The D-Fender of Health

A pharmacist's sunny side perspective on vitamin D

Have you ever heard of ‘sunshine vitamin’? ‘Sunshine vitamin’, also known as Vitamin D is a crucial nutrient that has gained increasing recognition for its numerous health benefits. Whilst the sun is the best source of vitamin D, it’s also worth noting that there may be a small handful of food sources out there that also has vitamin D. However, it’s difficult to get adequate vitamin D from diet alone. 

Another interesting fact about vitamin D is that there are many people out there who experience vitamin D deficiency due to factors such as climate or geographical locations that limit one’s sun exposure. People who live farther away from the equator may make less vitamin D in their skin.

Malaysia strategically sits on the equatorial line and ideally, we’re at a prime location for sufficient vitamin D needs. However, that’s not truly the case for many Malaysians out there.

We recently interviewed Dr. Shamin Mohd Saffian, Pharmacist at My Antidote Pharmacy and Senior Lecturer at the Faculty of Pharmacy, Universiti Kebangsaan Malaysia on this topic. He explained that upon his research (which involves approximately 14,000 participants), it was revealed that more than 60 percent of the participants were experiencing vitamin D insufficiency (not to be confused with deficiency).

Dr. Shamin Mohd Saffian, Pharmacist at My Antidote Pharmacy, Senior Lecturer at the Faculty of Pharmacy, Universiti Kebangsaan Malaysia

This caught our interest and we wanted to dig further into the topic of Vitamin D and everything there is to know about it. Here’s what Dr. Shamin has to say.

What is the role of vitamin D in the body and why is it important for overall  health?

Dr. Shamin Mohd Saffian: Vitamin D has many roles in the body, too many to list down. Perhaps the most well-known is its function to maintain calcium and phosphorus levels that are necessary for building bones. However, its role extends beyond just the maintenance of calcium and phosphorus levels in the body. Vitamin D plays a pivotal role in the immune system. There is strong evidence demonstrating that adequate vitamin D levels in the blood can prevent respiratory tract infections such as cough, cold, and pneumonia. Adequate vitamin D levels have also been shown to reduce the disease severity in COVID-19 and several other health conditions. There is also a lot of evidence on the role of vitamin D in cancer, heart diseases, insulin resistance, and preeclampsia. Hence, it is really important to maintain adequate levels of vitamin D in the body at all times.

Why is it crucial for us to obtain ample vitamin D, even in tropical climates like Malaysia where we are blessed with abundant sunshine?

Dr. Shamin Mohd Saffian: Despite popular belief that there is an abundance of sunlight year-round, the data from multiple studies conducted in Malaysia suggests otherwise. My research team recently published an article where we looked at data from almost 14000 participants and we found that the prevalence of vitamin D insufficiency was more than 60 percent. This was surprising and also alarming. It is likely that the hot and humid weather is the main contributor to people avoiding sun exposure. We are also sometimes told to limit outdoor activities during hot spells. Other important contributors are clothing and sunscreen use. I would recommend everyone to take note of the number of minutes they are exposed   to the sun in a day or even throughout the week. You may be surprised to discover that it may not even be half an hour.

How long does one have to be in the sunlight to absorb sufficient vitamin D? What is the suitable time to be under the sun to absorb vitamin D?

Dr. Shamin Mohd Saffian: This is an interesting question. The short answer is it varies  greatly. In order to understand this, let me elaborate further. Our body makes a precursor of vitamin D. This sits under the layer of the skin called the epidermis. When the uncovered  skin is exposed to UV-B, the precursor of vitamin D is converted to the storage form of vitamin D called cholecalciferol or 25OHD. This is the main circulating form of vitamin D that is activated by the kidneys when it is required by the body. Of note, there are three types of UV:

  • UV-A 
  • UV-B
  • UV-C

UV-C is the shortest wavelength of the three. UV-C gets filtered by the ozone and does not typically reach Earth. UV-B has a shorter wavelength than UV-A, but it is also easily filtered by clothing, sunscreen, or most things that create a shadow.

Besides that, when the skin gets exposed to the sun, it will form more melanin that filters out the UV-B (hence this is why you get darker when exposed to the sun more). Furthermore, the altitude also plays a role as the sun needs to travel further and gets filtered through the way. I would like to quote a local study that has demonstrated that minimal surface exposure (specifically, face and hands) to sunlight for 30 minutes, two times per week at 11 am, could result in a 40 percent increase in serum vitamin D levels. But then, this depends on the individual as well because some individuals may have sensitive skin, and being exposed to the sun for 30 minutes may cause irritation. So, all these factors make estimating the amount of sun required for adequate vitamin D levels tricky.

What are the main dietary sources of vitamin D, and is it possible to get enough vitamin D through diet alone?

Dr. Shamin Mohd Saffian: In general, it is difficult to get adequate vitamin D from diet alone. Dietary sources are mainly fatty fish; however, this is again, a bit tricky because it depends on the diet of the fish. Plant sources are mushrooms that have been exposed to UV-B radiation. Some other foods contain vitamin D but at low levels. Contrary to popular belief, milk does not contain a significant amount of vitamin D. Those that do are usually fortified. As you can see, it is relatively difficult to get vitamin D from diet alone, and furthermore, it is not the type of foods that are common in the Malaysian diet.


What are the recommended daily dosages of vitamin D for different age groups and populations?

Dr. Shamin Mohd Saffian: Vitamin D dosage recommendation varies with age groups and also varies widely between guidelines. These are the main two influential guidance documents for vitamin D in the scientific community. The Endocrine Society recommends a much higher upper limit of up to 10,000 IU per day for adults compared to the Institute of Medicine which recommends an upper limit of 4000 IU per day without blood testing. The Recommended Nutrition Intakes for Malaysia (RNI) follows the Institute of Medicines recommendations. Hence, in short, at least 600 IU for adults, children, and adolescents 600 IU/ day, infants under one-year-old 400 IU/ day. If the individual is obese (BMI>30), then he or she may require two to three times more. For adults, I would generally recommend 1500 – 2000 IU per day depending on how much natural sun exposure you get.

What are the symptoms and health conditions associated with vitamin D deficiency?

Dr. Shamin Mohd Saffian: If the individual has vitamin D deficiency (defined as <30 nmol/mL of 25OHD), it can cause rickets which is a condition in which the bones become soft and deformed. However, the majority of Malaysians are not vitamin D deficient but are vitamin D insufficient (defined as blood levels of 50 nmol/mL), so the symptoms may be less obvious. Low vitamin D has been associated with a whole host of conditions. It is associated with skeletal muscle weakness, compromised immune system, insomnia, and other psychiatric conditions. If the individual has low calcium (due to inadequate vitamin D), they can also get muscle cramps, spasms, numbness, and other symptoms related to calcium deficiency.


What are the potential risks and side effects of taking too much vitamin D?

Dr. Shamin Mohd Saffian: You can never overdose on vitamin D from sun exposure because any excess vitamin D made will be destroyed by the sun. You may get sunburn, but not vitamin D toxicity. In terms of supplements, yes of course! Bear in mind that we should only supplement using vitamin D3 (or D2 but this is rarely found in Malaysia), and not the active form of vitamin D called calcitriol. Vitamin D3 supplements are generally very safe up to 4,000 IU per day. Furthermore, in Malaysia, vitamin D sold as supplements have a maximum of 1000 IU per tablet or capsule, which is 4 tablets per day is still perfectly fine.

How can someone determine if they have a vitamin D deficiency, and are there specific tests that can be done?

Dr. Shamin Mohd Saffian: Yes. The most accurate will be to order a blood test of 25-Hydroxy Vitamin D or 25 OHD (not to be confused with 1,25 dihydroxy vitamin D; 1,25 OHD). This is not usually done in routine screening tests and therefore needs to be added on. Do request a vitamin D level test from your doctor and bring it to a qualified health professional to interpret the results.

Can vitamin D interact with other medications or supplements?

Dr. Shamin Mohd Saffian: Yes, vitamin D can be taken with other medications and supplements. Most of the interaction is affecting vitamin D absorption rather than the other way around. These are mainly those that affect fat absorption because vitamin D is a fat-soluble drug. Besides that, vitamin D affects the levels of calcium, magnesium, and other minerals. It is not necessarily dangerous, but it is best to seek a health professional’s advice if you are taking vitamin D with other medication.

Are there any medical conditions or medications that can interfere with the absorption or utilization of vitamin D?

Dr. Shamin Mohd Saffian: Yes. Ageing reduces the efficiency of the skin to make vitamin D. Other than that because vitamin D is fat-soluble, people with high body fat may require two to three times the normal doses or any medications that affect the fat in the body. Those who have altered function gastrointestinal tract such as inflammatory bowel diseases can affect how vitamin D is absorbed. There are also genetic variations that affect an enzyme called 25-hydroxylase, which is an enzyme that converts the storage form of vitamin D to the active form.

Is it safe to take vitamin D supplements while pregnant or breastfeeding? Are there any specific dosage recommendations for these populations?

Dr. Shamin Mohd Saffian: Yes, in fact, pregnant women are one of the groups at the highest risk of vitamin D deficiency. A recent study by Mustapa and colleagues reported vitamin D insufficiency of about 90 percent in late pregnancy. Low vitamin D levels are associated with an increased risk of preeclampsia. In terms of breastfeeding, the breast milk will contain very little vitamin D. If the mother is vitamin D deficient, this would be even less. Hence the infant will be vitamin D deficient for the whole period when he or she is exclusively breastfed.

Are there any natural alternatives to vitamin D supplementation that can help maintain adequate Vitamin D levels?

Dr. Shamin Mohd Saffian: Unfortunately, no. The most natural, free, and perhaps the healthiest way is to get sensible sun exposure several days a week.


  1. Mohd Saffian S, Jamil NA, Mohd Tahir NA, Hatah E. Vitamin D insufficiency is high in Malaysia: A systematic review and meta-analysis of studies on vitamin D status in Malaysia. Front Nutr. 2022 Nov 18;9:1050745. doi: 10.3389/fnut.2022.1050745
  2. Mustapa Kamal Basha MA, Abdul Majid H, Razali N, Abd Rashed A, Muhammad H, Yahya A. Longitudinal vitamin D deficiency among Malaysian 
  3. pregnant women and its correlation with neonatal serum 25-hydroxyvitamin D levels. Front Public Health. (2021) 9:654292. doi: 10.3389/fpubh.2021.654292
  4. Aris N, Mitra AK, Wan Mohamed WMI, Wan Muda WAM, Jan Mohamed HJ. Effects of occupational sunlight exposure and monsoon season on vitamin D concentration among outdoor and indoor workers in Malaysia. Malaysian J Nutr. (2020) 26:425–39. 10.31246/mjn-2020-0038
  5. Aris, Norliyana (2020) Risk factors of vitamin D deficiency and the effects of sunlight exposure and vitamin D supplementation on serum vitamin D level, adiponectin,  cardiometabolic risk factors and metabolic syndrome among adults in Kelantan. PhD thesis, Universiti Sains Malaysia 

This piece was an interview with a White Coat 360 pharmacist.