Is vitamin C effective in preventing dengue fever?

To start with, what exactly is dengue (DENG-gey) fever, and how does one contract it?

Dengue fever, a generally non-lethal illness, is predominantly found in tropical and sub-tropical regions. This is logical, given that it is transmitted by mosquitoes. Instead of spreading directly between people, the disease circulates when a mosquito bites someone infected with one of the four dengue viruses and then bites a healthy individual. Most cases reported in the continental United States involve travelers or immigrants.

Although dengue fever emerged as a significant issue only in the 1950s, it now affects approximately 400 million people annually [source: CDC].

In some instances, cases are so mild that patients remain asymptomatic. However, when symptoms do appear, they typically manifest four to 10 days after being bitten by an infected mosquito. Be vigilant for the following signs [source: CDC]:

If you experience any of these symptoms and have recently traveled to an area where dengue fever is prevalent, seek medical attention immediately. Contracting dengue fever more than once (which is possible due to the existence of four distinct dengue viruses) increases the risk of developing dengue hemorrhagic fever, a more severe form of the disease that can lead to serious bleeding, shock, and potentially death.

Currently, there is no vaccine or cure for dengue fever, making prevention the most effective strategy. Utilizing mosquito nets, repellents, and eliminating mosquito breeding sites are key measures to reduce the spread of dengue fever.

Once a person is infected with dengue fever, medical treatment options are limited [source: CDC]:

Although most individuals recover within a week, severe symptoms may necessitate hospitalization.

Recently, there has been intriguing discussion about dengue fever treatment and prevention. No miracle cures are involved—many believe that dengue fever can be prevented and treated with something readily available in your diet or supplements: vitamin C.

Is it really that simple? Is there credible scientific evidence supporting this idea?

Scientists vs. Naturopaths

To begin, it’s essential to grasp how vitamin C functions within the immune system.

Vitamin C, also referred to as ascorbic acid, plays multiple roles in the body. It supports the repair, growth, and development of tissues, aids in iron absorption, promotes wound healing, and maintains the health of bones, cartilage, and teeth. Additionally, vitamin C strengthens the immune system by enhancing antibody production and increasing white blood cell levels.

Vitamin C also elevates levels of interferon [source: Avery]. Interferon is a protein produced by our cells to combat—or, as its name implies, interfere with—viruses and diseases. It halts the replication of viruses or foreign substances, preventing infections from worsening. Research indicates that injecting interferon directly into cells can effectively block the dengue virus, stopping its progression [source: Diamond and Harris].

In recent years, homeopaths and alternative-medicine practitioners have discussed a potential connection between vitamin C and the treatment of dengue fever.

In theory, since vitamin C boosts interferon levels and interferon can slow the progression of dengue fever, it might seem plausible that vitamin C could cure the disease. However, it’s crucial to note that this remains purely theoretical at this stage.

Some proponents argue that vitamin C can help increase platelet counts, which often drop during dengue fever. Homeopaths recommend taking supplements alongside consuming foods rich in vitamin C and antioxidants, such as acai berries, oranges, blueberries, and tomatoes. However, there is no multi-source validated research to back this claim, nor are there studies proving that specific foods can elevate platelet levels.

Despite this, some naturopaths suggest taking 500 milligrams of vitamin C six times daily for both treatment and prevention, as well as to boost interferon production [source: Carahealth]. A cautionary note: This amounts to 3,000 mg of vitamin C per day, exceeding the upper daily limit by 1,000 mg. The Mayo Clinic states that the recommended daily intake (RDA) of vitamin C for adults is 65 to 90 mg, which most people can achieve through a balanced diet.

While it’s impossible to overdose on vitamin C since excess amounts are excreted in urine, excessive intake can lead to side effects, including:

Many of the assertions that vitamin C is a "miracle cure" for ailments ranging from the flu to viruses to cancer stem from the research of Linus Pauling [source: Offit]. Pauling, a renowned chemist, won the Nobel Prize in 1954 for his groundbreaking work on chemical bonds. In 1971, he published the book "Vitamin C and the Common Cold," a best-seller that continues to be cited today, despite studies highlighting potential risks of excessive supplement use.

Nevertheless, numerous scientific and medical studies have found no proof that vitamin C cures any of these conditions—and some suggest it may even pose risks [source: Offit]. Additionally, organizations such as the U.S. Food and Drug Administration, the American Medical Association, the Department of Health and Human Services, and others do not endorse vitamin C for preventing or treating colds—or dengue fever, for that matter.

So, does vitamin C prevent dengue fever? Scientific evidence says no. Naturopaths, however, say yes.