Vitamin D Deficiency: Most Effective Supplements

Vitamin D, often referred to as the "sunshine vitamin", is a unique fat-soluble vitamin that stands out for its properties similar to steroid hormones. Synthesized by the body from cholesterol under the action of the sun's ultraviolet (UV) rays, it plays a fundamental role in the regulation of calcium and phosphorus absorption, essential elements for bone health.

Physiological Role of Vitamin D

Vitamin D plays a central role in the regulation of calcium and phosphorus, two minerals essential for the formation and maintenance of strong bones and teeth. Once synthesized in the skin or ingested in dietary form, vitamin D is converted by the liver and kidneys into its active form, calcitriol. Calcitriol acts as a hormone by facilitating calcium absorption in the intestines and regulating its reabsorption by the kidneys. Additionally, vitamin D has a key role in muscle function and in modulating the immune system, notably by stimulating the production of cathelicidin, an antimicrobial protein that helps protect the body against infections, particularly in the respiratory tract.

Dietary Sources of Vitamin D

Although the human body can synthesize vitamin D through sun exposure, certain dietary sources are also crucial for maintaining adequate levels, especially during winter months or in regions where sun exposure is limited. Among food sources rich in vitamin D are fatty fish such as salmon, tuna, and sardines, as well as cod liver oil. Eggs, liver, and fortified dairy products are also good sources. Some mushrooms exposed to ultraviolet rays can contain vitamin D2, offering a plant-based alternative.

Consequences of Vitamin D Deficiency

A vitamin D deficiency can have serious health consequences. Among the symptoms and associated conditions are: 2 Decalcification: In adults, vitamin D deficiency can lead to bone weakness, pain, and increased bone fragility, including osteoporosis. 2 Rickets: In children, severe deficiency can cause rickets, characterized by bone deformity due to inadequate mineralization. 2 Cardiovascular Diseases: Insufficient vitamin D levels are linked to an increased risk of cardiovascular diseases, such as hypertension, atherosclerosis, and coronary heart disease. 2 Type 2 Diabetes: Vitamin D plays a role in insulin regulation, and a deficiency could promote the development of type 2 diabetes. 2 Immune and Autoimmune Disorders: Vitamin D deficiency is associated with an increased risk of autoimmune diseases, including multiple sclerosis, type 1 diabetes, and inflammatory bowel diseases. 2 Cancers: Low vitamin D levels are linked to an increased risk of certain cancers, including breast, prostate, colon, and skin cancers. Although research is ongoing, these associations suggest the importance of maintaining adequate vitamin D levels to potentially reduce the risk of developing these diseases. 2 Neurodegenerative Diseases: Some studies have suggested a link between vitamin D deficiency and an increased risk of neurodegenerative diseases, such as Alzheimer's disease and other forms of dementia. Populations at risk of deficiency include older adults, those with limited sun exposure, individuals with darker skin, as well as those who follow a diet low in vitamin D or suffer from intestinal absorption disorders.

Prevention of Deficiencies

To prevent vitamin D deficiency, it is essential to combine moderate sun exposure with a diet rich in vitamin D sources. In cases of increased risk of deficiency or if vitamin D levels are insufficient, supplementation may be necessary. Recommended doses vary depending on age, lifestyle, and individual needs. For healthy adults, a supplementation of 600 to 800 IU per day is often advised, while higher doses may be necessary to correct an existing deficiency.