Lucy Browne, Health & Bodycare team member and qualified nutritionist from Planet Organic’s Queen’s Park branch, talks us through the importance of vitamin D and explains why we need it, how we get it and how best to introduce vitamin D supplements into our daily routines.
What is Vitamin D?
Vitamin D is a fat-soluble vitamin and hormone. Almost all human cells contain vitamin D receptors, thus its functions are widespread. The action of vitamin D is unique in that it can influence our genetic material. Evidence suggests that vitamin D regulates up to 200 key human genes.
What are the Functions of Vitamin D?
- Supports strong immunity by providing potent anti-inflammatory benefits.
- Possesses powerful mood-enhancing properties.
- Regulates the levels of calcium and phosphorus in the body, needed to keep bones, teeth and muscles healthy.
Vitamin D exists in two forms, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Animal dietary sources contain vitamin D3, whereas plant dietary sources contain vitamin D2. “The Sunshine Vitamin” UVB sun rays convert provitamin D (cholesterol) present in human skin into vitamin D3. Thus, vitamin D is also referred to as "the sunshine vitamin".
Which is the Preferred Form of Vitamin D?
To reap the many rewards of vitamin D, we need to maintain optimal blood levels. The preferred form of vitamin D is D3, this is because it is more effective than D2 at raising blood levels of vitamin D. What is the Unit of Measure for Vitamin D? Vitamin D is expressed in either international units (IU) or micrograms (mcg or μg). 1 IU of vitamin D equates to 0.025 mcg. Conversely, 1 mcg of vitamin D equates to 40 IU. This is true regardless of its origin (plant, animal, sun).
What are the Drawbacks of Plant Dietary Sources?
Mushrooms are the only plant source of vitamin D, which is in the unfavourable form of vitamin D2. Mushrooms exposed to UVB light (100g) = 400 IU. UVB-exposed baker's yeast contains vitamin D2, but has shown poor bioavailability. As you can see it is near impossible to maintain a healthy vitamin D status through plant sources alone.
What are the Drawbacks of Animal Dietary Sources?
The amount of vitamin D3 per animal dietary source is low. The highest source being wild-caught salmon (100g) = 988 IU. Thus, to reach an adult (>18) daily dose of 2000 IU, from animal dietary sources alone, proves to be difficult. What are the Drawbacks of Vitamin D from Sunlight? Sunlight is the best source of vitamin D3 for humans, compared to dietary sources.
Although, many factors affect our ability to produce vitamin D from sunlight.
- Time of Day: Evidence suggests that vitamin D is best produced at midday. This is because UVB rays are most intense and the body is more receptive to producing vitamin D at midday.
- Colour of Our Skin: Melanin is a pigment within the skin that determines skin colour. It acts as a natural sunscreen, protecting our skin from harsh UV rays. Thus, people with darker skin need more time in direct sunlight than people with lighter skin. About 30 minutes to three hours longer, to produce the same amount of vitamin D.
- Amount of Skin Exposed: The more skin exposed to sunlight the more vitamin D you can produce. To meet your daily needs of vitamin D about a third of your skin needs to be in direct sunlight. This equates to exposing your face, arms and lower limbs.
- Sunscreen: Sunscreen contains compounds that block sunlight, exposing the skin to fewer UV rays. Sunscreen has been shown to block UVB rays, inhibiting vitamin D synthesis. Although the long-term impact of sunscreen on our vitamin D status remains inconclusive it is always important to wear sunscreen with the appropriate SPF to protect your skin.
- Time of Year: People living in the UK often cannot produce enough vitamin D during the winter (October – March). This is because the strength of the sun is of insufficient UV wavelength.
Vegans and vegetarians have no other choice than to utilise the sun to meet their daily needs. This is because plant sources are scarce and are only in the unfavourable form of vitamin D2. To keep your levels within an optimal range, it is wise to consider taking a vitamin D supplement. This is because many factors affect our ability to produce vitamin D from sunlight. Vitamin D supplements are also essential for those abstaining from sun exposure. As well as for those who do not consume enough vitamin D3 rich foods. Other high-risk groups include; pregnant women, the elderly and people with obesity.
How Much Vitamin D Should You Be Taking in a Supplement?
Vitamin D Deficiency:
- Recommendation (>18 years): 5000 IU daily for 2 months followed by a maintenance dose of 2000 IU daily.
Daily Requirements for Different Age Groups:
- 0-1 years: 400-1000 IU
- 1-18 years: 600-1000 IU
- >18 years: 1500-2000 IU
Liquid supplements may be better absorbed, especially for people with compromised digestive systems. Capsules are very useful to disguise unpleasant tastes. Essentially it boils down to personal preference.
Wild Nutrition Vitamin D3
Together Health Vitamin D3
Pure Encapsulations Vitamin D3 Drops
Natures Answer Vitamin D3 Drops
These two liquid Vitamin D drops are two of our best-selling products, however, my personal preference is the Pure Encapsulations Vitamin D3 Drops. This is a highly stable oil, making it an excellent carrier for fat-soluble Vitamin D3. The dose of Vitamin D per drop is suitable for all ages, making it easy for you to manipulate your personal dose depending on your age, blood levels and subsequent daily needs. Since there are 750 servings per bottle, it’s perfect for the whole family to share.