Vitamin D is essential for good health every day. Fixing calcium, strengthening our immune system, preventing certain pathologies, these are its benefits!
Why are so many of us deficient in vitamin D in winter? How to avoid any deficiency during the cold season?
What are the benefits of vitamin D?
Vitamin D is an essential nutrient for good health. It is involved in numerous metabolic reactions such as:
- stimulation of the immune system , allowing our body to react more quickly in the event of attack. It is a real health ally all year round, especially in winter;
- a probable reduction in the risk of the appearance of certain autoimmune diseases , acute pulmonary infections and cancers (breast cancer and colorectal cancer in particular);
- strengthening the intestinal absorption of phosphorus and calcium (Ca) . These mineral salts play a key role in the mineralization of teeth and bones;
- the binding of calcium to bones, which contributes to bone remodeling. Bone is a tissue in constant renewal. Schematically, certain cells regenerate it (osteoblasts), while others degrade it (osteoclasts). Better calcium fixation thanks to vitamin D is essential during growth, but also throughout life;
- maintaining muscular performance . This results in particular in a lower risk of reduced muscular capacity in seniors;
- prevention of certain cardiovascular diseases.
Furthermore, vitamin D and calcium supplementation is indicated as a preventative measure against osteoporosis.
Vitamin D deficiency: what are the health risks?
A vitamin D deficiency can cause various health problems , particularly:
- bone disorders, including rickets in children and osteomalacia (generalized osteopathy) in adults;
- a reduction in bone mass resulting from reduced calcium binding to the bones. The risk of fracture increases accordingly;
- a drop in muscle tone;
- tetany attacks.
Vitamin D deficiency: 40% of French people affected?
Objective data regarding vitamin D are often controversial. Thus, ANSES (National Agency for Food, Environmental and Occupational Health Safety) estimates that the quantity of vitamin D that we must consume each day is 15 micrograms for adults. In fact, 40% of French people present a more or less significant deficiency.
Furthermore, various studies show that the average vitamin D level in a healthy adult is greater than 30 ng/ml of blood. This is therefore double what ANSES recommends. Taking this hypothesis into account, it is no longer 40%, but many more French people who would actually be deficient.
This situation is also found in all other European countries, even more marked in the North and a little less in the South!
Currently, ANSES is carrying out a reassessment of the nutritional reference for the population (RNP). It is therefore very likely that the figures will be revised upwards.
How to meet your daily vitamin D needs?
Unlike calcium for example, vitamin D can be both absorbed and synthesized by the human body .
The synthesis of cholecalciferol thanks to the sun
A significant amount of the vitamin D we need every day is synthesized by our body. This is D3 or cholecalciferol.
Under the effect of ultraviolet rays, the human body produces cholecalciferol in the skin . In summer, daily exposure to the sun for fifteen to thirty minutes helps cover daily needs.
What foods are rich in vitamin D?
The other possible source of vitamin D is found on our plate . Moreover, since the 19th century, cod liver oil has been used to combat rickets, a severe form of deficiency during growth. It is mainly vitamin D2 or ergocalciferol.
Among the foods richest in vitamin D, we find per 100 g:
- cod liver oil : 250.00 mcg;
- smoked herring: 22.00 µg;
- grilled sardine : 12.30 µg;
- the egg: 11.4 µg for the yolk and 5.4 µg for the white;
- button mushroom : 7 µg;
- canned sardines : 7.10 µg;
- avocado: 5 mcg;
- the dark chocolate bar with more than 40% cocoa: 4.80 µg.
Why use a food supplement in winter?
During the winter period, many French people have more or less significant vitamin D deficiencies.
Reduced intensity of UV rays
During the summer, it is relatively easy to meet your daily vitamin D3 needs by exposing yourself to the sun for a few minutes. It's much more complicated in winter.
In fact, from October to April, ultraviolet rays are less powerful. The necessary exposure time to the sun therefore increases from around twenty minutes in summer to almost two hours per day in the low season. Few people can spend so much time outdoors in winter.
A diet that cannot cover 100% of needs
Vitamin D is very present in cod liver oil, in fatty fish and even in egg yolk. Foods that we don't necessarily eat every day.
Even if you take care in winter, it is often very difficult to make up for the lack of vitamin D3 synthesized in the skin by vitamin D present in food.
Disturbance of absorption
Medications, certain pathologies or simply age can cause less absorption of vitamin D by the digestive system.
Decrease in D3 synthesis with age
The aging of tissues, particularly the epidermis, inevitably leads to a drop in the quantity of vitamin D3 produced by exposure to the sun.
The same applies if the skin is covered with sunscreen, for example.
Food supplement rich in vitamin D: to make up for the lack in winter
From October to April, exposure to the sun alone is not sufficient to prevent vitamin D deficiency . Food can make up for this deficit, but only partially.
Without a food supplement rich in vitamin D, it is therefore difficult not to be deficient.
This is why it is wise to supplement for at least 6 months per year, and even more for people with low exposure to the sun.
When choosing your supplement, choose vitamin D3 over vitamin D2 .
Recent studies (those by Dr Laura Tripkovic of the University of Surrey in particular) have demonstrated the greater effectiveness of vitamin D3 in correcting deficiencies: blood levels rise more quickly with D3 supplements than with D2.
If in the past it was only available from animal extracts, today there are plant sources of D3: this is the case for our Argalys Essentiels vitamin D3 , extracted from lichen.
We also have a wide range of food supplements rich in plant-based vitamin D3: Multivitamins, Vegakid and Calcium, to keep fit and healthy throughout the winter period.
Obviously, it is also recommended to go out every day, exercise and eat the most balanced diet possible.
Our Essential supplement which covers your daily intake of Vitamin D3:
€14.50 for 4 months of coverage!