HIV and vitamin D deficiency: What is the link?

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People living with HIV may have an increased risk of vitamin D deficiency.

Research has found that up to 100% of those living with HIV-1, which is a type of HIV, have insufficient vitamin D levels. Also, at least 30% of people with HIV-1 have a vitamin D deficiency.

There are several risk factors for vitamin D deficiency that can affect individuals living with HIV and those without the condition, such as:

• lack of sun exposure
• lack of dietary sources of vitamin D or malabsorption
• dark skin pigmentation
• obesity
• smoking
• intravenous drug use
• liver disease
• kidney disease
• older age

A person living with HIV may also have an increased risk of vitamin D deficiency due to:

• certain antiretroviral therapy
• chronic inflammation
• immune activation
• the effect of HIV proteins on enzymes that play a role in vitamin D production in the body

HIV-1 affects how the body metabolizes vitamin D. HIV-1 can cause an increase in pro-inflammatory cytokines, a type of protein that prevents the body from synthesizing active vitamin D.

Certain antiretroviral therapies may also have an impact on vitamin D levels in the body.

According to a 2018 review, studies of cells cultured in a laboratory showed that protease inhibitors, particularly ritonavir, suppress forms of vitamin D. The suppression was dose-dependent and reversible. Human studies yielded mixed results.

Efavirenz also appears to decrease vitamin D levels. A 2014 study found that out of 690 participants, those taking efavirenz had a significant decrease in vitamin D levels over the course of 48 weeks, compared with people taking rilpivirine.

Tenofovir disoproxil fumarate (TDF) may also affect how the body metabolizes vitamin D, and it may increase the likelihood of bone loss.

Vitamin D plays an important role in the body’s immune response, which is how the body reacts to foreign or harmful substances and infections.

Vitamin D has anti-inflammatory and antimicrobial effects and helps regulate the immune system.

A 2020 article notes a link between infections and autoimmune diseases and vitamin D deficiency.

Researchers still need more evidence to determine whether regular vitamin D supplementation can prevent or alter the course of inflammatory or autoimmune conditions in those at risk.

The article concludes that vitamin D plays an important role in immune function and that avoiding vitamin D deficiency helps improve immune health and decreases the risk of autoimmune conditions.

Doctors can monitor vitamin D in HIV-positive people to ensure they have sufficient levels.

If a person is taking certain antiretrovirals that decrease the amount of vitamin D in the body, they may consult their doctor about a change in antiretroviral therapy.

The Department of Health and Human Services suggests changing certain drugs, if possible, such as switching from TDF to tenofovir alafenamide. If individuals are using TDF, they may need to use a vitamin D3 supplement.

The source recommends a person on antiretroviral therapy take up to 4,000 international units (IU) of vitamin D3 daily.

A small scale 2020 study also recommends that people who are receiving a combination of TDF, emtricitabine, and efavirenz should supplement vitamin D2 and calcium to reduce bone loss.

Authors of a 2019 review of 29 clinical studies report that vitamin D supplementation can effectively restore sufficient levels of the vitamin in people with HIV who have low vitamin D levels or vitamin D deficiency.

The studies included daily doses ranging from 400 to 14,000 IU. Doses between 4,000 and 7,000 IU were the most common.

In severe cases of vitamin D deficiency, a daily dose of 7,000 IU turned out to be the most effective across the studies. Supplementation at this level restored vitamin D to a sufficient level in 80% of the participants, with levels increasing after 12 months of treatment.

Once people reached a sufficient amount of vitamin D in the body, researchers recommended a maintenance dose to keep vitamin D levels stable.

However, high doses of vitamin D may pose risks. If calcidiol, which is a form of vitamin D, increases beyond 100 nanograms per milliliter, or if calcium in the blood increases beyond 2.70 millimoles per liter, it could produce adverse effects.

Nine of the trials included vitamin D supplementation that exceeded the recommended upper limit of 4,000 IU per day. Among all of the studies in the review, all supplementation turned out to be safe, with no reports of adverse effects.

However, each of the studies had a relatively short follow-up period, and therefore further research may provide more details about the long-term effects and safety of vitamin D supplementation.

Learn more about vitamin D supplement options here.

Vitamin D supplementation can help increase vitamin D levels in those with HIV-1 who have a vitamin D deficiency. Supplementation has proven effective regardless of:

• combination antiretroviral therapy
• geographical location
• ethnicity

In addition to preventing symptoms of deficiency, increased vitamin D levels may reduce the risk of potential HIV complications, such as:

• hyperparathyroidism
• microbial infections, such as tuberculosis
• chronic inflammation
• bone turnover, which is when the body reabsorbs old tissue and forms new bone tissue

Additionally, supplementation may increase the amount of the type of lymphocytes that HIV destroys, which are cells that help stimulate and regulate the immune system.

Researchers are still unclear about whether vitamin D supplementation has any effect on viral load, which is the amount of HIV per ml of blood.

Vitamin D deficiency is common in people living with HIV. This may be due to a combination of the direct effects of HIV on the body and of antiretroviral therapy, both of which can suppress the body’s ability to produce vitamin D.

Many studies have shown that vitamin D supplementation is safe for individuals living with HIV and that it can effectively restore sufficient levels of the vitamin.