Hereditary angioedema (HAE) is a condition that causes swelling, or edema, in different parts of the body. It mainly affects the upper respiratory tract, skin, and abdomen.

HAE is a type of angioedema that develops when the body does not make enough C1 inhibitor proteins. The job of C1 inhibitor is to control inflammation. Without it, levels of an inflammatory protein called bradykinin rise. Bradykinin increases the amount of fluid that leaks from blood vessels. This extra fluid gets into body tissues, causing excessive swelling.

HAE is a rare condition that affects about 1 in 50,000 people. Medications can treat symptoms of HAE and reduce swelling. Some preventive treatments are also available.

Stress and minor trauma are common triggers for symptoms. Sometimes, swelling can happen for no obvious reason. Some people find that food can cause symptoms. There is not much available research on the connection between diet and HAE, but here is what medical experts know so far.

Living with any chronic condition can take an emotional and physical toll. Eating a nutritious, balanced diet supports good overall health.

A 2022 study suggests that people with HAE are at higher risk for some other health conditions. This study showed higher rates of heart disease, high cholesterol, and high blood pressure in people with HAE.

A heart-healthy eating pattern may help reduce these risks. A nutritious diet can also support good mental health.

There is no specific diet for HAE, although some people find that certain foods trigger swelling. In those cases, people may need to reduce or avoid consumption of those foods.

A 2018 study explored possible food triggers for HAE. However, it was a small study, involving only 42 people.

Angioedema is a symptom that can occur as part of an allergic reaction. The angioedema attacks in a person with HAE are not due to food allergies, although the swelling is similar to what is seen in an allergic reaction.

The 2018 study found that an allergic reaction was not the cause of symptoms that resulted from trigger foods. Many of the suspected food triggers are sources of histamine, and it is possible that foods high in histamine are more likely to trigger HAE episodes.

The researchers believed that the following foods triggered symptoms in more than one person in the study:

  • onion and garlic
  • citrus fruits, apples, strawberries, and pineapple
  • fish
  • milk and cheese
  • chili

They suspected that the following foods triggered swelling in one person in the study:

  • green salad
  • tomato
  • kiwi
  • tree nut
  • peanut
  • shrimp
  • bread
  • banana
  • leek
  • chicken
  • chamomile
  • alcohol

There is not enough evidence to say for sure that a person with HAE needs to avoid or include specific foods. However, some people feel that foods can trigger swelling. If a person suspects that food is a trigger, they can keep a food and symptom journal to explore patterns.

There is interest in whether histamines may worsen swelling in people with HAE. Histamines are chemical messengers that the immune system releases in response to an injury or an invader. When an allergic reaction causes angioedema, histamines are involved. The angioedema of HAE does not result from an allergic reaction.

Some people with HAE do feel that they are sensitive to histamines. Older research suggests that reducing histamine intake may lessen the severity of swelling in some people.

Foods high in histamines include:

  • fermented foods
  • citrus fruits
  • aged cheeses
  • processed meats
  • alcohol

Medical experts recommend a heart-healthy diet because of the association between HAE and an increased risk of heart disease.

A Mediterranean diet has an association with lower rates of heart disease.

This eating pattern includes:

  • plenty of fruits and vegetables
  • whole grains
  • beans and lentils
  • poultry, fish, and seafood
  • nuts and seeds
  • moderate amounts of dairy products
  • healthy fats from sources such as fish, olive oil, avocado, nuts, and seeds

There is not enough evidence to suggest that people with HAE need to take certain supplements.

Depending on the frequency of a person’s HAE episodes and how that may affect food intake, a healthcare professional may recommend a multivitamin and mineral supplement. Regular blood work is important to screen for any nutrient deficiencies.

There is limited research on the role of supplements in managing HAE. Researchers have looked into the potential roles of omega-3s and vitamin D in HAE. Both nutrients may play a part in reducing inflammation in the body. For that reason, there are theories that they may be helpful for HAE.

One study explored the possibility of a link between HAE disease activity and vitamin D levels throughout the seasons. The study showed that 59.5% of participants with HAE had a vitamin D deficiency in winter and spring.

Researchers did not find an association between vitamin D deficiency and swelling episodes. Despite that, people with HAE should get their levels of vitamin D checked and take supplements as needed.

The Recommended Dietary Allowance for vitamin D is 15 micrograms (mcg), or 600 international units (IU), per day for adults aged 18–70. Above age 70, a person should get 20 mcg (800 IU) daily. Many people take this dose as a supplement to ensure they are meeting their needs.

Some research has explored whether omega-3 supplements may be helpful in reducing symptoms of HAE. Omega-3s can reduce levels of inflammation in the body. However, more research is needed to determine who may benefit from omega-3 supplements and at what dose.

For now, a person with HAE can increase their intake of omega-3s by eating more fatty fish such as trout, mackerel, salmon, sardines, and anchovies. They can also talk with their doctor to find out whether they need supplementation.

HAE is a condition that causes excessive swelling. Unlike some other types of angioedema, it is not the result of an allergy. Some people find that foods can trigger their symptoms. A food and symptom journal is the best way for a person to determine whether they are sensitive to certain foods.

For some, a low histamine diet can potentially be helpful. In addition, because the condition can increase the risk of heart disease, a person with HAE may benefit from a heart-healthy diet.

There is not enough evidence to suggest that everyone with HAE needs to take supplements. There may be some benefits to increasing omega-3 intake through diet or supplements. Additionally, many people with HAE have low vitamin D levels, and a supplement is the best way to get vitamin D levels into the normal range.