How Can Vitamin D Help You Lose Weight?

by Marixie Ann Obsioma, MT, undergrad MD on October 2, 2019
Last updated on May 23, 2021

If losing weight was as easy, we’d all be skinny as reeds. We can settle on our couches and watch our favorite shows on Netflix while munching on pizza, popcorns, and cans of soda. However, in reality, slimming down is not that simple. When you scan the internet and the supplement shelves at a local drugstore, you’ll see weight loss touted as a benefit of several kinds of products. While some have nothing to bolster their claims, the purported effects of vitamin D on weight loss are evidenced by science-based studies.

cod liver oil pills

You read that right! Aside from helping us to strengthen our bones and boost immunity, new researches show that vitamin D deficiency is related to weight gain and obesity (1). Nearly 50% of people around the world have low vitamin D levels (2). In the US, approximately 41.6% of the population is deficient (3). Older people, dark-skinned individuals, and breastfed infants are at greater risk (4). So, if you are one of those dieters who find it difficult to shed off pounds even when on a strict diet and regular exercise, you might want to check your vitamin D levels. In this article, you’ll find all about vitamin D, how it works for weight loss, its correct dosage and rich sources. Swipe up!

What is Vitamin D?

Vitamin D is a fat-soluble vitamin that we can get from our diet or supplements. We can also make it through good sun exposure. However, those who live far from the equator may not get enough vitamin D from the sun alone. At specific latitudes, very little or none can be produced by the skin for up to 6 months of the year (5).

Vitamin D is essential to keep our bones, teeth, and immune system strong and healthy. It helps facilitate calcium and phosphorus absorption (2). New evidence suggests that vitamin D can also help prevent a variety of chronic health conditions like depression, DM, heart disease, and cancer (6).

There are two main dietary forms – ergocalciferol (D2) and cholecalciferol (D3). Of the two, D3 is more effective at increasing vitamin D levels in the blood as D2 (7, 8).

Overweight people, those who have a higher BMI and body fat percentage, tend to have lower vitamin D blood levels (9, 10). Several theories have speculated about the association between obesity and decreased vitamin D levels. Some say it is because people consume less vitamin D-rich foods; others point to behavioral differences like not wanting to bathe in the sun. More so, certain enzymes are needed to make vitamin D active, and the levels may vary between people, including obese and non-obese individuals (11).

But, a study in 2012 noticed that as soon as vitamin D levels were adjusted for body size, there’ll be no difference between levels in obese and non-obese patients (12). This means that your needs will depend on your body size. If you are obese, you’ll likely need more than normal-weight people.

Interestingly, weight loss can also affect your vitamin D levels. A reduction in your body size can decrease your requirement. However, since the amount present in your body remains the same when you lose weight, your levels will actually increase (13, 14). The degree of weight loss may affect the extent to which its levels increase.

There’s evidence showing that even just a small amount of weight loss can lead to a modest increase in vitamin D blood levels. Those who lost at least 15% of their weight had increases that were 3 times more than those who only lost 5-10% of their weight (15).

Increasing Vitamin D Levels Can Help You Lose Weight

Evidence suggests that getting enough vitamin D can decrease body fat and encourage weight loss. At least 20 ng/ml is enough to promote strong bones and overall health (4). One research looked at more than 200 overweight and obese women for more than a year. All were put a calorie-restricted diet and workout routines. Half of them were given vitamin D supplements, while the rest had a placebo. Results showed that those who fulfilled their vitamin D requirements had more weight loss, averaging to 7 pounds (16).

Another research supplemented overweight and obese women with vitamin D for 12 weeks. Results showed that increasing vitamin D levels decreased body fat (17). Higher levels of vitamin D were also linked to less weight gain in more than 4600 elderly women for a span of 4.5 years (18). In summary, increasing your vitamin D may help promote weight loss.

How Does Vitamin D Induce Weight Loss?

Several studies attempt to explain vitamin D’s effects on weight loss. It shows that it can help you slim down by:

  • Restricting New Fat Cell Formation and Decreasing Fat Storage
    Vitamin D can potentially limit the formation of new fat cells in the body (19). It can suppress the storage of fat cells, effectively decreasing fat accumulation (20).
  • Decreasing Parathyroid Hormone, Cortisol, and Leptin Levels
    Stored vitamin D can signal the hypothalamus to lower PTH production, a hormonal substance that can cause the body to hoard fat around the waistline.
    Cortisol is a stress hormone that can encourage the storage of belly fat. It may likewise control stress eating.
    High levels of vitamin D release more leptin, a hormone that signals the body a feeling of fullness. This may also help improve insulin sensitivity toward healthy foods.
  • Increasing Serotonin and Testosterone Levels
    It may increase the levels of serotonin, a neurotransmitter that affects mood and sleep regulation (21, 22). It can also control appetite, increase satiety, decrease calorie intake, and reduce body weight (23).Higher vitamin D levels are also linked with higher testosterone levels, which can promote weight loss (24). A study on 165 men proved that vitamin D supplementation can greatly increase testosterone level as compared to placebo (25). Testosterone also showed to decrease body fat and help maintain long-term weight loss by increasing metabolism to burn more calories after eating and blocking the formation of new fat cells (26, 27, 28, 29, 30).
  • Improving Lean Muscle Mass and Strength
    Vitamin D has significant implications for musculoskeletal health. Evidence shows that supplementation with vitamin D during aerobic exercise and resistance training can increase calorie loss than a workout alone (31). It can help with energy output during exercise and may increase lean muscle mass within a year. Vitamin D also plays a huge role in muscle repair. It strengthens muscle fibers to facilitate fast recovery from cellular damage.
  • Promoting Sleep
    By improving the quality and duration of sleep, which results in restfulness after a workout. This gives you greater stamina to do more physical activities the next day.
  • Increasing Insulin Secretion
    Patients with type 2 diabetes and those who are prone to develop one can increase insulin secretion by increasing vitamin D levels (32). This can help fight hunger and overeating associated with insulin resistance and metabolic syndrome.

How Much is Needed?

Supplementing with vitamin D is not a “one size fits all” approach. There has been a debate about how much vitamin D our body needs. Studies indicate that the dosage must be adjusted based on body weight. Approximately 70-80 IU per kg is needed to maintain adequate levels (33). While the Endocrine Society suggests 1,500 to 2,000 IU per day, the Reference Daily Intake (RDI) is set at 600-800 IU for adults in the US, as recommended by the US National Academy of Medicine (34, 35).

Although toxicity is rare, it is best to avoid long-term vitamin D supplementation of more than 4,000 IU without supervision from a healthcare professional (36). The optimal vitamin D blood level is not well established but likely falls between 20-50 ng/ml (37, 38).

How To Increase Your Vitamin D Levels?

1. Get Out in the Sun

Vitamin D is also known as the “sunshine vitamin” because it is best obtained from sunlight. Our skin hosts cholesterol that works as a precursor for vitamin D. When exposed to UV-B radiation from the sun, it becomes vitamin D. Sun-derived vitamin D circulates longer as compared to those obtained from our diet (39).

However, the amount of vitamin D your body through sun exposure may depend on several variables. People with darker skin have more melanin, which can inhibit vitamin D production (40). Also, as we age, production becomes less efficient (41). Also, your chances of getting adequate sun exposure decrease if you live farther away from the equator. Certain types of sunscreen and clothing can also hinder vitamin D production.

2. Eat More Fatty Fish and Seafood

Fatty fish and seafood are excellent natural food sources of vitamin D. A 3.5 ounces serving of canned salmon can give you as much as 385 IU of vitamin D, which is about half of the Recommended Daily Intake (42). Other types of fish and seafood rich in vitamin D include mackerel, tuna, sardines, shrimps, oysters, and anchovies.

3. Consume Mushrooms

Mushrooms are the only completely plant-based source of vitamin D. Like us, they can make their own vitamin D, the D2 type, through UV light exposure (43). While vitamin D content would depend on the type of mushroom, some varieties like the wild maitake mushrooms can offer as much as 2,348 IU per 3.5 ounces serving. It is almost 300% of the Recommended Daily Intake (42, 44). But, be careful in identifying and purchasing wild mushrooms. Get from a trusted supplier to avoid poisonous varieties.

4. Add Egg Yolks in Your Diet

Egg yolks are another good source of vitamin D that can be easily added to your diet. Similar to other natural food sources, yolks have variable vitamin D content. Chickens who do not have access to the outdoors only produce eggs harboring 2-5% of the RDI. On the other hand, those who pasture raised can offer up to 4 times more, approximately 20%, depending on how much time they spent outside (45).
Chickens fed with grains rich in vitamin D may also produce yolks that can give more than 100% of the RDI (46).

5. Choose Fortified Foods

Since only a few foods naturally contain high levels of vitamin D, this nutrient is often added to staple goods through fortification. However, the availability of vitamin D fortified products may vary by country, and the quantity added may differ by type and brand. Commonly fortified goods include cow’s milk, soy milk, almond milk, hemp milk, cereals, yogurt, tofu, and orange juice. To be sure, check the label and look for “fortified with vitamin D” in the ingredients list.

6. Take A Supplement

Vitamin D supplementation works pretty well on most people. Evidence suggests that supplements with D3 may be more effective at increasing and maintain overall vitamin D levels (47). Also, it is important to buy high-quality supplements that have been independently tested by a third party for purity and quality. Some countries, including the US, do not regulate nutritional supplements, which negatively impacts quality.

7. Use UV Lamp

Though expensive, lamps that emit UV-B radiation similar to sunlight can help increase your vitamin D levels. This can be very helpful if your sun exposure is limited to geography or time indoors. UV radiation has been used therapeutically for several skin conditions, and just recently, it has been finally marketed as an aid to increase vitamin D levels (48). But be careful not to expose your skin too much because it may cause burning. Do not exceed 15 minutes of exposure at a time.

The Bottom Line

It is clear that there’s an intricate association between vitamin D levels and weight. Getting a sufficient amount of this nutrient can keep most of your hormone levels in check, which may help decrease body fat and promote weight loss.

In turn, weight loss benefits can increase vitamin D levels that maximize its other benefits like keeping your bones strong and decreasing your risk of some chronic health conditions. There’s no need to worry if you’re getting limited sun exposure. You can have it from the other sources listed above. Keep your weight under control and improve your overall health with vitamin D.


PhentermineDoctors has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Leave a Reply

Your email address will not be published.