Vitamin D, Obesity and COVID-19

Jan. 31, 2021

Recent headlines have highlighted the potential relationship between vitamin D status and COVID-19 severity.

The idea that vitamin D could potentially help prevent or treat COVID-19 is certainly an attractive idea, as vitamin D supplements are inexpensive, easily accessible and relatively low-risk compared to prescription medications.

Does having obesity impact a person’s vitamin D levels? Do lower levels of vitamin D put people at a disadvantage in regard to viruses such as COVID-19? How does obesity enter into this mix? Should we be running to the store to stock up on vitamin D supplements?

Answers to common questions about vitamin D levels and COVID-19, as well as how these relate to obesity, are provided below by Haylee Hannah, RD, registered dietitian and certified specialist in obesity and weight management, and Heather Waugh, CNP, nurse practitioner, from the UC Health Weight Loss Center.

What is vitamin D and why is it important?

Hannah: Vitamin D is one of the four “fat-soluble” vitamins. Though vitamin D is best known for its role in calcium metabolism and maintaining strong, healthy bones, vitamin D does so much more. Vitamin D is connected to everything, from maintaining a healthy immune system and nervous system, to preventing certain chronic diseases, to improving mental health.

Where does it come from and how much do we need?

Hannah: Often called “the sunshine vitamin,” vitamin D is unique in that when ultraviolet rays from the sun hit our skin, our bodies can produce some vitamin D on its own. Interestingly, it has been found that people who live in sunny climates, such as close to the equator, tend to be at lower risk for vitamin D deficiency and related diseases.

Aside from sunshine, vitamin D is found naturally only in a few foods, including fatty fish and mushrooms. Some foods are fortified with vitamin D, such as milk (including some plant-based milks), yogurt and some cereals. Like other nutrients, it is also available as a supplement. It is recommended that adults consume 600 IU of vitamin D per day, 800 IU if over the age of 70. This level was set assuming minimal sun exposure.

What does being deficient in vitamin D mean?

Hannah: Vitamin D deficiency has been described as a public health problem in its own rite, affecting over a billion people worldwide, and over 40% of the U.S. population. High-risk groups include people of elderly age, people with darker skin tones and people with chronic health conditions, such as obesity and kidney disease. Those following dietary patterns that lack vitamin D fortified foods, such as dairy products, are also at higher risk.

Does vitamin D play a role in a person’s ability to fight the COVID-19 virus?

Hannah: A few studies have examined the potential relationship between COVID-19 and vitamin D. It has been reported that people hospitalized with severe COVID-19 have shown vitamin D deficiency rates of up to 60-80%.

It is important to remember, however, that those at risk for vitamin D deficiency are also the same groups of people that are at higher risk for developing severe COVID-19, such as elderly populations, people of color and people with chronic health conditions, such as obesity. Because of this overlap of medical conditions and characteristics, we are unable to conclude that vitamin D deficiency itself leads to severe COVID-19.

Despite this uncertainty, there have been a few studies that have examined the effects of supplementing vitamin D in people with COVID-19. These studies have shown positive results, though critics contest that these studies have been small and contain several limitations that inhibit our ability to draw conclusions. Although supplementing may be beneficial to improving COVID-19 outcomes, to date, has not shown that supplementing vitamin D actually prevents COVID-19.

In summary, there is certainly mounting evidence that there could be a significant relationship between vitamin D status and COVID-19, but it is too early to be certain. More well-designed studies with larger sample sizes are underway. We can be certain that we will learn more over time.

Nutrition supplementation: Why is more not always better?

Hannah: We know that vitamin and mineral supplementation is beneficial in certain situations. The most significant improvements related to health are seen in replenishing the nutrients in people who are deficient. A great analogy is thinking about putting air in a tire. If one of your tires is lacking air, your vehicle will not function at its best. Replenishing the air in the tire will better restore the function of the entire vehicle. However, overfilling the tire would not make your vehicle function better, and actually could be detrimental to the tire. The same goes for nutrients. Enough is important, but too much may not help and could cause harm.

Vitamin D deficiency and obesity: What is the connection?

Hannah: Vitamin D deficiency is common in people with obesity, with reported prevalence rates as high as 90%. The higher risk of deficiency is thought to be related to several factors. One contributor could be less sun exposure. In addition, since vitamin D is fat-soluble, people with higher amounts of body fat will ‘sequester’ vitamin D in fat cells, leading to lower amounts circulating in the blood. Due to this, people with obesity typically need higher amounts of vitamin D to maintain adequate levels and/or to correct a deficiency.

Waugh: At the UC Health Weight Loss Center, every patient has their vitamin D level checked with their initial lab panel. Our team of experts work with each patient to establish a supplementation plan, if needed. Many of our patients find that weight loss does improve their ability to maintain adequate levels of vitamin D.  

Do vitamin D levels increase after having bariatric surgery?

Waugh: Vitamin D levels are different for each individual, however, most patients who have bariatric surgery are able to achieve normal, adequate vitamin D levels after their surgery is completed.

Should people who have obesity be concerned about contracting COVID-19?

Waugh: The COVID-19 crisis highlights the growing prevalence of obesity in the U.S. and around the world. More than two in three adults are overweight or have obesity, increasing the risk for heart disease, Type 2 diabetes, high cholesterol, stroke, gallbladder disease, osteoarthritis, sleep disorders and multiple cancers.

Obesity affects medical conditions due to the increase in size and the amount of fat cells in the body. A body mass index (BMI) measurement determines the rate of obesity by measuring height and weight. Adults who have a BMI of more than 30 are obese, those with a BMI of 35 are moderately obese and those with a BMI of more than 40 are identified as morbidly obese.

We can add COVID-19 to the list of documented risks for those who have obesity.

Adults with severe obesity, or a BMI of 40 or more, are at higher risk for complications from COVID-19. Severe obesity increases the risk of serious breathing issues, including acute respiratory distress syndrome (ARDS), which is a major complication of COVID-19), ARDS can cause difficulties with the care team’s ability to gain respiratory support for seriously ill patients. Further, underlying health conditions caused by obesity further increases risks.

If you have a BMI over 40, you are about 100 pounds overweight and your health risks increase dramatically. Even if you have not yet developed diabetes or other chronic diseases, it is still affecting your ability to heal and makes you more susceptible to illness. A virus, such as COVID-19, becomes more dangerous and difficult to treat.

Should you be supplementing vitamin D?

Hannah: Regardless of the potential relationship between vitamin D and COVID-19, we should still ensure that we are getting enough of the vitamin for other health reasons. It is a good idea to speak with your healthcare provider about your risk for vitamin D deficiency, and have your levels checked. If you have a deficiency, follow your provider’s guidance on how much vitamin D to take, and for how long, to achieve normal levels in your body. If you do not have a vitamin D deficiency and are not at risk for developing one, you do not need to supplement. Work on maintaining your vitamin D with diet and modest amounts of sun exposure.

We look forward to learning more about the vitamin D and COVID-19 connection as continued research progresses and provides more information.

Can weight loss help me achieve better health and protect myself against COVID-19?

Waugh: It is never too late to seek help for obesity. We have patients of all ages and obesity ranges, who, when they lose the excess weight, tell us it is like being able to start over and have their quality of life improve tremendously.

How has COVID-19 changed the Weight Loss Center’s care process?

Waugh: At the UC Health Weight Loss Center, we are offering virtual programs that enable us to make real connections with our patients, providing them with important information, education and continual support throughout their entire weight loss journey.

While we are limiting in-person time spent with our patients due to COVID-19, we are able to schedule appointments in our clinic as needed, with all safety protocols in place. Our team also continues to be very actively involved with them through telephone and video visits, as well as through the My UC Health (MyChart) patient web portal. We offer multiple venues for patients to talk with our providers – we are always here for them.

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The UC Health Weight Loss Center has locations in West Chester and Cincinnati, Ohio. If you have questions about our weight loss programs, please contact us at 513-939-2263.