Does Vitamin D Deficiency Cause Hunger?

Understanding Your Hormones Series

For some time low vitamin d levels have been associated with obesity, it has often been dismissed as being a correlation issue. People who are more sedentary tend to stay inside more and excersise less, thus having lower vitamin D levels due to less exposure to sunlight. 

Then there was also vitamin D's connection to energy levels and mood. This was also seen as a possible explainantion.

However, it seems that Vitamin D is related to hunger directly. Numerous studies have suggested that vitamin D may play a role in obesity, with potential implications for weight gain and the regulation of appetite. One hormone that has garnered significant attention in this context is ghrelin (aka the hunger hormone). Vitamin D deficiency, seems to cause an increase in both ghrelin and leptin. 

Meaning not getting enough vitamin D, makes you hungrier. And most concerning in this context, vitamin D deficiency is incredibly prevelant in countries with high obesity rates such as the US and the UK. With some US studies putting the rates at over 50% and higher in ethnic populations with darker skin tones, who don't absorb the vitamin so easily from sunlight, suggesting it could play a role. 

It also stands to reason that vitamin D would work this way from an evolutionary standpoint, if we consider the seasons. In most climates humans would typically get less vitamin D as the season changed to fall and would ideally need to start to store fat for winter months when food would be less freely available. Thus biologically this would make sense as a mechanism for survival.

In short, low vitamin D levels seem to result in an increase of hormones responsible for hunger in the body. On top of that vitamin D deficiency can result in low mood, poor sleep (which further raises hunger hormone production), low energy, worse performance in athletic persuits. Meaning poorer food choices due to mood, and lower calorie burn due to lethargy as well as making you hungy.

The Role of Vitamin D in Obesity

Vitamin D and its Metabolic Effects

Vitamin D, often referred to as the "sunshine vitamin," is a fat-soluble vitamin that plays a crucial role in various physiological processes, including calcium absorption, bone health, and immune function. However, emerging research has also highlighted its potential involvement in metabolism and weight regulation.

Vitamin D Deficiency and Obesity

Several epidemiological studies have reported an association between low vitamin D levels and obesity. Individuals with obesity tend to have lower circulating levels of vitamin D compared to those with a healthy weight. This observation has sparked interest in exploring the potential mechanisms underlying this relationship.

Ghrelin: The Hunger Hormone 

Ghrelin is a hormone primarily produced in the stomach and known for its role in regulating appetite and energy balance. It is often referred to as the "hunger hormone" due to its ability to stimulate food intake and promote weight gain.  

Studies Linking Vitamin D and Hunger

Study 1: Evaluating the Relationship Between Vitamin D Status and Ghrelin Levels

A cross-sectional study conducted by researchers in Turkey aimed to evaluate the relationship between vitamin D status and ghrelin levels in individuals applying to a clinic for various reasons. The study enrolled a total of 95 patients, who were classified into two groups based on their 25(OH)D levels. Group 1 consisted of individuals with 25(OH)D levels below 20 ng/ml, while Group 2 included those with 25(OH)D levels of 20 ng/ml or higher.

The results of the study revealed several interesting findings:

  • Patients in Group 1, with vitamin D deficiency, had significantly higher BMI and waist circumference compared to those in Group 2.
  • HDL-C levels were also lower in Group 1, indicating a potential dyslipidemic profile associated with vitamin D deficiency.
  • Ghrelin levels were significantly higher in Group 1, suggesting a potential compensatory mechanism in response to vitamin D deficiency.
  • A positive correlation was established between 25(OH)D levels and BMI, as well as 25(OH)D levels and HDL-C.

These findings provide evidence for a potential relationship between vitamin D deficiency, ghrelin levels, and obesity. However, further prospective clinical studies are needed to establish a causal link and clarify the exact pathogenesis of human obesity in the context of vitamin D and ghrelin.

Study 2: Exploring the Association Between Obesity, Vitamin D, and Hormonal Activity in Type 2 Diabetes

A study conducted in Bahrain, Saudi Arabia, and Kuwait aimed to investigate the association between obesity, vitamin D, and hormonal activity in patients with type 2 diabetes (T2D). The study enrolled 408 T2D patients and analyzed various parameters, including demographics, glycemic and lipid profiles, vitamin D levels, and ghrelin levels.

The results of this study revealed the following key findings:

  • Obese T2D patients, defined as having a BMI of 30 kg/m2 or higher, were more likely to be women, younger in age, and have a shorter disease duration compared to nonobese T2D patients.
  • Surprisingly, glycemic and lipid profiles were comparable between the obese and nonobese T2D patients, suggesting that obesity may not directly impact these metabolic parameters in individuals with T2D.
  • Vitamin D levels were significantly lower in obese T2D patients, indicating a potential association between obesity and vitamin D deficiency in this population.
  • Ghrelin levels, insulin levels, and insulin resistance (as measured by HOMA-IR) did not show significant differences between obese and nonobese T2D patients.

These findings suggest that while obesity may be associated with certain demographic characteristics and vitamin D deficiency in T2D patients, it does not appear to have a direct impact on glycemic control, lipid profiles, ghrelin levels, insulin levels, or insulin resistance.

Study 3: The Effect of Vitamin D-Fortified Yogurt Drink on Appetite-Regulating Hormones in Type 2 Diabetes Patients

In a single-blind randomized clinical trial, researchers sought to evaluate the effect of daily consumption of a vitamin D-fortified yogurt drink (doogh) compared to plain doogh on appetite-regulating hormones, including leptin and ghrelin, in patients with type 2 diabetes (T2D).

The trial included 100 subjects with T2D, who were randomly assigned to either the vitamin D-fortified doogh group or the plain doogh group. The intervention period lasted for 12 weeks, during which participants consumed their assigned doogh twice a day. Measurements of leptin and ghrelin were taken at the beginning and end of the intervention.

The findings of this trial revealed the following:

  • The group consuming the vitamin D-fortified doogh showed significant improvements in circulating 25(OH)D levels, fasting glucose levels, quantitative insulin check index (QUICKI), and high-sensitivity C-reactive protein (hs-CRP) levels compared to the plain doogh group.
  • Serum levels of both leptin and ghrelin increased significantly in the vitamin D-fortified doogh group, indicating potential modulation of appetite-regulating hormones.
  • Interestingly, despite the increase in both leptin and ghrelin, the leptin-to-ghrelin (L/G) ratio decreased, suggesting a potential shift in the balance of these hormones.
  • The changes in ghrelin levels and the L/G ratio remained significant even after adjusting for factors such as insulin sensitivity, body mass index (BMI), and hs-CRP levels.

These findings suggest that daily consumption of a vitamin D-fortified yogurt drink may lead to improvements in vitamin D status, glucose control, insulin sensitivity, and inflammation markers in T2D patients. Additionally, the increase in both leptin and ghrelin levels highlights the potential of vitamin D in modulating appetite-regulating hormones and potentially influencing weight management.

Vitamin D And Hunger

In conclusion, the relationship between vitamin D and ghrelin in the context of obesity and weight management is a complex one. While various studies have provided insights into this relationship, further research is needed to fully understand the mechanisms underlying these associations, although vitamin d's role as an appetite suppressant along with it's other benefits does mean that it could well play an important role in weight management. 

Especially in males as vitamin D also has several implacations for testosterone levels.

Understanding the interplay between vitamin D, ghrelin, and other metabolic factors may contribute to the development of targeted interventions for weight management and the prevention of obesity-related complications.