Vitamin D3 is the biologically active form of vitamin D, a fat-soluble vitamin which is necessary for a wide range of functions in the body including:
- supporting the immune system,
- aiding intestinal absorption of nutrients and
- contributing to healthy bones.
Sources of Vitamin D3
The major source of vitamin D3 in humans is through sunlight. When the skin is exposed to sunlight, the UVB rays synthesise vitamin D3 which then is involved in several reactions in the kidneys and liver to produce the active form of vitamin D (calcitriol). Vitamin D3 can be found in some foods but in small amounts. It is important to note that vitamin D3 can only be found in animal foods such as oily fish, eggs and red meat. Some kinds of margarine, breakfast cereals and plant-based milk may be fortified with vitamin D, but this is often in the form of vitamin D2. Vitamin D2 is not converted into the active form of vitamin D as easily or quickly as vitamin D3.
The Role of Vitamin D3
Once vitamin D3 has been converted into the active form of vitamin D, it can play several roles in the body. Vitamin D is necessary for increasing magnesium, calcium and phosphorus absorption in the intestine. In the bones, vitamin D helps regulate bone turnover and helps store calcium in the skeletal tissue. Vitamin D plays an important role in supporting the immune system as well as supporting brain cell signalling.
How Much Vitamin D3 Do We Need?
The recommended dose of vitamin D per day for adults and children over 1y.o. is 10 micrograms per day (NHS, 2020). This can be achieved from the end of March to early September through just 10-15 minutes of strong sunlight exposure. Although, those with darker skin may need longer in the sun because melanin lowers the skin’s ability to make vitamin D in response to sunlight exposure. Breastfed babies from birth to 1 year of age should be given a daily supplement containing 8.5 to 10 micrograms of vitamin D whereas formula-fed babies do not require a supplement as the formula is fortified with vitamin D.
The NHS recommends everyone to supplement with vitamin D3 during the winter months and if you spend the majority of times indoors, have dark skin or cover most of your skin when you do go outdoors then you should supplement year-round (NHS, 2020). During the current COVID-19 pandemic, the advice to supplement every day with 10 micrograms of vitamin D continues as we spend more time indoors.
Vitamin D Deficiency and Toxicity
As 90% of our vitamin D comes from sunlight, even if you eat fortified foods and animal products you are likely not to be getting enough. Symptoms of vitamin D deficiency include muscle weakness, fatigue, impaired mental health and may affect the immune system. During the winter months and if you are spending more time indoors, a supplement may be necessary to achieve the recommended dose and prevent deficiency.
Although you cannot overdose on vitamin D through sunlight, taking too many vitamin D supplements over a long period can cause too much calcium to build up in the body which can weaken the bones, damage the kidneys and affect the heart. If you choose to take vitamin D supplements, 10 micrograms a day is the dose recommended by the NHS (NHS, 2020).
Do not take more than 100 micrograms of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years. Children aged 1 to 10 years should not have more than 50 micrograms a day. Infants under 12 months should not have more than 25 micrograms a day.
Variations to Supplement with Vitamin D3
There are several ways to supplement vitamin D3 including via tablets, sprays and drops.
Vitamin D3 Tablets
Tablets such as Terranova Vitamin D3 2000iu Complex are a quick and convenient way to get your daily dose of vitamin D3 in a vegan capsule. Many vitamin D3 supplements are made using animal products such as sheep’s wool whereas these vegan tablets are made using lichen, an organism which is a combination of fungi and algae.
Vitamin D Sprays
If you struggle to take capsules, BetterYou DLux 1000 Vitamin D Oral Spray has a tasty, natural peppermint flavour and is easy to use. This product is not suitable for vegans, however, try BetterYou Vegan Health Oral Spray instead which combines vitamin B12, vitamin D3, iron and iodine; the vitamins and minerals commonly missed in a vegan diet.
Vitamin D Supplements for Children
To ensure infants reach the recommend daily dose of vitamin D, supplement drops such as BioCare Baby Vitamin D Drops can be used to support bone development and normal growth. Drops are ideal for convenient dosing and can be mixed with juice, water or milk to make them more appetising. For children, a tasty peppermint flavoured spray designed for kids like the BetterYou DLux Junior Vitamin D Oral Spray makes it easy to support their health without the stress of tablets.
Vitamin D3 and K2 Complex
Taking vitamin D3 with vitamin K2 can improve bone health as these vitamins work synergistically to ensure calcium is absorbed into the bone while preventing arterial calcification. Separately, vitamin K2 also regulates normal blood clotting. Terranova Vitamin D3 2000iu & K2 100µg offers these two vitamins combined in a convenient vegan tablet.
How to Take Vitamin D (When is the Best Time?)
The best time to take vitamin D3 is with a meal. This is because vitamin D3 is a fat-soluble vitamin and will be absorbed better when paired with food, ideally high-fat foods such as avocados, nuts and seeds.
What Vitamin D Dosage Is Best?
Vitamin D3 is an essential vitamin necessary in the human body for bone health, immune function and aiding the absorption of other nutrients. Supplementation is required for many population groups and there are several ways to consume the recommended dosage of 10 micrograms per day.