Immunity and the Mouth: What you need to know.

The mouth is an extension of the gut microbiome, where up to 80 percent of the immune system is primed. Similar to the gut, the mouth is the site of interaction between microbes and our immune cells. Not surprisingly, interest in oral immunology has skyrocketed due to COVID-19.

We all know that preventive measures like face masks, social distancing, and proper hygiene can help prevent contracting the virus. Research also shows that having healthy vitamin D levels can keep the immune system strong and ready to fight infections, pathogens, and diseases.

The link between oral health and vitamin D

Turns out that eating for healthy teeth may be eating for a healthy body. Vitamin D is a fat-soluble vitamin that has several vital functions in the body. It is essential for keeping teeth and bones strong and healthy — and plays a key role in managing the immune system by regulating how and which immune cells are formed.

Research shows that vitamin D deficiencies can lead to oral health conditions like cavities and gum disease — and can also impair the body’s ability to fight off pathogens like the new coronavirus, SARS-CoV-2. Multiple epidemiological studies of both children and adults have shown that insufficient vitamin D levels are linked to increased risk and greater severity of viral and bacterial infection, especially of the respiratory tract.

Who is at greatest risk for low levels of vitamin D?

The elderly, institutionalized, or hospitalized have the highest rates of vitamin D insufficiency is highest among people who are elderly, institutionalized, or hospitalized. In fact, 60% of nursing home residents and 57% of hospitalized patients were found to be vitamin D deficient in the United States — though it’s also prevalent among the hale and hearty. A study found that nearly two thirds of healthy, young adults in Boston were vitamin D insufficient by the end of winter.

Other groups at increased risk for vitamin D deficiency include:

• People who have limited sun exposure
• People with darker skin
• People who are obese
• People who have had gastric bypass surgery
• People with digestive issues that result in malabsorption

How to increase vitamin D levels via diet and lifestyle

As the only vitamin the body produces when exposed to sunlight, it's in shorter supply in the winter. Fifteen minutes of midday sun exposure on un-sunscreened skin, at least twice a week, will help keep vitamin D levels up, though more is better.

Eating a variety of vitamin D-rich healthy foods across food groups can also help boost vitamin D levels, here are some top choices:

• Oily fish like salmon, mackerel, herring, and sardines
• Canned tuna
• Pasture-raised egg yolks
• Cod liver oil
• Mushrooms (the only plant-based source of vitamin D)
• Vitamin D-fortified cow and plant-based milks
• Vitamin D-fortified organic yogurt
• Vitamin D-fortified orange juice

But can taking vitamin D supplementation help protect against COVID-19? It’s a BIG question on many healthcare professional’s minds.

While there's no cure or treatment for the novel coronavirus, several studies have investigated the effect of vitamin D supplementation — and conversely — vitamin D deficiency, on the risk of contracting the new coronavirus.

• A new research study of 216 people with COVID-19 found that 80% had insufficient levels of vitamin D in their blood

• A recent study of 235 hospitalized COVID-19 patients showed that a blood level of 25-hydroxyvitamin D of at least 30 n/ml, appeared to reduce the chances of adverse clinical outcomes and death. With patients over age 40, they found that those with adequate vitamin D levels were 51.5% less likely to become unconscious, hypoxic, or die than vitamin D-deficient patients.

• Other studies have demonstrated that vitamin D deficiency may harm immune function, increasing the risk of respiratory illness. Some studies have shown that vitamin D supplementation enhances immune response, helping protect the body against respiratory infections.

• A study of 11,321 people from 14 countries indicated that vitamin D supplementation decreased the risk of contracting acute respiratory infections in both those who had deficient and adequate vitamin D levels.

Unsurprisingly, people have been paying attention — The Washington Post reported that “according to Nielsen data from December, sales for vitamin D supplements increased 41.5% year over year.”

For most children and adults, 600 IU (international units) of vitamin D per day is recommended. Still, it can range up to 4,000 IU per diem depending on individual health concerns and needs. The average supplement is about 2,000 IU of vitamin D per pill.

O(VER)RAL Health

Vitamin D can help keep teeth strong and gums healthy, helping maintain optimal oral immunity. While it cannot protect one from developing COVID-19, data points to improved outcomes and immune response to respiratory infections and more — our oral health is indeed inextricably tied to overall health.