Vitamin D is beneficial for your own personal health. Everyone needs vitamin D as it helps in absorption and metabolism of calcium and phosphorus. Many studies have shown that a low serum vitamin D levels in your body is linked to an increased risk of certain types of cancers, autoimmune disease, neurological disease, insulin resistance, and cardiovascular disease.

It is especially important in pregnancy as it helps your developing baby’s bones, teeth, kidneys, heart, and nervous system to develop. Deficiency with vitamin D is also related to preeclampsia.

According to global guidelines, all pregnant women should take a 10 microgram (or 400 IU) supplement of vitamin D each day.

For Malaysia, the daily recommended dose of vitamin D is 15 micrograms (or 600IU). Numerous studies conducted by various investigators in different part of Malaysia have reported high prevalence of vitamin D deficiency and insufficiency. These findings also lend support for increasing RNI for vitamin D in this country. It is noteworthy that this higher recommendation assumes of minimal sunlight exposure. Thus, this recommendation is applicable to people in Malaysia as even with abundance of sunlight, high sunlight avoidance practices is found to be very prominent. Furthermore, there are limited choices of food with high level of vitamin D available to Malaysia. The tolerable Upper Intake (UL) levels of vitamin D for pregnant mummies is 100 ug/day. 

Sunlight exposure is the most natural way for the body to produce vitamin D, which is essential for supporting bone strength, immune function, and mental well-being. The sun’s ultraviolet B (UVB) rays trigger a process in the skin that leads to the production of vitamin D3, the active form of the vitamin. However, it’s important to understand how to get sunlight safely and effectively, especially for certain groups like pregnant women, who have unique considerations.
Pregnant women need to maintain healthy vitamin D levels to support their own health and the development of the baby. Vitamin D plays a crucial role in calcium absorption, bone health, and immune support. Insufficient vitamin D levels during pregnancy have been associated with increased risks of complications, including gestational diabetes, preeclampsia, and low birth weight in newborns.

• Safe Sun Exposure: Short, regular sessions of sunlight exposure, around 10–15 minutes for lighter-skinned individuals and potentially more for darker-skinned individuals, can help meet vitamin D needs while avoiding overexposure.

• Skin Sensitivity: Hormonal changes during pregnancy can make the skin more sensitive to UV rays, leading to a higher likelihood of sunburn and pigmentation changes, known as melasma or “pregnancy mask.” To manage this, pregnant women should limit midday exposure, wear protective clothing, and use mineral-based sunscreens on exposed areas after an initial period of sun exposure.

• Supplements if Needed: Due to limited sunlight access in some climates and the increased risk of skin sensitivity, pregnant women should consult their healthcare providers about vitamin D supplements, especially in winter months or when sun exposure is not feasible.

• Fair Skin: Individuals with fair skin tones generally need around 15 minutes of midday sun exposure on arms, legs, or face to produce sufficient vitamin D.

• Dark Skin: Those with darker skin tones, which naturally contain more melanin, may require up to two hours of exposure to achieve similar levels.

Other factors include:

• Time of Day: Midday sun (typically between 10 a.m. and 2 p.m.) provides the strongest UVB rays for vitamin D production.

• Season and Latitude: Those living farther from the equator or in areas with extended winters may experience reduced sunlight and could consider dietary sources or supplements during these months.

Sun exposure should be done thoughtfully to avoid the risks associated with overexposure, such as skin damage or increased cancer risk. Here are some best practices:

• Gradual Sun Exposure: Start with short periods of sunlight exposure (5–10 minutes) and gradually increase the time. This helps the skin adjust to sunlight and reduces the risk of sunburn.
• Use Sunscreen When Needed: After an initial period of sun exposure for vitamin D synthesis, apply a broad-spectrum sunscreen with at least SPF 30 to reduce the risk of skin damage. Mineral-based sunscreens with ingredients like zinc oxide are often recommended, especially for those with sensitive skin.
• Protect Eyes from UV Rays: Overexposure to UV rays can increase the risk of cataracts and other eye conditions. Sunglasses with 100% UV protection can help shield the eyes from harmful rays while allowing the skin to absorb beneficial sunlight.
• Stay hydrated: Drink plenty of water while spending some time under the sun. This is to prevent dehydration especially during hot weather.

• Enhanced Mood and Mental Well-being: Exposure to sunlight has been shown to boost serotonin levels, a hormone associated with improved mood and reduced symptoms of depression. This can be particularly helpful in managing seasonal affective disorder (SAD), a type of depression linked to low sunlight exposure in winter months.

• Better Sleep Quality: Sunlight helps regulate the body’s natural circadian rhythm by promoting the release of serotonin and melatonin, which are involved in the sleep-wake cycle. Early morning sunlight exposure has been shown to improve sleep quality and help those struggling with insomnia or irregular sleep patterns.

• Immune System Support: Beyond vitamin D, sunlight exposure has been associated with increased white blood cell production, which plays a role in defending the body against infection and illness.

• Reduced Risk of Certain Cancers: Moderate sun exposure has been linked to a reduced risk of certain cancers, including breast, prostate, and colon cancers. While UVB rays can be harmful in excess, balanced exposure may offer protective benefits by supporting healthy cell function.

To help ensure a steady supply of vitamin D, try to include outdoor activities in your routine. Whether it’s a short morning walk, an afternoon gardening session, or a lunch break in a sunny spot, these small moments outdoors add up to support overall health. Even on cloudy days, spending time outside can still provide indirect sunlight exposure, which has benefits beyond vitamin D production.

There are a few naturally occurring food sources of vitamin D which include fatty fish (salmon, tuna, sardine, herring, mackerel), cod liver oil and egg yolk (USDA, 2016). Meat, poultry, and vegetables are generally poor sources of vitamins. Dairy products are fair sources of vitamin D.
 
Commercially, vitamin D is fortified in cereals, bread, butter, and yoghurt. Beverages such as milk and soy milk are also fortified with vitamin D.
 
In Malaysia, the Malaysian Food Regulation permits the addition of vitamin D according to different categories of foods (MOH, 1985). The intake of foods fortified with vitamin D can increase vitamin D in the diet.

Vitamin D is only found in a small number of foods alone. Women with limited exposure to sunlight might also have higher possibility for not getting enough vitamin D. If you're worried about not getting enough vitamin D, seek advice from your healthcare provider whether you need to take a supplement. 

Vitamin D is essential for a healthy pregnancy, playing a critical role in supporting maternal and fetal bone health, immune function, and cell growth. During pregnancy, a woman’s vitamin D needs increase to support both her own health and the development of the baby. Vitamin D deficiency during pregnancy, which is common worldwide, can have serious implications for both mother and child. 

When a pregnant woman’s vitamin D levels are insufficient, there is an increased risk of complications for both the mother and the developing fetus. Some of the key risks include:

• Gestational Diabetes Mellitus (GDM): Vitamin D plays a role in insulin regulation, and deficiency has been linked to an increased risk of gestational diabetes, a form of diabetes that develops during pregnancy and can impact both mother and baby’s health.
• Preeclampsia: This pregnancy complication involves high blood pressure and can lead to serious health issues for the mother and baby if not managed. Vitamin D’s anti-inflammatory properties and role in blood pressure regulation may help reduce the risk of preeclampsia.
• Bone Health Issues: Vitamin D is crucial for calcium absorption, and a deficiency may lead to weakened maternal bones due to increased calcium demands during pregnancy. In severe cases, the mother may experience bone demineralization and pain, while the baby’s bone development may also be compromised.
• Increased Risk of Infections: Vitamin D supports immune health, and a deficiency may leave pregnant women more susceptible to infections that can further complicate pregnancy.

Maternal vitamin D deficiency can have direct consequences on the newborn’s health, including the following conditions:

• Low Serum Calcium in the Newborn: Low vitamin D levels in the mother can result in low serum calcium in the newborn, leading to symptoms such as muscle twitching or even convulsions in severe cases.
• Rickets: Severe vitamin D deficiency can cause rickets, a condition in which bones become soft and weak. Rickets can lead to skeletal deformities and stunted growth.
• Defective Tooth Enamel: Maternal vitamin D deficiency has also been associated with defective tooth enamel in children, potentially increasing their risk for dental issues later in life.

In addition to the immediate risks for the newborn, maternal vitamin D deficiency can affect fetal growth and development in significant ways. Population-based studies have linked vitamin D deficiency in pregnancy to:

• Low Birth Weight and Small for Gestational Age (SGA): Babies born to vitamin D-deficient mothers are more likely to have lower birth weights and a higher likelihood of being small for gestational age, which can lead to long-term health issues.
• Reduced Neonatal Bone Density: Babies born with vitamin D deficiency may have lower bone mineral content, which could affect bone health as they grow.
• Influence on Fetal Bone and Skeletal Development: Maternal vitamin D levels can impact fetal skeletal growth. Studies suggest that as early as 19 weeks of pregnancy, vitamin D deficiency may affect the development of the fetal femur, potentially impacting overall skeletal health.

Given the potential risks, it is essential for pregnant women to take proactive steps to prevent vitamin D deficiency. Here are several strategies to help maintain adequate vitamin D levels throughout pregnancy:

1. Regular Sunlight Exposure: The body naturally produces vitamin D when the skin is exposed to sunlight. Pregnant women can benefit from short periods of sunlight exposure, ideally during midday when UVB rays are strongest. However, this should be done carefully, as excessive sun exposure may lead to skin damage.
2. Dietary Sources of vitamin D: While food sources of vitamin D are limited, certain foods can help boost intake. These include:

• Fatty Fish: Salmon, mackerel, and sardines are rich in vitamin D.
• Fortified Foods: Many dairy products, plant-based milks, cereals, and orange juice are fortified with vitamin D.
• Egg Yolks and Mushrooms: These contain small amounts of vitamin D and can supplement dietary intake.
• Vitamin D Supplements: Given that sunlight and dietary intake may not be sufficient to meet the increased demands of pregnancy, supplements are often recommended. Prenatal vitamins typically contain vitamin D, but additional supplements may be necessary if a deficiency is identified. Healthcare providers may recommend higher doses depending on blood test results.
• Regular Monitoring of vitamin D Levels: Prenatal care often includes blood tests to monitor a range of nutrients, including vitamin D. Regular checks can help ensure that levels are adequate and that supplementation is effective if needed.

An excessive amount of vitamin D is more than 100 micrograms (4,000 IU) of vitamin D a day. Such an intake of vitamin D might cause vitamin D toxicity which is also known as hypervitaminosis D. It is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body. Vitamin D toxicity is usually caused by large doses of vitamin D supplements, it is not by diet or sun exposure.

The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones.