Vitamin D and the Winter Blues. Known in the medical field as Season Affective Disorder (SAD), winter depression is a mental condition in which people experience depressed mood during the same season each year. Winter depression is still a mystery to many health care professionals and there are varying schools of thought with relation to its cause, although most can agree that it may be related at least in part to light sensitivity, brain biochemistry, and Vitamin D deficiency.

The symptoms of Seasonal Affective Disorder can mimic those of major depressive disorder and can include decreased energy, increased appetite, increased need or desire for sleep, loss of interest in usually pleasurable or fulfilling activities, cravings for carbohydrates, irritability, and weight gain.

Although Seasonal Affective Disorder can occur during any season, in this part of the world it is most common in the late fall to early spring, a time characterized by shorter days, decreased sunlight, colder temperatures, and increased time indoors.

Vitamin D is known as the “sunlight hormone” because humans are designed to fulfill Vitamin D needs by producing it in response to exposure of their bare skin to the sun’s ultraviolet light. When exposure to sunlight is limited, levels of Vitamin D are naturally lowered, eventually resulting in deficiency.

How does Vitamin D deficiency lead to weight gain? One perspective is that of evolutionary biology. Among our ancient ancestors, sun exposure was the primary source of vitamin D. Their levels tended to be higher during the summer when people spent more time outdoors hunting and gathering, and lower during the cold winter months when the food supply was scarce and they entered a pseudo-hibernation mode. Physiologically, low levels of Vitamin D may be a signal for the body to shift into a wintertime metabolic pattern, characterized by fat storage and weight gain, which was imperative for the survival of our Paleolithic ancestors. Another perspective is that of simple brain biochemistry. Vitamin D naturally boosts serotonin, a brain chemical responsible for intestinal movements, mood, hunger, and sleep. When we become low in serotonin our mood drops and our bodies often experience cravings as a means to increase serotonin levels. Carbohydrates, as well as caffeine and nicotine, temporarily increase serotonin levels in the brain and temporarily elevated our mood. Unfortunately, the body will eventually become desensitized to this excess serotonin exposure and cravings will intensify. In addition to excess abdominal weight gain, additional signs of Vitamin D deficiency can include depression, chronic musculoskeletal pain, frequent respiratory infections, inflammatory disease, and certain autoimmune diseases.

For proper functioning, a healthy human body utilizes around 3000-5000 International Units (IU) of Vitamin D per day. Based on that figure, the Vitamin D Council recommends an intake of at least 5000 IU for healthy adults.

What you can do to beat the blues (and pounds)? Have your Vitamin D level checked. This can be done with a blood test. The 25-hydroxy Vitamin D level is the most accurate way to measure the amount of the body’s circulating Vitamin D. For optimum health, levels >50 ng/mL are recommended.
Consider Vitamin D supplementation. According to the Vitamin D council, it is very difficult to obtain adequate levels of Vitamin D through dietary intake alone. In individuals with inadequate exposure to sunlight, Vitamin D3 supplementation should be strongly considered. However, this should be done only after a baseline level has been obtained and with regular monitoring to prevent toxicity. In Vitamin D deficiency, recommended supplementation can range anywhere from 5000 IU per day to as much as 50,000 IU per week. Evaluation and supplementation of optimum Vitamin D levels are an important part of the groundwork of the Weightloss Clinics® program.
Get adequate B vitamins, calcium, and magnesium, either from diet or supplementation. These vitamins and minerals are necessary for serotonin synthesis and are co-factors for Vitamin D absorption.
Engage in activities that naturally boost serotonin levels, such as exercise.
Limit your intake of caffeine and refined carbohydrates such as breads, pastas, and desserts. These can boost your mood temporarily, but can desensitize your system to serotonin over time and lead to cravings and weight gain.
Schedule a consultation with Weightloss Clinics to learn more about how our physician-supervised weight loss program can help you reduce your hunger, boost your energy, and eliminate your cravings!

Tara Parr, MPAS, PA-C