Vitamin D for Weight Loss?

Parathyroid hormone is suspected of causing the body to hoard fat. We learn from that “stored vitamin D tells the hypothalamus to decrease the output of parathyroid hormone.” Conversely, when incoming vitamin D is too low, that shortage is interpreted as a signal to store fat throughout the body, and especially around the waist area. Also, we are told that:

[…] a study in Nutrition Journal found that overweight and obese women who took 1,000 IU of Vitamin D every day for 12 weeks lost a measurable amount of fat mass independent of other bodily changes.

The nutrient also engages in molecular signaling to inhibit inflammatory substances from adhering to cell walls and causing stress and inflammation. In addition, the body’s organs also have receptors that turn vitamin D into the activated or hormonal form known as calcitriol. This hormonal version of vitamin D helps repair cells, fights oxidation, and may even increase longevity.

There is good news for people with type 2 diabetes, or who are at risk for it, because D can increase insulin secretion. It can also increase the release of leptin, the hormone that says “I’m full.” For patients who undergo bariatric surgery, vitamin D supplementation is strongly advised.

Vitamin D helps the body convert tryptophan into serotonin, a hormone closely associated with increased mental energy and elevated mood. As with most weight-loss drugs, patients are warned that it only works in conjunction with a calorie-restricted diet and the expenditure of energy through regular exercise.

Several Russian medical institutions have also noticed how, in pediatric patients, vitamin D deficiency lines up with obesity and metabolic syndrome, and they have been working on this, too. Their research

[…] demonstrates the role of vitamin D insufficiency in immune reactions resulting in development of subclinical inflammation in fat tissue infiltrated with macrophages and lymphocytes. It also shows […] the function of vitamin D as an endocrine and paracrine regulator of the process of inflammation in adipose tissue.

The body is constantly engaged in transforming vitamin D into biologically active metabolites that do a lot of things. As it turns out, D is “not a vitamin in the classical interpretation,” but a “steroidal prehormone with autocrine, paracrine and endocrine action.”

The latest research is a meta-analysis from the University of Bahrain based on many scientific papers about “the effects of vitamin D supplementation (cholecalciferol or ergocalciferol) on weight loss through holistic measurements of Body Mass Index (BMI), weight and waist.”

Like any reputable meta-study, this one is careful to explain its own limitations. It does not solve all the world’s problems, but helps to lay a foundation. The foundation would be a definition of the feasibility of cholecalciferol D as a new weight-loss drug. One roadblock is, nobody knows yet exactly how it does what it does. Simone Perna writes,

A recent study has reported that cholecalciferol has physiological and biochemical effect in a way that reduces metabolic abnormalities and tissue damage that can result from adiposity. Cholecalciferol has a direct role in suppressing the PTH hormone, which promotes and triggers fat accumulation in the adipose tissue via increasing intracellular calcium.

Or, it may be that cholecalciferol helps the intestines absorb calcium. Or the magic may lie in the way it excites the insulin receptors and maintains calcium at the proper levels. Still, the authors take a strong stand:

Prescribing cholecalciferol and following an effective strategy for cholecalciferol supplementation should be an imperative practice, especially for overweight and obese individuals.

Your responses and feedback are welcome!

Source: “5 Ways Vitamin D Can Benefit Weight Loss,”, 09/28/18
Source: “Vitamin D Insufficiency in Overweight and Obese Children and Adolescents,”, 03/01/19
Source: “Is Vitamin D Supplementation Useful for Weight Loss Programs? A Systematic Review and Meta-Analysis of Randomized Controlled Trials,”, 07/12/19
Photo credit: Carol VanHook on Visualhunt/CC BY-SA

Leave a Reply

Your email address will not be published. Required fields are marked *

FAQs and Media Requests: Click here…

Profiles: Kids Struggling with Weight

Profiles: Kids Struggling with Obesity top bottom

The Book

OVERWEIGHT: What Kids Say explores the obesity problem from the often-overlooked perspective of children struggling with being overweight.

About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

Food & Health Resources