Vitamin D3: Immunity, bones, depression – A must-have in France?

Vitamin D3, or cholecalciferol, is much more than just a vitamin: it is involved in regulating many bodily processes. Essential for bone health, it also plays a key role in the immune system and may be associated with mood [1]. In France, a large part of the population is deficient, especially in winter [2] — often without recognizing the typical symptoms (fatigue, bone pain, low mood).

Why is vitamin D3 so important?

According to scientific literature and health authorities (HAS, ANSES), vitamin D3:

• Promotes calcium absorption and bone mineralization [1]
• Supports innate and adaptive immune defenses [3]
• Plays a role in the prevention of respiratory infections [4]
• Is associated, in cases of deficiency, with an increased risk of depressive symptoms [5]

It is naturally synthesized by the skin under the effect of UVB rays, but sun exposure is often insufficient, especially between October and March [2].

Vitamin D deficiency: a public health problem

According to the Esteban study by Santé publique France (2015–2016), a large majority of French people suffer from vitamin D insufficiency or deficiency in winter [2].

People at risk include:

• the elderly
• pregnant women
• children and adolescents
• people with dark skin or little sun exposure

Which supplement to choose?

The most effective form is vitamin D3 (cholecalciferol), which is better assimilated than D2 [6].

French recommendations (ANSES) suggest:

• 600 to 800 IU/day for adults
• 1000 to 2000 IU/day for deficient or at-risk individuals

Vitamin D3 can be taken in capsules, tablets, or ampoules. It is fat-soluble, so it is better absorbed when taken with a meal containing fats [7].

Our most popular vitamin D3 supplements

• Plant-Based Vitamin D-3, Softgels – Bone and Immune Support (NOW Foods)
• Vitamin D-3 & K-2, 1000 IU (NOW Foods) — synergistic for bone health
• Liquid Vitamin D-3 & MK-7, drops, 2500 IU (NOW Foods) — adjustable dosage bottle

Scientific References

1. Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357(3):266-81. (PubMed)
2. Santé Publique France – Esteban study on nutritional intake in France, 2016.
3. HAS – Vitamin D supplementation in the elderly, 2011.
4. Martineau AR et al. Vitamin D supplementation to prevent acute respiratory infections. BMJ. 2017;356:i6583. (PubMed)
5. Anglin RE et al. Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry. 2013;202:100-107. (PubMed)
6. EFSA – Scientific Opinion on Dietary Reference Values for vitamin D, 2016.
7. National Institute of Health (review of absorption mechanisms) — reference to be confirmed.