When floods, storms, or severe weather occur, changes may affect more than just transportation and daily routines. They may also affect:

• Access to fresh food

• Clean drinking water

• Food storage

• Access to stores and healthcare services

The World Health Organization (WHO) notes that floods can increase the risk of exposure to contaminated water and food, while also disrupting food systems and healthcare services. Therefore, safe drinking water, good hygiene, and food safety should always come first.

When access to a variety of foods becomes limited, getting enough essential vitamins and minerals is another aspect worth considering.

However, remember that vitamins cannot replace clean water, nutritious food, or medical care.

1. Vitamin C — An Important Vitamin to Get Enough Of 

Vitamin C plays important roles in:

• Immune system function

• Collagen production

• Wound healing

• Antioxidant protection

During an emergency, getting enough fresh fruits and vegetables may become more difficult. Therefore, obtaining Vitamin C from food or supplements when appropriate may be something to consider.

However, Vitamin C does not mean that it can directly prevent infections caused by flooding. According to information from the NIH, adequate Vitamin C intake is important for normal immune function, but in people who already receive enough nutrients, additional supplementation does not consistently prevent infections.

Food sources: Guava, oranges, kiwi, bell peppers, and various vegetables.

2. Vitamin D — Important When You Get Less Sunlight 

During storms or periods of prolonged rain, many people may spend more time indoors and receive less sunlight.

Vitamin D plays important roles in:

• Calcium absorption

• Bone health

• Muscle function

• Immune system function

The body can produce Vitamin D when the skin is exposed to UVB radiation from sunlight. However, actual sunlight exposure varies depending on the season, weather, clothing, and individual lifestyle.

Therefore, if storms cause changes in your lifestyle, the important goal is to get an adequate amount of Vitamin D based on your individual needs—not to take high doses in an attempt to prevent illness.

3. Vitamin A — Supports Immune Function and Healthy Body Tissues 

Vitamin A is another important nutrient involved in:

• Immune system function

• Cell growth and division

• Skin and mucosal health

• Vision

Vitamin A plays an important role in normal immune function and maintaining the integrity of tissues that act as protective barriers in the body.

Food sources: Eggs, milk, liver, and dark green or orange-yellow vegetables containing Provitamin A Carotenoids.

One important consideration is that Vitamin A is a fat-soluble vitamin. Taking high doses of Vitamin A supplements unnecessarily can lead to accumulation in the body and potentially cause adverse effects.

4. Vitamin E — An Antioxidant That Helps Protect Cells 

Vitamin E is an antioxidant that helps protect cells from oxidative damage caused by free radicals. It also plays a role in normal immune function.

Food sources of Vitamin E include:

• Almonds

• Sunflower seeds

• Vegetable oils

• Nuts

• Leafy green vegetables

When access to fresh or varied foods becomes limited, planning meals that still include healthy fat sources and Vitamin E-rich foods can contribute to overall nutritional adequacy.

However, this should not be interpreted to mean that high-dose Vitamin E supplementation can prevent infections, as evidence for supplementation to prevent infectious diseases remains inconsistent.

5. Vitamin B Complex — Important When Your Diet Becomes Less Varied 

B vitamins are involved in many essential processes, including:

• Converting food into energy

• Nervous system function

• Blood cell production

• DNA and genetic material synthesis

For example, Vitamin B6 is involved in more than 100 enzyme reactions, many of which are related to protein metabolism. Vitamin B12 plays important roles in nervous system function, red blood cell formation, and DNA synthesis.

Therefore, when meals become irregular or food choices are limited during an emergency, getting enough B vitamins remains important.

Should You Stock Up on All 5 Vitamins? 

Not necessarily.

If you normally eat a balanced and varied diet, you can obtain most vitamins from food.

The NIH states that getting adequate vitamins and minerals is important for normal immune function. However, if you are not deficient, taking additional supplements does not necessarily provide greater protection against or treatment for infections.

When preparing your home for storms or floods, priorities should include:

1. Clean drinking water

2. Safe, long-lasting food

3. Essential medications

4. First-aid supplies

5. Flashlights and communication devices

The CDC recommends preparing emergency supplies, including water, food, and necessary medications in advance, and being prepared to evacuate if instructed by local authorities.

What Should You Be Especially Careful About With Food During a Flood? 

This is actually more important than vitamins.

Do not eat food that has come into contact with floodwater.

Floodwater may contain pathogens, chemicals, and other contaminants. The WHO recommends discarding food that has been exposed to floodwater and using safe water for drinking and food preparation.

If there is a prolonged power outage, refrigerated food may also become unsafe. The CDC recommends that if you are unsure whether food is still safe to eat, it is safer to discard it rather than take the risk.

Summary: 5 Vitamins to Know About During Storms and Floods 

When floods or storms occur, the goal is not to “take as many vitamins as possible.” Instead, the priority should be maintaining adequate nutrition during a period when normal daily life may be disrupted.

🍊 Vitamin C — Supports immune function and collagen production
☀️ Vitamin D — Important for bones, muscles, and immune function
🥕 Vitamin A — Supports immune function, vision, and healthy mucosal tissues
🌻 Vitamin E — Provides antioxidant protection and supports immune function
⚡ Vitamin B Complex — Involved in energy metabolism, nervous system function, and cell production

During floods, however, clean water, safe food, essential medications, and following guidance from local authorities are more important than vitamin supplements.

Keeping vitamins at home should therefore be viewed as “being prepared to maintain adequate nutrition”, rather than a way to directly prevent illnesses caused by flooding.

References 

• World Health Organization (WHO). Floods: How to Protect Your Health.

• World Health Organization (WHO). Floods – Health Impacts and Response.

• Centers for Disease Control and Prevention (CDC). Preparing for Floods. Updated August 24, 2026.

• NIH Office of Dietary Supplements. Dietary Supplements for Immune Function and Infectious Diseases.

• NIH Office of Dietary Supplements. Vitamin C – Health Professional Fact Sheet.

• NIH Office of Dietary Supplements. Vitamin D – Health Professional Fact Sheet.

• NIH Office of Dietary Supplements. Vitamin A and Carotenoids – Health Professional Fact Sheet.

• NIH Office of Dietary Supplements. Vitamin E – Health Professional Fact Sheet.

• NIH Office of Dietary Supplements. Vitamin B6 / Vitamin B12 – Health Professional Fact Sheets.