Could vitamin D be affecting your weight? A new study shows this may be the case.

Various previous studies have reported the possible risks associated with vitamin D deficiency such as obesity and related health conditions such as type 2 diabetes, however research has been inconclusive as to whether vitamin D supplementation can cut down on obesity until recently.

Researchers from the University of Milan have suggested that people deficient in or with low levels of vitamin D are more likely to be obese or overweight and should take supplements.


This recent study enlisted 400 obese or overweight individuals who were deficient in vitamin D. These individuals were split into three groups: no vitamin D supplementation, vitamin D supplements of 25,000 International Units (IU) a month, or vitamin D supplements of 100,000 International Units (IU) a month.

All three groups were put on a low calorie diet as well for 6 months.

Results from the study after 6 months reveal that those people who were supplemented with vitamin D had significantly different outcomes than those who had no vitamin D supplementation. Individuals who supplemented with vitamin D lost more than double the weight than that of the individuals who did not supplement.

They also lost more in their waist circumference. Furthermore, those who were supplementing with 100,000 IU of vitamin D lost about 30% more weight and 40% more inches from their waist than the group who took 25,000 IU of vitamin D. This seems like a clear indicator of the correlation of vitamin D and obesity.

It is important to note that these results were seen in individuals who were vitamin D deficient. This data does not suggest that anyone trying to lose weight should run out to get mega-doses of vitamin D. However, researchers do suggest that all obese or overweight individuals have their vitamin D levels tested.

There are other ways to increase your vitamin D levels besides through supplements.


Vitamin D is often called the “sunshine” vitamin because when the sun reaches the skin, the skin can produce vitamin D in the body. Depending on where one lives, the time of day, the season, one’s age and skin color, an individual can obtain 80-100% of the vitamin D required by the body.

However, by the age of 70, the skin’s ability to produce vitamin D by the sun decreases to about 70%. It is important to get these UV rays from the sun but to also be aware of the damaging effects of the sun, thus, wearing sunscreen is crucial. 2

Dietary Sources 

Besides using the sun as the sole source of obtaining vitamin D, it is also found in many foods. The main food sources are fatty fish. These include sardines, mackerel, herring, salmon, tuna, and eel.

 vitamin d and obesity2

Another source is cod liver oil.

This was more common in the earlier part of the 20th century to prevent vitamin D deficiencies until milk was fortified with vitamin D. Now, most milk is fortified with this vitamin, making it easier to acquire. Some fortified ready-to-eat breakfast cereals can supply vitamin D as well.

Eggs, butter, and liver contain some vitamin D but would have to be consumed in large amounts to be effective.

Should I start taking vitamin D supplements to lose weight?

Probably not. While vitamin D may have some role in maintaining a healthy weight, it certainly is not the key to your weight loss journey. Before you even consider taking a vitamin supplement consider these two things:

– Do I consume enough dietary sources of vitamin D?
– Has my doctor diagnosed me with a vitamin D deficiency?

If the answer to those questions are “no”, you probably shouldn’t rush out to get a supplement. If you do not consume enough dietary vitamin D, that is a good place to start. If you haven’t had your blood level of vitamin D checked in a while, or at all, make an appointment to have your levels checked.

Overall, vitamin D is a key nutrient used by the body. It is necessary for skeletal health and weight management. Having adequate levels of vitamin D can make you less likely to become obese or overweight.

That being said, it will not help you miraculously lose weight. According to the study mentioned in this article, these weight loss results were seen in individuals who had a deficiency of vitamin D.

For those who are trying to lose weight and are not deficient, consider your other eating and lifestyle habits.


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