5 Reasons Why Your Vitamin D Levels Drop In Winter (Even Where It's Sunny)

Most people, especially those in hilly areas or smog-covered North India, assume that dip in vitamin D levels occurs during winter months because of a lack of sunlight. But, India is a tropical country and not all parts of the subcontinent have gloomy winter days. In fact, many in states like Kerala and West Bengal or Bihar may ask, "The sun is out, so why are my Vitamin D levels low?" The answer lies in sedentary lifestyles, being stuck in offices all day, low dietary consumption of Vitamin D foods, and many more reasons. Given that Vitamin D is responsible for nutrient absorption in the body and bone health, a deficiency in this crucial vitamin can cause health issues and a decline in metabolic health. An unexpected result of low Vitamin D can also be felt as mental health is affected when Vitamin D levels drop in the body.

So, here are the top five reasons why your Vitamin D levels may be low in the winter months, even in India's sunny regions.

5 Reasons Your Vitamin D Levels Drop In The Winter

The main reasons why Vitamin D levels drop in the winter, even where it's sunny, are due to the fact that the physics of sun exposure changes in the winter. This, along with lifestyle, clothing factors, and natural and protective factors, is one of the reasons that Vitamin D plummets in the cold winter months. Here is a detailed breakdown that will help you understand of each of these reasons can affect your Vitamin D levels:

Sun Exposure Changes In Winter

In the cold, harsh winter months, the sun is out, but it's lower in the sky and eclipsed by thick, heavy smog. In addition, the thick blanket of air pollution masks the little sunlight and blocks proper rays from reaching the ground. The ultraviolet rays of the sun (the ones that make Vitamin D) have to travel through more atmosphere, reducing their intensity by the time they hit your skin. In order to get an adequate dose of Vitamin D, get out in the sun between 10 am and 3 pm, as during this time, the ultraviolet rays are strong enough, and this window shrinks significantly in the winter months.

Lifestyle Factors

The modern lifestyle introduces gaps by making people spend most of their time indoors, which makes getting adequate sunlight impossible. The ultraviolet rays of the sun cannot penetrate the window's glass, so sitting beside a window with sunlight will not help. In addition, a large percentage of the urban population, about 90% spends their daytime indoors, and there is an expense factor that hinders people from using UV red light lamps to boost their Vitamin D levels.

Clothing Factors

The layered clothing factors preferred to be worn during winter months stop people from getting an adequate supply of the sun's rays (even when it is visible), as a significant area of the skin needs to be exposed to the sun for proper and effective synthesis. The scarves, socks, and jackets hinder the skin from getting a proper supply of sunlight, and this in turn stops the body from creating Vitamin D in the body. This is one of the major reasons why, in a tropical country like India, the harsh winters result in automatic low levels of Vitamin D in most people, resulting in a population that is more susceptible to seasonal diseases.

Sun Protection Habits

The double-edged sword here is that effective sun protection efforts, mainly done to prevent skin cancer, often result in blocking the sun's ultraviolet rays. And these rays are responsible for creating Vitamin D in the body. Using SPF (sun protective factor) 30, often recommended for Indian skin, blocks about 97% of the sun's ultraviolet rays. The key to protecting yourself from skin cancer while getting proper exposure to the sun's rays is an act of balance few can accomplish. The sun exposure should be planned in a short, safe way..

Melanin's Role In Indian Skin

The Indian skin tone has a higher percentage of melanin (a pigment in darker skin tones), and it is a protective natural sunscreen. This means that people with darker complexions need a lower level of sunscreen protection. But, this also means that people with darker complexions need significantly longer sun exposure to produce the same amount of Vitamin D as lighter-skinned people. This makes them more susceptible to deficiency in harsh winter months.

How To Increase Your Vitamin D In Winter Without The Sun

Diet: A diet that focuses on fortified foods like fresh milk, unprocessed cheeses, and cold-pressed juices. Alongside natural sources of Vitamin D, like fatty fish, egg yolks, and mushrooms, are needed to balance the Vitamin D levels in the body. Please note that food alone with not enough for balancing Vitamin D levels in the human body; there needs to be external sun exposure or red UV lamps for the synthesis of Vitamin D in the body through the skin.

Supplement: The most reliable way to obtain healthy Vitamin D levels during the winter months, especially for high-risk groups (children and the elderly).

Consult a doctor and get a blood panel done to analyse the exact level of Vitamin D, and always ask the doctor to prescribe the correct dosage of Vitamin D and the frequency of Vitamin D, depending on the results.

Sunshine is essential, but it is not a guarantee in the winter months. There is a great need to be aware of your Vitamin D levels and supplement when needed.

Disclaimer: This content, including advice, provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.

Reference:

Aparna, P., Muthathal, S., Nongkynrih, B., & Gupta, S. K. (2018). Vitamin D deficiency in India. Journal of Family Medicine and Primary Care.