What Vitamins And Supplements Are Good For The Flu?

Are you looking to prevent or manage the flu? Before taking supplements, you may want to consider first optimizing the diet. In an ideal world, the diet should provide all the vitamins and nutrients to fight infections. However, nutrient deficiencies are common nowadays and they increase the risk of infections. Supplements are a convenient way to often fill the gaps. What vitamins and supplements are good for flu prevention and/or management? Let’s review them in this article. 

The role of nutrition and sun exposure in fighting infections 

A healthy diet plays an essential role in immune system function in general, and the ability to fight viral infections, in particular. Individuals who aren’t not getting enough healthy foods are at risk of getting bacterial and viral infections and also developing more severe infections. Malnutrition suppresses the immune system and increases the susceptibility to infections. Excess weight/obesity creates a state of inflammation which further affects the immune system and the metabolism. 

Furthermore, chronic or severe infections lead to nutrient deficiencies and imbalances creating a vicious cycle- unless those nutrients are added through diet and supplements. 

The problem is that the modern diet is poor in vitamins, minerals, and healthy fats while including a lot of empty calories, high amounts of unhealthy (refined) sugars and fats. 

All micronutrients -vitamins and minerals and macronutrients -proteins, fats, and carbohydrates- are essential to optimal health. However, some of these nutrients are even more important than others when it comes to fighting the flu.

Besides nutrition, sun exposure is another key player in fighting infections. Vitamin D is found in small amounts in food and is mostly obtained from having the skin exposed to the sun. However, most people do not spend time in the sun, or if they do, they wear sunscreens. While sunscreen prevents skin damage and some cancers, they also block the production of vitamin D. 

Vitamin D

Based on a review conducted by Harvard researchers, severe clinical trials and other studies found that vitamin D reduces the risk of acute respiratory infections- including flu-  by 12-75%. The benefits of vitamin D supplements are seen in all age groups and individuals with chronic conditions. Flu symptoms are less severe and recovery is faster in those who take vitamin D in doses of 1000 IU daily or up. 

In the US, vitamin D supplements are widely available in different strengths, from 1000 IU (most popular supplements) to 10,000 IU per capsule (which is considered the upper limit daily dose). In other countries, high-strength formulas are not available. The typical dose for adults is 1000-3000 IU, although a vitamin D blood test could help evaluate if a person requires higher doses. Cod liver oil contains high amounts of vitamin D, too. Some foods like fatty fish and fortified milk contain this nutrient in smaller amounts. 

Vitamin C

Vitamin C supports a healthy immune system and has strong antioxidant and anti-inflammatory qualities. A  recent review of scientific evidence from Harward also highlights the role of this nutrient to fight viral illnesses. Well-designed (randomized controlled trials)  found that vitamin C supplements significantly decrease the incidence of respiratory tract infections. Hospitalized individuals with severe infections -including sepsis, and other serious health conditions also benefit from vitamin C supplements. 

The typical dose of vitamin C for adults is 1000 mg, and the upper limit is considered 3000 mg. To avoid stomach upset, choose buffered vitamin C over ascorbic acid. Some brands contain bioflavonoids for enhanced absorption of this nutrient. Many foods are rich in vitamin C including citrus fruits, berries, bell peppers, broccoli, cabbage, and green leafy vegetables. The veggies should be consumed fresh or steamed if possible, as vitamin C is destroyed by cooking.


Zinc is involved in hundreds of chemical reactions in the body, and it also supports the immune system’s response to fight infections. Elderly and those with chronic illnesses are at risk of zinc deficiency. Zinc supplements reduce the risk of getting a respiratory infection. In those who already got the flu, zinc supplements may help reduce the duration of symptoms by about 2 days. The daily dose is based on the form of zinc used- ie zinc citrate, chelate, bis-glycinate. Follow the label. 

Zinc supplements should be used on and off, for no more than 3 months at a time. Taking too much zinc can cause copper and other mineral imbalances. Some zinc formulas have added cooper for this reason. A multimineral with zinc may be a better choice long term, as it provides smaller, but consistent amounts of this nutrient. Zinc-rich foods include oysters, lean red meat, chicken, lentils, nuts and seeds, grains, and green leafy vegetables. 

While vitamins D, C, and zinc are the top three supplements to consider, there are others that have been researched.  For example, the mineral selenium,  probiotics, lactoferrin, elderberry can all help prevent or speed up the recovery process from the flu. Talk to a healthcare provider specialized in nutrition to learn more about these vitamins, and the right doses for you. 

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