Sunlight is the primary source of vitamin D, which is why it is commonly known as the ‘sunshine vitamin.’ When the skin is exposed to sunlight, it absorbs ultraviolet B (UVB) radiation and is converted into previtamin D3, which in turn transforms into vitamin D3, a fat-soluble vitamin that helps your body absorb calcium and phosphorus, according to a study published in the journal Dermato-Endocrinology.
Now that winter is here, so is the risk of vitamin D deficiency. We spoke to Divya Gopal, Consultant Dietitian and Nutritionist, Motherhood Hospitals, Banashankari, Bengaluru, who listed the factors that could be to blame.
Also Read: Vitamin D Toxicity: Signs You're Taking Too Much Of Vitamin D
Winter And The Risk Of Vitamin D Deficiency
Research has established winter as a major risk factor for vitamin D. According to a 2011 study involving 351 subjects—66.4% women and 33.6% men—aged between 11 and 69, the prevalence of vitamin D deficiency was found to be 87.5% (307) in winter, whereas it was 78.6% (276) in summer.
Another study published in Frontiers Nutrition suggested that vitamin D deficiency was more common during winter and spring than summer and autumn, urging people susceptible to the condition to take vitamin D supplements to prevent it.
According to Gopal, several factors can be responsible for it. Some of them include:
Limited sunlight exposure: During winter, the days are shorter, and people tend to spend more time indoors. Additionally, the angle of the sun is such that UVB rays have to travel through more atmosphere, reducing their intensity. This results in decreased exposure to sunlight, a primary source of vitamin D.
Clothing choices: Cold weather often leads people to wear more layers of clothing, which can further reduce the skin's exposure to sunlight.
Sunscreen use: Many experts recommend the use of sunscreen to protect the skin from damage caused by the sun. But by applying it, you could be blocking the UVB rays necessary for vitamin D synthesis, said Gopal.
Symptoms Of Low Vitamin D Levels
Vitamin D deficiency can cause several symptoms in the body. These include:
- Fatigue
- Body pain
- Weakness
- Loss of appetite
- Frequent sickness
- Muscle pain
- Increased risk of injury
- Hair loss
- Sleeping issues
In addition, untreated vitamin D deficiency can also lead to certain complications, such as bone issues and an increased risk of conditions like osteoporosis and rickets, muscle weakness, heightening the risk of a fall and injury, and mood disorders such as depression.
How To Increase Vitamin D Intake?
While exposure to sunlight is the best way to increase your vitamin D levels, other sources, including diet and supplements, can also prove effective in preventing deficiency.
“Fatty fish like salmon and mackerel, fortified dairy, plant-based milk, and egg yolks are dietary sources of vitamin D,” said Gopal.
She added, “In some cases, especially for individuals at high risk or with difficulty obtaining sufficient vitamin D from sunlight and diet, supplements may be recommended.”
However, when it comes to taking supplements, the expert recommended consulting with a doctor, as excessive intake can lead to toxicity.
“Testing blood levels of vitamin D can help determine if supplementation is necessary. Always follow your healthcare provider's advice for your specific situation,” she concluded.