February 29, 2024
Vitamin D is essential for the proper bones, teeth, and muscles function. This article looks at the reasons why vitamin D levels may be low, including insufficient sunlight, dietary factors, age-related factors, medical conditions, and genetics. The article also provides solutions to increase vitamin D levels, such as dietary changes, sunlight, and supplementation, among others.


Vitamin D deficiency occurs when your body doesn’t get enough vitamin D, which is necessary for maintaining healthy bones, teeth, and muscles. In this article, we will explore the possible causes for low vitamin D levels and suggest ways to prevent and treat it.

Reasons why we may not be getting enough vitamin D from sunlight

Our body can produce vitamin D with the help of sunlight. However, there are several reasons why we may not be getting enough sun exposure to produce adequate levels of vitamin D, including:

A. Spending too much time indoors

If you spend most of your time indoors or work in an office with no access to natural light, you may not be getting enough vitamin D from the sun. Even on a cloudy day, sunlight can provide significant amounts of vitamin D.

B. Living in a location that doesn’t receive enough sunlight

People living in areas that experience long winters or those who live at latitudes above 37 degrees may not receive enough UVB rays, which are responsible for triggering vitamin D synthesis in the skin.

C. Wearing protective clothing that blocks the sun’s rays

If you regularly wear long sleeves, pants, or hats that shade your face, you may be blocking the sun’s rays from reaching your skin and producing vitamin D.

Dietary factors that contribute to low vitamin D levels

While it’s possible to get vitamin D from some foods, there are several dietary factors that can lead to low vitamin D levels:

A. Diet lacking in vitamin D rich foods

If you don’t eat enough vitamin D-rich foods like fatty fish, dairy products, and fortified cereals, you may be at risk for vitamin D deficiency.

B. Food intolerances

Some people have food intolerances or allergies that prevent them from consuming vitamin D rich foods. For example, lactose intolerant individuals may avoid dairy products filled with vitamin D.

C. Malabsorption issues

People with digestive disorders such as Crohn’s disease or celiac disease may have difficulty absorbing vitamin D from their food.

D. Restrictive diets (e.g., veganism)

Individuals following a vegan or vegetarian diet may not consume enough vitamin D rich foods.

Age-related factors that contribute to low vitamin D levels

Age can also be a factor in low vitamin D levels. The following are age-related factors that may contribute:

A. Decreased skin’s ability to produce vitamin D

As we age, our skin becomes thinner and less efficient at synthesizing vitamin D from sunlight. This leaves older adults at greater risk for vitamin D deficiency.

B. Older people may be less likely to spend time outdoors

Older adults may be less mobile or spend more time indoors, depriving them of sun exposure needed for vitamin D synthesis.

Medical conditions that can affect vitamin D levels

Several medical conditions can impact vitamin D levels. They include:

A. Obesity

Obese individuals have higher levels of body fat, which can bind with vitamin D and reduce its availability for use by the body. As a result, obesity is associated with lower levels of vitamin D.

B. Chronic kidney disease

Individuals with chronic kidney disease may have lower levels of active vitamin D because the kidneys can’t convert it to its active form.

C. Chronic liver disease

People with specific types of liver disease may have diminished hepatic hydroxylase activity, which can make it difficult for the body to produce vitamin D.

D. Some hormonal disorders

Excess parathyroid hormone (PTH) circulating in the body can lower vitamin D levels. This may be due to calcium leakage from bones, which stimulates the production of PTH.

Medications or substances that may contribute to low vitamin D levels

Some medications can decrease vitamin D levels by hindering absorption or enhancing excretion. They include:

A. Steroids

Corticosteroids, such as prednisone, can interfere with vitamin D metabolism, making it harder for the body to absorb this vitamin from the diet.

B. Weight loss pills

Orlistat, the active ingredient in many over-the-counter weight loss pills, inhibits the absorption of dietary fats when consumed. Vitamin D is a fat-soluble vitamin, and this can interfere with its absorption.

C. Certain prescription medications

Other medications, such as anticonvulsants or medications for fungal infections, may affect the activity of vitamin D.

Genetics and vitamin D levels

Genetics also play a role in vitamin D levels. Certain gene variations can affect vitamin D synthesis, metabolism, and interactions with other hormones.

A. Explanation of how genetics affect vitamin D levels

Studies have identified several genetic polymorphisms associated with one’s ability to maintain and activate sufficient levels of vitamin D. Single nucleotide polymorphisms (SNPs) in genes such as CYP2R1, VDR, and GC have been linked with increased risk of vitamin D deficiency.

B. Potential for genetic testing

Genetic testing can identify an individual’s genetic variants that can impact their vitamin D metabolism. However, more research is needed to determine the usefulness of genetic testing in identifying and managing individuals with vitamin D deficiency.

How to increase vitamin D levels

If you have low levels of vitamin D, there are several ways to increase it:

A. Dietary changes

Consuming more vitamin D-rich foods can help increase your vitamin D levels. Fish such as tuna and salmon, egg yolks, and fortified foods such as milk and cereal are excellent sources.

B. Exposure to sunlight

The best way to obtain vitamin D is through sunlight. Spending 10-15 minutes in direct sunlight (with the face, arms, and legs exposed), a few times a week can help maintain adequate levels of vitamin D.

C. Supplementation

If you’re not getting enough vitamin D from sunlight or your diet, taking vitamin D supplements may be necessary. Supplementation can be in the form of capsules, drops, gummies, or tablets. It’s best to consult your healthcare provider about the right dosage for you.

D. Recommended daily dosage

The recommended daily intake of vitamin D varies according to one’s age, health conditions, and sun exposure. The National Institutes of Health recommends that adults between the ages of 19 to 70 consume 600 international units (IUs) of vitamin D per day, while those over 70 should get 800 IUs per day.


Vitamin D deficiency is common worldwide, but there are several reasons why some people may be more at risk of low levels. It’s important to identify the underlying cause of low vitamin D and take necessary actions to correct it. Including vitamin D rich foods in the diet, spending time under the sun, and taking supplements may help increase vitamin D levels. Seek medical advice if necessary to discuss the best way to maintain your vitamin D levels.

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