and minerals can work as substitutes.

Fortified Orange Juice

Several stores stock up on fortified orange juice with vitamin D and other nutrients like calcium. So add it to your breakfast menu and give your day the proper healthy kickstart.

Cereals and Oatmeal

Usually, cereals and oatmeal fortified with vitamin D and other nutrients are choices you can make. But always remember, they are processed, and one should consume them in moderation. However, they can still be an excellent option to consider.

Cereals and oatmeal contain many fibres and can help you lower blood sugar and cholesterol levels. Moreover, due to their fibre content, they help reduce constipation.

Signs of Vitamin D Deficiency

Without sufficient vitamin D, bones become thin and brittle. Adequate vitamin D in the body prevents rickets in children and osteomalacia in adults. Calcium also helps protect older adults from osteoporosis, where bones develop pores and become weak and prone to fractures. Moreover, vitamin D aids in the reduction of inflammation as well as modulation of processes. These include growth, glucose metabolism, neuromuscular and immune function.

Brittle Bones

Bones become weak and brittle since the body cannot absorb enough calcium due to lack of vitamin D. Low vitamin D levels can contribute to bone and lower back pain. Subsequently, they become more prone to fractures and cracks even by minor injuries. 

In old age, this can be a severe problem. In addition, low bone mineral density may signify vitamin D deficiency in the body.

Frequent Infections or Illnesses

Since vitamin D boosts immunity in the body, lack of this vitamin can cause frequent infections. As a result, the immune system becomes weak, and the body cannot fight against infectious microbes efficiently, which it would have otherwise.

Vitamin D helps in inhibiting inflammatory reactions. Lack of it can cause frequent infections in the upper respiratory tract, caused by inflammation of the mucous membranes in the upper respiratory tract.

Fatigue and Tiredness

Since vitamin D is essential for bone health, its inadequate amount in the body can cause bone and muscle weakness. In addition, it can lead to fatigue and a feeling of constant low energy in the body.

Research suggests that people facing fatigue due to vitamin D deficiency significantly improved fatigue symptoms when supplemented with it for five weeks.

Slow Wound Healing

Vitamin D increases the production of essential compounds for forming new skin as part of the wound-healing process.

The role of vitamin D in preventing inflammation and fighting Infection is essential for proper wound healing. Therefore, if the body is deficient in vitamin D, its wound healing capacity might decrease from the normal.

Mental Health Issues

Some researchers have associated vitamin D deficiency with depression, particularly in older adults. Therefore, doctors sometimes attribute constant depression or low feelings to lacking vitamin D. In that case, counselling and proper supplementation can help one feel better. 

Risk Factors of Vitamin D Deficiency

Apart from COVID-19 Infection, a lack of vitamin D can lead to several other health disorders. Some of them increase the risk of any other disease. Vitamin D plays a significant role in calcium homeostasis and bone metabolism in our body. Severe vitamin D deficiency leads to a decline in intestinal calcium and phosphorus absorption. Furthermore, it causes hypocalcemia, leading to secondary hyperparathyroidism. The secondary hyperparathyroidism then leads to phosphaturia and bone demineralisation. 

Vitamin D deficiency can result in osteomalacia in adults. It takes the shape of osteoporosis in old-aged adults and rickets in children. In adults, this condition is called osteomalacia. While in older adults, it is called osteoporosis. It is a condition in which bones become porous, brittle, and prone to fractures. Such fractures most commonly occur in the hip, wrist or spine.

Rickets is a disorder that affects bone development in children. Due to deficiency of vitamin D, some children can develop bow-shaped legs. It causes bone pain, poor growth and soft, weak bones, causing deformities. It also results in reduced absorption of calcium and phosphorus. The symptoms include delayed development, bow legs, weakness and pain in the spine, pelvis and legs. The treatment of rickets includes exposure to sunlight, a diet rich in vitamin D, calcium supplementation, medication and, in severe cases, surgery.


It is necessary to consume the right amount of vitamin D with the pandemic still looming on us. In addition, vitamin D has anti-inflammatory properties, which help prevent infections in the upper respiratory tract.

If you have low vitamin D levels, you should increase your exposure to the sun. It is natural and the easiest way to maintain vitamin D levels in the body. However, in most cases, exposure to sunlight is not enough. Therefore, you should consume vitamin D-rich foods like salmon, tuna, eggs, milk and cod liver oil. Moreover, supplements and medications are available for attaining optimal vitamin D levels in the body.

In addition, vitamin D is essential for maintaining bone and tooth health. It helps absorb calcium and phosphorus, which is crucial for maintaining bone metabolism. Lack of vitamin D in childhood can cause rickets or bow-shaped legs. In adults, it can cause osteomalacia, and in old age, it can cause osteoporosis. 

Frequently Asked Questions (FAQs) 

Q. What does vitamin D do for the body?

A. Vitamin D helps in calcium and phosphorus absorption, crucial for maintaining bone metabolism and tooth health in the body. In addition, it has anti-inflammatory properties. Finally, they protect you from infections in the upper respiratory tract. 

Q. How can I increase my vitamin D level?

A. The easiest and natural way to increase vitamin D levels in the body is sunlight exposure. However, dietary supplementation is also essential. Rich sources of vitamin D include salmon, tuna, eggs, milk and cod liver oil. Moreover, supplements and medications are also available for attaining optimal vitamin D levels in the body. 

Q. Is it good to take vitamin D every day?

A. Yes, you should take vitamin D every day by going out in the sun and consuming foods rich in it. These include salmon, tuna, eggs, milk and cod liver oil. The daily recommended intake of vitamin D is 600 IU. 

Q. How many minutes of the sun do you need for vitamin D?

A. Regular exposure to the sun is the most natural way to get vitamin D. In addition, to maintain adequate vitamin D levels. You should get 10–30 minutes of midday sunlight several times a week. People with darker skin need to spend a little more time than this because they have more skin pigment melanin which acts as a sun shield. 

Q. Can we take vitamin D at night?

A. It will help if you take vitamin D in the morning or afternoon. However, it can interfere with your sleep if consumed at night. That is because it can suppress the production of melatonin – the sleep-inducing hormone. In addition, vitamin D is a fat-soluble vitamin and can easily be absorbed with food. 

Q. Is vitamin D good for your skin?

A. Yes, vitamin D can be good for the skin. It promotes skin cell growth, repair, and metabolism in its active form as calcitriol. In addition, it enhances the skin’s immunity and helps to destroy free radicals that cause premature ageing. 

Q. Can you get vitamin D through clothes?

A. Different clothes provide different levels of UV protection. Covering up the skin doesn’t block out all UV rays. If you can see the light through a fabric, UV rays can get through too. And if UV rays can penetrate, the body can produce vitamin D.

About the Author

As the holder of a Post Graduate Diploma in Dietetics from the University of Mumbai, Alpa Momaya has always understood the value of good nutrition in an individual's life. She is a Registered Nutritional Practitioner (Canada) with over 15 years of experience in the field. Specializing in Clinical Nutrition, Pre & Post Natal Diets, and Weight Management, Alpa found her calling as a Sr. Nutritionist with HealthifyMe. Alpa's love for cooking and good nutrition has seen her contribute several recipes to the HealthifyMe database over the years. Additionally, she takes a keen interest in reading and painting.

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