What is vitamin D3?
Vitamin D actually encompasses two forms of vitamin : vitamin D2 (or ergocalciferol) and vitamin D3, also known as cholecalciferol. By itself, vitamin D3 accounts for 80 to 90% of total vitamin D intake.
The majority of vitamin D3 is produced by the body thanks to the sun’s rays. During exposure, UVB rays stimulate the precursor of vitamin D3 present in skin cells : 7-dehydrocholesterol. Vitamin D3 is then stored in the liver, muscles and fatty tissues.
When it is not produced, it is supplied to the body through the diet. Some foods are particularly rich in vitamin D3 : fatty fish, eggs, cheeses… Cholecalciferol is most often of animal origin but some mushrooms and plants may also contain it.
Also read | How to find the best vitamin D on the market?
Benefits of vitamin D3
Vitamin D3 is notably involved in bone calcification. It is responsible for the good health of bones, cartilage and teeth. Its role is even more important in children because it ensures the normal development of their skeleton and strengthens the bones.
To strengthen the skeleton, vitamin D3 improves the absorption of calcium and phosphorus via the intestines. Under the action of vitamin D3, calcium and phosphorus are then transported into the blood and stored in the bones.
But the benefits of vitamin D3 don’t stop there. It plays a role in many other functions of the body :
- Strengthens the immune system
- Maintains the muscle strength
- Improves cognitive functions
- Affects mood and depression
- Prevents certain diseases (osteoporosis, osteomalacia, rickets but also cancers, diabetes and heart disease)
Warning : to allow vitamin D3 to exert its full effect on the body, it is recommended to combine it with vitamin K2 (menaquinone). The latter improves the storage of calcium in the bones.
Symptoms of a vitamin D3 deficiency
Vitamin D3 deficiencies are more common in northern countries than in southern countries that enjoy better sunlight. It is generally recommended to have sun exposure of 30 to 45 minutes per day, which is not always feasible in winter in northern countries. In addition, the UVB rays that allow the synthesis of vitamin D3 decrease significantly during that period.
Certain factors can also increase the risk of vitamin D3 deficiency. Babies and children, pregnant women, and older adults are more at risk.
Vitamin D3 production from sunlight also depends on the pigmentation of the skin. The lighter the skin, the faster vitamin D is produced. People with darker skin need more sun exposure time to produce vitamin D3. High skin pigmentation can therefore increase the risk of deficiency.
Specific diets (such as vegetarian, vegan, or macrobiotic) can lead to vitamin D3 deficiency.
Finally, some conditions that cause intestinal malabsorption also increase the likelihood of vitamin D3 deficiency.
The different symptoms of a vitamin D3 deficiency are :
- Recurrent fractures and bone pain
- Cramps and muscle weakness
- Fatigue and depression
Don’t hesitate to consult a doctor to find out whether or not you have a vitamin D3 deficiency. You can then put a treatment in place together. Taking dietary supplements without medical advice is discouraged.
Recommended dietary intakes for vitamin D3
The recommended nutrient intakes of vitamin D3 depend on age, place of residence (more or less sunny), and life stage. Infants and children, pregnant women, and older adults have greater vitamin D3 needs.
- Pregnant women : 10 to 15 µg/day
- Infants : 20 to 25 µg/day
- Children under 3 years : 10 µg/day
- Children over 3 years : 5 to 6 µg/day
- Adolescents : 5 to 6 µg/day
- Adults up to 50 years : 5 to 6 µg/day
- Older adults : 10 to 15 µg/day
Top 5 foods rich in vitamin D3
To meet the recommended daily requirements for vitamin D3, here are the top 5 foods rich in cholecalciferol :
1. Cod liver oil
Beneath its unappealing appearance and sharp taste, cod liver oil contains a remarkable amount of vitamin D3 : 250 µg of vitamin D per 100 g.
If you’re not put off by its bitter and slightly fishy taste, take a teaspoon in the morning. Still have a glass of fruit juice nearby… Cod liver oil can also be taken in capsules or tablets.
2. Fatty fish
If you like fish, favor fatty fish to stock up on vitamin D3. Mackerel, sardines, eel, salmon, anchovies… are all possibilities. 100 g of mackerel provide 25.2 µg of vitamin D !
Cook these fish as healthily as possible, on the plancha for example. Serve them with small vegetables or, better yet, mushrooms, which are also good sources of vitamin D.
3. Eggs
Eggs, and more particularly the egg yolk, are an interesting source of vitamin D3 : 2.1 µg per 100 g of cooked egg yolk.
Eggs add variety. You can choose classic preparations (omelet, scrambled eggs, or fried eggs) or more original recipes. Prepare, for example, a delicious « oyakodon ». This Japanese dish takes the form of a bowl of rice, served with chicken and eggs.
4. Cheeses
In general, cheese provides a significant amount of calcium and vitamin D. But some cheeses are richer in vitamin D than others :
- Gruyère : 0.25 µg per 100 g
- Gorgonzola : 0.24 µg per 100 g
- Mozzarella : 0.16 µg per 100 g
Eat cheese at the end of a meal (before dessert) or include it in your recipes. Even though it may be hard to resist, eat cheese in moderation.
5. Spirulina
The spirulina (Arthrospira platensis) is a microscopic algae considered a superfood. Now consumed as a dietary supplement, it is an excellent source of protein and minerals. A single 3 g teaspoon of spirulina provides 9 µg of vitamin D.
Spirulina powder can be mixed into fruit juice or added to a smoothie recipe. Discover all our spirulina recipes here!
Of course, supplement this diet with about thirty minutes of sun exposure each day.
Dangers, adverse effects and overdoses of vitamin D3
Because vitamin D3 is stored in the liver, muscles and fatty tissues of the body, there is a real risk of overdose. When vitamin D3 is present in too large an amount in the body, it can be harmful and certain adverse effects may appear. Excess vitamin D3 manifests as :
- Headaches
- Digestive issues such as diarrhea, nausea, or vomiting
- Intense thirst with frequent urges to urinate
- High blood pressure and heart rhythm disorders
In pregnant women, vitamin D3 overdoses can unfortunately result in miscarriage or fetal malformation.
So be vigilant and always follow the dosages recommended by your doctor.
