Madrid, Spain – Often referred to in popular discourse as the “vitamin of eternal life”, vitamin D has drawn increasing scientific attention for its role in healthy ageing and disease prevention. Health specialists in Spain emphasise that this nutrient is essential not only for maintaining strong bones and muscle mass, but also for supporting immune defences, especially in individuals with limited exposure to sunlight.
Vitamin D, also known as calciferol, plays a central role in facilitating calcium absorption in the intestines — a biological process that allows the skeletal system to develop and function properly. While sunlight is commonly regarded as the primary source, experts stress that adequate levels can also be achieved through diet and, when necessary, supplementation, regardless of climate or geographic location.
According to nutritionist Jenny García, vitamin D belongs to the group of fat-soluble vitamins, meaning it is more effectively absorbed when consumed alongside dietary fats. Once absorbed, it is stored in the liver, adipose tissue and muscles. “Its importance extends beyond bone formation,” García explains. “Vitamin D is also necessary for the proper functioning of the immune system, influencing the body’s ability to respond to infections.”
Multiple pathways to adequate intake
Nutritionist Katherine Cántaro describes vitamin D as a unique micronutrient that can be obtained through three distinct pathways. The first is cutaneous synthesis triggered by ultraviolet radiation from sunlight. However, excessive or unprotected exposure carries risks, including skin burns and an increased likelihood of skin cancer, underscoring the need for moderation.
The second route is dietary intake. Natural food sources rich in vitamin D include oily fish such as salmon, tuna, trout and mackerel, fish liver oils, beef liver, dairy products, egg yolks and certain mushrooms. Avocado also contributes small amounts. A third option involves consuming fortified foods, including plant-based spreads, cereals, yoghurts, fruit juices and beverages enriched with vitamin D to compensate for dietary shortfalls.
Metabolic effects and consequences of deficiency
Scientific evidence indicates that insufficient vitamin D intake can disrupt bone metabolism and affect multiple body systems. García warns that deficiency has been associated with impaired immune and cardiovascular function. Research published in journals such as The Lancet Diabetes & Endocrinology suggests that individuals with adequate vitamin D levels may face a lower risk of developing type 2 diabetes.
Clinical observations further link low vitamin D status to an increased incidence of chronic conditions, including cardiovascular disease, autoimmune disorders, certain cancers and depression. From a structural perspective, prolonged deficiency weakens bone integrity and may lead to osteoporosis — a condition characterised by reduced bone density and a higher susceptibility to fractures, even after minor trauma.
Sun exposure and medical guidance
Recommended vitamin D requirements vary according to age and individual health factors. For much of the population, brief daily exposure to sunlight — approximately eight to fifteen minutes — is generally sufficient to support normal physiological needs. However, people living in regions with limited sunlight or persistently overcast conditions often rely more heavily on dietary sources and supplements.
Health authorities in Spain advise that any significant changes to diet or supplementation should be undertaken under professional supervision. Medical guidance helps prevent both deficiency and excessive intake, ensuring that vitamin D contributes safely and effectively to long-term health, functional independence and quality of life as people age.