- 6 September 2023
The Vitality Vitamin: Unlocking the Wonders of Vitamin D
The sun is one of the best sources of vitamin D. However, busy lifestyles make it challenging for many people to spend time outdoors and soak up the sun. Despite this, vitamin D is crucial for our health as it aids in the better absorption of calcium and phosphorus, which are essential nutrients for our bone health.
Vitamin D plays a significant role in bone development and maintenance. Insufficient vitamin D levels can lead to weak and fragile bones. While this is not commonly seen in children (rickets), vitamin D deficiency in adults makes them more prone to injury, potentially resulting in osteoporosis.
Sufficient vitamin D levels contribute to the reinforcement of the immune system, reducing the likelihood of infections and diseases. By supporting a healthier immune system, adequate vitamin D intake helps lower the risk of acquiring various illnesses.
Sources of Vitamin D
It can be obtained through dietary sources, and our bodies are able to synthesize on their own. A little amount of sun exposure is beneficial and essential for us. The Health Promotion Board (HPB) recommended that the best time to have sun exposure is anytime between 10 a.m. and 3 p.m., for at least 5 to 30 minutes, at least twice a week.
Other than that, vitamin D is a fat-soluble vitamin. It means these vitamins dissolve in fats and oils. Therefore, it was recommended to eat it with high fat foods such as eggs and nuts to maximize its effectiveness.
There are several dietary sources of vitamin D that can help ensure adequate intake. Here are some common food sources of vitamin D, for example:
- Vitamin D2 (ergocalciferol) from plant-based sources and fortified foods like mushrooms, dairy products and supplements
- Vitamin D3 (cholecalciferol) is found in animal-sourced foods, such as egg yolk and fish oil, and in natural sources that are produced when your skin is exposed to sunlight.
Vitamin D: How Much Is Too Little, How Much Is Too Much?
Food sources of Vitamin D & recommended daily allowances (RDA)
Age group | RDA Of Vitamin D (in mcg) |
3 months to < 7 years | 10mcg |
7 -18 years | 2.5mcg |
≥18 years | 2.5mcg |
Pregnant and lactating women | 10mcg |
Helpful fact: The recommended intake and nutritional analysis of vitamin D are often expressed in international units (IU). For conversion purposes, 1 mcg = 40 IU of vitamin D.
The amounts of vitamin D in 100 grams of some of its richest dietary sources are:
- Fish Liver Oil (鱼肝油）: 10,000 IU
- Tuna, canned in oil: 160 IU
- Mushrooms: 318 IU
- Malted milk powder: 397 IU
Who is at Risk of Vitamin D Deficiency? Exploring Influencing Factors
While the body has the ability to produce vitamin D, certain individuals are more susceptible to experiencing a deficiency. Various factors can play a role in influencing this vulnerability, such as:
- Elderly: The skin’s ability to synthesize vitamin D decreases over time. The elderly should spend more time outdoors to increase sunlight exposure and increase the opportunity for natural vitamin D production.
- Obesity / Obese individuals: The higher the body fat percentage in the body, the more it may affect the ability to absorb vitamin D from the skin.
- Breastfeeding: The American Academy of Pediatrics advises a daily oral supplementation of 400 IU to ensure sufficient vitamin D intake for breastfed infants.
- Skin Color: Darker skin tones have higher levels of melanin, which reduces the skin’s ability to absorb Ultraviolet B rays and consequently impacts the synthesis of vitamin D through sunlight exposure.
- Environment: People in these areas may have limited exposure to the sun’s ultraviolet B (UVB) rays, especially during Winter. Similarly, those who live in hot weather may also face challenges, as they tend to seek shelter indoors to avoid intense heat and strong sunlight.
Crucial Levels: Identifying the Threshold for Vitamin D Deficiency
You can check your serum vitamin D by doing a blood test:
Vitamin D Levels | Value (nmol/l) |
Too high and possibly harmful | 125 |
Sufficient | 50-125 |
At risk of inadequacy | 30-49 |
At risk of deficiency | ≤30 |
Moderation is the key. It is advised not to take more than 4000 IU of Vitamin D supplements in a day unless monitored by a doctor or healthcare professional. Although it is not common, too much vitamin D may cause toxicity like anorexia, weight loss, irregular heartbeats, and hardening of blood vessels and tissues due to increased blood levels of calcium, potentially leading to damage to the heart and kidneys.
Last but not least, it is important to note that capturing sunlight through a sunny office window or while driving in a car does not contribute to vitamin D synthesis. This is because window glass acts as a complete barrier, blocking UVB ultraviolet light, which is essential for the production of vitamin D in the body.
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