The Sunshine Vitamin

By Dr. Charlotte Hodges

As a bariatric surgeon, I routinely recommend to my patients that they supplement their diet with Vitamin D.  But why is this essential vitamin so important?  And, not just for weight loss patients?

Vitamin D is called an essential vitamin, because it cannot be made in the body.  It must be ingested.  Vitamin D is sometimes called the “sunshine vitamin,” because it is activated in the skin by sunlight. When our skin is exposed to sunlight, the 7-dehydrocholesterol in our skin to Vitamin D3.  Vitamin D3 then travels to our liver and then kidneys to be converted to the active formulation, also known as calcitriol.  Vitamin D is found in egg yolks and some fattier fish, such as salmon, tuna and sardines.  (These fish are also naturally higher in omega-3 fatty acids).  Because sunlight is important in the processing of this vitamin, researchers have looked at people living in areas with less sunlight exposure (further from the equator) and in people with darker skin.   Studies have shown that people living further away from the equator (who get less sun exposure) are at a higher risk for Vitamin D deficiency.   Additionally, people with darker skin may also be at risk for deficiency.  While melanin is protective against UBV rays, it can interfere with the processing of Vitamin D.

The FDA has long looked at nutrient deficiencies in our daily diets.  In the late 1800s, it was found that conditions like rickets (also known as scurvy) could be cured by diet.  It wasn’t until the 1930’s that the FDA began to fortify foods such as grains, cereal, and milk with Vitamin D.  This took the approximately 80–90% of children showing varying degrees of bone deformations due to vitamin D deficiency to being a very rare condition.

Holick M.F. (2010). “The Vitamin D Deficiency Pandemic: a Forgotten Hormone Important for Health”. Health Reviews. 32: 267–283.

So what does Vitamin D do?

Vitamin D helps to regulate calcium and phosphate in the body by controlling the amount of absorption of calcium into the gut from the foods that you eat.  This is important for the maintenance of strong bones and teeth.  When you are deficient in Vitamin D, you are at an increased risk for osteoporosis.  But is that all that Vitamin D does?  Studies now show that Vitamin D plays a much bigger role than just maintaining strong bones. 

Vitamin D and Cardiovascular Disease

In 2014, a review article in Circulation Research was published.  It showed that Vitamin D acts to decrease inflammation by signaling cells in our blood vessel walls.  Increased inflammation has been shown to be a key mediator in a variety of health problems.  Inflammation within the blood vessel walls can lead to atherosclerosis (clogged vessels).  Vitamin D works to reduce plaque build-up in our arteries and the hardening of the valves in the heart.  Patients with deficiency in this vitamin have a higher risk for developing high blood pressure, high cholesterol and diabetes mellitus. 

Circulation Research. 2014;114:379–393

Vitamin D in Dementia and Alzheimer’s disease

In a 2014 study published in Neurology, results confirmed that Vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease.  In the study, researchers found that people with low Vitamin D levels had a 53 percent increased risk of developing all-cause dementia.  Those who were severely deficient had a 125 percent increased risk.  Additionally, patients with a Vitamin D deficiency were 70 percent more likely to develop Alzheimer’s disease.

Neurology, August 6, 2014

Who is at risk for deficiency, and what are the recommended dosages?

Vitamin D is one of four vitamins that is fat-soluble.  Therefore, people who are unable to absorb fat well, such as bariatric patients and those with celiac disease, may need to take in more than the recommended daily allowance.  Additionally, patients who live further from the equator or spend less time in the sun are also at risk.  The US Institute of Medicine recommends a daily supplement of 600 to 800 IU daily.  While you could likely get this by eating oiler fish daily, you probably shouldn’t because of the risk of mercury found in these types of fish.  Bariatric patients who have a decreased ability to absorb Vitamin D will need to take a daily supplement of 5000 IUs.

Bottom Line

• Vitamin D is important for strong bones and prevention of osteoporosis and bone deformities.

• Vitamin D deficiency has been linked to cardiovascular disease and dementia/depression.

• Patients should include a Vitamin D3 supplement in their regimen, of at least 600-800 IUs daily.  Post-bariatric patients should take 5000 IUs daily.