Vitamin D: Why 80% of French People Are Deficient

Vitamin D is often called the “sunshine vitamin”. Yet in France, nearly 80% of the population has insufficient vitamin D status, particularly between October and April. In Paris, where winter sunlight is scarce, supplementation becomes an essential habit for maintaining healthy bones, a strong immune system and balanced mood. At Herba Barona, our supplement shop at 10 rue Théophile Roussel, Paris 12th, we’ve been helping customers choose the best vitamin D since 2006.

Why is vitamin D deficiency so widespread in France?

Several factors explain this widespread shortfall. First, Paris’s latitude (48°N) limits UVB-driven skin synthesis of vitamin D from November to March. Second, an urban lifestyle — closed offices, underground transport, screen time — further reduces sun exposure. Diet provides an average of only 100 to 200 IU per day, well below the 1,000 to 2,000 IU recommended by many experts.

The populations most at risk are older adults (skin synthesises less vitamin D with age), pregnant women, people with darker skin, indoor workers, and strict vegans. A blood test (25-OH-D) can check your status: below 30 ng/ml is considered insufficient; below 20 ng/ml, deficient.

The different forms of vitamin D

Vitamin D3 (cholecalciferol) vs D2 (ergocalciferol)

Vitamin D3 is the form naturally produced by the skin under UVB exposure. It is more effective than D2 at raising and maintaining blood levels of 25-OH-D. D2, of plant origin (irradiated mushrooms), is less stable and less well converted by the body. Today, plant-based D3 extracted from boreal lichen is available, which is perfectly suited to vegans.

Vitamin D3 alone or combined with vitamin K2?

Vitamin K2 (in the MK-7 form) plays a complementary role: it activates osteocalcin, a protein that directs calcium towards the bones rather than the arteries. The D3 + K2 combination is therefore particularly relevant for bone and cardiovascular health. This synergy is well documented in the scientific literature.

Which dosage should you choose?

Profile	Suggested daily dose	Notes
Healthy adult	1,000 to 2,000 IU/day	Standard maintenance dose
Deficient (< 20 ng/ml)	2,000 to 4,000 IU/day	For 2 to 3 months, then maintenance dose
Older adult	2,000 IU/day minimum	Reduced skin synthesis
Pregnant or breastfeeding	1,000 to 2,000 IU/day	Medical advice recommended

Daily supplementation is preferable to large, spaced-out doses (such as a 100,000 IU ampoule). A regular intake maintains a stable blood level and optimises the body’s use of vitamin D.

Our vitamin D selection in Paris at Herba Barona

At Herba Barona, we’ve selected the best vitamin D products available on the French market:

• Vitamin D3 Plant-Based Dynveo 2000 IU: extracted from boreal lichen, 100% plant-based, 60 capsules. The ideal choice for vegans and anyone looking for a high-quality D3.
• Vitamin D3 K2 MK7 Dynveo 2000 IU: the synergistic D3 + K2 combination in MK-7 form, for complete action on bones and calcium metabolism.
• Vitamin D3 Novoma 2000 IU: excellent value for money for accessible daily supplementation.
• Vitamin DEKA Dr Jacob’s: a complete formula combining vitamins D, E, K and A in drop form.
• Essentiel 3 Dynveo: an all-in-one formula combining omega-3, vitamin D and magnesium in a single capsule.

Browse our full range in the Vitamin D in Paris category.

Vitamin D and the immune system

Vitamin D plays a major role in regulating the immune system. It stimulates the production of defence peptides (cathelicidin, defensins) and modulates the inflammatory response. Several observational studies have shown a correlation between good vitamin D status and better resistance to winter respiratory infections. During autumn and winter in Paris, supplementation therefore makes a lot of sense.

Vitamin D and bone health

Without vitamin D, intestinal calcium absorption drops from 30-40% to just 10-15%. The body then draws on bone reserves to maintain blood calcium levels, gradually weakening the skeleton. An adequate intake of vitamin D, combined with calcium and vitamin K2, helps maintain normal bone structure. This is particularly important for post-menopausal women and older adults.

Vitamin D and mood

The link between vitamin D and psychological wellbeing is increasingly studied. Vitamin D receptors are present in many areas of the brain involved in mood regulation. In Paris, where the lack of winter light affects many people’s mood, good vitamin D status can contribute to overall wellbeing, alongside a healthy lifestyle.

How to optimise your vitamin D levels

• Sensible sun exposure: 15 to 20 minutes a day, arms and legs uncovered, between April and October (without sunscreen for this short duration).
• Diet: oily fish (salmon, mackerel, sardines), egg yolk, cod liver, dried shiitake mushrooms.
• Daily supplementation: essential from October to April in Paris, and often year-round for those with limited sun exposure.
• Annual blood test: ask your doctor for a 25-OH-D test to fine-tune your supplementation.

Frequently asked questions about vitamin D

Can you take too much vitamin D?

At common doses of 1,000 to 4,000 IU per day, the risk of overdose is extremely low. The European Food Safety Authority (EFSA) sets the upper limit at 4,000 IU/day for adults. Regular blood testing lets you check that your level stays within the optimal range (40-60 ng/ml).

Is it better to take vitamin D in the morning or evening?

Vitamin D is fat-soluble: take it with a meal containing some fat to optimise absorption. The time of day matters less than consistency.

Where can I buy quality vitamin D in Paris?

At Herba Barona, 10 rue Théophile Roussel, Paris 12th (Ledru-Rollin metro), we offer a carefully curated selection of vitamin D from trusted brands: Dynveo, Novoma, Dr Jacob’s. Our team offers in-store advice Tuesday to Saturday, 9:30am-6:30pm.